Horneri Extract Research Articles

Characterization of Active Component in Marine Alga Sargassum horneri Extract in Stimulating Bone Calcification in Vitro

The marine alga Sargassum horneri (S. horneri) has an anabolic effect on bone metabolism (J. Health Sci., 47, 533-538, 2001). The effect of the fractionated extracts obtained from S. horneri on bone calcium content and osteoclast-like cell formation in vitro was investigated. S. horneri was gathered from various coasts (Shimoda, Iwate, or China). Rat femoral-diaphyseal and -metaphyseal tissues were cultured for 24 hr in a medium containing either vehicle or a water-solubilized extract (25 μg/ml of medium) obtained from S. horneri. Diaphyseal and metaphyseal calcium contents were significantly increased in the presence of S. horneri extract from Shimoda, Iwate, or China. The active component of S. horneri extract in increasing calcium content in diaphyseal tissues was seen in the nearby fraction molecular weight (MW) of 1000. This effect completely disappeared upon heat treatment with 80°C for 30 min. Mouse marrow cells were cultured for 7 days in a medium containing 1,25-dihydroxyvitamin D3 [1,25(OH)2D3] (10-7 M) in the presence or absence of S. horneri extract (1.0 μg/ml of medium). The 1,25(OH)2D3-induced increase in osteoclast-like cell formation was markedly suppressed in the presence of the crude extract or a fraction more than MW 50000 of S. horneri extracts obtained from Iwate or China. This effect was also seen by heat treatment. The present study suggests that the active components of S. horneri extract in stimulating bone formation or suppressing osteoclastic bone resorption are different.

Preventive Effect of Marine Alga Sargassum Horneri Extract on Bone Loss in Streptozotocin-Diabetic Rats in Vivo.

The effect of Sargassum horneri (S. horneri) extract on bone components in the femoral-diaphyseal and -metaphyseal tissues of streptozotocin (STZ)-diabetic rats was investigated. Rats received a single subcutaneous administration of STZ (6.0 mg/100 g body weight), and then the animals were orally administered water-solubilized extract (10 mg/100 g body weight) of S. horneri once daily for 14 or 21 days. The administration of STZ caused a significant decrease in body weight and a significant increase in serum glucose, triglyceride, and calcium levels, indicating a diabetic state. These alterations were significantly prevented by the administration of S. horneri extract for 14 or 21 days. The administration of S. horneri extract to normal rats for 14 or 21 days did not have a significant effect on body weight or serum glucose, triglyceride, and calcium levels. Calcium content, alkaline phosphatase activity, and DNA content in the femoral-diaphyseal and -metaphyseal tissues were significantly decreased in STZ-diabetic rats. These decreases were significantly prevented by the administration of S. horneri extract for 14 or 21 days. The administration of S. horneri extract to normal rats for 14 or 21 days caused a significant increase in calcium content, alkaline phosphatase activity, and DNA content in the femoral-diaphyseal and -metaphyseal tissues. Femoral-diaphyseal and -metaphyseal tissues obtained at 14 days after STZ administration were cultured for 48 hr in a medium containing either vehicle or S. horneri extract (10, 25, or 50 μg/ml of medium) in vitro. Calcium content and alkaline phosphatase activity in the femoral-diaphyseal and -metaphyseal tissues obtained from STZ-diabetic rats was significantly increased in the presence of S. horneri extract (10, 25, or 50 μg/ml). The present results demonstrate that the intake of S. horneri extract has a preventive effect on bone loss in STZ-diabetic rats.

Stimulatory Effect of Sargassum Horneri Extract on Bone Formation in Rat Femoral-Diaphyseal and -Metaphyseal Tissues <i>in Vitro</i>

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 femoraldiaphyseal 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.

Anabolic Effect of Marine Alga Sargassum Horneri Extract on Bone Components in the Femoral-diaphyseal and -metaphyseal Tissues of Young and Aged Rats in Vivo.

The effect of Sargassum horneri on bone components in the femoral-diaphyseal and -metaphyseal tissues of young and aged rats was investigated. Rats were orally administered a water-solubilized extract (2.5, 5, and 10 mg/100 g body weight) of S. horneri once a day for 7 or 14 days. Calcium content, alkaline phosphatase activity and deoxyribonucleic acid (DNA) content in the femoral-diaphyseal and -metaphyseal tissues of young male (4 weeks old) rats was significantly increased by the administration of S. horneri extract (2.5, 5, and 10 mg/100 g) for 7 days. Moreover, these bone components in the femoral-diaphyseal and -metaphyseal tissues of aged female (50 weeks old) rats were significantly increased by the administration of S. horneri extract (10 mg/100 g) for 14 days. Meanwhile, body weight and serum calcium, zinc and inorganic phosphorus concentrations of female aged rats were not significantly altered by the administration of S. horneri extract (10 mg/ 100 g) for 14 days. The present study demonstrates that the oral intake of the water-solubilized extract of S. horneri can exhibit an anabolic effect on bone components of young rats in vivo, and that this effect is also seen in aged rats. The intake of S. horneri extract may have a preventive effect on bone loss with increasing age.

Inhibitory Effect of Marine Alga Sargassum horneri Extract on Bone Resorption in Tissue Culture in Vitro.

The effect of marine alga Sargassum horneri extracts on bone resorption in vitro was investigated. Femoral-diaphyseal and -metaphyseal tissues obtained from normal rats were cultured for 48 hr in Dulbecco's modified Eagle's medium (high glucose, 4.5%) supplemented with antibiotics and bovine serum albumin. The experimental cultures contained water-solubilized extracts (10, 25, and 50 μg/ml of medium) of S. horneri. The bone-resorbing factors parathyroid hormone (1-34) (PTH; 10-7 M) and prostaglandin E2 (PGE2; 10-5 M) caused a significant decrease in the diaphyseal and metaphyseal calcium content. The decrease in bone calcium content induced by PTH or PGE2 was completely inhibited by water-solubilized extracts (10, 25, and 50 μg/ml) of S. horneri. In addition, these extracts (25 and 50 μg/ml) completely prevented the PTH (10-7 M)- or PGE2 (10-5 M)-induced increase in medium glucose consumption and lactic acid production by bone tissues. Moreover, S. horneri extracts (10-50 μg/ml) blocked PTH (10-7 M)- increased acid phosphatase activity in the diaphyseal and metaphyseal tissues. These findings indicate that water-solubilized extracts of S. horneri have a direct inhibitory effect on bone resorption in tissue culture in vitro.