Effects of simvastatin on plasma antioxidant status and vitamins in hypercholesterolemic patients.

BACKGROUND: Statins are known to possess antioxidant properties in addition to their cholesterol-lowering effects. However, recent studies have suggested that statins reduce the levels of antioxidant vitamins such as vitamin E and coenzyme Q(10), possibly resulting in impaired left ventricular function. We investigated the effects of simvastatin on the blood lipids, LDL oxidation and plasma antioxidant status, and whether these effects were associated with changes in plasma antioxidant vitamin levels. METHODS: Simvastatin (20-40 mg/day) was administered for 8 weeks in seventy-six hypercholesterolemic patients. We measured plasma lipids, oxidized LDL, total radical trapping antioxidant potential (TRAP) and plasma antioxidant vitamin levels at baseline and after 8 weeks of simvastatin administration. RESULTS: Simvastatin significantly lowered serum levels of total cholesterol and LDL-cholesterol by 30.1% and 41.9%, respectively. A significant reduction in oxidized LDL levels (p<0.0001) and improvement in plasma antioxidant status as measured by TRAP (p<0.05) after the 8-week simvastatin treatment were observed. Regarding the effects of simvastatin on plasma antioxidant vitamin levels, there were significant increases in the levels of lipid-corrected retinol (p<0.001), alpha-tocopherol (p<0.001) and gamma-tocopherol (p<0.005) after the 8-week simvastatin treatment. Lipid-corrected levels of coenzyme Q10 and carotenoids remained unchanged after simvastatin treatment. CONCLUSIONS: Our results show that simvastatin reduced blood lipids and circulating oxidized LDL, and improved plasma antioxidant status without altering the antioxidant vitamin system. These data indicate that simvastatin not only decreases blood lipids and circulating oxidized LDL but also increases lipid corrected levels of antioxidant vitamins and may improve plasma antioxidant status synergizing with the biological effects of antioxidants.

Antioxidant activity of far-infrared radiated rice hull extracts on reactive oxygen species scavenging and oxidative DNA damage in human lymphocytes.

The antioxidant activities of methanolic extracts of far-infrared irradiated rice hull (FRH) and non-irradiated intact rice hull (IRH) were determined. The antioxidant effects against reactive oxygen species (ROS) were evaluated by measuring scavenging activities against 1,1-diphenyl-2-picrylhydrazyl (DPPH) radical, superoxide, hydrogen peroxide (H2O2), and nitric oxide radical and capacity for chelating metals. Except for H2O2 scavenging activity, FRH showed higher scavenging activity than IRH; for example, the 50% inhibitory concentration (mg/mL) values for DPPH radical scavenging of FRH and IRH were 0.067 and 0.085, respectively, as compared with 0.362 and 0.012 for butylated hydroxytoluene and alpha-tocopherol, respectively. The effect of rice hull extract on DNA damage induced by H2O2 in human lymphocytes was also evaluated by comet assay. The protective effect of rice hull extract increased as its concentration increased from 12.5 to 50 microg/mL, as indicated by DNA strand breakage decreasing from 38% to 22% with FRH and from 49% to 28% with IRH as compared with H2O2-treated positive controls. When human lymphocytes were post-incubated with rice hull extract for 30 minutes after exposure to H2O2, the protective ability of the rice hulls remained unchanged. These results suggest that methanol extracts of rice hulls possess significant ROS scavenging and metal chelating activities and protective effect against oxidative DNA damage.

Effect of heat treatment on the antioxidative and antigenotoxic activity of extracts from persimmon (Diospyros kaki L.) peel.

Heat treatment of persimmon peel (PP) increased the antioxidative activity of the 70% ethanolic extract (EE) and water extract (WE) from PP. EE and WE both prevented H2O2-induced DNA damage to human peripheral lymphocytes. The antioxidative and antigenotoxic activities of the PP extracts were significantly affected by heating.