Daidzein Treatment Research Articles

Effect of daidzein on in vitro fermentation by microorganisms from the goat rumen

Isoflavones are a group of phytoestrogens found in many plants, and daidzein is one of their major metabolites. Previous studies have shown that daidzein affects growth of rumen bacteria and intestinal microflora. This study investigated effects of daidzein on rumen microbial fermentation. Substrate containing ground Chinese wildrye hay (7 g/L), corn grain powder (2.1 g/L) and soybean meal (0.9 g/L) was fermented in vitro by mixed rumen microorganisms and substrate containing rice straw (8 g/L) by rumen anaerobic fungi from four rumen fistulated male goats. Results with mixed rumen microorganisms showed that daidzein treatment had no effect on the total VFA, but maximized propionate at about 10 mg/L (quadratic P<0.01). As a result, the ratio of acetate to propionate was minimized at 10 mg/L (quadratic P<0.05). Daidzein treatment also minimized NH 3-N at 10 mg/L (quadratic P<0.01), but had no effect on microbial crude protein. The fermentation time-course study showed that the effect of daidzein at 10 mg/L on production of acetate and propionate became significant after 1 h of fermentation, while the effect on NH 3-N content became evident after 5 h. In a culture of the rumen anaerobic fungus Neocallimastix sp., daidzein maximized cumulative gas production and specific growth rate to half of the gas pool at 10–50 mg/L, but had no effect on dry matter loss. Results indicate potential regulating effects of daidzein on rumen microorganisms that could be useful in the rumen function.

The prooxidant, rather than antioxidant, acts of daidzein in vivo and in vitro: Daidzein suppresses glutathione metabolism

The present study was performed to investigate the effects of chronic administration of daidzein on lipid peroxidation and glutathione concentration in the livers and brains of rats. Male Sprague-Dawley rats were divided into two groups, one of which was fed a normal diet and the other a vitamin E-free diet. Each of these groups was divided further into three subgroups and treated either with vehicle or with daidzein administered orally at either 2 or 20 mg/day for 4 weeks. The concentrations of α-tocopherol in the serum and the brain increased following daidzein treatment, and these increases were significantly greater in rats maintained on a vitamin E-free diet. Daidzein significantly decreased the concentration of malondialdehyde in the organs, and this decrease was more pronounced in vitamin E-deprived rats than in those maintained on a normal diet. Although the liver glutathione concentration was not affected, daidzein treatment (20 mg/day) decreased the glutathione concentration in the brain significantly and to a similar extent in vitamin E-deprived rats and those fed normal diet. In addition the daidzein metabolite, equol, severely decreased the ratio of GSH and GSSG in primary cortical neuron cells exposed to it. Collectively, these results suggest that daidzein may act not only as an antioxidant, but also a prooxidant in brain rats, this should be in the brains of rats.

Long-term combined administration of quercetin and daidzein inhibits quercetin-induced suppression of glutathione antioxidant defenses

In this study, we investigated the effects of long-term administration of quercetin with or without daidzein on glutathione and the enzymes involved in its metabolism in rat liver in vivo. Male Sprague-Dawley rats were divided randomly into four groups and given oral quercetin (20 mg/day) and daidzein (20 mg/day) alone or in combination, or vehicle alone for six weeks. The serum and liver α-tocopherol concentrations were significantly increased following administration of quercetin and daidzein alone or in combination. Glutathione concentration and glutathione reductase activity was significantly ( p < 0.05) decreased with quercetin treatment, while no such effect was observed with daidzein treatment. Interestingly, decrease in glutathione concentration and glutathione reductase activity by quercetin treatment was inhibited by combined administration of daidzein and quercetin. The malondialdehyde concentration was significantly decreased following administration of quercetin and daidzein alone or in combination. These results suggest that quercetin, but not daidzein, acts as a pro-oxidant agent by decreasing glutathione concentration and glutathione reductase activity. Interestingly, this pro-oxidant effect of quercetin was inhibited by the combined administration of quercetin and daidzein.

