Celery (Apium graveolens L.), coriander (Coriandrum sativum L.) and parsley (Petroselinum crispum) were purchased from a commercial market in Alexandria, Egypt, and their aerial parts were extracted separately with methanol. Each methanolic extract was then partitioned into a methylene chloride fraction and an aqueous mother liquor. The biological tests used 20 uropathogenic E. coli isolates obtained from private laboratories in Alexandria. Susceptibility testing showed that every isolate was resistant to amoxicillin-clavulanic acid, doxycycline and nalidixic acid, while all were susceptible to ertapenem, imipenem and meropenem. Twelve isolates were classified as strong biofilm formers, four as intermediate formers and four as non-biofilm formers.

The antibacterial results varied markedly among the herbs and fractions. Coriander’s total methanolic extract and aqueous mother liquor each produced a minimum inhibitory concentration of 3.75 micrograms per millilitre, the lowest value reported for the plant preparations. Its methylene chloride fraction required 100 micrograms per millilitre. Celery was less active: the total methanolic extract had a minimum inhibitory concentration of 50 micrograms per millilitre, while its aqueous mother liquor reached 25 micrograms per millilitre and its methylene chloride fraction showed no detectable activity under the tested conditions. Parsley’s total extract and aqueous mother liquor likewise had no detectable activity, although its methylene chloride fraction inhibited growth at 100 micrograms per millilitre. Ciprofloxacin and norfloxacin had minimum inhibitory concentrations between 0.9 and 1.9 micrograms per millilitre alone. When combined with coriander extract, the effects were described as additive, with no evidence of synergism or antagonism in the tested combinations.

Untargeted metabolomics produced markedly different profiles for the three herbs. Analyses were run in positive and negative electrospray ionization modes and incorporated retention time, accurate mass, predicted molecular formulas and tandem mass-spectrometry fragmentation patterns. Compound detection and processing initially yielded 4,861 features in negative mode and 3,155 in positive mode; after peak detection, deisotoping, chromatographic alignment and filtering, 580 and 512 aligned features, respectively, remained for chemometric analysis. The final annotation included flavonoids and glycosides, isoflavones, phenolic acids, coumarins, amino-acid derivatives, fatty acids and lipids, chlorins and a lignan. All 167 annotations were assigned level 2 confidence, meaning they were tentative identifications supported by library or literature spectral matches rather than confirmed with authentic standards.

Coriander had the richest and most diverse flavonoid and phenolic profile in this analysis. Its extracts contained quercetin, multiple quercetin conjugates, apigenin glucuronide, luteolin-7-O-glucoside, kaempferol-3-O-glucorhamnoside, several caffeoylquinic-acid derivatives, ferulic acid and assorted coumarins. Celery was distinguished by compounds including apiin, luteolin and apigenin conjugates, 4,5-dicaffeoylquinic acid and the coumarin marmesin. Parsley contained numerous furanocoumarins, including cnidilin, 5-hydroxyxanthotoxin, pinnatin, bergaptol and isoimperatorin, as well as rhamnetin and isorhamnetin conjugates. The researchers also detected chlorin-related molecules in all three herbs and the lignan eucommicin A in celery and coriander.

Principal component analysis, hierarchical cluster analysis and partial least squares discriminant analysis separated the three samples according to their metabolite profiles. In negative-ion mode, the first two principal components accounted for 95% of the observed variability, and the samples formed three distinct clusters. Coriander was associated with high levels of quercetin 3-O-rutinoside, eucommicin A and several hydroxylated C18 fatty acids, including three trihydroxy-octadecaenoic-acid features and hydroxy-octadecatrienoic- and hydroxy-octadecadienoic-acid features. Celery was associated with apiin, luteolin 7-O-apiosylglucoside, pyroglutamic acid, lunularic acid and a glycerophosphoinositol. Parsley was distinguished by fructose-phenylalanine and features including bergaptol. Supervised models separating celery from parsley reported R² and Q² values of 0.99 in both ionization modes, although the limited set of triplicate samples means these internal performance values should not be confused with independent validation.

Partial least squares regression then related metabolite abundance to the measured minimum inhibitory concentrations. The negative-ion model had cumulative R² of 0.92 and Q² of 0.87, while the positive-ion model had R² of 0.94 and Q² of 0.83. In both models, coriander’s metabolite pattern was inversely positioned relative to minimum inhibitory concentration, whereas parsley lay closest to the values associated with inactivity. Prominent variables associated with antibacterial activity included quercetin 3-O-rutinoside, trihydroxy-octadecaenoic-acid isomers, hydroxy-octadecatrienoic acid, hydroxy-octadecadienoic acid and eucommicin A. Positive-ion analysis additionally highlighted furanocoumarin hexosides, a methoxy-ethoxycarbonyl coumarin and a chlorin-related compound, 132-hydroxypheophorbide-A methyl ester. These are statistical associations within extract-level data, not demonstrations that any individual metabolite caused the observed inhibition.

All tested plant preparations also inhibited biofilm formation, whether used alone or in combinations with ciprofloxacin or norfloxacin. Biofilm mass was measured after 24 hours by fixing the attached biomass with methanol, staining it with crystal violet, releasing the dye with acetic acid and measuring absorbance at 630 nanometres. The study reported significant reductions in biofilm mass across the extract and antibiotic-combination conditions, including tests with sub-minimum-inhibitory-concentration levels of the plant extracts. The researchers discussed several possible contributors, including quercetin derivatives, phenolic compounds and coumarins that have activity against cell membranes, quorum sensing, extracellular polymeric substances and other biofilm-maintenance processes in earlier studies. Those mechanisms remain hypotheses for the herb extracts tested here, which were not separated into constituent compounds during the assays.

The bacterial collection also displayed several virulence-associated genes, adding context to the laboratory model. The fimH gene was present in 80% of the isolates, afa genes in 90%, papC in 76% and hly genes in 76%; the cytotoxic necrotizing factor gene occurred in 35%. These findings characterize the tested isolates but do not show that the herbal preparations affect the corresponding virulence traits. Moreover, the experiments were performed in vitro with commercial plant material, methanol-derived fractions and an artificial biofilm assay. They did not examine pharmacokinetics, host toxicity, urinary concentrations, treatment outcomes or the possibility of interactions with conventional drugs in patients.

For that reason, the results are best understood as a chemical and activity map for future research. The strongest candidates identified for isolation include quercetin 3-O-rutinoside, trihydroxy-octadecaenoic acid, hydroxy-octadecatrienoic acid, hydroxy-octadecadienoic acid and eucommicin A, together with selected coumarins and chlorin-related metabolites. The authors propose purifying these compounds, confirming their structures with authentic standards and complementary analytical methods, and testing them individually and in combinations against multidrug-resistant uropathogenic E. coli. Mechanistic work, cytotoxicity and selectivity assessments, and testing in appropriate in-vivo urinary tract infection models would still be required before any therapeutic or preventive application could be considered.

Subject of Research: Metabolite profiles associated with antibacterial and antibiofilm activity of celery, coriander and parsley against multidrug-resistant uropathogenic E. coli

Article Title: Integrative metabolomics and chemometric analysis reveal metabolites associated with antibacterial and antibiofilm activities of celery, Coriander, and parsley against multidrug-resistant uropathogenic Escherichia coli

Article References: Abdel-dayem, S. I. A., El Gedaily, R. A., Eltanany, B. M., Seiffein, N. L., Hani, G. A., Afifi, S. M., & Ali, D. E. (2026). Integrative metabolomics and chemometric analysis reveal metabolites associated with antibacterial and antibiofilm activities of celery, Coriander, and parsley against multidrug-resistant uropathogenic Escherichia coli. BMC Complementary Medicine and Therapies, 26(1), Article 313. https://doi.org/10.1186/s12906-026-05610-0

Image Credits: AI Generated

DOI: 10.1186/s12906-026-05610-0

Keywords: Uropathogenic E. coli, Multidrug resistance, Antibiofilm activity, Coriander, Metabolomics, Plant extracts, Quercetin, Fatty acids, Urinary tract infections, Integrative, chemometric, analysis

The strongest activity was measured in essential oils of Monarda fistulosa, Satureja pilosa, Origanum vulgare subsp. hirtum and Thymus longidentatus, together with a methanolic extract of Leucojum aestivum. The study examined methanolic extracts and essential oils from 17 plant species in the Amaryllidaceae, Asteraceae, Brassicaceae and Lamiaceae families.

