Bioconversion of quercetin and rutin and the cytotoxicity activities of the transformed products

► Cytotoxic activity of quercetin and rutin and its metabolites was investigated. ► Quercetin was converted into methylquercetin (2) and quercetin glucuronide (3). ► Rutin produced rutin sulphate (5), methylrutin (6) and rutin glucuronide (7). ► The results showed cytotoxic effect for rutin and rutin sulphate (5).