Effects of Uncaria rhynchophylla Extracts on Differentiation and Bone Mineralized Formation in Human Osteoblast-like SaOS-2 cells

Background & Objective : Uncaria rhynchophylla is traditional medicine herb used for enhancing body resistance against various diseases. The aim of this study was to identify if Uncaria rhynchophylla extracts induce osteogenic activity in human osteoblast-like SaOS-2 cells. Methods : The osteogenic activity of Uncaria rhynchophylla was evaluated on cell proliferation assay by WST-8, and osteoblast-specific genes, such as VEGF, type I collagen (Col I), osteocalcin (OCN), and osteopontin (OPN) by RT-PCR analysis and ELISA assay in osteoblasts-like SaOS-2 cells. Bone mineralization was stained with Alizalin red method. Results : Uncaria rhynchophylla had significantly increased cell proliferation at a dose dependent manner in human osteoblast-like SaOS-2 cells. Uncaria rhynchophylla markedly increased alkaline phosphatase (ALP), vascular endothelial growth factor (VEGF) mRNA expression at 7 days and dose dependently increased ALP activity and VEGF secretion in human osteoblast-like SaOS-2 cells. Also, Uncaria rhynchophylla time-dependently increased type I collagen (Col I), osteopontin (OPN), and osteocalcin (OCN) mRNA in SaOS-2 cells. Extracellular accumulation of proteins such as Col I and OCN was maximal increased by Uncaria rhynchophylla at 10 ${\mu}g/ml$. Also, Uncaria rhynchophylla significantly induced mineralization in the culture of SaOS-2 cells. Conclusion : This study showed that Uncaria rhynchophylla had enhanced proliferation, ALP activity, VEGF, bone matrix proteins such as OCN, OPN, and Col I, and mineralization in SaOS-2 cells. These results propose that Uncaria rhynchophylla can play an important role in osteoblastic bone formation, osteogenesis, and may possibly lead to the development of bone-forming drugs.