Catechin ameliorates depressive symptoms in Sprague Dawley rats subjected to chronic unpredictable mild stress by decreasing oxidative stress.

Catechin is an active ingredient of green tea. It is reported to inhibit corticosteroid-induced anxiety and depression-like symptoms. Considering the complex nature of depression, effects of catechin need to be studied in a clinically relevant depression model. The present study was designed to explore the antidepressant effect of catechin in Sprague Dawley rats subjected to chronic unpredictable mild stress (CUMS). Animals were subjected to CUMS and treated with (+)-catechin (50 mg/kg) or escitalopram (10 mg/kg) orally; a CUMS control and a vehicle control that was not exposed to CUMS were also established. Various stressors were applied daily in an unpredictable manner for 8 weeks achieve CUMS. Sucrose preference test were performed after 4 and 8 weeks and forced swim tests (FSTs) were conducted at weeks 4, 6 and 8. At the end of week 8, animals were sacrificed and the brain homogenate was studied for antioxidant parameters. Compared with the vehicle control, animals of the CUMS control group showed a significant decrease in sucrose intake. Catechin and escitalopram treatment significantly improved the sucrose intake compared with the CUMS control. A similar trend was observed in the FSTs, where catechin and escitalopram treatment significantly reduced the immobility time, and antioxidant parameters, including catalase, glutathione and superoxide dismutase levels were recovered in treated animals compared with the CUMS control. Thus, it was concluded that catechin reverses CUMS-induced depression in rats by ameliorating oxidative stress, which may help to develop a novel treatment for major depressive disorder.