These findings characterize the composition and experimental activity of one regional fruit sample; they do not establish clinical benefits in people. The investigation focused on European bilberry, Vaccinium myrtillus L., a small shrub that produces dark blue, juicy berries and grows in habitats including stony meadows, sparse coniferous forests and mountainous areas. It is widespread across Europe, Asia Minor, the Caucasus and Siberia, and its fruit has been used as food and in traditional medicine in Bulgaria and elsewhere.

The researchers collected fresh fruit in 2024 from the Belmeken region of the Rila Mountain. For measurements of total polyphenols, total flavonoids and antioxidant potential, the fruit was squeezed, and the resulting juice was filtered and frozen pending analysis. Detailed anthocyanin analysis used a separate set of five fruit samples.

Five grams of fruit were homogenized with 10 milliliters of 80% methanol, sonicated for 20 minutes and centrifuged at 10,000 times gravitational acceleration for five minutes. The extraction was repeated, the combined supernatants were evaporated, and the residue was redissolved in 5% methanol containing 1% formic acid. After solid-phase extraction, the investigators used ultra-performance liquid chromatography coupled to tandem mass spectrometry, or UPLC-MS/MS, to separate and identify anthocyanin forms.

Positive-ion electrospray ionization and multiple reaction monitoring were used to detect compounds, with high-energy collision dissociation at 45 volts providing the MS/MS transitions. Malvidins were the largest measured anthocyanin group, accounting for 38.08% of the total and measuring 128.9 ± 6.4 milligrams per 100 grams of fruit. Delphinidins followed at 33.15%, corresponding to 112.2 ± 5.6 milligrams per 100 grams.

Petunidins were present at 63.0 ± 3.1 milligrams per 100 grams and represented 18.6%, while cyanidins measured 34.4 ± 1.7 milligrams per 100 grams and represented 10.1%. The sum of the quantified groups gave the reported total anthocyanin content of 338.54 milligrams per 100 grams of fresh fruit. The juice was also assessed with broader colorimetric tests.

Total polyphenols measured 8.40 ± 0.29 milligrams of gallic acid equivalents per 100 milliliters, with the Folin-Ciocalteu reagent method used for this determination. Total flavonoids were 7.26 ± 0.11 milligrams of quercetin equivalents per 100 milliliters, based on an aluminum chloride colorimetric assay. Each measurement was performed at least three times, and the reported values are means with standard deviations.

These assays quantify broad classes of compounds expressed in reference-equivalent units rather than directly identifying every constituent present in the juice. Three complementary tests indicated substantial antioxidant potential in the tested sample. In the DPPH assay, it achieved 89.0 ± 2.1% scavenging.

The ferric reducing antioxidant power assay yielded 2.4 ± 0.09 millimoles of Fe(II) per liter. These results were obtained under defined laboratory conditions, where each method measured a particular form of radical scavenging or chemical reducing capacity. They therefore demonstrate antioxidant activity of the juice in those systems, not an improvement in health outcomes or oxidative-stress biomarkers in people.

The researchers next examined the juice in Saccharomyces cerevisiae. They treated exponential-phase cell suspensions for 30 minutes with bilberry juice at either 1% or 10%, using methyl methanesulfonate, abbreviated MMS, as a positive control for cellular injury. Juice alone did not reduce cell survival relative to untreated cells, indicating that the tested concentrations were not detectably cytotoxic within this experimental design.

When juice was combined with MMS, both concentrations produced significant cytoprotection, described as a 1.5-fold increase in cell survival with P < 0.0001. Survival in the combined-treatment groups was similar to control levels, and no statistically significant difference was detected between the 1% and 10% treatments. The cell-based analysis also measured physiologically active superoxide anions through an XTT-based procedure in which the compound enters living cells and is reduced by superoxide anions to colored formazans.

Bilberry juice alone did not induce reactive oxygen species relative to untreated cells, and the measured levels were comparable with control values. In the presence of MMS, however, both juice concentrations reduced the induced superoxide-anion signal by approximately fivefold. Levels in the combined treatments were described as indistinguishable from those of untreated cells, with no detectable advantage observed when the juice concentration increased from 1% to 10%.

Under this specific yeast model, the results therefore showed two linked observations: protection of cell survival and suppression of MMS-associated superoxide generation. The anthocyanin concentration measured in the Belmeken fruit exceeded values previously reported for two other Bulgarian locations. Earlier work cited by the investigators reported 217 milligrams per 100 grams for fruit from Velingrad and 162.4 milligrams per 100 grams for fruit from Troyan, compared with 338.54 milligrams per 100 grams in the present sample.

The Belmeken result was also higher than the cited values of 143.9 milligrams per 100 grams for a commercially available bilberry juice and 297.4 milligrams per 100 grams in another previous measurement. The authors identify regional, climatic and year-to-year factors as possible contributors to such variation, but the present comparisons were not controlled experiments designed to isolate those influences. The data show a higher concentration in the analyzed sample than in the cited reports, not a general or time-based ranking among Bulgarian sites.

Earlier studies reviewed in the paper provide experimental context while remaining distinct from the current findings. Bilberry extracts have reduced markers of oxidative damage in cultured skin and neuronal cells, and anthocyanin-rich extracts have protected mice from stress-induced liver injury in animal experiments. The paper also notes that human ingestion studies have not consistently found significant changes in biomarkers of antioxidant status or oxidative stress.

It points to variations in extract standardization, anthocyanin concentration and redox conditions as possible considerations, while also noting that effects attributed to antioxidant phytochemicals may be indirect or independent of antioxidant activity. These distinctions matter because the present work used fruit-derived juice, a single collection location, chemical assays and a yeast-cell model rather than a standardized clinical trial in humans. Anthocyanins are also vulnerable to degradation during industrial processing, which can affect the color and properties of bilberry-derived products.

The study’s combined measurements show that the Belmeken fruit contained a substantial and chemically differentiated anthocyanin reservoir, and the yeast experiments found biological activity under controlled conditions. The research did not test how processing, storage or passage through the digestive system changes the composition or effects of the juice, nor did it compare the clinical relevance of the two tested concentrations. Its support for Bulgarian bilberry as a source of anthocyanin-rich material therefore rests on the documented chemical profile, the laboratory antioxidant assays and the cytoprotective results in yeast.

More standardized and appropriately designed human studies would be required before any conclusion about therapeutic effects or disease prevention could be drawn.

Subject of Research: Chemical composition, antioxidant assays, and yeast-cell effects of Bulgarian bilberry juice

Article Title: Phytochemical composition and biological activity of bilberry fruit juice ( Vaccinium myrtillus L.) from Bulgaria

Article References: Kiselova-Kaneva, Y., Dimitrov, Z., Ignatov, I., Popova, T., Gotova, I., Todorova, T., Boyadzhiev, K., Angushev, I., & Ivanova, D. (2026). Phytochemical composition and biological activity of bilberry fruit juice (Vaccinium myrtillus L.) from Bulgaria. Pharmacia, 73, Article e188976. https://doi.org/10.3897/pharmacia.73.e188976

Image Credits: AI Generated

DOI: 10.3897/pharmacia.73.e188976

Keywords: bilberry, Vaccinium myrtillus, anthocyanins, polyphenols, antioxidant assays, Bulgaria, Rila Mountains, yeast cells, oxidative stress, UPLC-MS/MS, Phytochemical, composition

The results provide preliminary evidence that these anthocyanins can modulate the PI3K/Akt/GSK3β signaling pathway in a vertebrate model, but they do not establish a treatment for Alzheimer’s disease in people. The researchers induced selected Alzheimer’s-like features by exposing adult wild-type zebrafish to aluminum chloride in water for four consecutive days. On Day 4, fish also received an intraperitoneal aluminum chloride injection to reinforce model induction.

Donepezil, an acetylcholinesterase inhibitor used in Alzheimer’s treatment, served as the positive control. C3R, C3S, and C3X were each administered at 2 milligrams per kilogram by intragastric gavage once daily for five days, beginning with the first day of aluminum exposure. That common dose was selected from preliminary screening at 0.5, 1, and 2 milligrams per kilogram to standardize the comparison rather than to identify a separate maximum effective dose for each compound.

The principal experiment included 15 fish per group: untreated controls, aluminum-exposed model animals, donepezil controls, and one group for each cyanidin glycoside. Behavioral testing showed that the model reproduced several of the changes the investigators sought to study. In the novel object recognition test, aluminum-exposed fish spent less time exploring a novel object and showed less preference for it than untreated controls, indicating impaired recognition memory.

In the color-biased T-maze, model fish took longer to enter the rewarded green chamber and spent less time there after learning the task. All three cyanidin glycosides increased exploration of the novel object and improved T-maze performance relative to the model group. C3R and C3X also shortened the latency to enter the upper region of a novel tank, where exploration was reduced in the model group, indicating attenuation of anxiety-like behavior.

These memory effects were not attributable to a simple increase in general movement: total distance traveled and average velocity did not differ significantly between the model and treatment groups in the relevant novel object recognition and T-maze comparisons. Brain biochemical analysis indicated that the compounds partly reversed the cholinergic and oxidative abnormalities associated with aluminum exposure. C3R, C3S, and C3X shifted these measurements toward control values, as did donepezil.

