Ashwagandha Reverses the Dieldrin‑induced Cognitive Impairment by Modulation of Oxidative Stress in Rat Brain

Dieldrin (DLD) is an organochlorine pesticide heavily used in agriculture to control pests. Widespread exposures of DLD to human population are likely to contribute in neurological disorders. Withania somnifera (WSF), commonly known as “ashwagandha,” is used for its broad spectrum of pharmacological activity. The present study was designed to investigate the effect of WSF (100 mg/kg) on DLD (5 mg/kg)‑induced modulation of cognitive function and oxidative stress in male Wistar rats. Cognitive function was measured using step‑down latency (SDL) on a continuous avoidance apparatus and transfer latency (TL) on an elevated plus maze. Oxidative stress was estimated by measuring brain malondialdehyde (MDA) level, protein carbonyl (PC), and reduced glutathione (GSH) activity. Significant reduction in both acquisition and retention in SDL was found for the DLD‑treated group at the end of the exposure study as compared to the control (P < 0.001). DLD caused a significant prolongation in both acquisition and retention in TL after 28 days of the treatment as compared to the control (P < 0.001). Four‑week treatment of WSF antagonized the effect of DLD on SDL and TL at the 29th day. DLD produced a statistically significant increase in the brain MDA and PC levels (P < 0.001), and a significant decrease in the brain GSH activity (P < 0.001). Treatment with WSF attenuated the effect of DLD on MDA, PC, and GSH activities. Thus, the finding of this study suggests that WSF has potential in reversing cognitive dysfunction and oxidative stress induced by toxicants such as DLD in the brain.