Topic overview

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Flavonoids share a C6–C3–C6 skeleton and include subclasses such as flavones, flavonols, flavanones, flavanols, isoflavones, anthocyanins, and chalcones. Their formation involves the phenylpropanoid pathway, and glycosylation can affect solubility and stability. The lesson also introduces representative aglycones, biological activities, metabolism, and identification methods. Tannins are high-molecular-weight polyphenols that precipitate proteins, producing astringency. They are grouped principally as hydrolyzable tannins, which yield gallic or ellagic acid on hydrolysis, and condensed tannins, which can form anthocyanidins under acidic heat. Chemical tests, interactions that may reduce absorption, solubility patterns, and industrial uses help distinguish and contextualize these compounds.