Neuroprotective effect of alcoholic extract of Terminalia arjuna bark in experimental stroke induced rats

摘要

Terminalia arjuna Wight & Arn. (Combretaceae) is a tree having an extensive medicinal potential and popular in various Indigenous Systems of Medicine like Ayurveda, Siddha and Unani. Its stem bark possesses glycosides, large quantities of flavonoids, tannins and minerals. Flavonoids are reported to exert antioxidant, anti-inflammatory and lipid lowering effects. Evidence demonstrates that the impaired energy metabolism and the excessive generation of reactive oxygen species (ROS) contribute to the brain injury associated with cerebral ischemia. In the present study, the protective effect of T. arjuna bark alcoholic extract (TABE) was investigated in transient middle cerebral artery occlusion (MCAO)-induced focal cerebral ischemia-reperfusion injury in rats. Antioxidant activity of TABE was evaluated in vivo and in vitro. Male albino rats were divided into five groups: Normal, Sham-operated group, Ischemic control group, and TABE-pretreated groups (500 and 1000 mg/kg/p.o.). TABE was administered once a day, for 14 days. The rats were subjected to a 2 h right MCAO via the intraluminal filament technique and 22 h of reperfusion. Pretreatment with TABE significantly reduced the histological changes and neurological deficits. TABE at a dose of 1000 mg/kg significantly reversed the elevated total calcium levels, brain malondialdehyde (MDA) content and restored the decreased activities of Na~+-K~+ATPase, brain superoxide dismutase (SOD), catalase (CAT) and reduced glutathione levels (GSH). TABE when tested against generation of oxygen free radicals in vitro at the concentrations (64-1000 μg/ml), counteracted lipid peroxidation and the formation of DPPH, nitric oxide (NO) and superoxide anions (O_2~-) with IC_(50) values 646.40 μg/ml, 488.18 μg/ml, 787.29 μg/ml and 1006.81 μg/ml respectively. Results of present study indicated that TABE has a protective potential against cerebral ischemia injury and its protective effects may be due to its antioxidant property.