Plant material was collected from natural localities or obtained from the Institute of Biodiversity and Ecosystem Research and the Institute of Roses and Aromatic Plants. For methanolic extraction, 1 g of air-dried, powdered plant material was extracted with methanol for 24 hours at room temperature. After filtration, the solution was evaporated and the dry extract was stored at 4 °C until analysis. Essential oils were extracted by water distillation on a Clevenger apparatus using 50 g of dry plant material and 500 ml of water over two hours.

Acetylcholinesterase inhibition was measured using a modified version of Ellman’s colorimetric method in 96-well microplates. The assay used acetylcholinesterase from the electric eel Electrophorus electricus, acetylthiocholine iodide as the substrate, and 5,5′-dithiobis(2-nitrobenzoic acid). Samples were tested at concentrations between 0.001 and 1,000 µg/ml and incubated for 30 minutes at room temperature before substrate was added. Absorbance was measured at 405 nanometres after three minutes, and inhibition was calculated relative to a buffer control. Galanthamine served as the positive control.

Among the essential oils, M. fistulosa had the lowest reported half-maximal inhibitory concentration, or IC50, at 0.0042 mg/ml. The oil of S. pilosa followed at 0.0069 mg/ml. The O. vulgare subsp. hirtum and T. longidentatus oils had IC50 values of 0.30 and 0.72 mg/ml, respectively, while the L. aestivum methanolic extract had a value of 0.20 mg/ml. The galanthamine positive control had an IC50 of 0.0011 mg/ml, equivalent to 4.03 µM. IC50 values were measured in triplicate and reported as means.

A second group of seven methanolic extracts showed moderate activity, with IC50 values from 0.73 to 1.23 mg/ml. These extracts came from O. vulgare subsp. hirtum, Artemisia lerchiana, Artemisia santhonicum, Eupatorium cannabinum, Nepeta caria, Micromeria dalmatica and Salvia aethiopis. Several other samples had IC50 values above 1 mg/ml. For O. vulgare subsp. hirtum, the measured inhibition was stronger for the essential oil than for its methanolic extract.

The researchers used gas chromatography coupled with mass spectrometry to characterize compounds in the most active samples. Components were identified by comparing mass spectra and retention indices with authentic standards and a National Institute of Standards and Technology library. Carvacrol and thymol were major constituents of the essential oils of S. pilosa, O. vulgare subsp. hirtum and M. fistulosa. Carvacrol accounted for 51.18% of the oregano oil and 50.54% of the S. pilosa oil. Thymol represented 30.58% of the S. pilosa oil and 19.75% of the M. fistulosa oil. The M. fistulosa oil also contained thymoquinone at 25.41% and p-cymene at 21.82%.

In the T. longidentatus essential oil, the citral isomers neral and geranial accounted for 24.9% and 27.96% of the identified area. Galanthamine was the main alkaloid detected in the L. aestivum extract. The oregano methanolic extract contained carvacrol at 15.67%, compared with 51.18% in its essential oil, along with rosmarinic acid, flavonoid glycosides, malic acid and catechin. The authors noted that the difference in carvacrol content may be related to the difference in acetylcholinesterase inhibition, but the assay did not establish that individual compounds caused the measured effects.

The evidence in this study comprises in vitro enzyme measurements and GC/MS chemical characterization of selected samples. It does not demonstrate that the plant products kill or repel insects, protect crops under field conditions, or avoid effects on non-target organisms. The authors described the strong acetylcholinesterase activity as a prerequisite for potential insecticidal activity and recommended testing the plant products for insecticidal effects.

Subject of Research: In vitro acetylcholinesterase inhibition and chemical characterization of plant extracts and essential oils

Article Title: Plant products with acetylcholinesterase inhibitory activity for insect control

Article References: Georgiev, B., Nikolova, M., Aneva, I., Dzhurmanski, A., Sidjimova, B., & Berkov, S. (2022). Plant products with acetylcholinesterase inhibitory activity for insect control. BioRisk, 17, 309-315. https://doi.org/10.3897/biorisk.17.77052

Image Credits: AI Generated

DOI: 10.3897/biorisk.17.77052

Keywords: acetylcholinesterase inhibition, plant extracts, essential oils, in vitro assay, gas chromatography-mass spectrometry, insect control, carvacrol, thymol, galanthamine, Plant, products, acetylcholinesterase

The researchers compared extracts prepared from aboveground material collected from plants growing in their natural habitat near Sinemorets, Bulgaria, plants maintained in vitro, and plants adapted to an experimental field. The extracts did not show a clear overall relationship between cultivation setting and antimicrobial activity. Instead, their patterns of inhibition varied among microbial strains, with no consistent activity advantage associated with any one source of plant material.

To establish an in vitro collection, the team sterilized ripe, dried seeds with 70% ethanol for five minutes, placed them on a water-and-agar germination medium and transferred sprouting seedlings to Murashige and Skoog medium supplemented with 3% sucrose and 0.7% agar but no growth regulators. Cultures were maintained under controlled conditions with 16 hours of light and eight hours of darkness, a photosynthetic photon flux density of 60 mmol/(m²s), a temperature of 25 °C and 60–70% relative humidity.

Regenerated plants developed abundant leaf biomass and well-developed roots, permitting acclimation in three stages: one month in a phytotron chamber, one month in a greenhouse and subsequent planting at the experimental field of Sofia University “St. Kliment Ohridski.” Plants maintained at that site had an observed survival rate of 83%. This demonstrates that the researchers could multiply the species in vitro and transfer regenerated plants to an outdoor experimental site, although the study did not directly measure long-term persistence, genetic diversity, population-level performance or conservation of the species in the wild.

For antimicrobial testing, the investigators finely powdered three grams of dried aboveground material from each of the three plant sources. After triple sonication with chloroform, the biomass was extracted three times with methanol for 30 minutes. The resulting extracts were concentrated in a vacuum evaporator and dried to constant weight. Reported yields were 13.8% for wild material, 28.46% for in vitro material and 13.6% for field-adapted material. Each dried extract was dissolved in 5% dimethyl sulfoxide; the study did not establish whether the higher yield from in vitro material reflected increased production of antimicrobial compounds.

The extracts were tested against seven Gram-negative bacterial strains—Pseudomonas aeruginosa, Proteus mirabilis, Proteus hauseri, Enterobacter cloacae, Acinetobacter calcoaceticus, Escherichia coli and Klebsiella pneumoniae—three Gram-positive strains—Staphylococcus aureus, Staphylococcus epidermidis and Enterococcus faecalis—and the yeast Candida albicans. The bacteria were cultured overnight on Mueller-Hinton agar, while the yeast was cultured on Sabouraud dextrose agar. Initial screening used paper disks containing 8 mg of extract. Tetracycline and amikacin were positive controls for bacteria, nystatin was the positive control for C. albicans, and 5% dimethyl sulfoxide served as a negative control.

Plates were incubated for 24 hours for bacteria and 48 hours for the yeast, and inhibition zones were measured. Bacterial strains that appeared sensitive in this screen were then examined by micro-well dilution to determine minimum inhibitory concentrations. Extract concentrations ranged from 64 to 2 mg/ml before bacterial suspensions were added. Across the three plant sources, activity was detected against four tested organisms: A. calcoaceticus, K. pneumoniae, P. mirabilis and E. faecalis.

All three extracts inhibited A. calcoaceticus with minimum inhibitory concentrations of 8 mg/ml. The highest reported minimum inhibitory concentration was 16 mg/ml against K. pneumoniae, for which the smallest inhibition zone was 7 mm. P. aeruginosa produced zones described as bacteriostatic in the disk-diffusion assay, but activity was not detected in the microdilution assay. No extract showed activity against C. albicans. Overall, the extracts tended to be more active against Gram-negative than Gram-positive bacteria, although most tested strains were resistant to one or more extracts and the results did not establish a consistent advantage associated with a particular cultivation method.

The findings support the use of in vitro propagation and field acclimation as an experimental approach for maintaining this rare species while studying its biological activity. However, the evidence is limited to laboratory testing of methanolic extracts and the establishment of propagated plants; it does not establish therapeutic benefit in humans or animals, safety, or effectiveness as a conservation measure over long periods. The authors concluded that analysis of the plant’s chemical profile would be needed to determine which compounds were associated with the measured antimicrobial activity.

