Simple Modified Colorimetric Methods for Assay of Total Oxidative Stress and Antioxidant Defense in Plasma: Study in Diabetic Patients

Background: It is well established that oxidative stress and antioxidant defense of our body is associated with diabetes mellitus. Researchers have used different methods for estimation of oxidative stress and antioxidant defense, all of which have been criticized because of their limitations. Highly sophisticated methods are also not feasible in most of the clinical laboratories. The current study was aimed to estimate Total Oxidative Stress (TOS) and Total Antioxidant Defense (TAD) levels in plasma in patients with diabetes mellitus by two simple colorimetric tests developed and standardized in our laboratory and to find out their relationship with the fasting blood glucose (FBG) levels. Methods and Findings: Plasma TOS and TAD levels and fasting blood glucose (FBG) were measured, in sixty two recently diagnosed diabetic patients and compared with similar number of healthy volunteers as controls. The TOS values in patients (28.35 ± 11.21 mM of H2O2/l) are significantly higher (P<0.001) than that in the control group (11.01 ± 4.55 mM of H2O2/l) whereas the TAD values of patients (113.71 ± 100.98 mM/l equivalent of trolox) are significantly (Z<0.001) less than that of the controls (338.87 ± 167.34 mM/l equivalent of trolox). There is a significant positive correlation of FBG levels with TOS (r=0.269, P=0.034, Figure 3) and a significant negative correlation with TAD values(r=-0.267, P=0.036, Figure 4). Conclusions: The present study further reveals that diabetes mellitus is associated with oxidative stress. Plasma total oxidative stress and antioxidant defense is well correlated with FBG levels. Future study containing measurement of TOS and TAD values in plasma or in other body fluids can be conducted using these simple colorimetric and cost-effective methods even in a small clinical laboratory.