Transformation of tea catechins and flavonoid glycosides by treatment with Japanese post-fermented tea acetone powder

► Constituents of Japanese post-fermented tea were examined. ► The post-fermented tea contained tea catechin metabolites. ► The metabolites were identical to those produced by intestinal bacteria. ► The acetone powder of the tea converted tea catechins to the catechin metabolites. ► The acetone powder converted rutin and hesperidin to phenol carboxylic acids.