Subject of Research: Laboratory comparison of antimicrobial activity in Stachys thracica extracts from three cultivation settings

Article Title: Comparative determination of antimicrobial activity of the Balkan endemic species Stachys thracica Davidov during the process of ex situ conservation

Article References: Mantovska, D., Petrova, D., Yocheva, L., & Yordanova, Z. (2022). Comparative determination of antimicrobial activity of the Balkan endemic species Stachys thracica Davidov during the process of ex situ conservation. BioRisk, 17, 357-365. https://doi.org/10.3897/biorisk.17.77484

Image Credits: AI Generated

DOI: 10.3897/biorisk.17.77484

Keywords: Stachys thracica, Thracian woundwort, antimicrobial activity, plant extracts, in vitro propagation, ex situ conservation, Acinetobacter calcoaceticus, Gram-negative bacteria, microdilution assay, Comparative, determination, antimicrobial

The ethanol extract was prepared by mixing 10 g of powdered plant material with 100 mL of 70% ethanol and shaking the mixture for 24 hours at 21 ± 2 °C in darkness. After filtration and solvent evaporation, the extract was sterilized with ultraviolet light for 20 minutes and stored at 4 °C. Essential oil was obtained by water-distilling 100 g of dried powder for two hours with a Clevenger apparatus.

Gas chromatography-mass spectrometry identified nine compounds in the leaf essential oil and eight in the stem essential oil. The most abundant leaf-oil constituents were hexadecanoic acid at 8.08%, neophytadiene at 7.54% and phytol at 6.11%. In the stem oil, 2-methoxyphenol accounted for 7.01% and 3-(2-naphthyl)-1-butene for 5.15%.

The leaf extract contained nine identified compounds, led by 9,12,15-octadecatrien-1 at 12.29%, phytol at 10.39% and 9,12,15-octadecatrienoic acid at 9.84%. The stem extract also contained nine compounds, including toluene at 17.41%, hexadecanoic acid at 12.06% and cyclotrisiloxane at 10.50%. Antimicrobial assays used the standard strains Escherichia coli PTCC 1789, Pseudomonas aeruginosa PTCC 1791, Staphylococcus aureus PTCC 1826 and A. baumannii PTCC 1919.

In disk-diffusion tests, the preparations produced inhibition zones ranging from 14 to 44 mm. The leaf extract produced the largest zones against E. coli , P. aeruginosa and A. baumannii , at 44, 44 and 41.5 mm, respectively. S. aureus was the least susceptible in this assay: the largest zone against it was 18.5 mm, produced by the leaf extract.

In broth macro-dilution testing, minimum inhibitory concentrations ranged from 3.12 to 25 mg/mL across the preparations and bacteria. All four preparations had an MIC of 6.25 mg/mL against E. coli . The stem extract had an MIC of 6.25 mg/mL against P. aeruginosa , compared with 25 mg/mL for the other preparations.

Leaf essential oil was the most inhibitory against A. baumannii , with an MIC of 3.12 mg/mL, compared with 25 mg/mL for both extracts and stem essential oil. Against S. aureus , leaf essential oil, leaf extract and stem extract each had an MIC of 3.12 mg/mL, while stem essential oil had an MIC of 6.25 mg/mL. Minimum bactericidal concentrations were 12.5 mg/mL for all preparations against E. coli .

Against P. aeruginosa , leaf essential oil and stem essential oil required 50 mg/mL, while leaf extract and stem extract required 12.5 mg/mL. For A. baumannii , leaf essential oil had a minimum bactericidal concentration of 6.25 mg/mL, whereas leaf extract, stem extract and stem essential oil required 50 mg/mL. Against S. aureus , leaf essential oil, leaf extract and stem extract had values of 6.25 mg/mL, compared with 12.5 mg/mL for stem essential oil.

Additional experiments focused on leaf essential oil and A. baumannii . In a 96-well biofilm assay, the oil inhibited biofilm formation at higher tested concentrations. An ethidium-bromide efflux assay indicated that sub-MIC concentrations reduced the rate of dye pumping.

Real-time quantitative PCR was then used to assess expression of bap , abeM and adeB . Following treatment with 1.56 mg/mL leaf essential oil, expression relative to untreated controls was reduced by 25% for bap , 70% for abeM and 65% for adeB . The analyses were repeated three times, and statistical comparisons used one-way analysis of variance followed by Tukey’s test at P ≤ 0.05.

In the cell-culture experiment, researchers exposed MCF-7 cells to leaf essential oil at concentrations from 1.56 to 50 mg/mL for 24 to 72 hours. In the MTT procedure, purple formazan crystals were dissolved in dimethyl sulfoxide, and the measured optical density was directly proportional to the number of living cells. Viability decreased as the essential-oil dose increased.

The reported half-maximal inhibitory concentration was 4.66 µg/mL after 48 hours. This was an assay of one cell line and did not test anticancer effects in animals or people. The study provides chemical and laboratory activity data for plant material collected from one location, and the antimicrobial experiments used standard strains rather than a broader clinical-isolate collection.

The tested preparations also differed in composition, so the results do not identify which individual compound produced each effect. The authors stated that the essential oils and extracts show antimicrobial activity and that leaf essential oil affected the MCF-7 cell line, while further studies are warranted. Their suggestion that the preparations might be used alone or with antibiotics remains a prospect requiring additional research rather than a demonstrated clinical outcome.

Subject of Research: In vitro chemical and biological activity of Lycium shawii extracts and essential oils

Article Title: Detection of compounds in the essential oil and extract of Lycium shawii : Investigation on their anticancer, antimicrobial, antibiofilm and anti-efflux activities

Article References: Torabi, F., Hashemabadi, D., Kaviani, B., & Asadpour, L. (2025). Detection of compounds in the essential oil and extract of Lycium shawii: Investigation on their anticancer, antimicrobial, antibiofilm and anti-efflux activities. Italian Botanist, 20, 23-40. https://doi.org/10.3897/italianbotanist.20.138138

Image Credits: AI Generated

DOI: 10.3897/italianbotanist.20.138138

Keywords: Lycium shawii, essential oils, plant extracts, antibacterial activity, Acinetobacter baumannii, biofilm inhibition, efflux pumps, MCF-7 cells, in vitro study, Detection, compounds, essential

Biostimulants occupy a curious regulatory and scientific niche. Unlike fertilizers, they are not defined primarily by the nutrients they deliver, and unlike pesticides, they do not kill pests directly. Instead, as the review emphasizes, they regulate plant metabolism. The authors stress that plant-derived extracts almost never act through a single active constituent. A typical extract is a dense biochemical cocktail containing phytohormone-like compounds, antioxidants, osmoprotectants, phenolics, oligosaccharides, fatty acids, proteins and peptides. This compositional complexity is not a nuisance to be purified away; it is the point. Multiple molecules converge on multiple signaling pathways simultaneously, producing effects that no isolated compound could replicate.

The mechanistic core of the review centers on hormone signaling. Extracts modulate the major stress hormones of plants, including abscisic acid, salicylic acid, jasmonic acid and ethylene, which together orchestrate everything from stomatal closure during drought to the activation of pathogen defenses. Transcriptomic studies cited in the review show that treatment with extracts such as those from Ascophyllum nodosum, a brown seaweed long used in commercial biostimulant products, upregulates stress-responsive genes in crops ranging from Arabidopsis to soybean and tomato. In effect, the extracts behave like a training signal, priming the plant’s own defense machinery so that when real stress arrives, the response is faster and stronger.

Beyond hormones, the review catalogues a suite of physiological adjustments that extracts induce. Treated plants accumulate more osmolytes, small compatible solutes such as proline and glycinebetaine that help cells retain water and maintain turgor under drought or salt stress. Antioxidant defenses are strengthened, allowing plants to neutralize the reactive oxygen species that spike when photosynthesis is disrupted. Ionic homeostasis is restored, helping roots exclude sodium or compartmentalize it away from sensitive metabolic machinery. Perhaps most intriguingly, the review highlights evidence that extracts regulate water transport through aquaporins, the membrane channels that control the flow of water across plant cells, offering a direct physical route to improved drought tolerance.

