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Background and purpose: Icariin may be the active ingredient in Herba Epimedii, a Chinese herb commonly used for treatment of osteoporosis. The present study aims to delineate the mechanism(s) by which icariin prevents bone loss after ovariectomy (OVX) in vivo and stimulates osteoblastic functions in vitro. Experimental approach: Ovariectomized or sham-operated C57BL/6 mice were treated with vehicle, 17b-oestradiol or icariin for 6 weeks. Total and trabecular bome mineral density (BMD) as well as polar stress-strain index of distal femur were measured by peripheral computed tomography. The mRNA expressions of OPG and RANKL in tibia were studied by RT-PCR. Interactions between the oestrogen receptor (ER) antagonist ICI182,780 and icariin were studied in UMR 106 cells. The functional transactivation of ERa and ERb as well as ERa phosphorylation by icariin were also assessed. Key results: Icariin suppressed the loss of bone mass and strength in distal femur and increased the mRNA expression ratio of OPG/RANKL in tibia, following OVX. Icariin increased ER-dependent cell proliferation, alkaline phosphatase (ALP) activity, gene expression of OPG and the OPG/RANKL ratio in UMR 106 cells. Icariin did not activate ERE-luciferase activity in UMR 106 cells, via the ERa or the ERb-mediated pathway, but it did increase ERa phosphorylation at Ser118. Conclusions and implications:Our results indicate that icariin exerts anabolic effects in bone possibly by activating ER in a ligand-independent manner. Its ability to prevent OVX-induced bone loss without inducing uterotrophic effects supports its use as an alternative regimen for management of postmenopausal osteoporosis.

Herba epimedii (HEP) is one of the most frequently used herbs prescribed for treatment of osteoporosis in China. In the present study, the in vivo effects of HEP extract on bone metabolism were evaluated using 4-month-old ovariectomized (OVX) or sham-operated (Sham) female Sprague-Dawley rats orally administered with HEP extract (110 mg kg−1d−1), 17ß-estrogen (2 mg kg−1d−1) or its vehicle for 3 months. HEP extract significantly decreased urinary calcium excretion, suppressed serum alkaline phosphatase (ALP) activity and urinary deoxypyridinoline levels in OVX rats (P < 0.05 versus vehicle-treated OVX rats). Histomorphometric analysis indicated that HEP extract could prevent OVX-induced bone loss by increasing tibial trabecular bone area and decreasing trabecular separation in OVX rats (P < 0.05 versus vehicle-treated OVX group). The in vitro effects of HEP extract were also studied using rat osteoblast-like UMR 106 cells. HEP extract significantly stimulated cell proliferation in a dose-dependent manner (P < 0.01 versus vehicle-treated) and increased ALP activity at 200 μgml−1 (P < 0.01 versus vehicle-treated) in UMR 106 cells. It modulated osteoclastogenesis by increasing osteoprotegrin (OPG) mRNA and decreasing receptor activator of NF-κB ligand (RANKL) mRNA expression, resulting in a dose-dependent increase in OPG/RANKL mRNA ratio (P < 0.01 versus vehicle-treated). Taken together, HEP treatment can effectively suppress the OVX-induced increase in bone turnover possibly by both an increase in osteoblastic activities and a decrease in osteoclastogenesis. The present study provides the evidence that HEP can be considered as a complementary and alternative medicine for treatment of post-menopausal osteoporosis.

Background and purpose: Naringin, a flavanone glycoside in citrus fruits, has been recently reported to stimulate bone formation in vitro and in vivo. The present study was designed to determine if naringin could exert oestrogen-like protective actions in bone. ·day -1 increased BMD at trabecular-rich bone in OVX mice. Naringin (at both doses) significantly increased SSI at distal femur and lumbar spine and increased biomechanical strength (ultimate load and energy for breaking) at tibia diaphysis in OVX mice. The stimulatory effects of naringin on osteoblastic functions could be abolished by co-incubation with ICI 182780 in UMR-106 cells. Naringin failed to stimulate ERa-or ERb-mediated oestrogen response element-dependent luciferase activity but could significantly induce ERa phosphorylation at serine 118, in UMR-106 cells. Conclusions and implications: Naringin was effective in protecting against OVX-induced bone loss in mice and its actions might be mediated through ligand-independent activation of ER in osteoblastic cells.

Our study demonstrated that FLL improved Ca balance in aged female rats by increasing serum 1,25 (OH)(2)D(3) level and vitamin D-dependent CaBPs expression.

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Postmenopausal osteoporosis is a major age-related health problem for women who often have negative calcium balance due to decrease in intestinal calcium absorption, insufficient dietary calcium intake, as well as increase in urinary Ca loss associated with estrogen deficiency during menopause. 1)Hormone replacement therapy (HRT) has been an established regime for prevention of postmenopausal bone loss, 2,3) but recent evidence indicates that its long-term use is accompanied by side effects, such as the increased risk of breast, ovarian and endometrial cancer. 4,5) Thus, alternative means of proven efficacy and safety should be developed for prevention and treatment of postmenopausal osteoporosis.Traditional Chinese Medicine (TCM) has been widely used for thousands of years to treat fractures and joint diseases. Many herbs shown to have kidney-tonifying activities are used in TCM formulas for prevention and treatment of osteoporosis.6) Although these herbal medicines are seen as cost-effective alternatives by their traditional users, their international acceptance as a major regimen for prevention and treatment of osteoporosis would require extensive research using modern science.The source of the crude drug, Fructus Ligustri Lucidi (FLL, Chinese name, Nvzhenzi), is the fruit of Ligustrum lucidum Ait.7) It has been used in traditional Chinese medicine for over 1000 years, mainly to treat such ailments as menopausal problems, blurred vision, tinnitus, rheumatic pains, palpitations, backache, insomnia as well as to alleviate age-related symptoms.8-10) It was first described in the Chinese Materia Medica, Shen Nong Ben Cao Jing (Anonymous, ca. 200 B.C). In the theory of traditional Chinese medicine, it has the effects of maintaining healthy energy, and nourishing the liver and kidneys, is therefore a commonly prescribed herbal material in a number of formulae used to tonify the kidneys and strengthen bone. 11,12) Modern research has shown that FLL is useful for prevention of bone marrow loss in cancer patients receiving chemotherapy.13) Hao et al. observed that FLL induced ultrastructural changes on the corticotrophs of rat pituitary gland and provided morphological evidence for the action of FLL in modulating endocrine function.14) However, the beneficial effect on bone and mineral metabolism has not been scientifically evaluated.In this study, we investigated the effects of the crude FLL extract on bone and mineral metabolism, bone turnover marker and calcium balance in osteoporotic rats. The results provide evidence of the osteoprotective effects of this crude extract in ovariectomized rats. MATERIALS AND METHODS Measurement of Oleanolic Acid in Fructus LigustriLucidi (FLL) Extract Dried extract powder of Fructus Ligustri Lucidi was purchased from 999 Company (Shenzhen, China), and the yield of the extract from original plant was 42%. A voucher specimen was deposited in the Shenzhen Research Center of Traditional Chinese Medicine and Natural Products (Shenzhen, P.R.C.), where oleanolic acid was supplied. The con...