The glycosides also increased superoxide dismutase activity and glutathione content and reduced malondialdehyde, which the investigators used as a measure of lipid peroxidation. Together, these observations are consistent with reduced oxidative stress and partial restoration of cholinergic function. The experiment did not establish whether changes in oxidative stress preceded the behavioral or cellular effects, and it did not exclude contributions from other mechanisms.

Histological and ultrastructural examinations supported the idea that the treatments protected brain tissue. Hematoxylin and eosin staining showed loose cellular organization, reduced neuronal density, and vascular congestion in the model group, whereas treated fish displayed more intact tissue and greater cellular density. Nissl staining revealed fewer and more disorganized neurons and fewer Nissl bodies after aluminum exposure.

Treatment with each glycoside or donepezil significantly increased the amount of Nissl-positive material. Transmission electron microscopy showed disrupted membrane boundaries, cytoplasmic vacuolization, cellular edema, swollen mitochondria, and fewer identifiable organelles in model animals. C3R produced the clearest preservation of membranes, mitochondria, and other organelles, while C3S and C3X also produced improvements that left some edema and vacuolization.

These images provide morphological evidence of neuronal protection, but they cannot determine whether mitochondrial fission, fusion, or caspase-dependent apoptosis was directly affected. Gene-expression measurements showed that aluminum exposure altered molecular markers associated with cholinergic function, the amyloid precursor protein family, neurotrophic signaling, inflammation, and PI3K/Akt/GSK3β signaling. The model brain had increased expression of ache, aplp2, il6, il1b, tnfa, and rela, along with reduced chata, bdnf, and ntrk2b.

Expression of pik3r1 and akt2 decreased, whereas gsk3ba increased. C3R, C3S, C3X, and donepezil moved these measures toward control levels, with significant reductions in the elevated inflammatory transcripts and restoration of pathway-related transcripts. Western blotting produced a parallel protein-level pattern: treated fish had lower acetylcholinesterase and higher choline acetyltransferase, while phosphorylation of Tau at Ser396 declined.

Immunofluorescence imaging likewise showed weaker acetylcholinesterase signals and stronger choline acetyltransferase signals after treatment, with C3R producing relatively pronounced recovery. Aluminum exposure reduced the phosphorylation of PI3K p85 at Tyr458 and Akt at Ser473 while increasing the ratio of phosphorylated to total GSK3β at Tyr216. C3R and C3X significantly reversed these alterations, and donepezil produced similar effects.

C3S increased PI3K Tyr458 phosphorylation and reduced GSK3β Tyr216 and Tau Ser396 phosphorylation, but it did not significantly restore Akt Ser473 phosphorylation, indicating a partial pathway response. The interpretation requires care because Akt canonically influences GSK3β through inhibitory phosphorylation at Ser9 rather than Tyr216, and the study did not directly measure GSK3β kinase activity. The measurements therefore indicate coordinated pathway-associated regulation rather than proof that Akt directly controls GSK3β phosphorylation at Tyr216.

A separate experiment tested the functional involvement of PI3K signaling by administering the PI3K inhibitor LY294002 two hours before the cyanidin glycosides. Blocking PI3K attenuated the treatment-related increases in choline acetyltransferase, phosphorylated PI3K, and phosphorylated Akt. At the same time, it increased acetylcholinesterase, phosphorylated GSK3β, and phosphorylated Tau at Ser396.

The inhibitor result supports participation of PI3K/Akt signaling in the biochemical effects observed in the model, but it does not identify the direct molecular targets of the glycosides. Total PI3K, Akt, and GSK3β abundance did not change significantly among the relevant groups. Molecular docking was used to explore possible structural differences among the compounds.

C3R received the most favorable predicted scores for human PI3Kα and AKT1, followed by C3X and C3S for PI3Kα, while C3S ranked ahead of C3X for AKT1. These calculations are hypotheses about possible accommodation at the proteins, not evidence of direct binding or functional regulation, and they cannot fully account for C3R’s stronger biological effects in the experiment. Among the three compounds, C3R emerged as the most consistently effective candidate under the shared dose and short treatment schedule.

Its advantages appeared across behavioral testing, biochemical markers, histological and ultrastructural observations, cholinergic protein measurements, and PI3K/Akt/GSK3β-associated changes. The comparison does not show that C3R’s rutinoside-linked structure caused its stronger performance; the source presents the distinct sugar groups as a possible basis for further investigation rather than a demonstrated explanation. The results instead identify C3R as a priority for systematic follow-up.

Controlled gavage also ensured that the fish received measured compound doses, but it did not reproduce the gastrointestinal conditions, food matrix, and exposure patterns associated with eating cyanidin-rich foods. Translation of the findings remains limited in several ways. The model lasted only five treatment days and reproduced selected features such as cognitive impairment, oxidative stress, cholinergic dysfunction, inflammation, and increased Tau Ser396 phosphorylation.

It did not reproduce the chronic, age-dependent development of Alzheimer’s disease. The experiment also did not determine whether behavioral benefits persist after treatment ends, whether general antioxidant effects or interactions with aluminum contributed to the phenotype, or how the compounds behave after longer exposure. The gastrointestinal stability, bioavailability, metabolism, pharmacokinetics, and brain exposure of C3R, C3S, and C3X were not established, and species-specific differences limit direct extrapolation from zebrafish to mammals.

The researchers identified mammalian work, including tests in APP/PS1 mice, as a necessary next step for evaluating pharmacokinetic properties, blood–brain barrier penetration, efficacy, and direct targets. For now, the study offers a controlled in vivo screening result with broad but preliminary implications. Food-derived anthocyanins can produce measurable behavioral, biochemical, histological, ultrastructural, and molecular effects in an adult vertebrate exposed to a toxin-induced Alzheimer’s-like phenotype.

C3R performed best overall among the three equal-dose treatments, and the inhibitor experiment linked part of its biochemical profile to PI3K/Akt signaling. However, the work does not show that dietary supplementation could treat or prevent Alzheimer’s disease in humans.

Subject of Research: Neuroprotective effects of three food-derived cyanidin glycosides in an aluminum-induced Alzheimer’s-like adult zebrafish model

Article Title: Neuroprotective Effects of Food‐Derived Cyanidin Glycosides in an Alzheimer's Disease‐Like Zebrafish Model Through Modulation of PI3K/Akt/GSK3β Signaling

Article References: Wu, Y., Tie, F., Gao, Y., Li, J., Wang, R., Hu, N., Dong, Q., & Wang, H. (2026). Neuroprotective Effects of Food‐Derived Cyanidin Glycosides in an Alzheimer's Disease‐Like Zebrafish Model Through Modulation of PI3K/Akt/GSK3β Signaling. Food Science & Nutrition, 14(10), Article e72486. https://doi.org/10.1002/fsn3.72486

Image Credits: AI Generated

DOI: 10.1002/fsn3.72486

Keywords: cyanidin glycosides, cyanidin-3-O-rutinoside, zebrafish model, Alzheimer’s-like pathology, PI3K/Akt/GSK3β, cholinergic function, oxidative stress, Tau phosphorylation, anthocyanins, neuroprotection, Neuroprotective, Effects

The team grew six tea cultivars under identical conditions at an experimental field in Shengzhou, China: two green-leaf cultivars, including the Japanese benchmark variety Yabukita; two purple-leaf strains derived from the anthocyanin-rich cultivar Zijuan; and two yellow-leaf strains derived from Baijiguan. In spring 2024, all plants were shaded with black nets blocking 80 percent of sunlight for a deliberately short period, from the fish-leaf stage to one bud and two leaves. The researchers chose brief shading because light-sensitive yellow-leaf cultivars can gradually re-green under prolonged shade, which would erase the very pigmentation the study aimed to exploit. Fresh shoots were then processed into tencha through a standardized automated line, steam-fixed at 100 degrees Celsius for 20 seconds, dried in multiple stages reaching about 180 degrees Celsius, and finally stone-milled into powder passed through a 500-micrometer sieve. Each cultivar yielded three independently manufactured batches, which served as replicates for all downstream analyses.

Sensory evaluation followed the Chinese national standard GB/T 34778-2017, with five trained panelists scoring powder appearance, brew color, taste, and aroma in randomized, coded presentations. Green matcha, the quality reference, earned the highest overall score at 92.3, displaying the bright green color, fresh taste, and seaweed-like aroma prized in premium products. Yellow matcha scored nearly as well, between 90.4 and 91.7, with a fine powder, umami-dominated taste, and a mild glutinous aroma, despite its apricot-colored infusion. Purple matcha deviated most from conventional expectations: its appearance and infusion color scored lower, and it tasted noticeably bitter and astringent, but its aroma performance matched green matcha, with a fresh, holly-like fragrance the authors suggest could anchor aroma-based product differentiation.

Quantitative biochemical analysis explained these sensory splits. Using high-performance liquid chromatography and ultra-performance liquid chromatography, the team measured catechins, caffeine, and free amino acids in each powder. Green matcha contained substantially lower total catechins, epigallocatechin gallate, and caffeine than its colored counterparts, while accumulating higher levels of arginine and aspartic acid, amino acids associated with freshness and umami intensity. Because catechins and caffeine act synergistically to intensify bitterness and astringency, their relative scarcity in green matcha allowed savory amino acids to dominate perception. Purple matcha, by contrast, showed the highest levels of epigallocatechin, caffeine, and total alkaloids, a co-enrichment that plausibly explains its lingering after-bitterness even though its theanine content was respectable. Yellow matcha carried the highest theanine and glutamine concentrations, compounds that enhance umami and mouthfeel, alongside elevated epicatechin gallate, a catechin that contributes moderate astringency with a smoother sensory profile than EGCG.

