Two new flavanes and bioactive compounds from Daphne tangutica Maxim

Two new flavanes, named daphneflavan B (1) and daphneflavan C (2), along with two known biflavonoids, daphnodorin D1 (3) and daphnodorin D2 (4), were isolated from the roots of Daphne tangutica Maxim. Their structures were established on the basis of chemical, physicochemical, and spectroscopic evidences. Two compounds 3 and 4 were noted to have the most marked antitumor activity in vivo assay.