Abstract
The effect of Sargassum horneri extract on bone formation in the femoral-diaphyseal and -metaphyseal tissue of rats in vitro was investigated. Femoral-diaphyseal and -metaphyseal tissues were cultured for 24 hr in Dulbecco's modified Eagle's medium containing either vehicle or a water-solubilized extract (10 and 25 μg/ml of medium) obtained from various marine algae (S. horneri, S. ringgoldianum Harvey, and S. yamadae Yoshida et T. Konno). Diaphyseal and metaphyseal calcium contents were significantly increased in the presence of S. horneri extract. Such an effect was not seen in the presence of S. ringgoldianum Harvey or S. yamadae Yoshida et T. Konno extract. Heat-treated S. horneri extracts (for 30 min at 80°C) did not have an anabolic effect on bone calcium content. Alkaline phosphatase activity and deoxyribonucleic acid (DNA) content in the femoral-diaphyseal and -metaphyseal tissues were significantly increased by culture with S. horneri extract (25 μg/ml of medium) for 24 hr. The effect of S. horneri extract in increasing calcium content, alkaline phosphatase activity, and DNA content in the femoral-diaphyseal and -metaphyseal tissues was completely abolished in the presence of cycloheximide (10-6 M), an inhibitor of protein synthesis. The present study demonstrates that, among marine algae which belong to Sargassum, S. horneri extract has a unique stimulatory effect on bone formation and calcification in vitro.
