Differential effects of formononetin and cladrin on osteoblast function, peak bone mass achievement and bioavailability in rats.
Dietary soy isoflavones including genistein and daidzein have been shown to have favorable effects during estrogen deficiency in experimental animals and humans. We have evaluated osteogenic effect of cladrin and formononetin, two structurally related methoxydaidzeins found in soy food and other natural sources. Cladrin, at as low as 10 nM, maximally stimulated both osteoblast proliferation and differentiation by activating MEK-Erk pathway. On the other hand, formononetin maximally stimulated osteoblast differentiation at 100 nM that involved p38 MAPK pathway but had no effect on osteoblast proliferation. Unlike daidzein, these two compounds neither activated estrogen receptor in osteoblast nor had any effect on osteoclast differentiation. Daily oral administration of each of these compounds at 10.0 mg kg(-1) day(-1) dose to recently weaned female Sprague-Dawley rats for 30 consecutive days, increased bone mineral density at various anatomic positions studied. By dynamic histomorphometry of bone, we observed that rats treated with cladrin exhibited increased mineral apposition and bone formation rates compared with control, while formononetin had no effect. Cladrin had much better plasma bioavailability compared with formononetin. None of these compounds exhibited estrogen agonistic effect in uteri. Our data suggest that cladrin is more potent among the two in promoting parameters of peak bone mass achievement, which could be attributed to its stimulatory effect on osteoblast proliferation and better bioavailability. To the best of our knowledge, this is the first attempt to elucidate structure-activity relationship between the methoxylated forms of daidzein and their osteogenic effects.
Gautam AK, Bhargavan B, Tyagi AM, Srivastava K…
J. Nutr. Biochem. Apr 2011
Positive skeletal effects of cladrin, a naturally occurring dimethoxydaidzein, in osteopenic rats that were maintained after treatment discontinuation.
Effects of cladrin treatment and withdrawal in osteopenic rats were studied. Cladrin improved trabecular microarchitecture, increased lumbar vertebral compressive strength, augmented coupled remodeling, and increased bone osteogenic genes. A significant skeletal gain was maintained 4 weeks after cladrin withdrawal. Findings suggest that cladrin has significant positive skeletal effects.
We showed that a standardized extract of Butea monosperma preserved trabecular bone mass in ovariectomized (OVx) rats. Cladrin, the most abundant bioactive compound of the extract, promoted peak bone mass achievement in growing rats by stimulating osteoblast function. Here, we studied the effects of cladrin treatment and withdrawal on the osteopenic bones.
Adult female Sprague-Dawley rats were OVx and left untreated for 12 weeks to allow for significant estrogen deficiency-induced bone loss, at which point cladrin (1 and 10 mg/kg/day) was administered orally for another 12 weeks. Half of the rats were killed at the end of the treatments and the other half at 4 weeks after treatment withdrawal. Sham-operated rats and OVx rats treated with PTH or 17β-estradiol (E2) served as various controls. Efficacy was evaluated by bone microarchitecture using microcomputed tomographic analysis and fluorescent labeling of bone. qPCR and western blotting measured mRNA and protein levels in bone and uterus. Specific ELISA was used for measuring levels of serum PINP and urinary CTx.
In osteopenic rats, cladrin treatment dose dependently improved trabecular microarchitecture, increased lumbar vertebral compression strength, bone formation rate (BFR), cortical thickness (Cs.Th), serum PINP levels, and expression of osteogenic genes in bones; and reduced expression of bone osteoclastogenic genes and urinary CTx levels. Cladrin had no uterine estrogenicity. Cladrin at 10 mg/kg maintained acquired skeletal gains 4 weeks after withdrawal. Cladrin had positive skeletal effects in osteopenic rats that were maintained after treatment withdrawal.
Khan K, Sharan K, Swarnkar G, Chakravarti B…
Osteoporos Int Apr 2013
Total extract and standardized fraction from the stem bark of Butea monosperma have osteoprotective action: evidence for the nonestrogenic osteogenic effect of the standardized fraction.
The aim of this study was to determine the skeletal effects of Butea total extract (BTE) and its acetone soluble fraction (ASF) from Butea monosperma, which is rich in methoxyisoflavones, in ovariectomized (OVx) rats, a model for postmenopausal bone loss.
BTE (1.0 g kg d) and ASF (100 mg kg d) were given orally for 12 weeks to adult OVx rats. The sham-operated and ovariectomy + vehicle groups served as controls. Bone mineral density, osteoid formation (mineral apposition rate and bone formation rate), bone microarchitecture, and bone turnover/resorption markers were studied. Phytoestrogens in rats given BTE and ASF were analyzed by high-performance liquid chromatography. One-way analysis of variance was used to test significance of effects.
OVx rats treated with either BTE or ASF exhibited increased bone mineral density in trabecular bones and improved trabecular microarchitecture compared with the ovariectomy + vehicle group. ASF treatment was more efficient than BTE treatment in maintaining trabecular microarchitecture. Serum osteocalcin and urinary type 1 collagen levels in OVx rats treated with either BTE or ASF were significantly lower than those of the ovariectomy + vehicle group. ASF treatment led to increased mineral apposition rate and bone formation rate compared with ovariectomy + vehicle, whereas BTE had no such effect. In the uterotropic assay, BTE was mildly estrogenic in adult OVx rats. In immature rats, BTE exhibited both estrogenicity and antiestrogenicity. ASF had neither uterine estrogenicity nor antiestrogenicity. Analysis of phytoestrogens revealed significant enrichment of cladrin, isoformononetin, and medicarpin in ASF over BTE.
Derived from B monosperma, ASF at a 10-fold lower dose than that of BTE was effective in preventing OVx-induced bone loss and stimulated new-bone formation.
Pandey R, Gautam AK, Bhargavan B, Trivedi R…