The utilization of vegetable or fruit by-products as functional foods to protect against several diseases, including depression, has gained great interest. Litchi chinensis Sonn. (lychee; LC) peel is considered an important source of polyphenols, which could be beneficial for mental health. We investigated the antidepressant effect and possible mechanisms of LC peel extract in a rat model of chronic restraint stress (CRS). Five groups of male rats were used: naïve control, vehicle (distilled water) + stress, fluoxetine 20 mg/kg + stress, LC peel extract 150 mg/kg + stress, and LC peel extract 300 mg/kg + stress. All groups except the naïve control were exposed to CRS (6 hours/day for 56 days) to induce depression-like activity. Only the high dose of LC peel extract exerted an antidepressant effect on the rat’s behavior patterns in both the tail suspension (p < 0.001) and forced swimming (p < 0.001) tests, restored brain serotonin levels (p < 0.001), decreased lipid peroxidation (p < 0.05), improved superoxide dismutase activity (p < 0.001), and reduced plasma corticosterone (CORT) (p < 0.05). This study provides the first evidence that an ethanolic extract of LC peel possesses antidepressant activity mediated by its antioxidant effect, regulating the CORT hormone and normalizing serotonin concentrations.
Key words: Lychee peel, antidepressant, stress, depression, antioxidant
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