Dietary daidzein influences laying performance of ducks ( Anas platyrhynchos) and early post-hatch growth of their hatchlings by modulating gene expression

Our previous studies demonstrated that dietary supplementation of daidzein improves egg production in duck breeders during late periods of the laying cycle. The present study was aimed to clarify whether the growth of ducklings hatched from eggs laid by daidzein-treated hens would be affected, and to elucidate the mechanisms underlying potential trans-generational effects, by determining changes of hormone levels and mRNA expression of relevant genes. Daidzein was added to the basal diet of 415-day-old duck breeders at the level of 5 mg/kg. During 9 weeks of daidzein treatment, laying rate increased by 7.70%, average egg mass tended to increase, whereas yolk/albumen ratio decreased significantly. These changes were accompanied by significantly elevated plasma T 4 and E 2 levels, enhanced gonadotropin releasing hormone (GnRH) mRNA, but diminished estrogen receptor (ER)-β mRNA expression in hypothalamus of daidzein-treated hens. Ducklings hatched from daidzein-treated eggs were significantly smaller at hatching, but they caught up with their control counterparts by 4 weeks of age. Serum levels of T 4, pituitary GH, hepatic GH receptor (GHR) and type-1 IGF receptor (IGF-1R) mRNA expression were all suppressed markedly in the daidzein-treated group at hatching, but this suppression proved to be temporary, as at 4 weeks of age, expression levels of all investigated genes were restored. However, it is noteworthy that at 4 weeks of age an obvious down-regulation of hypothalamic GnRH mRNA expression was detected in ducklings maternally exposed to daidzein. Our results provide evidence that maternal exposure to daidzein affects post-hatch growth in the duck with accompanying changes in the secretion of metabolic hormones and expression of growth-related genes. Although the negative effect of maternal daidzein on embryonic growth could be eliminated 4 weeks after hatching, the long-term effect of maternal daidzein on reproductive function is not to be ignored and awaits further investigation.

The Phytoestrogen Daidzein Affects the Antioxidant Enzyme System of Rat Hepatoma H4IIE Cells

Phytoestrogens such as the soy isoflavonoid daidzein have potential health benefits. The antioxidant properties of phytoestrogens are considered to be responsible in part for their protective effects. The antioxidant enzyme (AOE) system plays an important role in the defense of cells against oxidative insults. To determine whether flavonoids can exert antioxidative effects not only directly but also indirectly by modulating the AOE system, we investigated the influence of the flavonoid daidzein on the expression of different AOE. Daidzein treatment of hepatoma H4IIE cells increased catalase mRNA expression two- to threefold. Expression levels of copper zinc superoxide dismutase (CuZnSOD) were not affected by exposure to daidzein. Manganese superoxide dismutase (MnSOD) mRNA expression levels decreased slightly and glutathione peroxidase (GPx) levels increased slightly after daidzein exposure. Changes in AOE mRNA expression levels were significant at 300 micromol/L daidzein. To elucidate the mechanisms underlying the strong increase in catalase mRNA, transfection experiments were performed. Transient transfection of hepatoma cells with reporter plasmids containing different parts of the upstream region of the catalase gene showed a significant one- to threefold increase in reporter gene activity after daidzein exposure. This indicates that daidzein can directly activate the rat catalase promoter region. Despite the increase in catalase mRNA, daidzein pretreatment of cells did not protect against oxidative stress resulting from H(2)O(2) exposure. On the contrary, daidzein itself exerted a mild oxidative stress. In conclusion, the changes in the AOE system provoked by daidzein affected the oxidant rather than the antioxidant properties of daidzein.

Feeding daidzein to late pregnant sows influences the estrogen receptor beta and type 1 insulin-like growth factor receptor mRNA expression in newborn piglets.

The present study was undertaken to determine the tissue-specific expression of estrogen receptor beta (ERbeta), and the effects of a daidzein supplement to the diet of pregnant sows on the expression of ERbeta, and type 1 insulin-like growth factor receptor (IGF-1R) genes in newborn piglets by using semi-quantitative RT-PCR. Eight sows received a dietary supplement of daidzein at a dosage of 8 mg per kg feed from day 85 of gestation, and six sows were used as controls. After parturition, 2 male neonatal piglets were selected from each litter for sampling. ERbeta mRNA was detected in intestine, lung, thymus, kidney, pituitary and hypothalamus tissues, but not in heart, adrenal, skeletal muscle, liver or placental tissues. Daidzein treatment significantly increased the birth weight of male piglets and markedly reduced the level of ERbeta mRNA in the hypothalamus, but not in the pituitary. An up-regulation of IGF-1R gene transcription was observed in skeletal muscles of newborn piglets. In addition, the IGF-1R mRNA was found to be most abundant in pituitary and hypothalamus, followed by skeletal muscle, thymus, and liver tissues in decreasing order. Our results demonstrate that (1) ERbeta is expressed in a tissue-specific manner in newborn piglets, (2) daidzein down-regulates ERbeta gene expression in the hypothalamus, possibly indicating central effects of daidzein, and (3) daidzein influences fetal growth associated with higher IGF-IR gene expression in skeletal muscle.