Histochemical analysis of OB-specific phenotypes induced by herbal extracts. MC3T3E1 cells were seeded and allowed to differentiate into mature OBs. Then, the cells were then cultured in the absence (Control) or presence of 10 μM AD, or 1, 10 and 100 μg/ml C. atratum, M. azedarach and C. turtschaninovii extracts. After 3 days, cells were subjected to crystal violet (CV), ALPase activity (ALP) and alizarin red (AR) staining, and examined under a microscope. Bar, 100 μm.