Effect of carotenoid on calcium content and alkaline phosphatase activity in rat femoral tissues in vitro: the unique anabolic effect of beta-cryptoxanthin.

The effects of various carotenoids and rutin on calcium content and alkaline phosphatase activity in the femoral-diaphyseal and femoral-metaphyseal tissues of young rats in vitro were investigated. Bone tissues were cultured for 48 h in serum-free Dulbecco's modified Eagle's medium containing either vehicle or a compound (10(-8)-10(-6) M). The presence of beta-cryptoxanthin (10(-7) or 10(-6) M) caused a significant increase in calcium content and alkaline phosphatase activity in the femoral-diaphyseal and femoral-metaphyseal tissues. Also, the lowest concentration (10(-8) M) of beta-cryptoxanthin used caused a significant increase in diaphyseal and metaphyseal calcium content. Lutein (10(-8)-10(-6) M) had no effect on diaphyseal and metaphyseal calcium contents and diaphyseal alkaline phosphatase activity, while 10(-7) and 10(-6) M lutein significantly decreased metaphyseal alkaline phosphatase activity. Lycopene (10(-8)-10(-6) M) or rutin (10(-8)-10(-6) M) did not have a significant effect on bone calcium content and alkaline phosphatase activity. The present study suggests that the carotenoid beta-cryptoxanthin has a unique anabolic effect on bone calcification in vitro.