At the chemical level, polyphenols encompass several subclasses—including flavonoids, phenolic acids, stilbenes, and lignans—each exhibiting unique biochemical attributes. Flavonoids, for example, are the most abundant class and are further divided into flavonols, flavones, isoflavones, and anthocyanins. This structural diversity underpins the wide-ranging biological effects of polyphenols. Their primary mode of action is often linked to their capacity to scavenge reactive oxygen species (ROS), thus mitigating oxidative stress—a pathological state implicated in chronic diseases such as cancer, diabetes, and neurodegenerative disorders.

One of the core revelations in contemporary polyphenol research is their role as modulators of intracellular signaling pathways. Beyond direct antioxidant activity, polyphenols influence gene expression by interacting with key transcription factors such as NF-κB, Nrf2, and AP-1. These interactions lead to regulation of inflammatory responses, detoxification enzymes, and cellular defense mechanisms. This regulatory potential explains how polyphenols contribute not only to neutralizing harmful molecules but also to reinforcing the body’s endogenous protective systems, thereby enhancing resilience against various pathophysiological insults.

The comprehensive review highlights the importance of bioavailability and metabolism of plant polyphenols as critical determinants of their physiological efficacy. Despite their abundance in dietary sources, the absorption, distribution, metabolism, and excretion (ADME) of polyphenols vary significantly among individuals due to differences in intestinal microbiota composition and enzymatic activity. Metabolite formation often results in derivatives with altered bioactivity and bioefficacy, which suggests that the health effects of polyphenols cannot be fully understood without considering the complex interplay between human metabolism and gut microbial communities.

Moreover, the review delves into the emerging evidence linking polyphenol-rich diets to modulation of the gut microbiome itself. Polyphenols serve as prebiotic compounds, fostering the growth of beneficial bacteria while inhibiting pathogenic species. This bidirectional relationship enhances host health by promoting microbial homeostasis and stimulating production of short-chain fatty acids, compounds known to improve intestinal barrier function and reduce systemic inflammation. Such insights position polyphenols as critical agents in maintaining gastrointestinal health and preventing dysbiosis-related conditions, including inflammatory bowel disease and metabolic syndrome.

In the domain of cardiovascular health, polyphenols have demonstrated promising therapeutic potential. Epidemiological and interventional studies indicate that regular consumption of polyphenol-laden foods, such as berries, cocoa, and green tea, lowers blood pressure, reduces LDL cholesterol oxidation, and improves endothelial function. Mechanistically, polyphenols enhance nitric oxide bioavailability, leading to vasodilation and reduced arterial stiffness. Additionally, their anti-inflammatory actions prevent progression of atherosclerotic plaques by attenuating monocyte adhesion and foam cell formation in vascular walls.

Cancer prevention is another critical area where polyphenols exhibit multifaceted effects. Cellular and animal models reveal that these compounds induce apoptosis, inhibit angiogenesis, and suppress proliferation of malignant cells. Polyphenols modulate key oncogenic pathways, including PI3K/Akt, MAPK, and Wnt/β-catenin, exerting selective cytotoxicity toward cancer cells while sparing normal tissue. Such selective action underscores their potential as adjunctive agents in chemoprevention and integrative oncology strategies.

The neuroprotective capabilities of plant polyphenols are gaining increasing prominence in light of the growing burden of neurodegenerative diseases such as Alzheimer’s and Parkinson’s. Polyphenols cross the blood-brain barrier and mitigate neuronal oxidative damage, reduce neuroinflammation, and enhance synaptic plasticity. Notably, compounds like resveratrol and curcumin have garnered attention for their ability to modulate amyloid-beta aggregation and tau protein phosphorylation—hallmarks of Alzheimer’s pathology—thus offering viable avenues for slowing disease progression.

Inflammation, as a pervasive driver of chronic diseases, is significantly influenced by polyphenolic intake. These compounds inhibit key enzymes involved in the production of pro-inflammatory mediators, such as cyclooxygenases (COX) and lipoxygenases (LOX). Through modulation of cytokine profiles and macrophage phenotype switching, polyphenols orchestrate a shift toward anti-inflammatory states. This immunomodulatory effect extends their relevance beyond nutrition into therapeutic domains, including autoimmune and allergic conditions.

