title: Drynaria fortunei-derived total flavonoid fraction and isolated compounds exert oestrogen-like protective effects in bone.
abstract: Drynaria fortunei (Kunze) J. Sm. (DF), a Chinese herb commonly used for the treatment of bone fracture, was previously shown to exert anabolic effects on bone. However, its active ingredients as well as the mechanisms of action are far from clear. The present study aimed to characterise the bone anabolic effects of DF flavonoid fraction (DFTF) in ovariectomised (OVX) mice and to determine if DFTF and its isolated compounds exert oestrogen-like effects in rat osteoblast-like UMR-106 cells. Young OVX C57/BL6J mice were treated orally with DFTF (0·087, 0·173 or 0·346 mg/g per d), 17b-oestradiol (2 mg/g per d) or its vehicle for 6 weeks. Serum and urine samples were collected for biochemical marker analysis. Bones were collected for computed tomography analysis. UMR-106 cells were treated with DFTF and isolated compounds naringin, (2S)-5,7,30,50-tetrahydroxy-flavonone 7-O-neohesperidoside (compound 1) and 5,7-dihydroxychromone 7-O-neohesperidoside (compound 2). DFTF exerted dose-dependent effects in improving bone mineral densities as well as bone strength at the femur, tibia and lumbar spine L1 in OVX mice. DFTF and the three isolated compounds stimulated osteoblastic cell proliferation and alkaline phosphatase activities in a dose-dependent manner. In addition, they stimulated the ratio of osteoprotegrin and receptor-activator NF-kB ligand mRNA expression, suggesting their involvement in inhibiting osteoclastogenesis. These stimulatory effects on osteoblastic functions were abolished in the presence of oestrogen receptor (ER) antagonist, ICI 182780. The present results suggested that DFTF is effective in protecting against OVX-induced bone loss in mice, and its actions in regulating osteoblastic activities appear to be mediated by ER.
authors.affiliation: Department of Applied Biology and Chemical Technology, The Hong Kong Polytechnic University, Hung Hom, Kowloon, Hong Kong, PR China.
authors.forename: Ka-Chun
authors.initials: KC
authors.lastname: Wong
authors.forename: Wai-Yin
authors.initials: WY
authors.lastname: Pang
authors.forename: Xin-Lun
authors.initials: XL
authors.lastname: Wang
authors.forename: Sao-Keng
authors.initials: SK
authors.lastname: Mok
authors.forename: Wan-Ping
authors.initials: WP
authors.lastname: Lai
authors.forename: Hung-Kay
authors.initials: HK
authors.lastname: Chow
authors.forename: Ping-Chung
authors.initials: PC
authors.lastname: Leung
authors.forename: Xin-Sheng
authors.initials: XS
authors.lastname: Yao
authors.forename: Man-Sau
authors.initials: MS
authors.lastname: Wong
mesh_terms: D000469:Alkaline Phosphatase / Q000378:metabolism; D000818:Animals; D015519:Bone Density / Q000187:drug effects; D050071:Bone Density Conservation Agents / Q000302:isolation & purification / Q000494:pharmacology / Q000627:therapeutic use*; D001842:Bone and Bones / Q000187:drug effects*; D049109:Cell Proliferation / Q000187:drug effects; D004305:Dose-Response Relationship, Drug; D004365:Drugs, Chinese Herbal / Q000494:pharmacology / Q000627:therapeutic use; D004958:Estradiol / Q000031:analogs & derivatives / Q000494:pharmacology; D005260:Female; D005269:Femur; D044950:Flavanones / Q000302:isolation & purification / Q000494:pharmacology / Q000627:therapeutic use; D005419:Flavonoids / Q000302:isolation & purification / Q000494:pharmacology / Q000627:therapeutic use*; D000077267:Fulvestrant; D008159:Lumbar Vertebrae; D051379:Mice; D008810:Mice, Inbred C57BL; D010006:Osteoblasts / Q000187:drug effects; D010010:Osteoclasts / Q000187:drug effects; D010024:Osteoporosis / Q000235:genetics / Q000378:metabolism / Q000517:prevention & control*; D053244:Osteoprotegerin / Q000378:metabolism; D010052:Ovariectomy; D048789:Phytoestrogens / Q000302:isolation & purification / Q000494:pharmacology / Q000627:therapeutic use*; D008517:Phytotherapy; D010936:Plant Extracts / Q000737:chemistry / Q000494:pharmacology / Q000627:therapeutic use; D029621:Polypodiaceae / Q000737:chemistry*; D012333:RNA, Messenger / Q000378:metabolism; D051381:Rats; D013977:Tibia
chemical_list: D050071:Bone Density Conservation Agents; D004365:Drugs, Chinese Herbal; D044950:Flavanones; D005419:Flavonoids; D053244:Osteoprotegerin; D048789:Phytoestrogens; D010936:Plant Extracts; D012333:RNA, Messenger; D000077267:Fulvestrant; D004958:Estradiol; D000469:Alkaline Phosphatase; C005274:naringin