Improved method of total antioxidant assay.

Commercially available analytical kits for the estimation of total antioxidant status are expensive and time-consuming. Most of the commercially available kits for total antioxidants estimation are based on the principle of suppression of ABTS radical cation formation by antioxidant in the serum sample. The method requires stringent assay conditions, like exact incubation time and the temperature (37 degrees C) of the reaction and on an average not more than 40 samples can be analyzed on a day. We have adapted the assay to a microplate, thereby allowing more number of samples to be analyzed per day. Further, the reagent volume required is one fourth than that for the original procedure thereby cutting cost. Thirty samples were analyzed by original method on spectrophotometer and our adapted microplate assay. The values of total antioxidant obtained by the two methods correlated well. Thus, total antioxidant can be estimated reliably using the microplate method.

Oxidative stress is closely related to clinical severity of pre-eclampsia

Pre-eclampsia is a hypertensive disorder of pregnancy in which enzymatic antioxidant defenses fail and tissues are injured. This prospective case-control study evaluated whether pre-eclamptic women and their newborns show higher degrees of oxidative stress than normal pregnancies and sought to determine if this stress is related to clinical severity. Forty-four pre-eclamptic and thirty healthy pregnant women attending two hospitals in Valparaíso, Chile, were studied. The following plasmatic variables of antioxidant capacity were evaluated: glutathione peroxidase activity (GPx), total antioxidant capacity measured by oxidation of ABTS substrate (2,2'-azino-bis (3-ethylbenzthiazoline-6-sulfonic acid), and superoxide dismutase activity (SOD). malondialdehide (MDA) was measured to evaluate lipoperoxidation. The evaluation was performed at diagnosis of pre-eclampsia, delivery, 30 days and 120 days post delivery. Newborns were studied at delivery through umbilical cord blood samples. Our analysis shows that antioxidant enzyme activity (SOD, GPx, ABTS) was significantly decreased, while lipoperoxidation (MDA) was increased in both pre-eclamptic groups compared to normal pregnant women (p<0.01). Statistically significant difference was found between mild and severe pre-eclamptic groups (p<0.01), for all biochemical markers studied. Therefore, the clinical severity of this pathology is closely related to the degree of oxidative stress.