title: Erythrina variegata extract exerts osteoprotective effects by suppression of the process of bone resorption.
abstract: Our previous study showed that Erythrina variegata L. (EV) inhibited bone loss and improved bone properties in ovariectomised rats. The purpose of the present study is to investigate the potential mechanism involved in mediating the osteoprotective actions of EV. Female Sprague-Dawley rats were fed a phyto-oestrogen-free diet and subjected to either ovariectomy or a sham operation. Ovariectomised rats were treated with genistein (40 mg/kg) as well as low (200 mg/kg), medium (500 mg/kg) or high (1000 mg/kg) doses of EV extract. Bone properties and mRNA expressions were evaluated by micro-computed tomography and quantitative RT-PCR, respectively. Osteoclast differentiation in RAW 264.7 cells was studied by tartrate-resistant acid phosphatase (TRAP) staining. High doses of EV could decrease urinary Ca and P excretion, maintain serum Ca and P level, and exert beneficial effects on the micro-structure and morphology of trabecular bone and cortical bone in ovariectomised rats. EV suppressed the up-regulation of cathepsin K mRNA and the down-regulation of osteoprotegrin mRNA in the tibia of ovariectomised rats. TRAP-positive cell numbers were significantly decreased in receptor activator of nuclear factor-κB ligand (RANKL)-induced RAW 264.7 cells when co-cultured with EV extracts. The present study indicated that the protective effects of EV on bone properties in ovariectomised rats are likely to be mediated by its inhibitory actions on the process of bone resorption via the suppression of osteoclast differentiation and maturation.
authors.affiliation: Centre of System Biomedical Sciences, University of Shanghai for Science and Technology, Shanghai 200093, People's Republic of China.
authors.forename: Yan
authors.initials: Y
authors.lastname: Zhang
authors.forename: Qi
authors.initials: Q
authors.lastname: Li
authors.forename: Xiaoli
authors.initials: X
authors.lastname: Li
authors.forename: Hoi-Ying
authors.initials: HY
authors.lastname: Wan
authors.forename: Man-Sau
authors.initials: MS
authors.lastname: Wong
mesh_terms: D000135:Acid Phosphatase; D000818:Animals; D050071:Bone Density Conservation Agents / Q000494:pharmacology* / Q000627:therapeutic use; D001862:Bone Resorption / Q000188:drug therapy* / Q000378:metabolism; D002118:Calcium / Q000378:metabolism; D056657:Cathepsin K / Q000235:genetics / Q000378:metabolism; D002454:Cell Differentiation / Q000187:drug effects; D004895:Erythrina; D005260:Female; D019833:Genistein / Q000494:pharmacology / Q000627:therapeutic use; D007527:Isoenzymes; D008264:Macrophages / Q000187:drug effects / Q000378:metabolism; D051379:Mice; D010010:Osteoclasts / Q000187:drug effects* / Q000378:metabolism; D010024:Osteoporosis / Q000378:metabolism / Q000517:prevention & control*; D053244:Osteoprotegerin / Q000235:genetics / Q000378:metabolism; D010052:Ovariectomy; D010758:Phosphorus / Q000378:metabolism; D008517:Phytotherapy; D010936:Plant Extracts / Q000494:pharmacology* / Q000627:therapeutic use; D053245:RANK Ligand; D012333:RNA, Messenger / Q000378:metabolism; D051381:Rats; D017207:Rats, Sprague-Dawley; D020133:Reverse Transcriptase Polymerase Chain Reaction; D000071681:Tartrate-Resistant Acid Phosphatase
chemical_list: D050071:Bone Density Conservation Agents; D007527:Isoenzymes; D053244:Osteoprotegerin; D010936:Plant Extracts; D053245:RANK Ligand; D012333:RNA, Messenger; D010758:Phosphorus; D019833:Genistein; D000135:Acid Phosphatase; C000605511:Acp5 protein, mouse; D000071681:Tartrate-Resistant Acid Phosphatase; D056657:Cathepsin K; D002118:Calcium