The effect of tochu bark on bone metabolism in the rat model with ovariectomized osteoporosis.

In this study, Tochu bark extract was examined to find out whether it is effective in preventing bone loss after menopause. Six-week-old Sprague-Dawley female rats were ovariectomized (OVX) or were sham-operated (sham). The rats in the OVX and the sham groups were fed a low-calcium diet (Ca 0.01%, P 0.3%) for 33 days. Thereafter, the rats in the OVX group were subdivided into two groups: a control group and a Tochu group. The diet for the Tochu group contained 2% Tochu bark extract (Ca 0.3%, P 0.3%). The diet for the control group and the sham group was the control diet; it contained 0.3% Ca and 0.3% P. The rats in each group were fed each experimental diet for the next 31 days. The bone mineral density (BMD) and the breaking strength of the control group were lower than those of the sham group. However, the BMD and the bone strength had improved in the Tochu group. These results suggest that the Tochu bark extraction could be effective in the prevention of osteoporosis. Moreover, in the Tochu group, intestinal Ca absorption increased. This means the Tochu bark extract accelerated the intestinal Ca absorption. This could possibly affect the increase of the BMD and the bone strength. Moreover, the muscle weight of the Tochu group was higher than that of the control group. These results suggest that Tochu bark extract is also effective for the improvement of the bone and the muscle metabolism in sedentary people with back pains and/or joint pains.