Inhibitory effect of constituents of Bu-Shen-Jian-Gu-Tang on osteoclast-like cell formation

The constituents of Bu-Shen-Jian-Gu-Tang and their inhibitory activities on osteoclast-like cell formation were investigated. Bu-Shen-Jian-Gu-Tang was fractionated by a Diaion HP-20 column with EtOH-H2O, and the 60% and 90% EtOH-H2O fractions showed more potent inhibitory activities on osteoclast-like cell formation and bone resorption. Chemical investigation of these two fractions resulted in the isolation of 11 compounds, for which the structures were elucidated based on spectroscopic analysis and chemical reactions. The inhibitory activities of the isolated compounds on osteoclast-like cell formation were evaluated. Among the eleven compounds, icariin (1), icarisid II (2), 2"-O-rhamnosylicariside II (3), kaempferol (8), chikusetsusaponin IVa (10) and chikusetsusaponin V (11) showed potent inhibitory activities at a concentration of 2 μM without toxic effects. The preventive effect of Bu-Shen-Jian-Gu-Tang on bone loss may be due to the inhibitory activities of these compounds.