Steroidal Glycosides from the Rhizomes of Anemarrhena asphodeloides and Their Antiplatelet Aggregation Activity

Five new steroidal glycosides, timosaponin J (1), timosaponin K (2), (25S)-karatavioside C (5), timosaponin L (6), and (25S)-officinalisnin-I (8), together with eight known steroidal saponins, timosaponin E-1 (3), purpureagitosid (4), timosaponin BII (7), timosaponin B III (9), anemarrhenasaponin I (10), anemarrhenasaponin III (11), anemarrhenasaponin A(2) (12), and timosaponin A III (13), were isolated from the rhizomes of Anemarrhena asphodeloides. Their structures were elucidated on the basis of spectroscopic and chemical evidence. The aglycones of compounds 1 and 2 are new aglycones. Compounds 1-13 were evaluated for their platelet aggregation activities, and compound 13 exhibited the strongest inhibitory effect on adenosine diphosphate (ADP)-induced platelet aggregation.