The review also draws attention to the rhizosphere, the teeming microbial zone around plant roots. Extracts influence rhizosphere interactions and microbiome dynamics, according to the authors, thereby improving nutrient acquisition and systemic resilience. Studies combining seaweed extracts with plant growth-promoting rhizobacteria in wheat, rice, onion and cucumber report synergistic effects on growth and yield that neither partner achieves alone. This reframes biostimulants not merely as foliar tonics but as ecosystem engineers that reshape the underground communities on which crop nutrition depends, a perspective increasingly central to soil health science.

Case studies across stress types give the review its agronomic weight. Under drought, moringa leaf extract has improved rice yield and grain quality through enhanced antioxidant activity, while seaweed extract has bolstered sugarcane drought resistance by modulating root architecture and soil properties. Under salinity, extracts from Ascophyllum, willow, licorice root and grape seed have each improved photosynthetic stability and ion balance in crops such as tomato, maize, pea and faba bean. Heat stress studies in wheat and maize report that moringa and sorghum water extracts preserve photosynthetic pigments, while cold stress trials in barley and tomato show brown seaweed extracts triggering cold-acclimation gene expression. Biotic stress studies add another layer, with laminarin from brown algae eliciting grapevine defenses against downy mildew and botrytis, and seaweed extracts reducing fungal disease on carrot foliage.

Application strategy emerges as a critical variable. The review distinguishes between foliar sprays, seed priming and soil drenching, noting that dose, timing and method can determine whether an extract helps or does nothing at all. Seed priming with moringa leaf extract has reduced chilling injury in spring maize and improved rice seedling establishment under water deficit, while foliar application has induced terminal heat tolerance in quinoa. Processing matters too: the review notes that extraction methods, from mechanical disruption to enzyme-assisted techniques, shape which phytochemicals survive into the final product, and that even storage temperature can alter cytokinin and auxin concentrations in seaweed concentrates.

The most forward-looking section concerns nanotechnology. Plant-mediated nanoparticles and nano-formulations, the authors report, improve the stability, delivery efficiency and bioavailability of bioactive phytochemicals. Examples span the emerging literature: Sargassum-synthesized zinc oxide nanoparticles inducing salt tolerance in maize, neem-mediated silver nanoparticles improving drought-stressed soybean growth, Spirulina-derived carbon dots used for seed nanopriming in rice, and nano-encapsulated biostimulants enhancing photosynthetic efficiency in heat-stressed peppers. Nano-encapsulation can also protect volatile or easily degraded compounds, such as essential oils, from rapid environmental loss. The authors caution, implicitly, that nanoparticle-plant interactions, including uptake, transport and potential toxicity, remain active areas of investigation, and that environmental implications must be weighed alongside agronomic gains.

What emerges from the synthesis is a picture of plant-derived biostimulants as systems-level interventions rather than simple inputs. A single seaweed extract may simultaneously adjust hormone signaling, boost antioxidant capacity, alter root growth, feed beneficial microbes and prime defense genes, all without introducing novel genetic material or synthetic chemistry. For farmers facing increasingly erratic rainfall, salinizing soils and heat waves, this profile is attractive precisely because it works with the plant’s existing physiology rather than overriding it. The review’s case studies consistently report improvements in photosynthetic stability, stress tolerance and yield under optimized application strategies, suggesting that the gap between laboratory promise and field performance is narrowing.

The authors close with a research agenda that reads like a roadmap for the next decade of the field. Future progress, they argue, will require integrating multi-omics approaches, combining transcriptomics, metabolomics and proteomics to resolve exactly which molecules in a complex extract drive which responses, alongside microbiome profiling to track how extracts reshape root communities over time, and precision nanotechnology to deliver the right bioactive to the right tissue at the right moment. If that integration succeeds, the humble plant extract, long dismissed as folk agronomy, could become a cornerstone of sustainable agriculture, helping crops weather a climate that is growing less forgiving by the season.

Subject of Research: Mechanisms of plant-derived biostimulants in enhancing crop stress tolerance and sustainable agriculture

Article Title: Mechanistic insights into plant-derived biostimulants for sustainable agriculture and stress tolerance

Article References: Mishra, A., Bhatt, U., & Soni, V. (2026). Mechanistic insights into plant-derived biostimulants for sustainable agriculture and stress tolerance. Plant Biosystems, 160(6), Article 295. https://doi.org/10.1007/s44473-026-00314-2

Image Credits: AI Generated

DOI: 10.1007/s44473-026-00314-2

Keywords: biostimulants, plant extracts, seaweed extracts, abiotic stress, drought tolerance, salinity stress, phytohormones, antioxidants, nanotechnology, soil microbiome, sustainable agriculture, moringa oleifera

The research team set out to test whether extracts from the seeds of this hardy savanna tree could control Colletotrichum capsici, the fungus responsible for cowpea anthracnose. In Cameroon, the disease is a major driver of yield losses estimated between 45 and 85 percent, and farmers typically respond with synthetic chemical pesticides. Those products, while effective, carry well-documented drawbacks: they can be costly for smallholder farmers, and their intensive use raises concerns about environmental contamination and risks to human and animal health. Biopesticides derived from locally available plants offer a biodegradable, low-toxicity alternative, and the desert date tree has a long history of biological activity, with prior studies attributing insecticidal, fungicidal, antimicrobial, and vermicidal properties to its bark, roots, and seeds.

The trials took place in Akonolinga, in agro-ecological zone V of Cameroon, a forest zone with bimodal rainfall where the sub-equatorial climate delivers roughly 1,633 millimeters of rain per year across two rainy seasons, with average temperatures of 23 to 27 degrees Celsius and humidity around 80 percent. The site, left fallow for four years, sits on acidic, lateritic, sandy loam ferralitic soils. Researchers from the study worked with two improved cowpea varieties supplied by the Institute of Agricultural Research for Development: V1, called Tiligré, a 70-day cycle variety, and V2, Lori 24-130, which is notably resistant to insect pests. Both varieties carry strong yield potential of 1,500 to 2,000 kilograms per hectare.

The experimental design was a split-plot layout with four replicates spread over 400 square meters. The two varieties formed the main plots, while five treatments occupied randomized sub-plots: an untreated control, an aqueous seed extract, an acetone extract, a methanol extract, and a synthetic fungicide containing 80 percent maneb. Each experimental unit measured roughly 3 by 2 meters and contained three rows sown at 80 by 40 centimeter spacing. The trials ran across two growing campaigns, in 2020 and 2021, allowing the team to assess consistency under natural field conditions.

Preparing the extracts was a hands-on process. Mature desert date fruits were collected beneath the trees, stripped of their outer layers by soaking, sun-dried, and crushed to obtain the kernels. The almond-like seeds were then milled into powder. For the aqueous extract, 500 grams of powder macerated in 5 liters of water for at least 24 hours, producing a 100 gram per liter solution that was filtered through muslin cloth and loaded into a backpack sprayer with powdered soap as a wetting agent to improve adhesion to plant surfaces. The organic extracts required macerating 500 grams of powder in 2 liters of acetone or methanol at 70 degrees Celsius for 48 hours, followed by filtration and concentration in a rotary evaporator until essential oils were obtained. All extracts were diluted at a rate of 7 milliliters per liter of water before application. The pathogen itself was confirmed by culturing infected pods on potato dextrose agar and examining the fungus microscopically, where C. capsici reveals its signature gray mycelial mass, black bristles protruding from conidial masses, and unicellular, hyaline, falcate conidia.

The results were striking. By nine weeks after sowing in the 2020 campaign, disease incidence in untreated control plots climbed to 75.38 percent for Tiligré and 76.01 percent for Lori 24-130. In plots treated with the aqueous extract, incidence fell to 20.91 and 28.24 percent respectively, while acetone extract plots recorded 22.75 and 29.28 percent. The synthetic fungicide still led with 14.6 and 14.19 percent. But in the 2021 campaign, the story shifted: the aqueous, acetone, and methanol extracts all outperformed the fungicide, recording incidence as low as 19.13, 19.25, and 17.93 percent for Tiligré, compared with 25.54 percent for the maneb treatment. Control plots reached 79.06 percent. All differences were statistically significant at P less than 0.001 across varieties, treatments, and their interaction.