To move beyond targeted measurements, the researchers deployed widely targeted metabolomics on a UPLC-MS/MS platform, annotating a remarkable 3,139 non-volatile metabolites spanning amino acids, flavonoids, terpenoids, alkaloids, lipids, nucleotides, and more. Quality-control samples pooled from all extracts showed Spearman correlation coefficients above 0.97, indicating strong analytical reproducibility. Principal component analysis separated the six samples cleanly by leaf-color phenotype: the first principal component, explaining 28.3 percent of variance, distinguished green from purple matcha, while the second, at 21.3 percent, separated the yellow samples. Samples clustered tightly within color groups, confirming that metabolic similarity runs along pigmentation lines rather than randomly across cultivars.

Differential metabolite analysis, using strict statistical thresholds of false-discovery-corrected significance, variable importance in projection scores of at least one, and fold changes of at least two, identified 131 differentially accumulated metabolites between green and purple teas, 114 between green and yellow, and 76 between purple and yellow. Sixteen metabolites were shared across all three comparisons, including representative flavonoids, amino acids, organic acids, phenylpropanoids, and alkaloids. Pathway enrichment analysis pointed to flavonoid biosynthesis and amino acid metabolism as the major axes of divergence. In the green-versus-purple comparison, phenylalanine metabolism, flavone and flavonol biosynthesis, D-amino acid metabolism, and aminoacyl-tRNA biosynthesis were prominently enriched, consistent with the fact that phenylalanine feeds the phenylpropanoid pathway that produces the anthocyanins responsible for purple leaves.

Those anthocyanins showed up clearly in the data. Purple matcha was enriched in cyanidin-3-O-galactoside, cyanidin 3-rutinoside, kuromanin, rutin, and several other anthocyanins and flavonols, compounds that confer both the distinctive purple hue and the stronger bitterness and astringency recorded by the sensory panel. The study also detected elevated L-valine, a bitter amino acid that can participate in Maillard reactions during high-temperature processing to form pyrazines associated with roasted, nutty aromas, and two terpenoids, citronellal and sclareol, linked to citrus-floral and musky-amber notes respectively. Yellow matcha, meanwhile, accumulated high levels of L-lysine, L-glutamine, phenylalanine, histidine, leucine, isoleucine, and proline, underpinning its umami-sweet character, along with flavonol glycosides such as isoquercitrin and quercitrin, which deepen the yellowish-green infusion color and, despite extremely low taste thresholds, add moderate bitterness. The authors caution that because anthocyanins were not quantified in the same leaves before and after processing, the magnitude of pigment degradation during matcha manufacture cannot be established from this data alone.

Aroma chemistry added a third dimension. Using headspace solid-phase microextraction coupled to gas chromatography time-of-flight mass spectrometry, the team identified 67 volatile compounds, with terpenes the most abundant class at 25.37 percent of the profile, followed by esters, alcohols, and ketones. Green matcha contained the richest volatile complement, dominated by aldehydes such as heptanal, benzeneacetaldehyde, and beta-cyclocitral, along with the carotenoid degradation products dihydroactinidiolide and beta-ionone, which together produce the signature seaweed-like, herbal, and violet-floral notes of premium matcha. Purple matcha’s volatiles skewed toward floral and fruity territory, with abundant leaf alcohol derivatives including (Z)-3-hexen-1-ol, terpineol, and phenylethyl alcohol. Yellow matcha’s profile was led by terpenes and alcohols such as beta-ocimene, alpha-copaene, and humulene, contributing fruity and herbal notes, while trace heterocyclics like pyrrole and indole may account for subtle nutty and roasted undertones that complement its mellow, rice-soup-like mouthfeel.

The practical implications extend beyond flavor curiosity. China’s tea industry has registered more than 400 new cultivars in the past five years, roughly a quarter of them leaf-color variants, yet these genetic resources remain largely absent from matcha production. By demonstrating that purple and yellow cultivars produce matcha with distinct, chemically grounded, and in the yellow case nearly benchmark-equivalent sensory profiles, the study provides a biochemical framework for cultivar selection and product diversification. A purple matcha could be marketed for its holly-like aroma and anthocyanin content, while a yellow matcha could target consumers seeking maximum umami with a distinctive glutinous character. The researchers also flag open questions: optimal shading regimes for non-green cultivars remain unknown, anthocyanin stability during the high-temperature drying stages needs quantitative tracking, and the focused differential comparison used one representative cultivar per color group, so cultivar identity and leaf-color effects cannot be fully disentangled statistically. Still, the message is clear. The color of a tea leaf is a chemical announcement, and matcha makers are only beginning to listen.

Subject of Research: Metabolic and volatile compound differences underlying the flavor of matcha from green-, purple-, and yellow-leaf tea cultivars

Article Title: Metabolic characteristics and chemical basis of matcha from cultivars with different leaf colors

Article References: Ding, S., Liu, D., Liu, H., Gong, Y., Mei, P., Ye, Y., Wang, P., Zhang, C., Chen, J., Ma, C., & Zhao, X. (2026). Metabolic characteristics and chemical basis of matcha from cultivars with different leaf colors. Frontiers in Nutrition, 13, Article 1951952. https://doi.org/10.3389/fnut.2026.1951952

Image Credits: AI Generated

DOI: 10.3389/fnut.2026.1951952

Keywords: matcha, tea cultivars, metabolomics, anthocyanins, theanine, catechins, flavonoid biosynthesis, volatile compounds, leaf color, sensory evaluation, food chemistry, Camellia sinensis

Guava (Psidium guajava L.) is a tropical fruit tree grown widely across Asia, Africa, and the Americas. While most people know it for its sweet fruit, the plant also exhibits natural variation in leaf color, with some cultivars producing purple foliage and others producing the more typical green. The biological basis for this difference had not been systematically explored until now. The research team, led by scientists from Shihezi University and the Guangdong Academy of Agricultural Sciences, set out to characterize both the chemical composition and the gene expression patterns underlying the two leaf phenotypes.

The researchers employed targeted metabolomics to profile the flavonoid-related compounds present in the leaves of each cultivar. Flavonoids are a large family of plant secondary metabolites that include anthocyanins, which provide red, purple, and blue pigmentation, as well as proanthocyanidins, which are condensed tannins that contribute to astringency and defense. By quantifying these metabolites in both purple and green leaves, the team could determine which compounds accumulate preferentially in each phenotype.

The results revealed a clear divergence. In the green-leaved cultivar “Zhenzhu,” proanthocyanidins constituted a larger proportion of the measured flavonoid pool. In contrast, the purple-leaved “Ziguo” showed a predominance of anthocyanins, with cyanidin derivatives identified as the major pigment class. This finding indicates that the two cultivars are not simply differing in the total amount of flavonoids they produce but rather in how those flavonoids are partitioned between alternative end products of the same core pathway.

To understand the genetic basis of this metabolic shift, the researchers performed transcriptomic sequencing on the leaves of both cultivars. Transcriptomics allows scientists to measure the activity levels of thousands of genes simultaneously, revealing which genes are turned up or down in one condition relative to another. In this case, the comparison between purple and green leaves highlighted a set of differentially expressed genes involved in flavonoid biosynthesis.

One of the most striking observations concerned the proanthocyanidin branch of the pathway. The genes responsible for converting common flavonoid precursors into proanthocyanidins, including key structural enzymes such as ANR (anthocyanidin reductase) and LAR (leucoanthocyanidin reductase), were expressed at significantly lower levels in the purple-leaved cultivar. This downregulation suggests that “Ziguo” actively suppresses the proanthocyanidin pathway, leaving more substrate available for the competing anthocyanin branch.

The researchers also identified candidate genes involved in the transport and storage of these compounds within plant cells. Anthocyanins and proanthocyanidins must be moved from their site of synthesis in the cytoplasm to their final destinations, typically the vacuole, where they accumulate to visible concentrations. A glutathione S-transferase gene designated PgGSTF9 was expressed at notably higher levels in the purple cultivar, consistent with a role in shuttling anthocyanins to the vacuole. Conversely, a gene called PgDTX, implicated in proanthocyanidin transport, showed reduced expression in the purple leaves, potentially limiting the accumulation of proanthocyanidins in that compartment.

Beyond structural genes and transporters, the study also examined transcription factors, the regulatory proteins that control the expression of multiple biosynthetic genes at once. The researchers found that certain candidate regulatory genes showed differential expression between the two cultivars, suggesting that the shift in flavonoid partitioning is coordinated at the transcriptional level rather than arising from changes in a single enzyme. This type of coordinated regulation is common in plant secondary metabolism, where transcription factor complexes control entire biosynthetic branches in response to developmental or environmental cues.

The findings carry practical implications for guava breeding and ornamental horticulture. Purple-leaved guava varieties are valued for their visual appeal in landscaping, and understanding the molecular basis of leaf coloration could help breeders develop new cultivars with enhanced pigmentation. More broadly, the study contributes to a growing body of knowledge about how plants allocate flux through the flavonoid pathway, a question with relevance to fruit quality, nutritional value, and stress tolerance in many crop species.

