Kudzu (Pueraria lobata) vine ethanol extracts improve ovariectomy-induced bone loss in female mice

Bone-loss-improving action of kudzu vine ethanol extracts (PVEE) was clarified. PVEE was composed roughly of 80% fiber, 10% puerarin, 3.6% daidzin, 2.5% 6″-O-malonyldaidzin, and the other minor isoflavones. Ten-week-old ovariectomized (OVX) mice were fed diets containing PVEE (20 mg/kg body weight/day) for 8 weeks. The bone resorption markers (urinary deoxypyridinoline and tartrate-resistant acid phosphatase activity) was elevated in OVX mice and was significantly decreased in OVX mice that consumed PVEE for 8 weeks. Consistent with the decrease in the markers, the number of matured osteoclasts in the distal femur was diminished in OVX mice fed PVEE diets. PVEE diets also suppressed the decrease in femoral bone mineral density (BMD) by OVX. PVEE showed the affinity for estrogen receptor α and β nearly 1/10000 weaker than 17β-estradiol. No hypertrophy in the uterus by the PVEE diet was observed. These results suggest that PVEE could be a promising resource for a functional food that improves osteoporosis.