Severity, the degree to which leaves, stems, and pods were attacked, followed a similar trajectory. In 2021 at nine weeks after sowing, aqueous extract plots recorded severity of just 10.6 percent for Tiligré and 20.48 percent for Lori 24-130, acetone plots 12.2 and 12.3 percent, and methanol plots 11.63 and 14.39 percent. Untreated plots suffered severity of 64.14 and 59.82 percent. The fungicide plots recorded 9.78 and 9.1 percent in 2020 and 27.03 and 9.47 percent in 2021, meaning the plant extracts matched or exceeded the chemical standard in the second season. The researchers suggest the mechanism likely involves biochemical compounds in the extracts forming complexes with polysaccharides and proteins on the outer layer of fungal cells, destabilizing cell membrane function and leading to pathogen death, though the precise mode of action remains unclear.

Yields told an equally compelling story. In 2020, aqueous extract plots produced 794.05 kilograms per hectare for Tiligré and 926.63 for Lori 24-130, compared with just 518.03 and 545.055 kilograms in control plots. Acetone and methanol extracts delivered similar gains, with acetone reaching 859.15 and 860.23 kilograms per hectare. In 2021, the pattern held, with aqueous extract plots yielding 852.97 and 935.79 kilograms per hectare and acetone plots 823.69 and 961.68, against control yields of 385.37 and 760.47. The fungicide still produced the highest yields in some plots, reaching 1,050.68 kilograms per hectare for Lori 24-130 in 2021, but the plant extracts closed much of the gap. Across both campaigns, the Lori 24-130 variety proved the most productive overall.

Multivariate analyses reinforced the picture. Principal component analysis captured 86.45 percent of total variability in 2020 and 91.27 percent in 2021 on the first two axes, consistently separating untreated control plots, which clustered near high incidence and severity, from treated plots, which grouped with favorable growth parameters such as leaf number, plant height, collar diameter, and high yield. Cluster analysis produced the same dichotomy, with control treatments isolated from all extract and fungicide treatments. The data show that the desert date seed extracts reduced disease and increased yields in the same way as the chemical fungicide during both campaigns.

The findings position Balanites aegyptiaca seed extracts as a viable component of integrated pest management for cowpea anthracnose. Because the tree is locally available across the Sahel and savanna zones, its seeds can be harvested, processed, and applied by the very farmers who need them, at a fraction of the cost of imported chemicals. The extracts are biodegradable and carry low toxicity for humans and the environment, addressing the core criticisms of synthetic pesticide overuse. As cowpea continues to feed millions across Africa’s arid and semi-arid belts, where few other crops thrive, a simple water-based extract from a desert tree could prove one of the most practical tools yet for keeping anthracnose at bay and harvests secure.

Subject of Research: agricultural science

Article Title: Bio-effectiveness of Balanites aegyptiaca (L.) Del. seed extracts against Colletotrichum capsici (Syd.) Butler & Bisby causal agent of anthracnose in cowpeas ( Vigna unguiculata (L.) Walps.) under natural conditions

Article References: Tize, T., Ngatsi, P. Z., Lontsi Dida, S. L., Njome Toka, A., Songwe Atindo, T., Ndongo, E. B., Sale Essome, C., & Ndongo, B. (2024). Bio-effectiveness of Balanites aegyptiaca (L.) Del. seed extracts against Colletotrichum capsici (Syd.) Butler & Bisby causal agent of anthracnose in cowpeas (Vigna unguiculata (L.) Walps.) under natural conditions. Innovations in Agriculture, 7, 1-9. https://doi.org/10.3897/ia.2024.131803

Image Credits: AI Generated

DOI: 10.3897/ia.2024.131803

Keywords: cowpea, anthracnose, Balanites aegyptiaca, biopesticide, Colletotrichum capsici, Cameroon, plant extracts, integrated pest management, food security, sustainable agriculture, Bio-effectiveness, Balanites

The research began with a systematic bioprospecting exercise. Fifteen species were selected from the Qinling Mountains on the basis of local abundance and regional representativeness, ranging from familiar solanaceous herbs to Allium species, legumes and Asteraceae shrubs. Plant material was rinsed, air-dried, oven-dried at 45 degrees Celsius, ground and sieved before being extracted with ninety-five percent ethanol at a solid-to-liquid ratio of one to four for forty-eight hours, with the process repeated twice on the residue. The combined filtrates were concentrated on a rotary evaporator to yield crude extracts, which were then dissolved into stock solutions and diluted to test concentrations. This simple but rigorous pipeline allowed the team to compare all fifteen species on an equal footing before committing resources to any single candidate.

Laboratory bioassays were built around three complementary measures of pest suppression: direct larvicidal toxicity, antifeedant activity and oviposition repellency. For the toxicity screen, five-centimeter cabbage leaf discs were dipped in each extract at fifty milligrams per milliliter, air-dried, and offered to twenty starved third-instar larvae per dish, with mortality scored at twenty-four, forty-eight and seventy-two hours. The results revealed striking interspecific differences and a clear time-dependent pattern. At twenty-four hours, Atropa belladonna extract already led the field with a corrected mortality of 58.87 percent, well ahead of Asparagus dauricus, Allium ochotense, Tupistra wattii and Blumea riparia var. megacephala. By seventy-two hours, A. belladonna had reached 83.11 percent, the only extract to break the eighty percent barrier, while B. riparia var. megacephala climbed to 73.53 percent. Ten of the fifteen extracts never exceeded fifty percent mortality, and Solanum nigrum was barely distinguishable from the ethanol control.

The behavioral assays told an equally compelling story. In the leaf-disc antifeedant test, smaller treated and untreated discs were offered to larvae, and consumed leaf area was measured after forty-eight hours. B. riparia var. megacephala and A. belladonna again dominated, with antifeedant rates of 87.45 and 89.46 percent respectively, meaning larvae ate only a small fraction of the foliage consumed by untreated controls. Extracts of A. ochotense, A. dauricus and Bauhinia championi also held rates above eighty percent, while several others faded over time. The oviposition assay extended the effect beyond feeding: potted Chinese cabbage plants sprayed with extract and caged with twenty adult moths received far fewer eggs than ethanol-treated controls. B. riparia var. megacephala reduced egg-laying by 82.14 percent, leaving just 1.25 eggs per plant, and A. belladonna achieved 78.57 percent repellency. Together, the data suggested these two plants attack the moth at multiple points in its life cycle.

With two standouts identified, the researchers asked whether combining them would improve performance. Eleven treatments were prepared in a volumetric series spanning pure A. belladonna to pure B. riparia var. megacephala, and the median lethal concentration of each was determined by probit analysis. Alone, A. belladonna showed an LC50 of 76.69 milligrams per milliliter against the more toxic B. riparia var. megacephala at 95.53. The critical result came from the eight-to-two mixture, which lowered the LC50 to 65.76 milligrams per milliliter, better than either single extract. Using the co-toxicity coefficient framework of Chinese pesticide standards, where values at or above 120 indicate synergism, at or below 80 indicate antagonism and values between indicate additivity, the eight-to-two blend scored 110. The authors are careful to call this an additive effect rather than true synergism, but the absence of any antagonistic combination, even at ratios where the weaker extract dominated, is a meaningful signal that the two extracts are chemically compatible partners.

Why might these particular plants be so potent? The team draws on phytochemical literature to build plausible, though deliberately tentative, mechanistic hypotheses. Atropa belladonna, the infamous deadly nightshade, is rich in tropane alkaloids including hyoscyamine, scopolamine and norhyoscyamine, compounds known to interact with insect muscarinic acetylcholine receptors and thereby disrupt cholinergic signaling and neural transmission. Blumea species, by contrast, produce sesquiterpene-rich volatile oils and diverse flavonoids, compound classes associated elsewhere with feeding deterrence, digestive enzyme inhibition and interference with detoxification enzymes. Allium ochotense owes its activity, if the pattern holds, to sulfur-containing compounds and steroidal saponins that can induce oxidative stress and permeate cell membranes. Because the study did not perform chemical profiling of the extracts, these explanations remain literature-supported hypotheses rather than demonstrated mechanisms, and the authors are explicit about that limitation.

Translating laboratory promise into a sprayable product required formulation chemistry. The combined eight-to-two extract was tested against four organic solvents, and ethanol was chosen over dimethyl sulfoxide and methanol for its lower toxicity and favorable stability, while petroleum ether failed solubility requirements outright. Four surfactant systems were then screened. Formulations containing pesticide emulsifier 500# combined with NP-2 remained homogeneous and transparent through high-temperature storage at 54 degrees Celsius for fourteen days, low-temperature storage near freezing for a week, and dilution testing, whereas OP-10 and emulsifier 601# showed precipitation under stress. Concentration optimization settled on five percent emulsifier 500# and eight percent NP-2. The final emulsifiable concentrate contained ten percent active ingredients, seventy-seven percent ethanol and the two emulsifiers, and it passed the physicochemical stability benchmarks, though the authors caution that these accelerated tests are not a substitute for a full shelf-life evaluation.