From a scientific perspective, the work illustrates the power of combining metabolomics with transcriptomics to dissect complex metabolic phenotypes. Neither approach alone would have been sufficient to reveal the full picture. The metabolite profiling identified what compounds differ between the two cultivars, while the gene expression data pointed to the enzymatic and regulatory mechanisms responsible for those differences. Together, they provide a coherent model in which suppressed proanthocyanidin biosynthesis, enhanced anthocyanin transport, and altered transcriptional regulation jointly produce the purple leaf phenotype. Future research will likely focus on validating the candidate genes identified in this study through functional characterization, potentially using transgenic approaches or gene editing to confirm their roles in vivo.

Subject of Research: Flavonoid metabolism underlying purple leaf coloration in guava

Article Title: Integrated metabolomics and transcriptomics characterize anthocyanin accumulation in purple-leaved guava (Psidium guajava L.)

Article References: Xue, S., Lai, D., Chen, J., Hu, S., & Shao, X. (2026). Integrated metabolomics and transcriptomics characterize anthocyanin accumulation in purple-leaved guava (Psidium guajava L.). BMC Plant Biology. https://doi.org/10.1186/s12870-026-09972-y

Image Credits: AI Generated

DOI: 10.1186/s12870-026-09972-y

Keywords: guava, anthocyanins, proanthocyanidins, flavonoid biosynthesis, leaf coloration, metabolomics, transcriptomics, Psidium guajava, cyanidin, plant pigmentation, gene expression, horticulture

The review, led by Dharmasoth Rama Devi of the Vignan Institute of Pharmaceutical Technology with colleagues in India, systematically integrated literature through August 2026, stratifying evidence into chemical, computational, cell-based, animal, and human levels. Unlike earlier reviews that focused separately on ethnomedicine, anthocyanins, or cyclotides, the team explicitly linked preparation identity, study design, bioavailability, and safety, asking a deceptively simple question at each step: which exact product was tested, and at what exposure?

Chemically, the species is genuinely distinctive. Its blue petals owe their color to ternatins, a family of polyacylated delphinidin anthocyanins whose acylation stabilizes the pigment far better than many common anthocyanins, making the flower attractive as a natural, pH-responsive food colorant. The plant also delivers flavonol glycosides such as kaempferol and quercetin derivatives, phenolic acids, root triterpenoids like taraxerol, seed sterols, and, most unusually, a rich repertoire of cyclotides: head-to-tail cyclic peptides locked by a cystine-knot motif that resists digestion and shows membrane-active antimicrobial and cytotoxic properties. A separate enzyme from the plant, butelase-1, is a powerful peptide ligase now used to stitch engineered peptides together in the laboratory.

Yet the reviewers draw a sharp line between these biotechnology assets and what a cup of flower tea actually delivers. Recent genomic work showing that cyclotides arise from hijacked nitrogen-fixation-related albumin genes, and a 2026 petal study expanding the cyclotide inventory, say nothing about whether a crude infusion delivers a pharmacologically meaningful peptide dose. The same logic applies across the metabolite classes: roots, seeds, leaves, and petals have different chemical profiles, so evidence from one preparation cannot be transferred to another.

That preparation-specific logic also undercuts a familiar shortcut in botanical literature. Tests such as DPPH and ABTS measure chemical radical-scavenging in a test tube; the review insists these are analytical redox characterizations, not pharmacology, and that half-maximal values from them should never be presented as clinical potency figures. In one illustrative cell study, ternatin-rich and quercetin-glycoside-rich petal fractions modulated inflammation in LPS-stimulated macrophages through different, partly ROS-independent mechanisms, demonstrating that total phenolic content cannot serve as a universal explanatory mechanism.

The preclinical record is broad but uneven. Rodent studies report memory and cholinergic benefits from root extracts, including a chemically standardized bio-enhanced fraction tested in chronic cerebral hypoperfusion; flower extracts improved metabolic and inflammatory endpoints in obese and diabetic-dyslipidemic mice; root preparations eased edema, bronchospasm, cough, and allergy models; and leaf and root extracts attenuated acute toxin-induced liver and kidney injury in mice. The review rates these signals as biologically plausible but consistently limited by incomplete extract characterization, short durations, inconsistent blinding, and uncertain dose translation to humans.

Human evidence is the weakest link. It consists of small acute crossover trials in healthy or overweight men showing transient changes in postprandial glucose, insulin, triglycerides, and antioxidant status, plus two exploratory adjunctive studies: a retrospectively registered trial of flower decoction alongside tuberculosis therapy, and a 2026 study of flower tea with metformin in people with type 2 diabetes and diabetic distress. Neither established a treatment effect; both lacked placebo controls, adequate randomization and blinding, marker-standardized preparations, and pharmacokinetic monitoring of botanical-drug interactions.

Bioavailability data add further caution. Intact ternatins were detected in rat plasma within fifteen minutes of oral dosing, but peak concentrations reached only about 0.141 micromolar, and human pharmacokinetics remain entirely unknown. Anthocyanin tracer studies in other species suggest systemic exposure is dominated by degradation and conjugated metabolites rather than the parent pigments. Cyclotide proteolytic stability does not imply oral absorption, and their sequence-specific risks of hemolysis, cytotoxicity, and immunogenicity are uncharacterized for repeated human exposure. A 14-day mouse toxicity study found no mortality at 500 to 1,000 milligrams per kilogram but liver and kidney histopathological changes at 2,000 milligrams per kilogram, and no chronic safety threshold has been established.

Regulators have taken notice. In 2022, the European Food Safety Authority recorded safety objections to a traditional-food notification for dried butterfly pea flowers, citing the possibility of risk from cyclotides with reported hemolytic, cytotoxic, immune, and uterine effects, alongside gaps in the documented history of safe use. The reviewers stress that customary beverage consumption cannot be extrapolated to concentrated extracts, chronic medicinal dosing, or purified constituents, and that theoretical interactions with CYP enzymes, transporters such as P-glycoprotein, and co-administered antidiabetic or CNS drugs remain prospective testing priorities rather than established hazards.

The bottom line is a disciplined roadmap rather than a debunking. The authors argue that Clitoria ternatea should be treated as a family of distinct products: a validated natural food colorant and beverage with genuine near-term commercial prospects, a candidate standardized botanical extract requiring replicated dose-response, pharmacokinetic, interaction, and safety studies, and a peptide-discovery platform built on cyclotides and butelase-1 that should follow conventional peptide-drug development. Therapeutic claims, they conclude, will require authenticated materials, marker-based standardization, exposure-linked pharmacology, and adequately powered randomized trials, standards that today’s viral wellness narratives have not yet met.

Subject of Research: Phytopharmacology of Clitoria ternatea (butterfly pea), including its metabolites, bioavailability, clinical evidence, and safety

Article Title: Clitoria ternatea as a phytopharmacological resource: plant metabolites, mechanistic evidence, translational prospects, and safety considerations

Article References: Devi, D. R., Maheswari, S. N., Saranya, R. K., Aashritha, S., Sankar, N. G., Gurrala, N. A., Karak, P., & Das, S. K. (2026). Clitoria ternatea as a phytopharmacological resource: plant metabolites, mechanistic evidence, translational prospects, and safety considerations. Frontiers in Pharmacology, 17, Article 1922024. https://doi.org/10.3389/fphar.2026.1922024

Image Credits: AI Generated

DOI: 10.3389/fphar.2026.1922024

Keywords: Clitoria ternatea, butterfly pea, ternatins, anthocyanins, cyclotides, butelase-1, bioavailability, phytopharmacology, botanical standardization, clinical evidence, safety, food colorant

The experiment was set up on a soil that was slightly alkaline, with a pH of 7.5, and notably poor in organic carbon, nitrogen, and available phosphorus. That starting point mattered. Nutrient-limited soils are precisely the kind of environment where a fertilizer input is most likely to reveal differences between plant genotypes, because each ecotype’s internal physiology must decide how to spend the newly available resources. The researchers hypothesized that organic manure and NPK fertilizer would not act identically across ecotypes, and instead would differentially regulate vegetative and reproductive traits depending on the plant’s origin.

To test this, the team obtained three ecotypes of summer savory, from Mashhad, Shiraz, and Karaj, and subjected them to five fertilization treatments: an unfertilized control, organic manure at 25 and 50 tonnes per hectare, and NPK fertilizer at 50 and 100 kilograms per hectare. The trial was laid out as a factorial randomized complete block design with three replicates, a standard but rigorous arrangement that allows the effects of ecotype, fertilizer, and their interaction to be separated statistically. The researchers then measured a broad panel of morphological, physiological, and phytochemical traits, from plant height and leaf biomass to chlorophyll and anthocyanin content, flower number, and the percentage of essential oil in the harvested material.

The analysis, which combined analysis of variance (ANOVA), principal component analysis (PCA), and structural equation modeling (SEM), delivered a clear verdict: both ecotype and fertilizer mattered, and crucially, so did their interaction. For reproductive traits and pigment-related traits in particular, the ecotype-by-fertilizer interaction was statistically significant, meaning that the best fertilizer for one ecotype was not necessarily the best for another. This kind of genotype-by-environment interplay is exactly what breeders and agronomists watch for when deciding whether a crop recommendation can be generalized or must be tailored to a specific seed lot or region.

