Glycoside modification of oleanolic acid derivatives as a novel class of anti-osteoclast formation agents.

Oleanolic acid, a natural product, possesses an anti-osteoclast formation activity. Targeting at discovery of novel and potent anti-bone resorption agents, 22 glycosides of oleanolic acid derivatives (including d-galactopyranosides, d-glucopyranosides, d-xylopyranoses, d-arabopyranoses and d-glycuronic acids) were synthesized at phase-transfer-catalyzed conditions (K(2)CO(3), Bu(4)NBr, CH(2)Cl(2)-H(2)O) and their inhibitory activity on the formation of osteoclast-like multinucleated cells (OCLs) induced by 1alpha, 25-dihydroxy vitamin D(3) was evaluated in a co-culture assay system. The structure-activity relationships of these compounds were also discussed.