Cowpea isoflavones enhance the osteoblast differentiation and antioxidant capacity in synergy with vitamin D and β-carotene: A mechanistic in vitro study

Abstract

Background: Osteoporosis (OS) is a pathological condition that makes bones susceptible to fractures by affecting the balance between bone formation and resorption. Recent literature uncovered the possible potential of bioactive compounds with antioxidant mechanisms to counter the issue. Cowpea (CP) isoflavones based on our previous study, vitamin D and natural antioxidant β-carotene for its pleotropic protective effects were assessed alone and in combination. Aim: The study aims to assess the antioxidant and osteoblast differentiation abilities of cowpea isoflavones alone and in combination of vitamin D (VD) and β-carotene (BC) in the human osteosarcoma cell line Saos2. Methods: Saos2 cells were maintained in cell culture conditions and concentrations of CP extract (genistein  +  daidzein), BC and VD required to increase cell proliferation were estimated using MTT assay. Upon treating cells with the EC50 concentrations, lysates were prepared and levels of alkaline phosphatase (ALP) and osteocalcin were evaluated using ELISA. Oxidative stress parameters and osteoblast differentiation markers were evaluated. Results: CP extract (genistein  +  daidzein), BC and VD concentrations which enhanced the cell proliferation rate were determined and elevated levels of ALP and osteocalcin upon treatment was observed. Anti-oxidant stress parameters studied showed an increase in cells upon treatment compared to control. Significant alterations in levels of protein involved in osteoblast differentiation are observed upon treatment. Conclusion: Cowpea isoflavones has shown a significant activity against OS by elevating antioxidant parameters and inducing osteoblast differentiation in the present study.