Isoflavone C-glycosides isolated from the root of kudzu (Pueraria lobata) and their estrogenic activities

► Six isoflavones were isolated from the root of Pueralia lobata. ► Their chemical structures were characterized on the basis of NMR and MS analyses. ► One of them was a novel α-apiofuranosyl C-glucoside. ► Their estrogenic activities were evaluated using yeast two-hybrid assay. ► The C-glucosides showed no activities, however, O-glucoside showed the activity.