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ABSTRACT: Fructooligosaccharides stimulate the growth of Bifidobacteria, which cleave isoflavone glycosides to yield corresponding aglycones, and convert metabolites by enhancing enterohepatic recirculation of isoflavones in rats. In the present study, we determined the synergistic effect of dietary isoflavone glycosides and fructooligosaccharides on postgastrectomy osteopenia in rats. Nine-week-old male Sprague-Dawley rats were gastrectomized (n = 20) or sham operated, (control, n = 5) and then randomly assigned to 5 diet groups: sham-a purified diet control, gastrectomized-control, gastrectomized-isoflavone (0.2% isoflavone glycosides), gastrectomized-fructooligosaccharides (7.5% fructooligosaccharides), and isoflavone and fructooligosaccharides (0.2% isoflavone glycosides + 7.5% fructooligosaccharides). After 6 weeks, the rats were killed and biological samples were collected. In gastrectomized rats, fructooligosaccharides prevented femoral bone fragility, but isoflavone without fructooligosaccharides did not inhibit postgastrectomy osteopenia. Isoflavone and fructooligosaccharides exhibited a synergistic in the distal metaphyseal trabecular bone, indicated by peripheral quantitative computed tomography. Moreover, fructooligosaccharides increased calcium absorption and equol production from daidzein in gastrectomized rats. These results indicate that isoflavone alone did not inhibit postgastrectomy osteopenia, but the combination of isoflavone and fructooligosaccharides improved the inhibition of trabecular bone loss by increasing calcium absorption and equol production through fructooligosaccharides supplementation.
Journal of Clinical Biochemistry and Nutrition 09/2012; 51(2):156-60. · 1.98 Impact Factor
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ABSTRACT: We compared the effects of the S-enantiomer and racemic forms of equol on bone using ovariectomized (OVX) mice. Femoral bone mineral density and bone strength decreased in the OVX mice, but not in OVX mice administered 0.5 mg/d S-equol. This, however, did not hold for racemic equol. Serum and urine S-equol concentrations were higher in the mice administered S-equol than in those administered racemic equol. These results suggest that the inhibitory effects of S-equol on bone fragility in OVX mice are greater than those of racemic equol.
Bioscience Biotechnology and Biochemistry 05/2012; 76(5):1018-21. · 1.28 Impact Factor
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ABSTRACT: Daidzein, a major isoflavone predominantly found in soybean, is mainly metabolized to equol and O-desmethylangolensin (O-DMA) by the human gut microflora. Equol exhibits a stronger estrogenic activity than daidzein, however, only approximately 30% of the population has been identified as equol-producers and there are too few direct evidences of the effects of the other major metabolite, O-DMA on estrogen-deficient status. The purpose of this study is therefore, to compare the effect of both O-DMA and equol on bone and lipid metabolism in vivo and in vitro. For the in vivo study, 8-week-old female mice were assigned to five groups as follows: sham-operated (sham), ovariectomized (OVX), OVX + 0.5 mg/day O-DMA (OVX + O-DMA), OVX + 0.5 mg/day equol (OVX + Eq), and OVX + 0.03 microg/day 17beta-estradiol (OVX + E2) administration. Three weeks after the intervention, O-DMA and equol did not affect uterine atrophy in OVX mice. The bone mineral density (BMD) of the femur was lower in the OVX group than in the sham group. The administration of equol but not O-DMA, maintained BMD through the intervention. Values of whole body fat mass and plasma lipids were lower in the equol and O-DMA treated OVX mice than those in OVX mice. In the in vitro study, equol significantly inhibited the osteoclast formation induced by 1alpha,25(OH)(2)D(3) in a dose-dependent manner in a co-culture system of mouse bone-marrow cells with primary osteoblastic cells. However, O-DMA slightly inhibited osteoclast formation, and the effect was not dose dependent. These results suggest that the effects of O-DMA on bone and lipid metabolism in OVX mice and osteoclast cell cultures are weaker than those of equol.
European Journal of Nutrition 08/2008; 47(5):273-9. · 2.75 Impact Factor
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ABSTRACT: Soybean isoflavones have structures similar to that of estrogen and have received attention as alternatives to hormone replacement therapy for the prevention of postmenopausal osteoporosis. Daidzein, a major isoflavone found in soybean, is metabolized to equol by gut microflora, and the metabolite exhibits a stronger estrogenic activity than daidzein. However, there is no direct evidence that equol affects bone metabolism. In this study, we examined the effect of equol on the inhibition of bone loss in ovariectomized (OVX) mice. Female mice (8 wk old) were assigned to 5 groups as follows: sham-operated (sham), OVX, OVX + 0.1 mg/d equol administration (0.1 Eq), OVX + 0.5 mg/d equol administration (0.5 Eq), and OVX + 0.03 microg/d 17beta-estradiol administration (E(2)). Equol and E(2) were administered s.c., using a mini-osmotic pump. At 4 wk after the intervention, uterine weight was less in the OVX mice than in sham-operated mice (P < 0.05). The weight was maintained in the E(2) group. In contrast, administration of equol at doses used in this study did not affect uterine atrophy in OVX mice. Bone mineral density (BMD) for the whole body in the OVX group measured by dual-energy X-ray absorptiometry was lower than that in the sham group, whereas administration of 0.5 mg/d Eq as well as E(2) maintained the BMD. The BMD of the femur and lumbar spine in the OVX group was also lower than those in the sham group, and treatment with 0.5 mg/d Eq maintained it. Notably, the BMD of the proximal femur in the 0.5 Eq group was the same as that of the sham group. E(2) inhibited bone loss from all regions induced by OVX. These results suggest that equol, a major metabolite of daidzein, inhibits bone loss apparently without estrogenic activity in the reproductive organs of OVX mice.
Journal of Nutrition 10/2004; 134(10):2623-7. · 3.92 Impact Factor
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ABSTRACT: Fructooligosaccharides (FOS) stimulate the growth of bifidobacteria, which cleave isoflavone conjugates to yield the corresponding aglycones and metabolites. In a previous study, FOS modified the absorption and enterohepatic recirculation of isoflavones in rats. In the present study, we determined the effect of the combination of dietary FOS and isoflavone conjugates on bone mass in ovariectomized (OVX) and surgical control mice. After undergoing OVX or sham operation, female ddY mice (8 wk old, n = 64) were randomly assigned to four groups: a purified control diet (AIN-93G) group, a FOS diet (AIN-93G + 5% FOS) group, an isoflavone diet (AIN-93G + 0.2% isoflavone conjugates) group, or a FOS and isoflavone diet (AIN-93G + 5% FOS + 0.2% isoflavone conjugates) group. After 6 wk, the mice were killed and the blood and femora were sampled immediately. In OVX mice, both isoflavone conjugates and FOS prevented femoral bone loss. An additive effect of dietary isoflavone conjugates and FOS was observed by dual-energy X-ray absorptiometry in the distal part of the femur and in trabecular bone, by peripheral quantitative computed tomography. Moreover, FOS increased cecal beta-glucosidase activity and equol production from daidzein in both OVX and surgical control mice fed isoflavone conjugates. These results suggest that FOS increase the bioavailability of isoflavones, leading to cooperative effects in the prevention of osteopenia in OVX mice.
Journal of Nutrition 08/2002; 132(7):2048-54. · 3.92 Impact Factor
