Transformation of trachelogenin, an aglycone of tracheloside from safflower seeds, to phytoestrogenic (−)-enterolactone by human intestinal bacteria

► Trachelogenin was converted to enterolactone by human intestinal bacteria. ► The metabolites of trachelogenin were isolated and identified. ► The enterolactone converted from trachelogenin was (−)-enantiomer. ► The ligand binding affinity of the compounds to oestrogen receptors was evaluated.