New steroidal glycosides from the rhizome of Anemarrhena asphodeloides.

ABSTRACT

Two new steroidal saponins, timosaponin X (1) and timosaponin Y (2), and one new pregnane glycoside, timopregnane B (3), were isolated from the rhizomes of Anemarrhena asphodeloides, as well as three known compounds 25S-timosaponin BII (4), protodesgalactotigonin (5), and timosaponin BII-a (6) isolated from this plant for the first time. By the detailed analysis of 1D, 2D NMR, MS spectra, and chemical evidences, the structures of new compounds were elucidated as 26-O-ß-d-glucopyranosyl-(25S)-5ß-22-methoxy-furost-3ß,26-diol 3-O-ß-d-glucopyranosyl-(1 → 2)-α-l-arabinopyranoside (1), 5ß-pseudo-spirost-3ß,15α,23α-triol 3-O-ß-d-glucopyranosyl-(1 → 2)-ß-d-galactopyranoside (2), (5ß,17α)-Δ((16)(17))-20-one-pregn-2ß,3ß-diol 3-O-ß-d-glucopyranosyl-(1 → 2)-ß-d-galactopyranoside (3).