Dried lemon peel extract improves memory and reduces anxiety-like behavior in rats exposed to chronic immobilization

Abstract

Background and Aims: Chronic immobilization is a type of stress that causes behavioral disorders such as anxiety and memory deficits by inducing oxidative stress and inflammation and changing the level of neurotransmitters in the brain. In this research, we investigated the effect of the hydroalcoholic extract of dried lemon peel (Citrus aurantifolia) on learning, spatial memory, and anxiety-like behavior in adult male rats exposed to chronic immobilization. Materials and Method: To induce immobilization stress, the rats were placed in the restrainer for 6 hours every day for 21 consecutive days. Lemon extract (400 mg/kg) was also treated by gavage to the animals. Spatial learning and memory were assessed using the Morris blue maze, and anxiety was studied using an elevated plus maze. Results: The lemon extract treatment made the animals exposed to immobilization stress swim more time and distance in the target quarter in the water maze compared with the stress group (P < 0.05). The extract increased the percentage of entry into the open arm (P < 0.01) and the percentage of time spent in the open arm (P < 0.05) of the elevated plus maze in these animals. Conclusion: Dried lemon peel extract improved learning and spatial memory in animals exposed to chronic immobilization and reduced anxiety-like behavior in them. Dried lemon peel extract probably has a neuroprotective effect.

Keywords

• anxiety
• chronic immobilization stress
• citrus aurantifolia
• rat
• spatial memory