Five new oleanolic acid glycosides from Achyranthes bidentata with inhibitory activity on osteoclast formation

Bioassay-directed fractionation of a butanol-soluble fraction of methanol extract of the root of Achyranthes bidentata resulted in the isolation of 5 new oleanolic acid glycosides 1-5, namely, 18-(beta-D-glucopyranosyloxy)-28-oxoolean-12-en-3beta-yl 3-O-(beta-D-glucopyranosyl)-beta-D-glucopyranosiduronic acid methyl ester (1), achyranthoside C dimethyl ester (2), achyranthoside C butyl dimethyl ester (3), achyranthoside E dimethyl ester (4), and achyranthoside E butyl methyl ester (5), together with 10 known compounds. Their structures were established on the basis of spectroscopic interpretation and chemical methods. All the oleanolic acid glycosides inhibited the formation of osteoclast-like multinucleated cells (OCLs) induced by 1alpha,25(OH)2D3 in a co-culture assay system.