Polyphenols in Agriculture and Human Health: A Comprehensive Review of Their Biological Functions and Benefits

Polyphenols are a diverse group of naturally occurring secondary metabolites widely distributed in plants, where they play critical roles in growth, development, and defense against biotic and abiotic stresses. In recent decades, polyphenols have attracted considerable scientific interest due to their multifunctional properties and their significance in both agriculture and human health. In agriculture, polyphenols contribute to plant resilience by enhancing tolerance to environmental stresses such as drought, salinity, temperature extremes, heavy metal toxicity, and pathogen attack through antioxidant activity, signaling regulation, and antimicrobial effects. These properties improve crop productivity, quality, and sustainability while reducing reliance on synthetic agrochemicals. In human health, dietary polyphenols exhibit potent antioxidant, anti-inflammatory, cardio protective, antidiabetic, neuroprotective, and anticancer activities. Their beneficial effects are mediated through modulation of cellular signaling pathways, regulation of oxidative stress and inflammation, improvement of endothelial and metabolic functions, and interactions with the gut microbiota. Despite growing evidence supporting their health-promoting properties, challenges related to bioavailability, metabolism, and variability among polyphenol sources remain important areas for future research. Overall, polyphenols represent a crucial link between sustainable agriculture and human well-being, offering promising opportunities for improving crop performance, food quality, and disease prevention. This review summarizes current knowledge and discusses future perspectives regarding the utilization of polyphenols in agricultural and biomedical applications.