A particularly intriguing aspect addressed in the review involves the interplay of polyphenols with cellular energy metabolism. Polyphenols enhance mitochondrial biogenesis and function, thus promoting efficient adenosine triphosphate (ATP) production and reducing oxidative damage from mitochondrial dysfunction. This bioenergetic modulation is fundamental in managing metabolic diseases like type 2 diabetes and obesity, where mitochondrial impairment plays a central role.

The review also draws attention to the challenges faced in translating polyphenol research from bench to bedside. Factors such as standardization of polyphenolic extracts, dose optimization, and long-term safety profiles are critical considerations for clinical application. Furthermore, the complex nature of polyphenols demands advanced analytical techniques for precise quantification and profiling in biological matrices, a necessity for robust pharmacokinetic studies and personalized nutrition approaches.

Technological advancements in encapsulation and delivery systems, such as nanoemulsions and liposomes, are highlighted as promising innovations that enhance polyphenol stability and bioavailability. These strategies aim to overcome degradation in the gastrointestinal tract and ensure targeted release at sites of action. Such progress is pivotal for maximizing health benefits and developing polyphenol-based nutraceuticals or pharmaceuticals with consistent efficacy.

Importantly, the review underscores the synergistic effects arising from complex polyphenol mixtures present in whole foods, contrasting with isolated compounds often studied in vitro. This holistic perspective aligns with dietary recommendations favoring consumption of diverse plant-based foods rather than reliance on supplements, echoing the concept of food as medicine within integrative health paradigms.

Looking to the future, the authors advocate for interdisciplinary research bridging plant biochemistry, microbiology, clinical sciences, and computational biology to unravel the comprehensive impact of polyphenols. Precision nutrition, informed by individual genetic, metabolic, and microbiome profiles, emerges as a frontier for personalized polyphenol interventions aimed at disease prevention and health optimization.

In conclusion, the profound bioactivity of plant polyphenols underscores their indispensable role in human health maintenance and disease mitigation. This comprehensive review not only consolidates current understanding but also charts new directions for research and application. As the global burden of chronic diseases escalates, embracing the potential of polyphenols may offer accessible, effective, and natural solutions, heralding a new era in preventive and therapeutic nutrition.

Subject of Research: Multifaceted role of plant polyphenols in human health

Article Title: Multifaceted role of plant polyphenols in human health: a comprehensive review

Article References:
Kapoor, B., Bhardwaj, S., Singh, R. et al. Multifaceted role of plant polyphenols in human health: a comprehensive review. Food Sci Biotechnol (2025). https://doi.org/10.1007/s10068-025-01991-z

Image Credits: AI Generated

DOI: https://doi.org/10.1007/s10068-025-01991-z

Stomach cancer ranks among the deadliest cancers worldwide, frequently diagnosed at late stages when therapeutic interventions become less effective. While genetic predisposition, Helicobacter pylori infection, and environmental factors are well understood contributors to its development, recent attention has shifted toward preventive strategies emphasizing diet and bioactive compounds. Polyphenols, flavonoids, and other phytochemicals obtained from fruits and vegetables have been extensively studied for their anti-inflammatory, antioxidant, and anticarcinogenic properties. This review uniquely spotlights native Brazilian flora as a rich, yet underexplored, source of such compounds, advocating for a paradigm shift in the preventive oncological landscape.

The investigation highlights ten indigenous species with promising anticancer attributes, including açaí (Euterpe oleracea), cacao (Theobroma cacao), guava (Psidium guajava), pitanga (Eugenia uniflora), jambu (Acmella oleracea), and physalis (Physalis spp.). These plants have been observed to exhibit significant cytotoxic effects on gastric cancer cell lines, notably HGC-27 and SGC-7901, implicating various mechanisms such as apoptosis induction, cell cycle arrest, and inhibition of proliferative signaling pathways. The study underscores physalin compounds isolated from Physalis species that suppress expression of critical cyclins and cyclin-dependent kinases implicated in cell cycle progression while activating caspase cascades to trigger programmed cell death.

