The comparative effects of oryzanol and ferulic acid on the lipid metabolism and antioxidative status of high fat-fed mice were investigated. The mice were given a diet containing 17% fat (HF), supplemented with oryzanol (HF-O) or ferulic acid for 7 weeks. The control mice (NC) were fed with normal diet. The HF mice exhibited increased body weight gain, plasma and hepatic total cholesterol and triglyceride concentrations, and lipid peroxidation rate, and reduced high-density lipoprotein cholesterol level. In general, they also showed lower hepatic antioxidant and higher lipid-regulating enzymes activities relative to that of NC group. Addition of oryzanol or ferulic acid in the diet counteracted these high fat-induced hyperlipidemia and oxidative stress via increased faecal lipid excretion and regulation of antioxidant and lipogenic enzymes activities. This study illustrates that oryzanol and ferulic acid have relatively similar hypolipidemic actions and could be effective in lowering the risk of high fat diet-induced obesity.

The effect of dietary feeding of rice bran and phytic acid on the glucose metabolism in high fat-fed C57BL/6N mice fed was investigated. The mice were given with either a high fat diet only (HF group) or a high fat diet supplemented with rice bran (HF-RB group) or phytic acid (HF-PA group) for 7 weeks. The control mice (NC group) received a normal diet. At the end of the experimental period, the HF group exhibited substantially higher blood glucose level than the NC group. However, the HF-RB and HF-PA groups showed a marked decrease in the blood glucose level relative to HF mice. Furthermore, significantly higher glucokinase (GK) activity and lower phosphoenolpyruvate carboxykinase (PEPCK) activity were observed in HF-RB and HF-PA mice compared with that of the NC and HF ones. It was also found that the glucose-6-phosphatase (G6pase) activity and hepatic glycogen concentration were considerably higher in HF-RB and HF-PA groups, respectively, than that of the HF mice. These findings demonstrate that both rice bran and phytic acid could reduce the risk of high fat diet-induced hyperglycemia via regulation of hepatic glucose-regulating enzyme activities.

Fresh ginseng roots were aged in an oven at 80℃ for 14 d. The in vitro and in vivo antioxidant activities of this aged ginseng, in comparison with those of the white and red ginsengs, were evaluated. In in vitro antioxidant assays, the ethanolic extracts from aged ginseng showed significantly higher free radical scavenging activity and reducing power than those of the white and red ginsengs. In in vivo antioxidant assays, mice were fed a high fat diet supplemented with white, red, or aged ginseng powders. High fat feeding resulted in a significant increase in lipid peroxidation and a substantial decrease in antioxidant enzymes activities in the animals. However, diet supplementation of ginseng powders, particularly aged ginseng, markedly reduced lipid peroxidation and enhanced the antioxidant enzymes activities. The results illustrate that the aged ginseng has greater in vitro and in vivo antioxidant capacity than the white and red ginsengs. The aged ginseng also showed considerably higher total saponin, phenolic, and flavonoid contents, indicating that its antioxidant capacity may have been partly due to its high levels of antioxidant compounds. This new ginseng product may be useful as a functional food with strong antioxidant potential.