Molecular Mechanisms of Anti‐Inflammatory and Immunomodulatory Activities of Key Phytochemicals: A Comprehensive Review

Phytochemicals derived from medicinal plants represent a rich and largely underexploited source of anti‐inflammatory and immunomodulatory agents. Chronic inflammation and dysregulated immune responses underpin many tropical and global diseases, including infectious, autoimmune, and metabolic disorders. This review examines the spectrum of plant‐derived compounds with defined bioactivity in inflammation and immune regulation. To ensure comprehensive coverage of current research, an extensive literature search was conducted across multiple scientific databases, including Web of Science, ScienceDirect, SpringerLink, Wiley Online Library, PubMed/MEDLINE, Scopus, and Google Scholar. The search encompassed publications available up to May 2025. Combinations of relevant Medical Subject Headings (MeSH) terms and free‐text keywords were used, such as “phytochemicals,” “medicinal plants,” “anti-inflammatory activity,” “immunomodulatory effect,” “plant-derived compounds,” “flavonoids,” “alkaloids,” “terpenoids,” and “polyphenols” (including modulation of cytokines, NF‐κB, MAPK, NLRP3 inflammasome, T‐cell, and macrophage functions), and relevance to tropical‐disease contexts. Boolean operators ( AND, OR, and NOT ) were applied to refine and broaden the search. Reference lists of retrieved articles and related reviews were also manually screened to identify additional relevant studies. Numerous phytochemicals such as quercetin, curcumin, baicalin, resveratrol, and others demonstrate multitarget anti‐inflammatory effects including the suppression of proinflammatory cytokines (IL‐1β, IL‐6, TNF‐α), inhibition of NF‐κB/MAPK pathways, modulation of T‐helper and regulatory T‐cell profiles, and attenuation of inflammasome activation. Emerging studies highlight immunomodulatory roles in enhancing host resistance or dampening overactivation in infection, allergy, and autoimmunity. However, human data remain limited, and the pharmacokinetic, toxicity, and compositional profiles of standardized plant extracts are still poorly defined. Medicinal plant phytochemicals offer promising leads for anti‐inflammatory and immunomodulatory therapy, especially in tropical regions where safe, affordable agents are needed. To translate these into practice, well‐designed trials, standardized extracts, rigorous safety evaluations, and studies on disease‐specific immune mechanisms are essential. This review provides a comprehensive reference and highlights key research gaps and future directions.