BMP2 and osteoporosis: Naringin (Figure 8) is the main active ingredients of drynariae flavonoids, which could inhibit the retinoic acid-induced osteoporosis in rats, increase BMP-2 expression and induce the bone formation, enhance the proliferation and osteogenic differentiation of human bone mesenchymal stem cells (BMSCs) in osteoporosis diseases [59, 60].