Flavonoids are a diverse group of polyphenolic compounds found in plants, fruits, vegetables, and beverages like tea and wine. They consist of a 15-carbon skeleton arranged in a C6-C3-C6 configuration, featuring two benzene rings (A and B) connected by a heterocyclic pyrone ring (C). As secondary metabolites, flavonoids play crucial roles in plant pigmentation, UV protection, and defense against pathogens. In humans, they are renowned for their antioxidant, anti-inflammatory, and potential anticancer properties, acting as free radical scavengers and modulating enzyme activity. Common subclasses include flavonols (e.g., quercetin), flavones (e.g., luteolin), flavanones, isoflavones, and anthocyanidins. They contribute to the sensory properties of foods, such as color and bitterness in spices. Bioavailability varies; they are often glycosylated in nature, enhancing water solubility, but aglycones are more lipophilic. Research from peer-reviewed sources like the Journal of Agricultural and Food Chemistry indicates flavonoids may reduce chronic disease risks, including cardiovascular diseases and diabetes, though efficacy depends on structure and dosage. Overall, they are integral to nutrition and pharmacology, with ongoing studies exploring their therapeutic applications.