The decisive test came in the field. In a randomized complete block trial on cruciferous vegetables in Jingyang County, the ten percent botanical formulation diluted one hundred times was compared with emamectin benzoate, a widely used macrocyclic lactone insecticide, and a water-sprayed control across twelve plots. The pattern of action differed sharply between treatments. Emamectin benzoate, which paralyzes insects by acting on glutamate-gated chloride channels, showed faster knockdown in the first day. The botanical spray started slowly, delivering only 10.86 percent control at day one, but its performance climbed steadily as its toxic, antifeedant and reproductive effects accumulated. By seven days after application, the botanical formulation had achieved 58.35 percent control, statistically indistinguishable from the 60.58 percent achieved by emamectin benzoate. Meanwhile, the untreated plots saw larval populations surge by more than thirty percent, underscoring how much pressure the pest exerts when left alone.

The researchers and outside observers alike stress that 58.35 percent is moderate efficacy, not commercial-grade knockout, and the trial covered a single site and one growing season. But the trajectory is what makes the study noteworthy: a crude plant combination, formulated without synthetic active ingredients, matching a leading chemical insecticide within a week of application suggests genuine development potential rather than a laboratory curiosity. The authors outline the road ahead with commendable candor. Chemical profiling by LC-MS or GC-MS and bioassay-guided fractionation are needed to identify the actual active constituents. Safety evaluation is not optional, because natural origin does not equal safety: A. belladonna’s tropane alkaloids can pose risks to humans, livestock and beneficial insects at sufficient exposure, so mammalian toxicity, non-target effects, residues and environmental fate all require dedicated study. Resistance management potential, multi-location trials and dosage optimization round out the agenda. If those hurdles are cleared, the Qinling Mountains may have supplied an unlikely gift to cabbage growers worldwide: a plant-based spray that the diamondback moth has not yet learned to beat.

Subject of Research: Botanical insecticide screening and field evaluation against the diamondback moth Plutella xylostella

Article Title: Bioactivity screening of plant ethanol extracts against Plutella xylostella and field evaluation of an optimized botanical combination formulation

Article References: Zhang, J., Wang, X., Xu, X., Gustave, W., & Zhang, X. (2026). Bioactivity screening of plant ethanol extracts against Plutella xylostella and field evaluation of an optimized botanical combination formulation. Acta Biochimica Polonica, 73, Article 16918. https://doi.org/10.3389/abp.2026.16918

Image Credits: AI Generated

DOI: 10.3389/abp.2026.16918

Keywords: Plutella xylostella, diamondback moth, botanical insecticide, Atropa belladonna, Blumea riparia, plant extracts, antifeedant activity, insecticide resistance, emulsifiable concentrate, integrated pest management, field trial, cruciferous vegetables

The motivation behind the research sits at the intersection of agriculture and green chemistry. Plant-derived extracts are increasingly investigated as sources of environmentally compatible compounds that could replace synthetic chemicals in agricultural applications, from crop protection to soil amendments. Nettle is an attractive candidate because it is widely available, grows readily in Ethiopia, and is known to contain a diverse array of secondary metabolites. Yet the value of any plant extract depends heavily on how efficiently those compounds are recovered, and the authors note that information on optimized extraction of Ethiopian Urtica dioica leaves has remained limited. Without that information, any downstream application would rest on guesswork rather than on a characterized, reproducible process.

The extraction method at the heart of the study is the Soxhlet technique, a workhorse of natural products chemistry that has been in use for well over a century. In a Soxhlet apparatus, a solvent is repeatedly cycled through the plant material: solvent vapor rises, condenses, drips onto a thimble holding the powdered leaves, and once the siphon fills, the solvent carrying dissolved compounds drains back into the boiling flask. Each cycle exposes the plant matrix to fresh solvent, which is why Soxhlet extraction is prized for its thoroughness. But the same thoroughness comes with sensitivity to conditions. Too much heat can degrade thermolabile compounds or drive off volatile ones; too little time leaves valuable chemistry locked in the plant tissue; and the solid-to-solvent ratio governs how much material the solvent can dissolve before it approaches saturation.

Rather than testing conditions one variable at a time, the team employed response surface methodology, or RSM, a statistical framework that treats an industrial or laboratory process as a mathematical surface whose height, in this case the extraction yield, depends on the settings of several input variables. Within RSM, the researchers used a central composite design, a specific experimental layout that efficiently samples the corners, faces, and center of the experimental space. The design allowed them to vary three factors simultaneously: extraction temperature across a range of 50 to 70 degrees Celsius, extraction time from 3 to 5 hours, and the solid-to-solvent ratio from 0.125 to 0.1875 grams per milliliter. By fitting a quadratic model to the resulting yield data, they could capture not only the individual effect of each factor but also the interactions between them, which one-variable-at-a-time experiments would miss entirely.

The statistical quality of the fitted model proved strong. The quadratic model was highly significant, with a p-value below 0.0001, indicating that the relationship between the process variables and extraction yield was unlikely to be a statistical accident. Equally important, the lack-of-fit test came back non-significant, with a p-value of 0.0749. In the language of experimental design, a significant lack of fit would signal that the quadratic equation was missing genuine structure in the data, whereas a non-significant result means the model adequately describes the response surface across the tested range. That combination, a significant model with an insignificant lack of fit, is exactly what an experimenter hopes to see before trusting the model to make predictions outside the exact conditions that were physically tested.

With the validated model in hand, the researchers turned to numerical optimization to find the point on the response surface where yield is maximized. The optimum landed at an extraction temperature of 64.62 degrees Celsius, an extraction time of just 3.01 hours, and a solid-to-solvent ratio of 0.139 grams per milliliter. Under those conditions, the model predicted an extraction yield of 0.330 percent by weight. Several features of that optimum are noteworthy. The predicted best temperature sits comfortably inside the tested range rather than at an extreme, suggesting a genuine interior maximum where the benefits of increased solubility and diffusion are balanced against the risks of thermal degradation. The optimal time of roughly three hours, at the low end of the tested window, hints that most of the extractable material is recovered early and that extended extraction adds little, a finding with real implications for energy consumption and throughput if the process is ever scaled up.

Optimization alone, however, says nothing about what is actually in the extract, so the team complemented the yield study with a preliminary chemical characterization using two complementary techniques. Fourier-transform infrared spectroscopy, or FTIR, probes the vibrational signatures of chemical bonds, allowing researchers to identify the functional groups present in a sample, such as hydroxyl groups characteristic of phenols and flavonoids, carbonyl groups found in many plant metabolites, and the carbon-hydrogen frameworks of lipids and waxes. Thin-layer chromatography, or TLC, takes a different approach, separating the extract’s constituents as they migrate at different speeds across a coated plate, revealing how many distinct chemical fractions the extract contains. Together, the two methods provided preliminary evidence of diverse functional groups and multiple chromatographic fractions in the nettle leaf extract, confirming that the optimized process recovers chemically rich material rather than a narrow, uninteresting fraction.

The significance of the work extends beyond the specific numbers. For researchers working with plant extracts as candidates for agricultural or pharmaceutical use, the study demonstrates a disciplined pipeline: define the process variables, model their combined effects statistically, validate the model, optimize it, and only then characterize the product. That sequence matters because an unoptimized extraction can bias the chemical profile of an extract, enriching some compounds while leaving others behind, which in turn makes biological testing difficult to reproduce. By establishing an optimized laboratory-scale extraction condition and a preliminary chemical profile for Ethiopian Urtica dioica leaves, the authors have created a reproducible baseline that other laboratories can adopt, compare against, and refine.

There are also broader implications for how underutilized plants are developed as resources. Ethiopia’s nettle populations have long been part of local knowledge, but transforming that traditional resource into a standardized product requires exactly the kind of quantitative process engineering this study provides. The modest yield of 0.330 percent by weight may sound small, but for many plant secondary metabolites such figures are typical, and the value lies in the identity and activity of the extracted compounds rather than in bulk mass. The open-access publication, funded without external support and carried out with chemicals and instruments provided by Bahir Dar University, also illustrates how well-equipped institutions in the Global South can contribute rigorous, citable process chemistry to the global natural products literature.

