Antioxidant property of Celastrus paniculatus willd.: a possible mechanism in enhancing cognition

In the present study aqueous, methanolic, chloroform and petroleum ether extracts of seeds of Celastrus paniculatus were investigated for their effect on cognitive functions in rats. Male Wistar rats weighing 200-250 g each were used to study effect on learning and memory through use of the shuttle-box, step-through, step-down and elevated plus maze paradigms. Only the aqueous seed extract (200 mg/kg body wt. for 14 days) showed an improvement in learning and memory in both the shuttle-box and step-through paradigms. Therefore, further experiments were conducted using the aqueous extract at 100, 200 and 300 mg/kg body wt. doses in different paradigms of cognition. All three doses of the aqueous extract increased the number of avoidances in the shuttle-box and step-through latency the in step-through apparatus, but no significant difference was observed between the doses tested. In the step-down apparatus, the 200- and 300-mg/kg body wt. doses of aqueous extract showed a significant increase in step-down latency, whereas no significant difference was observed in the elevated-plus-maze paradigm between drug-treated and vehicle-treated groups. Since the behavioral impairments are associated with oxidative stress, we investigated the effect of the aqueous extract on oxidative stress parameters. Among the three doses tested, only 200 and 300 mg/kg body wt. stimulated a significant decrease in the brain levels of malondialdehyde, with simultaneous significant increases in levels of glutathione and catalase. The present findings indicate that the aqueous extract of Celastrus paniculatus seed has cognitive-enhancing properties and an antioxidant effect might be involved.