Garlic extract attenuates immobilization stress-induced alterations in plasma antioxidant/oxidant parameters and hepatic function in rats

Objective: To investigate the oxidative stress induced by 6 h of immobilization stress in Albino Wistar rats. Further, the pre- and post-treatment of aqueous garlic extract was studied to evaluate its preventive and curative efficacy on stress-induced altered oxidative parameters in rats. Methods: Albino Wistar rats were exposed to 6 h of immobilization stress, and received garlic extract (100 mg/kg body weight) treatment pre- or post-stress exposure. The oxidative status of plasma after various treatments were evaluated by determining the levels of reduced glutathione, glucose, uric acid, thiobarbituric acid reactive substances, aspartate aminotransferase (AST), alanine transaminase (ALT), alkaline phosphatase (ALP) and the activities of superoxide dismutase, catalase and glutathione-S-transferase by standardized procedures. Results: Immobilization of rats generated oxidative stress in rat plasma, by decreasing the activities of antioxidant enzymes, glutathione levels and glucose, while increasing the lipid peroxidation, serum glutamic oxaloacetic transaminase, serum glutamic pyruvic transaminase, ALP and uric acid compared to the non-stressed controls (P<0.01). The garlic extract administration both pre- and post-stress exposure significantly prevented the rise in the diagnostic liver enzymes and reverted the decrease of antioxidant enzymatic activities compared to the stressed group (P<0.05 or P <0.01). Post-stress treatment of extract was found more effective than pre-stress treatment in reverting the values back to normal (P<0.01). Conclusion: Garlic extract seems promising as a nutritional supplement for scavenging free radicals generated in the plasma and to prevent resulting oxidative stress.