摘要To the editor:I read with great interest the recent article by Liu et al.1 Icariin exerts its beneficial effects in osteoporosis in a number of ways.Icariin accentuates osteoblast maturation.Icariin increases the activity of alkaline phosphatase and up regulates receptor activator of nuclear factor κ-B ligand (RANKL) expression thereby enhancing bone formation.2 It also affects the bone morphogenic protein-2 (BMP-2)/Smad4 pathway and thereby up regulates both BMP-2 and Smad4 expression leading to the formation of calcified nodules in bone tissue.In fact,icariin exhibits greater efficacy in increasing osteogenic differentiation in comparison to other natural flavonoids such as genistein.3 Besides the above mentioned effects,up regulation of osteoprogeterin is another of the effects of icariin.