Drynaria fortunei-derived total flavonoid fraction and isolated compounds exert oestrogen-like protective effects in bone.

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.

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.

Naringin improves bone properties in ovariectomized mice and exerts oestrogen-like activities in rat osteoblast-like (UMR-106) cells.

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.

Experimental Approach: Young C57/BL6J mice were ovariectomized (OVX) and treated orally with naringin (0.

Icariin protects against bone loss induced by oestrogen deficiency and activates oestrogen receptor-dependent osteoblastic functions in UMR 106 cells.

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, 17beta-oestradiol or icariin for 6 weeks.

Short- to mid-term effects of ovariectomy on bone turnover, bone mass and bone strength in rats.

To determine the short- to mid-term effects of ovariectomy on bone turnover, bone mass and bone strength in rats. SD rats aged 12 weeks were randomly divided into No-treatment, Sham and OVX groups. The rats were sacrificed for sample collection at week 0, week 4 and week 18 after surgical operation.

Ovariectomy worsens secondary hyperparathyroidism in mature rats during low-Ca diet.

Estrogen deficiency impairs intestinal Ca absorption and induces bone loss, but its effects on the vitamin D-endocrine system are unclear. In the present study, calciotropic hormones levels, renal vitamin D metabolism, 1,25-dihydroxyvitamin D3 [1,25(OH)2D3]-dependent intestinal calcium absorption, and bone properties in 3-mo-old sham-operated (sham) or ovariectomized (OVX) rats fed either a normal-Ca (NCD; 0.6% Ca, 0.

Anti-osteoporotic effect of Erythrina variegata L. in ovariectomized rats.

The present study was designed to investigate whether Erythrina variegata L. (EV), which belongs to the leguminous family, exerted any beneficial effects on bone in ovariectomized rats. Daily oral administration of the EV extract at 300 and 600 mg/kg for 14 weeks to rats prevented the OVX-induced increase in the serum OCN, ALP, and urinary DPD levels.

Effects of Fructus Ligustri Lucidi extract on bone turnover and calcium balance in ovariectomized rats.

The aim of this study was to evaluate the effect of Fructus Ligustri Lucidi (FLL), a kidney-tonifying Chinese herbal medicine, on the biochemical markers of bone turnover, calcium metabolism and balance in osteoporotic rat model developed by ovariectomy. Four weeks after surgical operation, animals were randomly assigned to one of the four treatments for 14 weeks: sham-operated control treated with vehicle (sham, n=8), ovariectomized group treated with vehicle (OVX, n=8), OVX group treated with 17beta-estradiol (E(2), n=10, 2 microg/kg/d) and OVX group treated with FLL extracts (FLL, n=10, 550 mg/kg/d). Serum osteocalcin and urinary deoxypyridinoline levels were upregulated in rats in response to OVX, suggesting that the bone turnover rate was accelerated in these animals.

The osteoprotective effect of Herba epimedii (HEP) extract in vivo and in vitro.

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 kgd), 17ss-estrogen (2 mg kgd) 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.

Age-related alteration of vitamin D metabolism in response to low-phosphate diet in rats.

The responses of renal vitamin D metabolism to its major stimuli alter with age. Previous studies showed that the increase in circulating 1,25-dihydroxyvitamin D (1,25(OH)2D3) as well as renal 25-hydroxyvitamin D3 1-alpha hydroxylase (1-OHase) activity in response to dietary Ca or P restriction reduced with age in rats. We hypothesized that the mechanism involved in increasing circulating 1,25(OH)2D3 in response to mineral deficiency alters with age.

Adaptive responses of 25-hydroxyvitamin D3 1-alpha hydroxylase expression to dietary phosphate restriction in young and adult rats.

Regulation of vitamin D metabolism alters with age. The present study is undertaken to investigate if the loss of renal 1,25-dihydroxyvitamin D(3) (1,25(OH)(2)D(3)) production in response to dietary phosphate (P) restriction in adult rats is due to an alteration in the renal expression of 25-hydroxyvitamin D(3) 1-alpha hydroxylase (1-OHase). Young (4-6 weeks old) and adult (12-14 weeks old) male Sprague Dawley rats were fed either normal P (NPD) or low P diet (LPD) for 0-5 days.

Acute and chronic effect of dietary phosphorus restriction on protein expression in young rat renal proximal tubules.

Renal proximal tubules play a vital role in phosphorus (P) homeostasis. It is well known that dietary P restriction up-regulates the activities of 25-hydroxyvitamin D(3)-1alpha-hydroxylase (1-OHase), an enzyme that is involved in activation of vitamin D and thereby maintaining P balance. However, the mechanism involved in such regulation is not known.

Study of substrate-enzyme interaction between immobilized pyridoxamine and recombinant porcine pyridoxal kinase using surface plasmon resonance biosensor.

Pyridoxal kinase (PK) is an important enzyme involved in bioactivation of vitamin B(6). Binding of PK with its substrate is the prerequisite step for the subsequent catalytic phosphorylation of the substrate. In the present study, a surface plasmon resonance biosensor (BIAcore) was employed to characterize the binding interaction between wild-type porcine PK and an immobilized substrate, pyridoxamine.