Effect of Sargassum horneri extract on circulating bone metabolic markers: Supplemental intake has an effect in healthy humans

Abstract

The extract of Sargassum horneri (S. horneri) has been shown to have an anabolic effect on bone components due to stimulating bone formation and to inhibiting bone resorption in rat femoral tissues in vitro and in vivo. This study was undertaken to determine the effect of supplemental intake of the water-solubilized S. horneri extract on circulating bone metabolic markers in healthy humans. Thirty-six volunteers, aged 20-60 years (16 men and 20 women), were enrolled in this study. Volunteers were divided into three groups; placebo tablet without S. horneri extract (5 men and 7 women), tablet containing S. horneri extract at 300 mg/day (6 men and 7 women) or 900 mg/day (5 men and 6 women). Placebo or S. horneri extract tablet was ingested once a day for 4 or 8 weeks. Bone-specific alkaline phosphatase and γ-carboxylated osteocalcin are serum bone markers of bone formation, and bone tartrate-resistant acid phosphatase (TRACP) and N-telopeptides of type I collagen are markers of bone resorption. Serum bone-specific alkaline phosphatase or γ-carboxylated osteocalcin concentration was not significantly changed after the intake of S. horneri extract (300 or 900 mg/day) for 4 or 8 weeks. Serum bone TRACP activity was significantly decreased after the intake of S. horneri extract (300 or 900 mg/day) for 8 weeks. Serum N-telopeptides of type I collagen concentration was significantly decreased after the intake of S. horneri extract (900 mg/day) for 8 weeks. Meanwhile, serum calcium, inorganic phosphorus, and other biochemical findings were not changed after the intake of S. horneri extract (300 or 900 mg/day) for 4 or 8 weeks. This study demonstrates that the prolonged intake of S. horneri extract has inhibitory effects on bone resorption in humans.