As with any preliminary characterization, the authors are careful about scope. FTIR and TLC establish the presence of diverse chemistry but do not identify individual compounds, a task that would require more powerful tools such as high-performance liquid chromatography coupled with mass spectrometry. The study likewise does not test the extract’s biological activity in agricultural settings, which remains the logical next step now that a consistent extraction protocol exists. Still, the work captures something of a quiet revolution in natural products research: the stinging nettle, a plant most people avoid touching, is being handled with the same statistical rigor that governs petrochemical refineries and pharmaceutical manufacturing. In the hands of chemical engineers armed with central composite designs and response surfaces, even a common weed becomes a process to be understood, optimized, and, perhaps one day, deployed in service of more sustainable agriculture.

Subject of Research: Optimization of Soxhlet extraction of Urtica dioica leaf extract using response surface methodology

Article Title: Optimization of Soxhlet extraction conditions and preliminary phytochemical characterization of Urtica dioica leaf extract using response surface methodology

Article References: Getahun, S. A., Abera, W. G., Enyew, T. W., & Aklilu, H. A. (2026). Optimization of Soxhlet extraction conditions and preliminary phytochemical characterization of Urtica dioica leaf extract using response surface methodology. BMC Plant Biology. https://doi.org/10.1186/s12870-026-10102-x

Image Credits: AI Generated

DOI: 10.1186/s12870-026-10102-x

Keywords: Urtica dioica, stinging nettle, Soxhlet extraction, response surface methodology, central composite design, extraction optimization, phytochemical characterization, FTIR, thin-layer chromatography, natural products, plant extracts, Bahir Dar University

The appeal of Diospyros lies in its extraordinary phytochemical arsenal. Leaves, bark, and fruit of these species are loaded with flavonoids such as quercetin and kaempferol, hydrolysable and condensed tannins, phenolic acids like gallic acid, and pentacyclic triterpenoids including betulin, lupeol, and betulinic acid. These molecules perform a remarkable double duty during synthesis. Their hydroxyl and carbonyl groups donate electrons to reduce copper(II) ions from precursor salts such as copper sulfate into metallic copper, cuprous oxide, or cupric oxide nanostructures. Simultaneously, the same biomolecules adsorb onto the freshly formed particle surfaces, forming a protective organic corona that prevents aggregation and, to some extent, shields the copper from rapid oxidation.

The synthesis itself follows the classic bottom-up logic of nanoparticle formation: reduction, nucleation, growth, and stabilization. When copper ions meet the extract, phenolic compounds are oxidized to quinone-like structures as they transfer electrons, a process often signaled by a visible color change. Supersaturation then triggers rapid nucleation, and the tiny copper clusters grow through coalescence and Ostwald ripening into particles typically ranging from 10 to 80 nanometers. Reaction parameters exert fine control over the outcome. Alkaline pH enhances the deprotonation of phenolics, accelerating reduction and yielding smaller, well-dispersed particles, while acidic conditions slow the process and favor larger, less stable products. Elevated temperature speeds nucleation and improves crystallinity, but excessive heat can degrade the very biomolecules responsible for capping.

The review illustrates this parameter sensitivity with striking species-specific examples. Diospyros malabarica, synthesized at alkaline pH 8 to 10 and 60 to 80 degrees Celsius, produces particles as small as 17.4 nanometers thanks to enhanced reduction kinetics. Diospyros vilosa, rich in tannins and processed at 70 to 80 degrees Celsius, yields an even finer 5 to 20 nanometer fraction. Diospyros lotus at near-neutral pH produces larger 20 to 50 nanometer particles stabilized by phenolic capping, while Diospyros kaki under moderate conditions delivers uniform 25 to 45 nanometer particles. These comparisons underscore a central message: nanoparticle characteristics are not accidental but emerge from the interplay between reaction conditions and each species’ distinctive phytochemical fingerprint.

Characterization studies reinforce this structure-property relationship. UV-visible spectroscopy reveals surface plasmon resonance bands for metallic copper nanoparticles in the 560 to 600 nanometer range, with Diospyros kaki leaf-mediated synthesis showing a distinct peak near 580 nanometers. Fourier-transform infrared spectroscopy identifies the hydroxyl, carbonyl, and aromatic signatures of the capping phytochemicals, and crucially, shifts in these peaks before and after synthesis provide direct evidence of coordination between copper and the biomolecules. X-ray diffraction confirms crystalline phases, distinguishing face-centered cubic metallic copper from monoclinic CuO, while transmission electron microscopy visualizes predominantly spherical particles wrapped in a thin organic layer. X-ray photoelectron spectroscopy adds definitive identification of oxidation states, revealing that many green-synthesized products are actually mixed-phase systems of Cu, Cu2O, and CuO.

That oxidation behavior is both a challenge and an opportunity. Metallic copper nanoparticles are inherently unstable, with high surface energy and a strong affinity for oxygen driving rapid conversion to cuprous and cupric oxide. The review notes that incomplete phytochemical capping often produces hybrid Cu/Cu2O/CuO systems, and that strategies such as inert-atmosphere synthesis, alkaline pH, and storage in oxygen-free conditions can preserve the metallic state. Interestingly, the oxidized phases are not merely defects; they possess distinct catalytic and biological properties that may be advantageous for specific applications, provided researchers precisely characterize and report what they have actually made.

The biomedical performance of these plant-derived particles is where the story becomes genuinely exciting. Diospyros-mediated copper nanoparticles have demonstrated dose-dependent cytotoxicity against cancer cell lines, with nanoparticles from Diospyros malabarica fruit extract showing an IC50 of 58.63 micrograms per milliliter against U87-MG glioblastoma cells, and related plant-mediated copper oxide nanoparticles generally falling in the 40 to 80 micrograms per milliliter range. The proposed mechanism centers on reactive oxygen species generation, which triggers DNA damage, cell-cycle arrest, mitochondrial dysfunction, cytochrome c release, and caspase activation, ultimately inducing apoptosis in malignant cells. Surface-bound betulinic acid, abundant in Diospyros, is known to promote this intrinsic apoptotic pathway, suggesting a synergistic partnership between the copper core and its phytochemical coating.

Antimicrobial results are equally compelling. Nanoparticles synthesized with Diospyros malabarica extract produced inhibition zones of 18.2 millimeters against Escherichia coli and 16.5 millimeters against Staphylococcus aureus, while Diospyros ebenum-derived particles leverage naphthoquinones and flavonoids that disrupt microbial cell walls and amplify oxidative stress. Beyond medicine, the particles show promise as green catalysts, degrading organic dyes such as methylene blue and rhodamine B with reported efficiencies of 85 to 95 percent within 120 minutes, and rapidly converting 4-nitrophenol to 4-aminophenol, a model reaction that positions them as low-cost alternatives to noble-metal catalysts.

The authors are candid about the obstacles standing between laboratory promise and real-world impact. A bibliometric analysis reveals the scale of the gap: a broad search for copper nanoparticles retrieves more than 218,000 documents, but combining the terms with plant extract and Diospyros narrows the field to roughly 158, with no clinical trials at all. Reproducibility suffers because phytochemical composition varies with species, season, and geography. Standardized synthesis and testing protocols are lacking, minimum inhibitory concentrations vary widely between studies, and most anticancer claims rest on in vitro monocultures without proper normal-cell controls. Long-term in vivo toxicity, pharmacokinetics, and biodistribution data remain scarce, and the paradoxical dual behavior of copper, antioxidant in chemical assays yet pro-oxidant in biological environments, demands more careful interpretation than many current studies provide.

Looking forward, the review charts a data-driven path to maturity. Artificial intelligence and machine learning could predict optimal synthesis conditions by linking phytochemical composition and reaction parameters to nanoparticle properties, enabling safe-by-design development. Hybrid nanocomposites such as CuO/ZnO and biofunctionalized systems may amplify synergistic effects through controlled ion release and improved interfacial interactions. The authors also spotlight Diospyros melanoxylon, the tendu tree of Indian forestry, as a conspicuously underexplored species whose rich tannin and triterpenoid profile suggests strong reducing and capping potential. If the field can deliver standardized protocols, rigorous biosafety evaluation, and scalable production, persimmon-derived copper nanoparticles could evolve from a curious green chemistry experiment into a credible platform for low-toxicity nanotherapeutics, antimicrobial coatings, and sustainable wastewater treatment.