Some of the standout combinations were striking. The Shiraz ecotype fertilized with the higher rate of organic manure, 50 tonnes per hectare, produced the greatest vegetative growth, the highest leaf biomass, and the highest chlorophyll a content of any treatment in the trial. In other words, when the goal is green, leafy, photosynthetically active biomass, the Shiraz population responded most enthusiastically to a heavy dose of organic matter. By contrast, the Karaj ecotype under the highest rate of NPK fertilizer, 100 kilograms per hectare, produced more flowers and accumulated more anthocyanins, the red-purple pigments that often signal a shift in a plant’s metabolic priorities. And across the board, the high-rate NPK treatment was associated with a higher percentage of essential oil in the plant tissue.

That split is the conceptual heart of the paper. The authors interpret these patterns as evidence of distinct resource allocation strategies between biomass-related traits and essential-oil-related traits, rather than a uniform response to fertilization. In plain terms, a plant cannot spend its nitrogen budget twice: resources channeled into building stems, leaves, and chlorophyll are not simultaneously available for synthesizing the terpenoid compounds that make up the essential oil, and vice versa. The fact that organic manure mainly favored biomass and pigment accumulation while high-rate NPK favored oil percentage and reproductive output suggests that the two fertilizer types are not interchangeable levers but rather push the plant along different metabolic trajectories.

The multivariate statistics sharpened this picture considerably. Principal component analysis grouped the measured traits into two coordinated modules, one linking growth and biomass characteristics and the other gathering metabolite-related traits, which is consistent with the idea that these two suites of characteristics are regulated at least partly independently. Structural equation modeling then went a step further, testing hypothesized causal pathways among the trait groups. The SEM results indicated positive associations between physiological traits, phytochemical traits, and essential-oil-related traits, suggesting that a plant that is photosynthesizing efficiently and accumulating pigments also tends to be one that produces more oil. But there was a twist: phenology, the timing of developmental stages such as flowering, was negatively associated with essential oil percentage, hinting that plants that rush into reproduction may do so at the expense of oil accumulation in the harvested tissue.

For growers of medicinal and aromatic plants, the practical implications are potentially significant. Summer savory is cultivated commercially for its essential oil, which is used in food flavoring, cosmetics, and traditional medicine, and the oil content of the harvest is often the single most economically important quality metric. If the choice between organic manure and mineral NPK fertilizer, and the rate at which either is applied, can shift the balance between raw biomass and oil concentration, then fertilizer recommendations for this crop may need to be written per ecotype rather than per species. A farmer growing the Shiraz ecotype for leafy green biomass would be advised to reach for well-rotted manure, while one targeting oil yield from the Karaj ecotype might do better with a higher rate of mineral NPK, at least under the soil and climate conditions of this trial.

The authors are careful to frame their conclusions within the limits of the study. The experiment was conducted at a single location over a single growing season, which means that the observed ecotype-by-fertilizer interactions, while statistically robust within the trial, have not yet been tested across the range of soils, climates, and years in which summer savory is actually grown. Essential oil composition in particular is notoriously sensitive to environmental conditions, harvest timing, and post-harvest handling, so the authors call for multi-location and multi-season studies to clarify the mechanisms underlying fertilizer-induced changes in oil chemistry. Until such studies are done, the findings should be read as a strong signal rather than a final prescription.

Even so, the study adds to a growing body of evidence that in medicinal and aromatic crops, the old agronomic habit of treating fertilization as a purely yield-oriented decision is due for an update. When the product of the crop is not just bulk but a specific chemical fingerprint, the fertilizer decision becomes a chemistry decision as well. For summer savory, at least, the new data suggest that the ecotype a grower plants and the nutrient regime applied to it together determine whether the harvest will be a pile of lush green leaves or a distillation flask full of aromatic oil, and that getting the pairing right may be worth as much as any single input itself.

Subject of Research: Effects of organic manure and NPK fertilizer on growth, biomass, pigments, and essential oil of Satureja hortensis ecotypes

Article Title: Multi-dimensional analysis of fertilizer-treated Satureja hortensis L. ecotypes: growth dynamics, biomass production, and phytochemical fingerprints

Article References: Ghanbari Moheb Seraj, R., Esmaeili, H., Tariverdizadeh, N., Hasanzadeh, A., & Mohebodini, M. (2026). Multi-dimensional analysis of fertilizer-treated Satureja hortensis L. ecotypes: growth dynamics, biomass production, and phytochemical fingerprints. BMC Plant Biology. https://doi.org/10.1186/s12870-026-10217-1

Image Credits: AI Generated

DOI: 10.1186/s12870-026-10217-1

Keywords: summer savory, Satureja hortensis, organic manure, NPK fertilizer, essential oil, chlorophyll, anthocyanins, phenology, ecotypes, medicinal plants, plant physiology, agronomy

The review, led by Jingxian An of the Food Science and Technology Programme at the National University of Singapore, examines how low-frequency, high-intensity ultrasound can address three interconnected challenges in pigmented rice processing: modifying starch structure, reducing processing time, and extracting anthocyanins efficiently. The authors emphasize that ultrasound is not a new technology—research on ultrasonic depolymerization dates back to 1933—but its application to pigmented rice remains comparatively underexplored.

Pigmented rice varieties, including black, red, purple, and purple-red rice, are distinguished from their non-pigmented counterparts by an abundance of bioactive compounds, particularly flavonoids, anthocyanins, and proanthocyanidins. Cyanidin-3-glucoside is the predominant anthocyanin, reaching concentrations up to 470 milligrams per 100 grams, followed by peonidin-3-glucoside at up to 40 milligrams per 100 grams. These concentrations vary considerably among cultivars, and the predominant phenolic compounds also differ among color types: anthocyanins are particularly abundant in black and purple rice, while the pigmentation of red rice is more strongly associated with proanthocyanidins concentrated in the outer layers of the grain.

The processing challenges are closely tied to the starch properties of pigmented rice. Its relatively ordered starch-granule structure, together with interactions between starch and endogenous phenolic compounds, can restrict enzyme accessibility and require longer soaking, cooking, or structural-modification treatments. However, increasing treatment duration or intensity to improve starch functionality may simultaneously accelerate anthocyanin degradation. An appropriate processing technology must therefore balance three related objectives: effective starch modification, shorter cooking and drying times, and rapid anthocyanin recovery with minimal pigment degradation.

Ultrasound addresses these challenges through acoustic cavitation, a phenomenon that occurs only in liquid media. Alternating compression and rarefaction waves induce the formation and violent collapse of microscopic bubbles, generating shear forces, microjets, and localized pressure and temperature gradients. In starch-water systems, these physical effects can disrupt starch-granule organization, producing surface erosion, cracks, depressions, and increased porosity. When applied to rice starch, ultrasonic treatment can alter granule morphology and molecular organization, thereby enhancing swelling properties, reducing short-range molecular order and relative crystallinity, and modifying gelatinization characteristics.

The review highlights that ultrasound can be combined with other processing techniques to improve efficiency. Ultrasound-assisted enzymatic treatment can increase starch surface accessibility and facilitate enzyme-substrate interactions, thereby accelerating structural modification. Studies have shown that ultrasound-assisted cellulase treatment improved the textural properties and modified the in vitro starch digestibility of brown rice noodles, while ultrasonic enzyme treatment improved the cooking and eating quality of brown rice. However, the authors caution that evidence directly linking shortened ultrasound-assisted processing to improved anthocyanin retention in pigmented rice remains limited and condition-dependent.

Drying presents another opportunity for ultrasound application. After harvesting, paddy rice must be dried to a moisture level suitable for safe storage and milling, but higher drying temperatures and prolonged storage can accelerate the loss of heat-sensitive phenolic compounds. Ultrasound pretreatment can alter plant-tissue structure and increase porosity, thereby facilitating the migration of free, immobilized, and some bound water. Evidence from non-rice plant matrices suggests that ultrasound pretreatment may contribute to quality preservation by reducing the activity of enzymes such as polyphenol oxidase and peroxidase, which are associated with color deterioration and bioactive compound loss. Nevertheless, the authors stress that direct pigmented-rice studies measuring anthocyanin retention are required before a preservation advantage can be concluded.

The strongest rice-specific evidence currently concerns ultrasound-assisted extraction. Pigmented rice bran, a major byproduct of rice milling, is particularly rich in anthocyanins but has traditionally been used as animal feed or discarded as a low-value material. Ultrasound-assisted extraction enhances the recovery of bioactive compounds through acoustic cavitation, which disrupts plant cell walls and membranes, thereby facilitating the release of anthocyanins into the solvent. Representative studies demonstrate impressive yields: ultrasound-assisted extraction of black rice bran using water recovered around 173.25 milligrams of cyanidin-3-glucoside equivalents per liter, while extraction from red rice bran using acidified aqueous ethanol achieved a validated anthocyanin yield of 5.512 milligrams per gram. The magnitude of these effects varies with frequency, power, treatment time, temperature, reactor geometry, and the physicochemical properties of the solvent and sample matrix.

