Antidepressive effect of ginseng extract G115 in ethanol-treated mice

Abstract

Comorbid alcoholism and depression results from the decrease of brain-derived neurotrophic factor (BDNF) levels and the increase of cortisol levels. Evidence for the efficacy of antidepressants used in co-morbid depression and alcoholism is inconsistent while there are high risks of adverse effect and drug interaction problems. Previous studies have been reported the antidepressive effect of ginseng extract and ginsenosides in rodents. The present study aimed to determine the antidepressive effect and antidepressive mechanisms of ginseng extract G115 in ethanol-treated mice. Mice in water-treated group were given either sterile water (10 ml/kg) , amitriptyline (10 mg/kg) or ginseng extract G115 (100, 200, 400 or 800 mg/kg) orally 1 hour before injecting sterile water (10 ml/kg i.p.). Mice in ethanol-treated group received either sterile water (10 ml/kg), amitriptyline (10 mg/kg) or ginseng extract G115 (100, 200, 400 or 800 mg/kg) orally 1 hour before injecting ethanol (3 g/kg i.p.). The treatments were given once daily for 8 consecutive days. Forced swimming test and locomotor activity test were performed 1-day after the last treatment. Brain and blood were collected for further analysis of brain BDNF levels and serum corticosterone levels. Repeated ethanol treatment caused depression-like behaviors in mice and decreased BDNF levels in the hippocampus and prefrontal cortex. However, ethanol treatment did not alter serum corticosterone levels. In water-treated mice, ginseng extract G115 (100, 200 and 800 mg/kg) decreased immobility time in forced swimming test. In addition, ginseng extract G115 (100 and 200 mg/kg) increased BDNF levels in the hippocampus and ginseng extract G115 (800 mg/kg) increased serum corticosterone levels indicating that ginseng extract G115 had anti-depressant-like effect in normal mice possibly due to the increases of hippocampal BDNF and serum corticosterone levels. In ethanol-treated mice, ginseng extract G115 (100, 200 and 800 mg/kg) showed the antidepressive effect in forced swimming test. Moreover, ginseng extract G115 (100, 200, 400 and 800 mg/kg) increased BDNF levels in the hippocampus and ginseng extract G115 (200 and 800 mg/kg) increased BDNF levels in the prefrontal cortex. However, ginseng extract G115 had no effect on serum corticosterone levels in ethanol-treated mice. In summary, this study demonstrated for the first time that ginseng extract G115 had antidepressive effect in ethanol-treated mice via the increase of BDNF levels in the hippocampus and prefrontal cortex. The results of this study provided scientific information of the potential and mechanism of ginseng extract G115 as an antidepressant to treat ethanol-induced depression.