Effect of strawberry (Fragaria x ananasa) as antidepresant activity on mice induced by stress

Depression is a physiological disorder on the brain and may induce the reduction levels of monoamine neurotransmitters, serotonin and the increased levels of stress hormone, corticosterone. The use of antidepressant drugs causing side effect, therefore natural agents are used as alternative therapy. The objectives of this study are to determine the effect of strawberries in the murine experiments in increasing serotonin level as well as decreasing in the immobility time of mice on Forced Swimming Task (FST). Forty-eight male outbreed of 4 weeks old mice strain Swiss Webster with average body weight of 18-22 grams were divided into six groups of eight mice, as follows: (1) non-stressed, (2) Chronic Mild Stressed (CMS), (3) strawberry extract (with dose of 464.1 mg/kg) and CMS, (4) strawberry extract (with dose of 928.2 mg/kg) and CMS, (5) fisetin (with a dose of 10 mg/kg) and CMS, and (6) amitriptyline (an antidepressant, with a dose of 3.25 mg/kg) and CMS as a comparison group. Chronic Mild Stress (CMS) method were used as induction of stress consisted of seven different stressors and assigned randomly for 35 days. Provision of treatment was made during the 14 days preparations on day 22 to day 35. At the end of treatments, all mice were assigned on FST test for immobility time measurements. Next, all mice were decapitated and the brains were isolated. Serotonin levels were measured using High Performance Liquid Chromatography (HPLC) with UV-visible light detector. The results showed that the immobility time of group mice which were given by the strawberries (928.2 mg/kg) and fisetin had shorter duration than the positive control group. Furthermore, the level of serotonin in the test group increased compared to CMS group. Corticosterone levels of treatment mice were increased significantly compared to non-stressed mice. Therefore, it can be concluded that strawberries are able to improve depressive symptoms by decreasing immobility time and increasing levels of serotonin compared with CMS group.