The effects of a wheat germ rich diet on oxidative mtDNA damage, mtDNA copy number and antioxidant enzyme activities in aging Drosophila

Effects of glutathione on mitochondrial DNA and antioxidant enzyme activities in Drosophila melanogaster

The free radical theory in aging assumes that the accumulation of macromolecular damage induced by toxic reactive oxygen species plays a central role in the aging process. The intake of nutritional antioxidants can prevent this damage by neutralizing reactive oxygen derivatives. Glutathione (GSH; en-L-Glutamyl-L-cysteinyl glycine) is the lowest molecular weight thiol in the cells and as a cofactor of many enzymes and a potent antioxidant plays an important role in maintaining normal cell functions by destroying toxic oxygen radicals. In this study, the effects of GSH on SOD, GST and catalase enzymes and mtDNA damage were investigated at various time intervals by giving reduced glutathione to Drosophila. It was observed that 3-week GSH administration did not have a statistically significant effect on SOD and GST activities whereas GSH application decreased the catalase enzyme activities significantly. Although the decrease in antioxidant capacity with age was observed in SOD and catalase enzymes, such a situation was not observed in GST enzyme activities. There was no statistically significant difference between the control and GSH groups in mtDNA copy number values, while in the GSH group, oxidative mtDNA damage was high. These results may be due to the prooxidant effect of GSH at the dose used in this study.

The effects of wheat germ supplementation on metabolic profile in patients with type 2 diabetes mellitus: A randomized, double-blind, placebo-controlled trial

The aim of the present trial was to examine the effects of wheat germ (WG) consumption on metabolic control and oxidative stress status of type 2 diabetes mellitus (T2DM) patients. Eighty participants with T2DM were randomly allocated to receive 20-g WG (n = 40) or placebo (n = 40) in a randomized double-blind clinical trial for 12 weeks. Serum lipid profiles, glycaemic indices, total antioxidant capacity, and malondialdhyde (MDA) were assessed. A total of 75 subjects completed the trial. Compared with the placebo, WG consumption led to significant reduction in total cholesterol (TC) concentrations (p = .04). There was a trend regarding TC to high density lipoprotein ratio (p = .08) following 12 weeks WG consumption, although they were not statistically significant after correcting for multiple testing. In addition, within-group comparison revealed a significant rise in total antioxidant capacity concentration (p = .001) in WG group. We observed no significant effects of WG intake on glycaemic status, blood pressure, MDA, triglyceride, and low density lipoprotein levels. WG consumption for 12 weeks could decrease serum TC levels and had no significant effects on other metabolic variables and MDA in patients with T2DM. Though observed health benefit effects were small, it might lead to a major impact on wider public health.