A Comprehensive Review of Biological Properties of Flavonoids and Their Role in the Prevention of Metabolic, Cancer and Neurodegenerative Diseases

Dietary flavonoids are emerging as multifunctional bioactive compounds with significant implications for the prevention and management of chronic diseases. Integrating the latest experimental, clinical, and epidemiological evidence, this review provides a comprehensive synthesis of flavonoid classification, chemistry, dietary sources, and bioavailability, with special attention to their structural diversity and core mechanisms. Mechanistic advances related to antioxidant, anti-inflammatory, antimicrobial, anti-obesity, neuroprotective, cardioprotective, and anticancer activities are highlighted, focusing on the modulation of critical cellular pathways such as PI3K/Akt/mTOR, NF-κB, and AMPK. Evidence from in vitro and in vivo models, supported by clinical data, demonstrates flavonoids’ capacity to regulate oxidative stress, inflammation, metabolic syndrome, adipogenesis, cell proliferation, apoptosis, autophagy, and angiogenesis. An inverse correlation between flavonoid-rich dietary patterns and the risk of obesity, cancer, cardiovascular, and neurodegenerative diseases is substantiated. However, translational challenges persist, including bioavailability and the optimization of delivery strategies. In conclusion, a varied dietary intake of flavonoids constitutes a scientifically grounded approach to non-communicable disease prevention, though further research is warranted to refine clinical applications and elucidate molecular mechanisms.