Natural Bioactive Compounds as Immunomodulatory Agents: Implications for Innate and Adaptive Immune Regulation in Human Health

Recent advances in nutritional immunology have highlighted the role of food-derived bioactive compounds in modulating immune responses. With increasing prevalence of chronic and immune-related diseases, the identification of natural compounds capable of regulating innate and adaptive immunity has gained considerable attention. This review aims to synthesize current evidence on the immunomodulatory effects of key natural compounds, including flavonoids, β-glucans, omega-3 polyunsaturated fatty acids, alkaloids, and short-chain fatty acids. We summarize their cellular targets, molecular mechanisms, and outcomes on immune balance, with emphasis on cytokine modulation, toll-like receptor signaling, antigen presentation, and oxidative stress regulation. The review integrates findings from in vitro, in vivo, and clinical studies to evaluate the translational relevance of these compounds. Tables and figures provide comparative insights into compound-specific effects and mechanistic pathways. Although promising, most data remain preliminary and underscore the need for further clinical validation. Understanding how these compounds influence immune homeostasis offers potential for preventive nutrition strategies and adjuvant therapy in immune dysregulation. This work provides a foundation for future research into food-based immune modulation and supports the growing paradigm of food as medicine.