Subject of Research: Green synthesis of copper nanoparticles using Diospyros plant extracts and their biomedical applications

Article Title: The current development in green synthesis of copper nanoparticles using Diospyros species: sustainable nanotechnology and biomedical applications

Article References: Gupta, P., Shukla, Y. K., Suryavanshi, A., & Bharti, S. K. (2026). The current development in green synthesis of copper nanoparticles using Diospyros species: sustainable nanotechnology and biomedical applications. Discover Chemistry, 3(1), Article 499. https://doi.org/10.1007/s44371-026-00937-6

Image Credits: AI Generated

DOI: 10.1007/s44371-026-00937-6

Keywords: green synthesis, copper nanoparticles, Diospyros, nanotechnology, phytochemicals, antimicrobial, anticancer, reactive oxygen species, sustainable chemistry, nanomedicine, catalysis, plant extracts

The review’s central finding is quantitative and striking. Conventional plant-extract-based green inhibitors, drawn from leaves, seeds, spices, and agricultural wastes, typically deliver inhibition efficiencies between roughly 69 and 96.41 percent in aggressive media such as hydrochloric and sulphuric acid. When those same plant-derived phytochemicals are paired with nanomaterials, the efficiency window shifts decisively upward, with nanoengineered systems consistently reaching approximately 85 to 99 percent, and most documented formulations surpassing 90 percent. Green-synthesized silver nanoparticles produced from tobacco extract, for example, provided 98 percent protection for carbon steel in 0.5 M hydrochloric acid, while silicate nanoparticles derived from rice husk ash achieved 99 percent inhibition in the same aggressive medium. These are not marginal gains; they represent the difference between a promising laboratory curiosity and a technology that could genuinely compete with toxic chromates and imidazolines in industrial service.

The mechanism behind the improvement is rooted in electrochemistry. Corrosion proceeds through coupled half-cell reactions: at anodic sites, iron dissolves as Fe2+ ions and releases electrons, while at cathodic sites, dissolved oxygen or protons consume those electrons, ultimately generating the hydrated iron oxides we know as rust. An inhibitor works by disrupting one or both of these processes, usually by adsorbing onto the metal surface and forming a barrier film. The review shows that nanoparticles act as adsorption promoters and anchoring platforms for organic inhibitor molecules. Because of their enormous surface area-to-volume ratio, nanoparticles offer vast numbers of active sites where plant-derived compounds can pack densely, producing compact, low-porosity protective layers that block chloride ions, oxygen, and protons from reaching the metal.

The electrochemical evidence is compelling. In one representative study, zinc oxide nanoparticles synthesized from Convolvulus arvensis leaf extract raised the charge transfer resistance of carbon steel from 200 to 359.3 ohms per square centimeter, a direct measure of how effectively the surface resists the flow of corrosion current. Simultaneously, corrosion current densities and double-layer capacitances dropped, indicating that fewer active sites remained available for anodic dissolution or cathodic reduction. Electrochemical impedance spectroscopy showed growing semicircle diameters with increasing inhibitor concentration, confirming that charge transfer at the metal-solution interface was being progressively suppressed. Potentiodynamic polarization studies classified most of these nano-inhibitors as mixed-type, meaning they suppress both the anodic and cathodic branches of the corrosion reaction through a combination of physisorption and chemisorption.

The catalog of successful green nanomaterials is expanding rapidly. Cadmium oxide nanoparticles synthesized using Syzygium cumini acted as mixed-type inhibitors for mild steel in acid, thickening the surface layer and lowering double-layer capacitance. Silver nanoparticles mediated by Macrolepiota mushrooms protected mild steel in recirculating cooling water systems while simultaneously suppressing biofilm formation thanks to inherent antibacterial properties. An olive leaf extract-titanium nanocomposite boosted inhibition efficiency of mild steel in acid from 83.5 to 93.4 percent at low inhibitor concentrations. Chitosan-cobalt and chitosan-tin sulphide nanocomposites reached 97 and 85 percent efficiency respectively in 1 M hydrochloric acid, well above plain chitosan at 77 percent. A polypropylene glycol composite reinforced with honey-mediated green silver nanoparticles delivered 94 percent protection in 0.5 M sulphuric acid through chemisorption.

Beyond dispersed inhibitors, the review highlights nanocoatings and nanocomposites as a second frontier. Nanocoatings, films thinner than 100 nanometers deposited on metal substrates, form dense barrier layers with lower porosity and fewer defects than conventional coatings, shortening the diffusion pathways available to electrolytes. Nanocomposite coatings, in which nanofillers such as graphene oxide, nanoclays, or biogenic metal oxide particles are dispersed in polymer matrices, fill microscopic gaps, resist blistering and delamination, and dramatically increase the tortuosity of the path that oxygen and chloride ions must navigate to reach the substrate. The most futuristic entrants are smart, self-healing systems: halloysite nanotubes or mesoporous silica nanocontainers loaded with green inhibitors such as plant alkaloids, amino acids, or tannins, which release their cargo only when a pH shift or defect signals that corrosion has begun. The nanocoatings market is projected to grow by roughly 20 percent between 2020 and 2030, reflecting industrial appetite for these longer-lasting protections.

Yet the authors are careful to draw a distinction that much of the literature blurs: green synthesis does not automatically make a green inhibitor. A nanoparticle prepared with plant extract reduces the environmental footprint of production, but true greenness requires low toxicity to aquatic and terrestrial organisms, biodegradability into harmless products, minimal leaching of nanoparticles during service and disposal, and an acceptable life-cycle impact from raw material extraction through end of life. The review proposes a practical framework built on ecotoxicity indicators such as LC50 and standardized bioassays, biodegradation testing, immobilization studies to track nanoparticle release, and full life-cycle assessment. Nanotechnology, in this framing, is an enabling tool that amplifies the performance of inherently green inhibitors, not a substitute for sustainability itself.

Significant obstacles remain before nanoengineered green inhibitors can leave the laboratory. Plant-mediated synthesis suffers from batch-to-batch variability driven by seasonal, geographic, and processing differences, which alters nanoparticle size, shape, and surface chemistry and therefore undermines reproducibility. Achieving uniform nanoparticle dispersion in polymer matrices is a persistent engineering challenge, because agglomeration creates pores and cracks that become highways for corrosive species. Most critically, nearly all published performance data come from short-term electrochemical tests under controlled laboratory conditions; long-term durability under marine atmospheres, ultraviolet exposure, and high-temperature industrial environments remains largely unmeasured, and photocorrosion of metal oxides such as ZnO and TiO2 could erode protection over years of service.

The path forward, the authors argue, lies in moving from proof-of-concept studies to application-oriented research guided by advanced tools. In situ techniques such as electrochemical atomic force microscopy and scanning electrochemical microscopy, coupled with density functional theory calculations and molecular dynamics simulations, could enable the rational design of inhibitor-nanomaterial systems with tailored adsorption behavior. Stimuli-responsive nanocontainers, autonomous self-healing coatings containing biogenic healing agents, and multifunctional nanocomposites that combine corrosion resistance with antibacterial and antifouling action could serve demanding maritime, energy, and biomedical sectors. If scalability, dispersion, and field validation can be solved, nanoengineered green corrosion inhibitors stand ready to replace a century of toxic chemistry with protection derived from tobacco leaves, rice husks, and honey, at efficiencies that once seemed attainable only with hazardous compounds.

Subject of Research: Nanoengineered green corrosion inhibitors combining plant extracts and nanomaterials for sustainable metal protection

Article Title: Fundamental and sustainability of nanoengineered green corrosion inhibitors

Article References: Okolo, D. C., Anumudu, J., Omekawum, N. C., & Ndukwe, A. I. (2026). Fundamental and sustainability of nanoengineered green corrosion inhibitors. Discover Electrochemistry, 3(1), Article 34. https://doi.org/10.1007/s44373-026-00123-4

Image Credits: AI Generated

DOI: 10.1007/s44373-026-00123-4

Keywords: corrosion inhibition, green chemistry, nanoparticles, plant extracts, electrochemical impedance spectroscopy, nanocoatings, silver nanoparticles, zinc oxide, sustainability, steel protection, self-healing coatings, life-cycle assessment