The effect of isoflavone-containing soybean extract (nijiru) administration on bone components in rats was investigated. Rats were orally administered nijiru solution (100mg/ml/100g body weight) twice a day for 7 and 14 d. Nijiru suspension contained saponin (66μg/ml), daidzin (77μg/ml), daidzein (0.6μg/ml), genistin (58μg/ml), and genistein (0.6μg/ml). The solution administered for both periods caused a significant elevation of calcium content, alkaline phosphatase activity, and deoxyribonucleic acid (DNA) content in the diaphyseal and metaphyseal tissues of the femur in rats, while administration for 14 d did not cause a significant alteration in body weight or serum calcium and inorganic phosphorus concentrations, indicating that the solution may not have a toxic effect. This study demonstrates that intake of isoflavone-containing nijiru has an anabolic effect on bone components in rats, suggesting its role in the prevention of osteoporosis.
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