In vivo and in vitro estimation of Davallia mariesii on osteoporotic bone regeneration

Ethnopharmacological relevance: Postmenopausal osteoporosis is one of the major bone health issues in the world. There is an unmet medical need for osteoporosis that disproportionately impacts women. Exploring botanicals to prevent or treat osteoporosis is currently an urgent subject. Rhizomes of D. mariesii Davallia mariesii T. Moore ex Baker (Davalliacea) is an indigenous herbal medicine used for injuries from fractures, contusions and strains in Asia.

Aim of the study: In the present study, we investigated the anti-osteoporotic effect of water extract of rhizomes of D. mariesii (DMH) on bone loss-induced by ovariectomy in mice and also its impact on osteogenesis in primary human osteoblasts (HObs). Additionally, we performed the quantitative analysis of compounds in the DMH extract.

Materials and methods: Ovariectomized (OVX) C57BL/6J mice were orally administrated with DMH extract for 12 weeks and examined by using microcomputed tomography for microarchitecture parameters. DMH extract was bio-guidedly fractionated and isolated to obtain active compounds using HObs. Cell viability was assessed by MTT assay. Early and late osteogenesis were analyzed by alkaline phosphatase activity and mineralization assay. Molecular mechanisms were explored by real-time quantitative PCR. Compound contents in the DMH extract was identified and quantified by using liquid chromatography tandem mass spectroscopy (LC-MS/MS).

Results: DMH ameliorated bone mineral densities of vertebrae and the femur. Through microarchitecture observations, DMH significantly decreased the bone surface/volume ratio and trabecular separation, and also increased the connectivity density in the OVX group. After bio-guided fractionation and isolation, we found eriodictyol-7-O-β-d-glucuronide (2) significantly increased alkaline phosphatase activity and 5-O-β-d-(6-O-vanilloylglucopyranosyl)gentisic acid (3) substantially enhanced mineral deposition. In HObs, 3 was more potent in upregulating expressions of bone morphogenetic protein-2, bone sialoprotein, osteopontin, osterix, and estrogen receptor-α. The amount of bioactive 3 in the DMH was 5.68 ± 0.64 mg/g of dry weight using LC-MS/MS.

Conclusion: Based on these results, D. mariesii seems to be a potential ethnobotanical resource for developing anti-osteoporosis agents and designing future standardized quality control measures.

Keywords: 5-O-β-d-(6-O-Vanilloylglucopyranosyl)gentisic acid; Davallia mariesii; Osteoporosis; Ovariectomy; Primary human osteoblasts.