Anxiolytic effects of standardized extract of Centella asiatica (ECa 233) after chronic immobilization stress in mice

Ethnopharmacological relevance: Centella asiatica has long been used for various neurological disturbances in Southeast Asian countries. The present study aims to demonstrate the anxiolytic effect of ECa 233, a standardized extract of C. asiatica containing triterpenoids not less than 80%, in comparison to diazepam. Materials and methods: The test compound was given orally to non-stressed mice and mice subjected to chronic immobilization stress. Anxiolytic effect was assessed by an elevated plus maze (EPM), a dark-light box and an open-field tests. Results: Anxiolytic effect of ECa 233 was clearly demonstrated in non-stressed mice subjected to acute stress in all behavioral tests employed. In the EPM test, chronically stressed mice showed significant decrease in the number of open arm entries, shortening the time spent in open arms and an increase of the latency to leave the central area, suggesting their release from the stress. In addition, ameliorating effect of ECa 233 was observed on the body weight and serum corticosterone which were adversely affected by immobilization stress. Madecassoside and asiaticoside, equal to their respective contents of the effective doses of ECa 233, exclusively presented anxiolytic effects in EPM, while no distinct effect was observed on the body weight and serum corticosterone. Conclusions: The present study demonstrated anxiolytic effect of ECa 233 in both acutely and chronically stressed animals. These effects could be mainly accounted by madecassoside and asiaticoside, suggesting a possible use of ECa 233 for the treatment of both acute and chronic anxiety in the pathological state.