Antidepressant-like effects of methanolic extract of Bacopa monniera in mice

BACKGROUND Bacopa monniera has been used as a cure for various ailments that include anxiety, epileptic disorders, dementia, blood purifier, cough and rheumatism, and some important local uses of the plant are in dermatitis, anemia, diabetes, promote fertility and prevent miscarriage for many years in Bangladesh. According to this background, the aim of the study was to evaluate the antidepressant-like effect of the methanolic extract of B. monniera (MEBM) in different behavioral models such as forced swimming test (FST), measurement of locomotor activity test (MLAT) and tail suspension test (TST) on mice after two weeks treatment. METHODS Mice were divided into five groups (n = 5/group): control group (deionized water), standard group where Imipramine hydrochloride (30 mg/kg) was used as standard drug and three test groups where three doses of the methanolic extract of B. monniera (MEBM) (50, 100, and 200 mg/kg) was used for two weeks treatment. All the drug and test samples were administered via gavage through oral route. To assess the antidepressant-like effect of MEBM forced swimming test (FST), tail suspension test (TST) and measurement of locomotor activity test (MLAT) have been done in mice. RESULTS The results showed that a strong and dose-dependent antidepressant effects in different mice models. The main findings of the MEBM significantly reduced the duration of immobility times in the forced swimming test (p < 0.001). Likewise, the extract significantly decreased the immobility time in the tail suspension test (p < 0.001). Moreover, we employed an additional measurement of locomotor activity test to check the motor stimulating activity of the MEBM. The extract also significantly increased the locomotion, rearing and defecation effects in comparison to the control group (p < 0.001). CONCLUSION The present results clearly demonstrate that the methanolic extract of B. monniera possesses antidepressant-like activity in the animal behavioral models. The current study warrants further investigation into identification of the active compounds in herbal medicines, in particular extract of B. monniera with antidepressant-like effects.