Neuroprotective effect of Celastrus paniculatus on chronic stress-induced cognitive impairment.

OBJECTIVE: Several studies report that chronic stress results in impaired spatial learning and working memory and enhanced anxiety-like behavior. However, not many studies have looked into the possible ways of reversing stress-induced deficits. Celastrus paniculatus (CP), a traditional ayurvedic herbal medicine, was used to treat cognitive deficits in mentally retarded children. CP oil has been reported to have neuroprotective and antioxidant activities. However, the effects of CP oil on chronic stress-induced cognitive deficits are unclear. In the present study, we intended to analyze the neuroprotective effects of CP oil on stress-associated cognitive dysfunctions.

MATERIALS AND METHODS: Chronic stress was induced by subjecting rats to restrainers for 6 h a day for 21 days. CP oil (400, 600 mg/kg) or vehicle was administered intraperitoneally (i.p.) after stress protocol once a day over the next 14 days. Groups used in the present study: normal control, stress, stress + vehicle, stress + CP oil at 2 different doses (400 and 600 mg/kg, i.p.). After the drug treatment, open field and elevated plus maze (EPM) were used to analyze anxiety-like behavior, and partially baited radial arm maze (RAM) and T-maze were used to evaluate spatial learning and memory capabilities. Analysis has been done using two-way ANOVA followed by Bonferroni's post hoc test and one-way ANOVA followed by Tukey's post hoc test.

RESULTS: Stressed rats showed enhanced anxiety-like behavior in EPM ( P < 0.001) and impaired performance in RAM ( P < 0.001) and T-maze tasks ( P < 0.001) compared to normal animals. In contrast, CP oil treatment to these rats improved their performance in both RAM ( P < 0.001) and T-maze ( P < 0.001). In addition, CP oil significantly reduced stress-induced anxiety behavior ( P < 0.001).

CONCLUSION: Chronic treatment with CP oil is to improve cognitive abilities in chronically stressed rats. The current study provides a novel perspective on beneficial effect of herbal therapy on stress-induced cognitive dysfunctions.