Effect of A. paeoniifolius extracts on bone growth and osteoporosis via inhibiting RANKL-mediated pathway

Abstract

Osteoporotic fractures are commonly observed in postmenopausal women. The major risk factor involved is estrogen deficiency. Phytoestrogens, structurally identical to 17-estradiol, have been shown to decrease bone turnover markers, increase bone mineral density, and provide protection against osteoporosis. The present study involves probing the molecular mechanism of Amorphophallus paeoniifolius (AP) rich in phytoestrogens viz kaempferol, rutin, quercetin, and gallic acid, as some therapeutic moieties in the treatment of osteoporosis. The study involves extraction of AP followed by MTT assay for cytotoxicity, and RT-PCR for evaluating the mRNA expression of RANKL, ALP, IL-6, Osteopontin (OPN), and Osteocalcin (OCN ) and western blot analysis of RANKL, along with bone mineralization assay. In the MTT assay, AP extracts showed biocompatibility in both MG-63 and UMR-106, with downregulation of osteoclast differentiation factors RANKL, and IL-6 and upregulation of osteoblastic markers OPN, OCN , and ALP through RT-PCR analysis at 50 μg/ml. In western Blot analysis, decreased protein expression of RANKL indicates reduced bone resorption. A significant increase in Alizarin red dye staining intensity during treatment confirms the progression of calcium deposition, thereby ensuring bone remineralization. The study reveals that AP, promotes osteoblast differentiation, bone re-mineralization, and re-calcification by the downregulation of the RANKL-mediated pathway, suggesting potential therapeutic efficacy for the treatment of post-menopausal osteoporosis.