Polyphenols are a diverse group of naturally occurring organic compounds characterized by the presence of multiple phenol units. They are abundant in plants and contribute to the color, flavor, and resistance to diseases. Structurally, polyphenols are classified into several categories, including flavonoids, phenolic acids, polyphenolic amides, and other polyphenols, each with distinct chemical structures and properties. Flavonoids, for example, include subgroups like flavones, flavonols, and anthocyanins, which are responsible for the vibrant colors in fruits and vegetables.

Polyphenols are renowned for their antioxidant properties, which help neutralize harmful free radicals in the body, potentially reducing the risk of chronic diseases such as heart disease, cancer, and neurodegenerative disorders. They also exhibit anti-inflammatory, anti-carcinogenic, and cardioprotective effects. Common dietary sources of polyphenols include fruits, vegetables, tea, coffee, red wine, and dark chocolate. In the context of nutrition and health, polyphenols are studied for their potential benefits in promoting overall well-being and preventing disease. Their role in the human diet is significant, as they contribute to the health benefits associated with plant-based foods.