Effect of Ajwain Extract and Carvone on Behavioral Disorders Induced by Chronic Immobilization in Adult Male Rats

Introduction: In this study, we examined the impact of a hydroethanolic extract derived from ajwain and carvone (a compound present in ajwain), on learning, spatial memory, and anxiety levels in adult male rats that were chronically immobilized. Methods: There were 60 rats used in this study, divided into six groups of 10 rats each. To expose stress, 30 rats (in 3 groups including Stress, Stress-Carvone, and Stress-Ajwain groups) were placed in a restrainer for 6 hours every day for 21 consecutive days. Stress-Carvone and Stress-Ajwain groups received carvone (20 mg/kg) and ajwain extract (500 mg/kg) by gavage respectively. Thirty rats were also used in three groups (Control, Carvone, and Ajwain groups). Spatial learning and memory were studied using the Morris water maze, and anxiety was assessed by the elevated-plus maze. Results: Compared to the control group, chronic immobilization caused the rats to swim a longer time (P < 0.01) and distance (P < 0.05) to reach the hidden platform, and a shorter time and distance to swim in the target quarter (P < 0.05) in the Morris water maze. The percentage of entering the open arm in the elevated plus maze (P < 0.001) and the percentage of time staying in this arm (P < 0.01) were lower than the control group.  The carvone improved the performance of stressed animals in the Morris maze, but the ajwain extract had no effect on the memory deficit of stressed animals. Furthermore, treating ajwain extract and carvone increased the percentage of entry into the open arm and the percentage of time spent in the open arm in animals exposed to stress. Conclusion: Ajwain extract and carvone reduce anxiety behavior in rats exposed to chronic immobility stress; carvone treatment prevents memory impairment in these animals. It is possible that the extract of ajwain (partially through carvone) is effective in reducing damage caused by stress in the nervous system.