Despite these advantages, the review acknowledges several limitations. Excessive sonication may generate localized heating and reactive radicals, potentially degrading anthocyanins and other phenolic compounds rather than preserving them. Non-uniform acoustic fields and attenuation of ultrasonic energy in dense or heterogeneous materials can result in uneven treatment. At the industrial scale, equipment cost, probe erosion, energy efficiency, and reproducibility also require further evaluation. The authors conclude that ultrasound should be considered a complementary processing technology rather than a universally superior replacement for conventional methods, and that future research should focus on optimizing processing parameters tailored to specific rice varieties, investigating novel ultrasound-assisted combinations with emerging technologies, and conducting techno-economic assessments to evaluate the long-term feasibility of ultrasound-assisted processing in commercial settings.

Subject of Research: Ultrasound-assisted processing of pigmented rice for anthocyanin retention and extraction

Article Title: Ultrasound in Pigmented Rice Processing: A Versatile Approach for Anthocyanin Retention and Extraction: A Review

Article References: An, J., Liu, C., & You, K.-M. (2026). Ultrasound in Pigmented Rice Processing: A Versatile Approach for Anthocyanin Retention and Extraction: A Review. Food Science & Nutrition, 14(10), Article e72476. https://doi.org/10.1002/fsn3.72476

Image Credits: AI Generated

DOI: 10.1002/fsn3.72476

Keywords: ultrasound, anthocyanins, pigmented rice, food processing, starch, extraction, Pigmented, Rice, Processing, Versatile, Approach, Anthocyanin

The review, authored by Marika Avitabile of the Department of Chemical Sciences at the University of Naples Federico II, systematically maps the phytochemical potential of floral by-products and the technical routes for converting them into functional food packaging. The timing is significant. The food packaging sector is under simultaneous pressure from environmental regulation, consumer demand for sustainable materials, and the well-documented shortcomings of bioplastics themselves. Biopolymers such as chitosan, pectin, alginate, starch, and cellulose derivatives have emerged as promising alternatives to conventional plastics, but their intrinsic hydrophilicity, limited mechanical strength, and insufficient barrier properties have hindered widespread adoption. The review proposes a convergence: use floral waste to fix biopolymer packaging’s weaknesses while simultaneously solving floral industry’s waste problem.

The chemistry of discarded flowers is remarkably diverse. Phenolic acids such as gallic, caffeic, and ferulic acid contribute strong antioxidant activity and can inhibit lipid oxidation in food systems. Flavonoids including quercetin, kaempferol, and rutin exhibit antimicrobial and anti-inflammatory properties and can stabilize biopolymer matrices through hydrogen bonding. Anthocyanins, the pigments responsible for the vivid colours of many flowers, provide antioxidant activity and can act as natural pH indicators, enabling smart packaging capable of monitoring food freshness. Carotenoids such as lutein and β-carotene, abundant in species like Calendula officinalis and Tagetes erecta, offer UV-protective properties and can improve the photostability of biopolymer films. Terpenoids including linalool, geraniol, citronellol, and eucalyptol, characteristic of aromatic flowers such as lavender, rose, jasmine, and Callistemon citrinus, possess strong antimicrobial activity against foodborne pathogens.

Distillation residues from the fragrance industry often retain significant amounts of these compounds, making them particularly valuable for extraction. Beyond their chemical richness, floral waste also provides sensory properties: many extracts retain pleasant aromas that can enhance the sensory appeal of packaging materials or mask undesirable odors, a characteristic especially relevant for coatings applied directly to fresh produce. The combination of antioxidant, antimicrobial, and aromatic properties makes floral by-products an ideal source of natural additives for active packaging. However, the practical valorisation of floral by-products faces obstacles that limit industrial uptake. Floral residues are highly perishable, with enzymatic browning, microbial growth, and moisture accumulation occurring within hours after harvest. Their heterogeneous composition, arising from differences in cultivar, growth conditions, maturity stage, and post-harvest handling, makes it difficult to obtain extracts with reproducible phytochemical profiles. Logistics of storage and transport require controlled temperature and humidity to prevent degradation of phenolics and volatile terpenoids.

Recovering bioactive compounds from floral waste requires extraction methods that preserve chemical integrity while minimizing environmental impact. Traditional solvent extraction is effective but often relies on organic solvents and long processing times. Green extraction technologies offer more sustainable alternatives and are increasingly adopted for food-grade applications. Ultrasound-assisted extraction (UAE) is widely used for floral matrices due to its ability to disrupt plant cell walls and enhance mass transfer. The cavitation effect generated by ultrasound waves accelerates the release of phenolic compounds and flavonoids, reducing extraction time and solvent consumption. UAE is particularly suitable for delicate materials such as rose petals and lavender residues, where thermal degradation must be avoided. Microwave-assisted extraction (MAE) provides rapid heating and efficient solvent penetration, making it ideal for compounds with moderate thermal stability, such as carotenoids and certain flavonoids. MAE can significantly increase extraction yields while reducing energy consumption, though its main limitation is the potential degradation of highly volatile terpenoids, which require careful optimization of temperature and time.

Supercritical CO2 extraction is the method of choice for volatile and lipophilic compounds, including terpenoids and aromatic molecules. CO2 is non-toxic, non-flammable, and leaves no solvent residues, making it suitable for food-contact applications. The tunability of pressure and temperature allows selective extraction of specific compounds. Distillation residues from jasmine, rose, and Callistemon citrinus are particularly well suited to this technique. Natural deep eutectic solvents (NADES) represent an emerging class of green solvents with high solubilizing power for polyphenols and flavonoids. NADES are biodegradable, low-toxicity, and compatible with food applications. Their ability to form hydrogen bonds with phenolic compounds enhances extraction efficiency. Aqueous enzymatic extraction offers another environmentally friendly approach: enzymes such as pectinases, cellulases, and hemicellulases break down plant cell walls, releasing bound phenolic compounds under mild conditions that preserve the integrity of heat-sensitive compounds. Hydrodistillation, although one of the oldest extraction methods used in the fragrance industry, remains highly relevant and deserves explicit consideration within green extraction frameworks. Modern hydrodistillation systems have been optimized to reduce water consumption, improve heat recovery, and minimize environmental impact. Importantly, hydrodistillation generates two valuable fractions: an essential oil phase containing highly concentrated volatile compounds, and an aqueous distillate enriched in water-soluble aromatic molecules. Moreover, the solid residues remaining after hydrodistillation still contain significant amounts of polyphenols and flavonoids, making them suitable for subsequent extraction through UAE, MAE, or NADES. This multi-step valorisation approach positions hydrodistillation as a central component of integrated biorefinery strategies for floral waste.

The integration of floral extracts into biopolymer matrices requires careful consideration of compatibility, stability, and release mechanisms. Successful incorporation depends on polarity, hydrogen-bonding capacity, and ionic interactions. Phenolic compounds interact strongly with chitosan through electrostatic and hydrogen-bonding mechanisms, whereas anthocyanins require pH values below 4 to maintain their flavylium cation form and avoid colour loss. Extract loading typically ranges from 0.5% to 5% w/w, as higher concentrations may plasticize the matrix, reduce tensile strength, or alter film transparency. Conversely, moderate phenolic loading can increase crosslinking density and improve mechanical performance. Chitosan is one of the most widely used biopolymers for active packaging due to its intrinsic antimicrobial activity and film-forming properties. The incorporation of floral extracts into chitosan films enhances antioxidant activity, improves UV protection, and can create synergistic antimicrobial effects. The cationic nature of chitosan facilitates interactions with phenolic compounds, improving film cohesion and mechanical strength. Pectin and alginate films are particularly suitable for hydrophilic extracts rich in polyphenols. These polysaccharides form gels through ionic crosslinking and can encapsulate bioactive compounds within their network. Floral extracts can improve the oxygen barrier properties of pectin-based films and modulate their mechanical behaviour. Starch-based films benefit from improved mechanical strength, enhanced hydrophobicity, and increased thermal stability. Phenolic compounds can interact with starch chains, reducing retrogradation and improving film flexibility. Cellulose-based films, including those reinforced with nanocellulose, offer excellent transparency and oxygen barrier properties, and nanocellulose provides a high surface area for interactions with phenolic compounds, improving their dispersion and stability.

Nanostructuring plays a crucial role in improving the stability, bioavailability, and controlled release of floral extracts within biopolymer matrices. Most floral extracts are highly sensitive to heat, light, oxygen, and pH fluctuations, and many terpenoids are volatile. Nanostructuring strategies mitigate these issues by providing physical barriers and controlled-release matrices. Nanoemulsions and pickering emulsions protect hydrophobic terpenoids from evaporation and oxidation, while nanocellulose or lignin nanoparticles stabilize phenolics through adsorption and hydrogen bonding. Pickering emulsions, stabilized by solid particles rather than surfactants, offer exceptional stability and are well suited for the encapsulation of floral extracts. Nanocellulose, chitin nanocrystals, and protein nanoparticles can adsorb irreversibly at the oil-water interface, protecting volatile compounds from oxidation and evaporation. The incorporation of nanocellulose, lignin nanoparticles, or chitin nanocrystals into biopolymer matrices improves mechanical strength, barrier properties, and thermal stability. Lignin nanoparticles provide strong antioxidant activity and protective properties, complementing the functionality of floral extracts. Electrospun nanofibers offer a high surface area and tunable porosity, making them ideal for the encapsulation and controlled release of floral extracts. Electrospinning allows the incorporation of both hydrophilic and hydrophobic compounds and can produce multilayer structures with distinct functional properties. Nanofibrous coatings can be applied directly to food surfaces or used as active layers in multilayer packaging systems.

