Tamarindus indica stem bark extract attenuates depression and spatial memory deficits in mice

Title: Tamarindus indica stem bark extract attenuates depression and spatial memory deficits in mice Running title: Tamarindus indica reversed depression and memory loss in mice Abstract Objective: Depression is a prevalent psychiatric disorder that affects individuals from all walks of life, impairing cognitive functions and daily life. This study investigated the potential therapeutic effects of Tamarindus indica stem bark extract on depression and spatial memory deficits in ketamine-exposed mice. Method: Tamarindus indica stem bark extract was extracted using 90% v/v methanol. The extract was screened for phytochemicals followed by acute toxicity study using Lorke’s method. Schizophrenic mice models were developed following ketamine administration at sub-anesthetic dose (20 mg/kg) daily for seven (7) days, consecutively. The mice were randomly assigned into five groups (n = 5 per group) as follows: Group I received normal saline (10 ml/kg, i.p.); Groups II, III, and IV received graded doses of Tamarindus indica extract at 400, 200, and 100 mg/kg, respectively; and Group V received risperidone (2.0 mg/kg, i.p.).Tail suspension test and Forced swimming test were used to assess depression while Y maze was used to assess spatial working memory. Results: The extract showed the presence of glycosides, saponins, phenols, and alkaloids. The LD50 value obtained was approximately 2,150 mg/kg. Tamarindus indica stem bark extract effectively improved the depressive symptoms by significantly (P < 0.0001) reversing the immobility time with the 400 mg/kg dose exhibiting the highest activity compared to control group in both TST and FST. Also, Tamarindus indica stem bark extract significantly (P < 0.0001) increased the number of spontaneous alternation compared to the control group. Conclusion: Tamarindus indica stem bark extract may effectively reverse depression and memory impairment in ketamine model of schizophrenia. Keywords: Tamarindus indica, Depression, Cognitive impairment, Ketamine-induced model.