Chantriolide C, a new withanolide glucoside and a new spirostanol saponin from the rhizomes of Tacca chantrieri.

A new withanolide, chantriolide C (1) and a new spirostanol saponin, chantrieroside A (2) were isolated from the rhizomes of Tacca chantrieri, together with another five known steroidal compounds. Their structures were established as (22R)-1alpha,12alpha-diacetoxy-2alpha,3alpha;6alpha,7alpha-diepoxy-27-[(beta-D-glucopyranosyl)oxy]-5alpha-hydroxywith-24-enolide (1) and (25R)-spirost-5-en-3-yl-O-alpha-L-rhamnopyranosyl-(1-->2)-O-[O-beta-D-glucopyranosyl-(1-->4)-alpha-L-rhamnopyranosyl-(1-->3)]-beta-D-glucopyranoside (2). The structures of the new saponins were determined by detailed analysis of their 1 dimensional (1D) and 2D NMR spectra, and chemical evidences.