At a molecular level, the review elucidates the multifaceted roles of natural phytochemicals in modulating key regulators of tumor growth and survival. For example, physalin B, as demonstrated by Fang et al. (2022), represses cyclin D1, cyclin D3, CDK4, CDK6, and cyclin E, thereby impeding cellular progression from the G1 phase to S phase. Concurrently, it enhances apoptotic machinery by elevating caspase-8, caspase-3, caspase-7, and PARP protein levels, leading to effective gastrointestinal tumor cell elimination. Another compound, physapubescin B, shown by Dai et al. (2020), suppresses STAT3 phosphorylation, disrupting transcription of oncogenic targets such as XIAP and c-Myc, and impairs inflammatory mediators like IL-11, thus illustrating a complex network of anticancer activity.

Inflammation and oxidative stress are pivotal drivers of gastric carcinogenesis, and the antioxidant properties of native Brazilian plant extracts potentially attenuate these pathological processes. Polyphenolic constituents quench reactive oxygen species and modulate inflammatory cytokines, creating a microenvironment less conducive to tumor initiation and progression. Such bioactivities suggest a chemopreventive role wherein regular dietary intake of these plants or their derivatives may significantly reduce stomach cancer incidence.

Despite these encouraging in vitro findings, the authors candidly discuss the limitations inherent in the current body of research. The overwhelming majority of studies focus on cellular models, offering mechanistic insights but lacking translational depth. Animal model investigations are sparse, and no clinical trials have thus far examined efficacy or safety in humans. This gap underscores the necessity for rigorous preclinical and clinical studies to validate these compounds’ therapeutic potential and bioavailability within physiological contexts.

Recognizing Brazil’s unparalleled botanical diversity, the review appeals to the scientific community to intensify interdisciplinary research, integrating ethnobotany, pharmacology, and molecular oncology. Advances in high-throughput screening, metabolomics, and bioinformatics present unparalleled opportunities to identify novel bioactive molecules, optimize extraction methods, and elucidate precise modes of action. Such endeavors could accelerate the transition from bench research to clinical application, fostering innovative, natural, and accessible approaches to stomach cancer prevention.

Moreover, the review advocates for sustainable exploration strategies respecting indigenous knowledge and biodiversity conservation. Collaborations with local communities could facilitate the ethical sourcing of plant materials, ensuring equitable benefit-sharing and cultural preservation while tapping into centuries-old traditional medicinal practices known for their efficacy and safety profiles.

The promising anticancer effects observed with the native Brazilian plants extend beyond single-target mechanisms, instead revealing complex interactions with cellular signaling networks. These multifactorial effects are particularly advantageous in tackling genetically heterogeneous tumors such as gastric cancer, which often develop resistance to conventional single-target therapies. Natural compounds with broad-spectrum bioactivity offer a strategic advantage, presenting opportunities for combination regimens aimed at synergistic tumor inhibition.

In conclusion, this review serves as a pivotal milestone accentuating the underestimated value of Brazil’s botanical wealth in addressing a critical oncological challenge. It calls for a concerted global effort to bridge the gap between preliminary laboratory evidence and real-world therapeutics. As scientists continue to unravel the intricate pharmacological tapestry woven by nature, native Brazilian plants emerge as promising candidates in the quest to mitigate the global burden of stomach cancer through chemoprevention, ultimately contributing to enhanced public health outcomes worldwide.

Subject of Research: Not applicable

Article Title: The chemopreventive effects of native Brazilian plants on stomach cancer: A review of the last 25 years

News Publication Date: 8-May-2025

Web References:

• https://www.oncoscience.us/current-volume/
• http://dx.doi.org/10.18632/oncoscience.618

References:

• Fang et al. (2022). Study on physalin B effects on gastric cancer cell cycle and apoptosis.
• Dai et al. (2020). Effects of physapubescin B on STAT3 signaling in gastric cancer cells.

Image Credits: Copyright: © 2025 Lemos et al. This is an open access article distributed under the terms of the Creative Commons Attribution License (CC BY 4.0).