Mutagenic activity of quercetin and related compounds.

The mutagenic activities of several flavonoids and flavonoid metabolites were examined by means of Salmonella typhimurium mutants that reveal base-pair substitution and frameshift mutagens. Of the compounds tested (naringin, rutin, neohesperetin, hesperetin, dihydroquercetin, quercetin, quercetin pentaacetate, permethylquercetin, m-hydroxyphenylacetic acid, and m,p-dihydroxyphenylacetic acid), only quercetin was mutagenic without microsomal activation. With activation, however, the mutagenic activity of quercetin was increased significantly and that of quercetin pentaacetate was revealed. The health implications of these findings and aspects of flavonoid structural requirements for mutagenic activity are discussed.