Anabolic Effects of Bee Pollen Cistus ladaniferus Extract on Bone Components in the Femoral-Diaphyseal and -Metaphyseal Tissues of Rats in Vitro and in Vivo

Abstract

The effects of bee pollen extract on bone components in the femoral-diaphyseal (cortical bone) and -metaphyseal (trabecular bone) tissues of rats in vitro and in vivo were investigated. Bone tissues were cultured for 48 hr in serum-free Dulbecco's modified Eagle's medium containing either vehicle or water- or ethanol-solubilized extracts (10, 100, or 1000 μg/ml of medium) obtained from the bee pollen of Cistus ladaniferus. Calcium content in the femoral-diaphyseal or -metaphyseal tissues was significantly increased in the presence of water-solubilized extract (100 or 1000 μg/ml) and ethanol-solubilized extract (1000 μg/ml). An increase was also observed in the presence of water-solubilized extract (100 μg/ml) obtained from Fagopyrum esculentum, Camellia sinesis, or Brassica napus L. Alkaline phosphatase activity and DNA content in the femoral-diaphyseal or -metaphyseal tissues in vitro were significantly increased in the presence of water-solubilized extract (100 or 1000 μg/ml) obtained from the bee pollen. The effects of the bee pollen extract (100 μg/ml) in increasing bone components were completely inhibited in the presence of cycloheximide (10-6 M), an inhibitor of protein synthesis, in vitro. Moreover, the calcium content and alkaline phosphatase activity in the femoral-diaphyseal or -metaphyseal tissues were significantly increased by the oral administration of water-solubilized extracts (5 or 10 mg/100 g body weight) obtained from the bee pollen of Cistus ladaniferus once daily for 7 days. The DNA content in the diaphyseal or metaphyseal tissues was significantly increased by the oral administration of water-solubilized extract (10 mg/100 g) of bee pollen cistus. The dose of 1.0 mg/100 g caused a significant increase in the diaphyseal and metaphyseal alkaline phosphatase activity or the metaphyseal DNA content in vivo. This study demonstrates that the extract of bee pollen has an anabolic effect on bone components in rats in vitro and in vivo.