Antioxidant activity of tannoid principles of Emblica officinalis (amla) in chronic stress induced changes in rat brain.

Effect of tannoid principles emblicanin A, emblicanin B, punigluconin, and pedunculagin of E. officinalis was assessed on chronic unpredictable footshock-induced stress-induced perturbations in oxidative free radical scavanging enzymes in rat brain frontal cortex and striatum. Chronic stress, administered over a period of 21 days, induced significant increase in rat brain frontal cortical and striatal superoxide dismutase (SOD) activity, concomitant with significant reduction in catalase (CAT) and glutathione peroxidase (GPX) activity. The changes in the enzyme activities was accompanied by an increase in lipid peroxidation, in terms of augmented thiobarbituric acid-reactive products. Administration of Emblica tannoids (10 and 20 mg, po) for 21 days, concomitant with the stress procedure, induced a dose-related alteration in the stress effects. Thus, a tendency towards normalization of the activities of SOD, CAT and GPX was noted in both the brain areas, together, with reduction in lipid peroxidation. The results indicate that the reported antistress rasayana activity of E. officinalis may be, at least partly due to its tendency to normalize stress-induced perturbations in oxidative free radical scavenging activity, in view of the postulate that several stress-induced diseases, including the process of aging, may be related to accumulation of oxidative free radicals in different tissues.