O-GLcNACase as biomarker of antioxidant status in healty women under isoflavones supplementation

Consumption of soy has been correlated to a lower incidence of chronic diseases, among which CVD characterized by a high oxidative stress, that has been partially attributed to isoflavone (IF) intake. We evaluated the antioxidant effects of 80 mg/d of total IF supplementation in 13 healthy women (age 29 ± 8) for 6 months followed by 2 months of suspension; blood samples were collected every two months (T=0, 1, 2, 3 and 4). Plasma concentrations of IF, RBC activities of O-GlcNAcase, considered good marker of cellular stress, and of cytosolic hesosaminidase (Hex-c), total plasma antioxidant capacity (Lag-time), RBC membrane fluidity (rs) and DNA oxidative damage (comet assay) were evaluated. Statistical analysis were performed by ANOVA for repeated measure (p<0.05). IF plasma concentrations and Lag-time increased (p<0.05) according to dietary intervention and rs increased at T=2 vs. T=1 and T=4 (p<0.05). DNA damage (due to H2O2) significantly decreased during supplementation, with a significant inverse correlation with plasma IF concentration. OGlcNAcase and Hex-c activities did not change after 2 months of IF supplementation, while they increased at T=2 and T=3 vs. T=1 (p<0.05). Results suggest a positive effect of IF supplementation against oxidative stress and confirm previous studies indicating O-GlcNAcase as a good tool for monitoring antioxidant status.