The incorporation of floral extracts into biopolymer-based packaging has been explored for a wide range of food products. Fresh produce benefits from coatings and films enriched with phenolic-rich extracts, which reduce microbial growth, delay ripening, and minimize weight loss. The antioxidant and antimicrobial properties of floral extracts help maintain colour, texture, and nutritional quality during storage. Meat and fish products are particularly susceptible to lipid oxidation and microbial spoilage. Packaging materials functionalized with terpenoid-rich extracts from lavender, rosemary, or C. citrinus can inhibit the growth of pathogens such as Listeria monocytogenes and Staphylococcus aureus while reducing oxidative rancidity. Dairy products, especially high-moisture cheeses, benefit from the antimicrobial and antioxidant properties of floral extracts, and chitosan-based coatings enriched with phenolic compounds can reduce surface microbial growth and delay spoilage. Bakery products are prone to mold growth, which can be inhibited by packaging materials containing flavonoid-rich extracts. The incorporation of anthocyanin-rich extracts can provide natural coloration and enable the development of pH-responsive smart packaging capable of indicating spoilage. The versatility of floral extracts allows their application across diverse food categories, addressing both microbial and oxidative challenges simultaneously.

Despite their potential, several challenges remain before floral waste-derived packaging reaches supermarket shelves. Floral waste composition is highly variable, requiring standardized extraction and characterization methods. Many bioactive compounds are sensitive to oxidation and heat, making stabilization and controlled release essential. Additional concerns must be considered when translating floral extract-based packaging to real applications: chitosan-based materials may pose allergenicity risks for individuals sensitive to crustacean-derived chitin, requiring clear labelling and safety assessment. Hydrophilic biopolymers such as pectin, alginate, and starch are susceptible to microbial contamination under high humidity, necessitating proper drying, storage, and possibly the inclusion of natural antimicrobial agents. Regulatory approval requires toxicological evaluation and migration studies. Nanostructuring strategies could be further strengthened by designing multi-layer architectures where nanostructured active layers are physically separated from the food-contact surface, reducing migration concerns while maintaining functional efficacy. Before scaling up, it is crucial to evaluate the trade-off between process complexity and sustainability. Future studies should focus on low-energy valorisation routes and integrated biorefinery frameworks to ensure both ecological and economic feasibility. The valorisation of floral by-products aligns with circular bioeconomy principles and offers a promising pathway toward multifunctional sustainable packaging, transforming what was once discarded as waste into high-value ingredients for the future of food preservation.

Subject of Research: Valorisation of floral industry by-products as bioactive sources for biopolymer-based active food packaging

Article Title: Valorisation of floral industry by-products as sources of bioactive compounds for functionalized biopolymer-based packaging: a mini review

Article References: Avitabile, M. (2026). Valorisation of floral industry by-products as sources of bioactive compounds for functionalized biopolymer-based packaging: a mini review. Frontiers in Soft Matter, 6, Article 1899570. https://doi.org/10.3389/frsfm.2026.1899570

Image Credits: AI Generated

DOI: 10.3389/frsfm.2026.1899570

Keywords: floral waste, bioactive compounds, biopolymers, active packaging, green extraction, chitosan, anthocyanins, nanoemulsions, circular bioeconomy, food shelf life, sustainability, Valorisation

Anthocyanins are glycosylated forms of anthocyanidins, built on a flavylium ion backbone with a C6-C3-C6 carbon structure: a 15-carbon skeleton of two aromatic rings connected by a three-carbon bridge forming a heterocyclic ring. Six major anthocyanidins—petunidin, malvidin, peonidin, cyanidin, delphinidin, and pelargonidin—account for roughly 90 percent of those found in nature. Beyond their role as plant pigments, these compounds exhibit antioxidant, anti-inflammatory, neuroprotective, and anticancer activities, and previous work has documented broad-spectrum antiviral effects against several RNA viruses, including suppression of influenza neuraminidase.

The review identifies the SARS-CoV-2 main protease, Mpro, as the most extensively investigated molecular target. Because Mpro cleaves viral polyproteins into functional units required for replication and maturation—and because its structure differs substantially from any human protease—it has become one of the most attractive antiviral targets against COVID-19. Numerous independent molecular docking studies have demonstrated favorable predicted interactions between structurally diverse anthocyanins and the Mpro catalytic site, particularly the catalytic residues His41 and Cys145, with no clear cellular cytotoxicity reported. Notably, polyacylated anthocyanins such as tecophilin, cyanodelphin, gentiodelphin, and phacelianin consistently exhibited stronger predicted binding than diacylated or monomeric forms, suggesting that structural modification may enhance inhibitory activity.

Several studies have begun to provide experimental validation of these computational predictions. Cyanidin-3-O-sambubioside isolated from kokum fruit demonstrated approximately 79 percent inhibition of Mpro activity at 100 micromolar in an in vitro enzymatic assay, with favorable docking to the catalytic dyad and no cytotoxicity to BEAS-2B cells. Cyanidin 3-O-galactoside from cranberry showed potent Mpro inhibition with an IC50 of 9.98 micromolar in FRET-based enzymatic assays, while whole cranberry anthocyanin extracts achieved an IC50 of 23.58 micrograms per milliliter. More recently, a high-resolution mass spectrometry-based screening platform identified delphinidin-3-glucoside from blueberry as a covalent Mpro inhibitor, producing dose-dependent inhibition of SARS-CoV-2 replication in Vero E6 cells with an IC50 of approximately 35.8 micromolar—comparable to the established Mpro inhibitor baicalin.

Beyond Mpro, anthocyanins have been proposed to interact with other viral replication proteins, particularly the RNA-dependent RNA polymerase and helicase. A comprehensive virtual screening of naturally occurring polyphenols identified cyanidin-3-O-rutinoside, petunidin-3,5-O-diglucoside, and delphinidin-3-O-rutinoside as the strongest predicted RdRp inhibitors, with binding energies exceeding those of remdesivir. A multitarget docking study found that cyanidin 3-O-glucosyl-rutinoside bound strongly across Mpro, RdRp, and helicase simultaneously. However, the review notes that no studies have conclusively demonstrated direct enzymatic or structural inhibition of these proteins, and the available evidence remains largely limited to computational predictions.

Anthocyanins may also interfere with viral entry by disrupting the interaction between the spike glycoprotein receptor-binding domain and the host ACE2 receptor. In the large-scale multitarget docking study, cyanidin 3-O-glucosyl-rutinoside demonstrated the strongest predicted interactions with both spike protein and ACE2, with docking scores of -10.07 and -13.26 respectively, outperforming the reference compounds remdesivir and hydroxychloroquine. Additional anthocyanins, including pelargonidin-3-rhamnoside and cyanidin-7-arabinoside, were predicted to bind favorably to the spike receptor-binding domain. The review emphasizes, however, that experimental evidence supporting this entry-blocking mechanism remains scarce and should currently be regarded as computational prediction requiring biochemical and cell-based validation.

The review also highlights a complementary mechanism: modulation of host inflammatory responses. Excessive cytokine activation is associated with COVID-19 severity and tissue damage. Using an in vitro model of SARS-CoV-2 spike protein S1-induced inflammation, black rice germ and bran extract rich in cyanidin-3-O-glucoside and peonidin-3-O-glucoside significantly suppressed expression of the inflammatory genes NLRP3, IL-1β, and IL-18, while reducing secretion of IL-6, IL-1β, and IL-18 in A549 lung epithelial cells and THP-1 macrophages. The extract was effective at 12.5 to 100 micrograms per milliliter, with purified constituents active at 1.25 to 10 micrograms per milliliter, operating through inhibition of the NF-κB/NLRP3 inflammasome signaling pathway.

Evidence from anthocyanin-rich plant extracts adds further complexity. Standardized European black elderberry fruit extract, containing 4.6 percent total polyphenols and 3.5 percent anthocyanins, demonstrated in vitro antiviral activity against the original Wuhan strain and the Alpha, Beta, Gamma, Delta, and Omicron variants, with cyanidin-3-sambubioside-5-glucoside exhibiting the strongest inhibition among major components. A subsequent study found that combining elderberry extract standardized to 3.2 percent anthocyanins with quinine produced synergistic antiviral effects against SARS-CoV-2 in Calu-3 lung cells, with a Bliss independence score of 27.8. The review cautions that because extracts contain multiple polyphenols and other phytochemicals, the relative contribution of anthocyanins alone cannot be determined with certainty.

Despite encouraging computational and preclinical evidence, the review identifies poor physicochemical stability and low bioavailability as major translational challenges. Only approximately 2 percent of ingested anthocyanins are reported to retain their intact C6-C3-C6 structure after ingestion. These compounds are highly susceptible to degradation by pH, temperature, oxygen, and light—under acidic conditions they exist predominantly as the red flavylium cation, whereas neutral and alkaline environments promote quinonoidal base formation, reducing both stability and biological activity. Such degradation may occur during food processing, storage, gastrointestinal digestion, and systemic absorption, potentially limiting the concentrations required to achieve the antiviral effects observed in vitro.

