Osteoprotective activity from Pholidota articulata Lindley (Orchidaceae): A traditional plant used for healing fractures in Uttarakhand Himalaya, India

Pholidota articulata Lindley (PA) family Orchidaceae is commonly used for healing fractures in folk traditions of Uttarakhand Himalaya, India. Bone remodeling is a constant and dynamic process that requires the involvement of osteoblasts, which helps in bone formation and mineralization. Present study was aimed to characterize the fracture healing properties of PA to validate the folklore claims of healing fractures. The osteogenic potential of ethanolic extract of PA was evaluated using Ovariectomized (Ovx) estrogen deficient adult female Balb/c mice (an animal model for post-menopausal osteoporosis). Subsequently, three phenanthrene derivatives isolated from ethyl acetate fraction of PA and evaluated through alkaline phosphatase assay (ALP) and mineralization assay. The ethanolic extract of PA exhibited significant restoration of trabecular micro architecture in both femoral and tibial bones, better bone quality and devoid of any uterine estrogenicity. One of the isolated phenanthrene derivatives, oxoflavidin enhanced ALP activity (a marker of osteoblast differentiation), mineral nodule formation and mRNA levels of osteogenic markers like BMP-2, Type 1 Collagen, RUNX-2 and osteocalcin. These results supported and validate the bone healing properties of PA and demonstrate the therapeutic potential for osteogenic activities during post-menopausal osteoporosis.