Structure elucidation by NMR spectroscopy of a new acetylated saponin from Centratherum anthelminticum

A new glycosylated triterpene has been isolated from the seeds of Centratherum anthelminticum, a medicinally important plant. The structural analysis of its acetylated derivative was performed by 1H, 13C NMR, 1H-1H COSY, HMQC, HMBC and DEPT spectroscopy. The saponin was shown to contain hederagenin and six sugar residues forming two glycosyl chains. The complete structure of the saponin was established as 3-O-beta-D-glucopyranosyl-(1-->3)-alpha-L-rhamnopyranosyl-(1-->2)-alpha-L-arabinopyranosyl]-28-O-beta-D-glucuronopyranosyl-(1-->4)-alpha-L-rhamnopyranosyl-(1-->3)-beta-D-glucopyranosyl]-hederagenin.