Theaflavins are a group of polyphenolic compounds formed during the oxidation of catechins in the production of black tea. They are responsible for the characteristic color and astringency of black tea. Theaflavins are known for their antioxidant properties and potential health benefits, including anti-inflammatory and cardiovascular protective effects. They are not volatile and are slightly soluble in water, moderately soluble in alcohol, and insoluble in fats. Theaflavins contribute to the flavor profile of black tea and are studied for their potential role in reducing the risk of chronic diseases.