2003 年 49 巻 2 号 p. 123-128
The effect of wasabi leafstalk (Wasabia japonica MATTUM.) extract on bone components in the femoral-diaphyseal and -metaphyseal tissues of aged female rats in vitro and in vivo was investigated. Femoral-diaphyseal and -metaphyseal tissues were cultured for 48 hr in Dulbecco's modified Eagle's medium (serum free) containing either vehicle or wasabi leafstalk extract (10, 25 or 50 μg/ml of medium). The presence of wasabi leafstalk extract (50 μg/ml) caused a significant increase in calcium content, alkaline phosphatase activity and deoxyribonucleic acid (DNA) content in the diaphyseal and metaphyseal tissues in vitro. However, the effect of wasabi leafstalk extract (50 μg/ml) in increasing bone components was completely abolished in the presence of cycloheximide (10-6 M), an inhibitor of protein synthesis. Moreover, rats were orally administered wasabi leafstalk extract (10 or 20 mg/100 g body weight) once daily for 7 days. The calcium content, alkaline phosphatase activity and DNA content in the femoral-diaphyseal and -metaphyseal tissues of aged rats was significantly increased by the administration of wasabi leafstalk extract (10 or 20 mg/100 g) for 7 days in vivo. Meanwhile, body weight, serum calcium and inorganic phosphorus concentrations of female aged rats were not significantly altered by the administration of wasabi leafstalk extract (10 or 20 mg/100 g) for 7 days. The present study demonstrates that wasabi leafstalk extract has an anabolic effect on bone components in vitro and in vivo. The intake of wasabi leafstalk extract may have a preventive effect on bone loss with increasing age.