Anti-Osteoporotic Components of Rubus chingii

Phytochemical studies of Rubus chingii Hu afforded a new chromone (1), identified as rubusin B, along with six known compounds, kaempferol (2), rubusin A (3), quercetin (4), beta-sitosterol (5), oleanolic acid (6), and liballinol (7). All the chemical structures were identified using 1D and 2D NMR data and MS data. It was found that compounds 1-4 displayed anti-osteoporotic activities to different degrees, quercetin and kaempferol significantly increased alkaline phosphatase (ALP) activity and can stimulate osteoblastic activity, and rubusin A and B strongly inhibit osteoclastic cell and bone resorption even at a concentration of 0.01 ppm.