Antiosteoporotic activity of Davallia formosana

Ethanopharmacological relevance: In Taiwanese folk medicine, Davallia formosana is used to treat bone diseases, including osteoporosis. Aim: This study evaluated the anti-osteoporotic effect of ethanolic extract derived from Davallia formosana (DFE). Materials and methods: In this in vitro study, we investigated the inhibitory action of DFE on RANKL-stimulated osteoclastogenesis. The in vivo effects of DFE on bone metabolism were evaluated using ovariectomized (OVX) rats orally administered DFE (200, 500 mg/kg), alendronate (2.5 mg/kg, three times a week) or its vehicle for 12 weeks. Results: This in vitro study demonstrated that DFE inhibited osteoclast differentiation, and also isolated the active component, (-)-epicatechin 3-O-beta-D-allopyranoside (ECAP). DFE did not affect the body or vaginal weight in OVX rats. The bone mineral density and bone calcium content in OVX rats were lower in the control group showing that DFE was able to prevent significant bone loss. In addition, the three point bending test and the microcomputer tomography scanning showed that DFE treatment enhanced bone strength and inhibited the deterioration of trabecular microarchitecture. In the biochemical assay, DFE decreased urinary deoxypyridinoline and calcium concentrations, but did not inhibit serum alkaline phosphatase activities, indicating that it ameliorated bone loss via inhibition of bone reabsorption. Conclusions: These results suggest that DFE may represent a useful remedy for the treatment of bone reabsorption diseases such as osteoporosis. In addition, ECAP could be used as a marker compound to control the quality of DFE. (C) 2011 Elsevier Ireland Ltd. All rights reserved.