Osteoprotective effect of Phaseolus vulgaris L in ovariectomy-induced osteopenia in rats

Abstract

Phytoestrogens and phytoestrogen-containing plants are currently being explored as potential candidates for the treatment of estrogen-related disorders. The aim of this study was to evaluate the anti-osteoporotic effect of the phytoestrogen-rich plant Phaseolus vulgaris L, commonly known as French beans. Adult Sprague-Dawley rats were either bilaterally ovariectomized (OVX) or sham operated. OVX and sham control groups were administered vehicle, whereas the other two OVX groups were given 0.15 mg/kg estradiol and 1 g/kg methanolic extract of P vulgaris L seeds (MPV) orally for 10 weeks (10 rats per group). At autopsy, blood, urine, bones, and uteri of the animals were collected. Serum was evaluated for estradiol, calcium (Ca), phosphorus, alkaline phosphatase, tartarate resistant acid phosphatase, and urine for Ca. The bone density, ash density, mineral content, and mechanical strength of bones was evaluated. Scanning electron microscopic analysis of bones (tibia) was performed. Results were analyzed using analysis of variance and Tukey's multiple comparison test. Compared with the OVX control, MPV (1 g/kg PO) significantly decreased serum alkaline phosphatase and reduced serum tartarate resistant acid phosphatase and urinary Ca levels. It caused an increase in bone density, ash density, and bone mechanical strength and significantly increased bone Ca. Improvement in bone microarchitecture was indicated by image analysis of scanning electron microscopic photomicrographs. No increase in weight of atrophic uterus in OVX animals was observed with MPV treatment. Treatment with MPV prevented estrogen deficiency-induced osteopenia without affecting the uterine mass. The promising results of the study warrant further investigation of French beans as a potential candidate for the treatment of postmenopausal osteoporosis.