Pterocarpus soyauxii (Fabaceae) Heartwood Aqueous Extract Exhibits Anti-osteoporotic Activities in a Postmenopausal-like Model

Previous studies showed that Pterocarpus soyauxii (P. soyauxii) exhibits estrogenic activities ease menopausal disorders. The objective of this study was to evaluate anti-osteoporotic activities of the aqueous extract of P. soyauxii heartwood in ovariectomized (Ovx) Wistar rats. To achieve this, an 84-day postmenopausal osteoporosis model was used. Twenty-five female rats were ovariectomized and 5 others were sham-operated (Sham). After 84 days of hypoestrogenism, Ovx animals were divided into 5 groups including a group receiving distilled water at 10 mL/kg, a group receiving estradiol valerate (E2V) at 1 mg/kg, and three groups receiving P. soyauxii extract at 100, 200, and 300 mg/kg; Sham-operated animals received vehicle (10 mL/kg). After 28 days of treatment, animals were sacrificed. Blood was collected in EDTA tubes for blood count and in dry test tubes. Some femoral and seric biochemical analyses were carried out. The relative mass of both tibia and femur, and femoral density were assessed. As result, oophorectomy significantly increased the level of white blood cells (WBC) (p ˂0.01), MDA (p ˂0.01), nitrites (p ˂0.001), and urinary calcium/urinary creatinine ratio (p ˂0.01). Ovx animals presented a low femoral calcium and phosphorus levels (p ˂0.05) likewise ALP activity in both serum and femur compared to sham group. Thus, they also presented numerous resorption lacunae in the tibia and femur and a disorganization of tibia trabecular bone. P. soyauxii extract at 300 mg/kg significantly decreased WBC (p ˂0.05), MDA (p ˂0.01), and nitrites (p ˂0.001) compared to vehicle. At the dose of 200 mg/kg, P. soyauxii extract significantly increased femoral calcium (p ˂0.05), seric phosphorus (p ˂0.01), and ALP activity (p ˂0, 05) in both femur and serum, as well as relative femoral mass (p ˂0.05) and density (p ˂0.001). Furthermore, the plant extract at 200 and 300 mg/kg reduced resorptive lacunae and reconstituted trabecular bone in Ovx animals. Overall, aqueous extract of P. soyauxii exhibits anti-osteoporotic activities in a postmenopausal-like model in Wistar rats.