Several strategies are being explored to overcome these limitations. Structural modification through glycosylation and acylation, physical protection through microencapsulation and nanoencapsulation, stabilization via complex formation with macromolecules, and co-pigmentation techniques all aim to preserve structural integrity and enhance systemic availability. Encapsulation technologies coat extracted bioactive compounds with protective materials—typically GRAS-classified biopolymers composed of proteins, carbohydrates, or their combinations—to shield them from extreme environments within the body and allow them to reach the small intestine intact. Nanoparticles are of particular interest because their high surface-area-to-volume ratio can enhance stability, solubility, and bioavailability while providing more reactive sites for interaction. The review concludes that while anthocyanins represent promising natural compounds for further antiviral investigation, additional mechanistic studies, in vivo validation using animal models, comprehensive pharmacokinetic evaluations, and well-designed clinical trials are required before their clinical potential against COVID-19 can be established.

Subject of Research: Anthocyanins as potential SARS-CoV-2 antivirals: mechanisms, evidence, and translational challenges

Article Title: Antiviral potential of anthocyanins against SARS-CoV-2: current evidence, translational challenges, and future perspectives

Article References: Lu, P. (2026). Antiviral potential of anthocyanins against SARS-CoV-2: current evidence, translational challenges, and future perspectives. Frontiers in Virology, 6, Article 1897871. https://doi.org/10.3389/fviro.2026.1897871

Image Credits: AI Generated

DOI: 10.3389/fviro.2026.1897871

Keywords: anthocyanins, SARS-CoV-2, COVID-19, antiviral, flavonoids, Mpro, RdRp, ACE2, bioavailability, elderberry, potential, against

Roselle, Hibiscus sabdariffa L., is a member of the Malvaceae family whose fleshy, acid calyces are the raw material for hibiscus tea, jams, sauces, and infusions consumed worldwide. The calyces are chemically rich: they carry organic acids, a broad suite of phenolic compounds, and anthocyanins, the water-soluble pigments responsible for the drink’s signature ruby color. Those same anthocyanins are notoriously fragile, degraded by light, heat, oxygen, shifts in pH, and enzymatic activity. Because drying is the essential step that makes roselle storable and marketable beyond the harvest window, the conditions under which water is removed can directly determine how much of the crop’s bioactive chemistry reaches the cup.

The research team, led by Teresa Avelina Trujillo-Robles of El Colegio de la Frontera Sur, worked with a roselle population cultivated in the community of Guadalupe Victoria, in the municipality of Villaflores, Chiapas. The producer had maintained the population for about ten years within a diversified tropical polyculture, making it a genuine example of farmer-managed agrobiodiversity rather than a commercial variety. On November 20, 2022, the team harvested fifteen plants at random, cutting each roughly five centimeters above the soil. The calyces were manually separated from the capsules, pooled into a single batch, and then randomly divided among three drying treatments, a design intended to equalize the starting material across methods.

The three treatments represented a gradient of technology and cost. The first, labeled JASI, involved 832 grams of fresh calyces dried in an electric oven at 40 degrees Celsius for 33 hours until constant mass, a controlled but energy-dependent method. The second, JAST, was the traditional approach: 3,740 grams spread on wooden boards and left in direct sunlight for five days, or 120 hours. The third, JASCE, used the same mass of calyces arranged on raised wooden mesh beds about 30 centimeters above the soil, covered with 50 percent shade netting, and dried for the same five days. Outdoor samples were turned four times daily and moved under a roofed, ventilated area at night; no rain fell during the drying period. A commercially purchased Sudan-type roselle was oven-dried and included purely as a descriptive external reference, excluded from statistical testing because its production and handling history differed and was not fully documented.

After drying, the calyces reached an overall moisture content of 11.0 plus or minus 0.5 percent, about 89 percent dry matter, a level consistent with Mexican Official Standard NOM-116-SSA1-1994. The team then prepared aqueous extracts the way a tea drinker would: 0.5 grams of ground, sieved material steeped in 10 milliliters of water at 98 degrees Celsius for 20 minutes. From these infusions they measured total phenolic content by the Folin-Ciocalteu method, total monomeric anthocyanins by differential pH spectrophotometry, and four antioxidant responses: DPPH and ABTS radical scavenging, ferric reducing activity, and cupric reducing activity. Each assay ran in technical triplicate, and the triplicates were averaged to yield one value per calyx portion, so the statistics rested on three portion-level observations per treatment.

The headline result concerned anthocyanins. Total monomeric anthocyanin concentrations differed significantly among the three local drying treatments, with the shade-covered raised beds delivering the highest mean at 72.2 plus or minus 6.2 milligrams of delphinidin-3-glucoside equivalents per gram of dry calyces. Direct sun drying produced an intermediate 62.8 plus or minus 9.2, while the oven treatment yielded the lowest local mean at 49.3 plus or minus 8.5. A Games-Howell post hoc comparison pinpointed the significant difference as lying between the shade-bed and oven treatments, with the sun-dried group not statistically distinguishable from either. Total phenolic content, by contrast, ranged only from 23.7 to 27.1 milligrams of gallic acid equivalents per gram across the local treatments, and the analysis of variance found no significant differences among them, although the shade-bed group again posted the highest numerical mean. The commercial reference sample sat well below the local material on both measures, at 19.3 for both phenolics and anthocyanins.

Perhaps the most striking chemical outcome was what did not change. None of the four antioxidant assays detected significant differences among the local drying treatments. DPPH values clustered around 12 to 13 milligrams of Trolox equivalents per gram, ABTS values ranged from roughly 118 to 128, and ferric and cupric reducing activities hovered in the high 70s to low 90s in percentage terms regardless of drying method. The authors are careful about what this means: with only three observations per treatment and incomplete replication of the drying units, the absence of detected differences is not evidence of equivalence. It simply means the design could not resolve differences if they existed. The divergence between the anthocyanin results and the antioxidant results is chemically plausible, since DPPH and ABTS measure radical-scavenging behavior while the ferric and cupric assays probe reducing capacity, and each responds differently to extract composition and interactions among metabolites.

The study’s limitations are candidly acknowledged and matter for interpretation. The three oven-dried portions shared a single oven chamber, so they were not independent at the drying-device level, while the sun and shade treatments each used three separate physical units, an asymmetry that forces cautious reading of any comparison involving the oven treatment. The outdoor drying environment was not instrumented for temperature, humidity, solar radiation, or air velocity, drying kinetics were never recorded, and the two outdoor treatments ran for a fixed 120 hours while the oven ran to constant mass, meaning the treatments ended on different operational criteria. Because no fresh-calyx baseline was analyzed, the findings describe final concentrations only and cannot demonstrate retention, preservation, or improvement relative to the undried material. Only one population, one production cycle, one locality, and one drying campaign were studied, and pooling calyces from fifteen plants erased plant-to-plant variation as an experimental level.

Within those constraints, the practical signal is clear enough to justify further work. Shade-covered raised-bed drying requires no electricity during the outdoor phase, uses simple physical infrastructure, and lifts the crop away from soil contact while cutting direct solar exposure, a combination compatible with the hypothesis that reduced heat and radiation load preserves anthocyanins. The authors frame this as postharvest valorization in a deliberately narrow sense: accessible processing that yields favorable measured chemical attributes, without claiming demonstrated gains in farmer income, consumer acceptance, market performance, or conservation outcomes. From a conservation-through-use perspective, the logic is that if locally maintained crops can be processed cheaply into products with strong chemical profiles, farmers have more reason to keep growing them, which in turn keeps diverse local populations in production.

What happens next depends on replication. The authors call for future studies with independently replicated drying units for every treatment, repeated across production cycles and locations, and with direct environmental monitoring, drying curves, water activity measurements, instrumental color data, microbiological stability testing, sensory evaluation, and detailed profiles of individual phenolics and anthocyanins. Economic and adoption indicators would complete the picture, since a technically superior drying method matters little if it is too costly or labor-intensive for the smallholders it is meant to serve. For now, the study stands as a measured argument that the cheapest technology on the farm, a raised bed and a sheet of shade cloth, deserves a place in the conversation about how tropical crops keep their chemistry, and their value, after the harvest.

Subject of Research: Effects of postharvest drying methods on bioactive compounds and antioxidant capacity in a farmer-maintained roselle population in Chiapas, Mexico

Article Title: Postharvest drying of a farmer-maintained roselle population in Chiapas, Mexico: bioactive compounds and antioxidant capacity

Article References: Trujillo-Robles, T. A., Jiménez-Martínez, C., Sánchez Chino, X. M., Martínez-Herrera, J., León-Martínez, N. S., Castellanos-Albores, J., & Olivo-Vidal, Z. E. (2026). Postharvest drying of a farmer-maintained roselle population in Chiapas, Mexico: bioactive compounds and antioxidant capacity. Frontiers in Conservation Science, 7, Article 1978755. https://doi.org/10.3389/fcosc.2026.1978755

Image Credits: AI Generated

DOI: 10.3389/fcosc.2026.1978755

Keywords: roselle, Hibiscus sabdariffa, postharvest drying, anthocyanins, antioxidant capacity, agrobiodiversity, smallholder agriculture, Chiapas, phenolic compounds, shade drying, food chemistry, crop conservation