Method for the measurement of antioxidant activity in human fluids

Aim-To develop a new, simple, and cheap method for estimating antioxidant a ctivity in human fluids. Methods-The assay measured the capacity of the biological fluids to inhibit the production of thiobarbituric acid reactive substances (TBARS) from sod ium benzoate under the influence of the free oxygen radicals derived from F enton's reaction. A solution of 1 mmol/litre uric acid was used as standard . Results-The following mean (SD) antioxidative activities were found las uri c acid) in the various biological fluids: serum, 2.04 (0.20) mmol/litre; ur ine, 176.5 (25.6) mu mol/litre; cerebrospinal fluid, 95.0 (26.9) mu mol/lit re; aqueous humour oculi, 61.25 (9.9) mu mol/litre; saliva, 838.5 (48.2) mu mol/litre; tears, 247.0 (17.0) mu mol/ Litre; ascites fluid, 270.0 (63.3) mu mol/litre; kidney cyst fluid, 387.1 (28.1) mu mol/litre. Small samples o f the biological material were needed for the analyses: 10 mul of serum and 50-100 mul Of Other body fluids. In the sera of 48 healthy individuals the re was a significant positive correlation between values obtained with the Randox method las a reference method) and the new method proposed here (cor relation coefficient, 0.8728; mean difference between methods, <0.4%). Conclusions-This method is easy, rapid, reliable, and practical for the rou tine measurement of total antioxidant activity in serum and other human bod y fluids. Small samples of biological material are needed for the analyses and the results are comparable with the reference (Randox) method.