Two New Steroidal Saponins with Antifungal Activity from Hosta plantaginea Rhizomes

Two new steroidal saponins, (25R)-3 beta-hydroxy-5 alpha-spirost-9-en-12-one 3-O-beta-D-galactopyranoside (hostasaponin A, 1), and (25R)-2 alpha,3 beta-dihydroxy-5 alpha-spirost-12-one 3-O-beta-D-galactopyranoside (hostasaponin B, 2), together with a new natural product, 2 alpha,3 beta-dihydroxy-5 alpha-pregn-16-en-20-one (3), were isolated from the rhizomes of Hosta plantaginea, a perennial herb used mainly as an ornamental plant and folk medicine for fungal infection and various inflammations. The active evaluation results showed that 1 and 2 possess potent inhibition activity against Candida albicans, with MIC values less than 20 mu g/mL.