Total flavonoid fraction of the Herba epimedii extract suppresses urinary calcium excretion and improves bone properties in ovariectomised mice.
Flavonoids are the active components of Herba epimedii (HEP), a commonly used herb for the management of osteoporosis in China over the centuries. The present study aims to characterise the in vivo effects of its total flavonoid (TF) fraction on bone properties and mineral metabolism as well as to study the mechanism involved in achieving its protective effects against ovariectomy (OVX)-induced bone loss. TF suppressed OVX-induced increase in urinary Ca excretion as well as loss of bone mass and strength at the distal femur in mice in a dose-dependent manner. The changes in urinary Ca excretion were inversely correlated with the expressions of renal Ca transport protein (CaBP-28K) and vitamin D receptor mRNA in OVX mice. TF (100 μg/g) treatment prevented the deterioration of trabecular bone microarchitecture induced by OVX in mice. In addition, TF treatment increased the expression of type I collagen and osteocalcin mRNA and the ratio of osteoprotegerin/receptor activator of NF-κB ligand mRNA, and suppressed the increase in IL-6 mRNA induced by OVX in the femur of mice. The present results indicate that the optimal dosage of the TF fraction of HEP for the improvement of bone properties and mineral metabolism in OVX mice was between 50 and 100 μg/g. Mechanistic studies indicated that TF might increase renal Ca reabsorption, stimulate the process of osteoblast formation as well as suppress the process of osteoclastogenesis in OVX mice.
Chen
Wen-Fang
WF
Department of Applied Biology and Chemical Technology, The Hong Kong Polytechnic University, Kowloon, Hong Kong.
Mok
Sao-Keng
SK
Wang
Xin-Luan
XL
Lai
Ka-Hang
KH
Lai
Wan-Ping
WP
Luk
Hon-Kit
HK
Leung
Ping-Chung
PC
Yao
Xin-Sheng
XS
Wong
Man-Sau
MS
D000818:Animals; D001483:Base Sequence; D015519:Bone Density / Q000187:drug effects; D001842:Bone and Bones / Q000000981:diagnostic imaging / Q000187:drug effects* / Q000378:metabolism; D002118:Calcium / Q000652:urine*; D002135:Calcium-Binding Proteins / Q000235:genetics; D024042:Collagen Type I / Q000235:genetics; D017931:DNA Primers / Q000235:genetics; D004305:Dose-Response Relationship, Drug; D004365:Drugs, Chinese Herbal / Q000008:administration & dosage / Q000737:chemistry / Q000494:pharmacology*; D004958:Estradiol / Q000494:pharmacology; D005260:Female; D005419:Flavonoids / Q000008:administration & dosage / Q000302:isolation & purification / Q000494:pharmacology*; D015850:Interleukin-6 / Q000235:genetics; D007668:Kidney / Q000187:drug effects / Q000378:metabolism; D051379:Mice; D008810:Mice, Inbred C57BL; D015675:Osteocalcin / Q000235:genetics; D010024:Osteoporosis / Q000188:drug therapy* / Q000235:genetics / Q000652:urine; D053244:Osteoprotegerin / Q000235:genetics; D010052:Ovariectomy; D008517:Phytotherapy; D053245:RANK Ligand / Q000235:genetics; D012333:RNA, Messenger / Q000235:genetics / Q000378:metabolism; D018167:Receptors, Calcitriol / Q000235:genetics; D055114:X-Ray Microtomography
D002135:Calcium-Binding Proteins; D024042:Collagen Type I; D017931:DNA Primers; D004365:Drugs, Chinese Herbal; D005419:Flavonoids; D015850:Interleukin-6; D053244:Osteoprotegerin; D053245:RANK Ligand; D012333:RNA, Messenger; D018167:Receptors, Calcitriol; C506031:Tnfrsf11b protein, mouse; C505689:Tnfsf11 protein, mouse; D015675:Osteocalcin; D004958:Estradiol; D002118:Calcium