标题：Characterization of the Active Component in Bee Pollen Cistus ladaniferus Extract in Stimulating Bone Calcification and in Inhibiting Bone Resorption in Vitro
摘要：The bee pollen Cistus ladaniferus ( C. ladaniferus ) extract has an anabolic effect on bone metabolism. The effects of the fractionated extracts obtained from bee pollen on bone calcium content and osteoclast-like cell formation in vitro were investigated. Rat femoral-diaphyseal and -metaphyseal tissues were cultured for 48 hr in a medium containing either vehicle or a water-solubilized extract with the membrane fractions obtained from bee pollen. The active component of bee pollen in increasing calcium content in diaphyseal tissues was seen in the fraction of molecular weight (MW) of less than 1000, and it was not observed in fractions of greater than MW 1000. Culture with the fractionated bee pollen extract (25 or 50 μ g/ml of medium) of less than MW 1000 caused a significant increase in calcium content in the diaphyseal or metaphyseal tissues. The parathyroid hormone (PTH; 10-6 M)-induced decrease in diaphyseal calcium content was significantly prevented in the presence of the fractionated bee pollen extracts (10 μ g/ml) of less than MW 1000 or greater than MW 1000. Mouse marrow cells were cultured for 7 days in a medium containing PTH (10-6 M) in the presence or absence of the fractionated bee pollen extract (10 or 50 μ g/ml). The PTH-induced increase in osteoclast-like cell formation was markedly suppressed in the presence of extracts of less than MW 1000 as compared with that in the presence of fractions of greater than MW 1000. The effects of the fractionated bee pollen extracts of less than MW 1000 in increasing diaphyseal calcium content and in inhibiting PTH-induced osteoclastic cell formation were significantly decreased upon heat treatment for 20 and 60 min at 80°C. This study demonstrates that the active component of bee pollen C. ladaniferus extract, which stimulates bone formation and inhibits osteoclastic bone resorption, is the fraction with MW less than 1000.
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