Antipsychotic-like effect of ethyl acetate fraction of Terminalia macroptera leaf in mice

Psychosis is a chronic neuropsychiatric disorder that affects millions of individuals worldwide and impairs the quality of life and productivity of the patients. Terminalia macroptera Guill & Perr. (Combrataceae) is a plant that is used in the management of anxiety related disorders. The present study investigates the antipsychotic effects of ethyl acetate fraction of T. macroptera (EFTM) leaf in ketamine-induced psychosis in mice. Acute toxicity of EFTM was determine using Lorke's method. Ketamine (25 mg/kg) was injected once daily for 7 consecutive days in Swiss albino mice to induce psychosis. The effect of the extracts (100, 200 and 400 mg/kg) was evaluated against psychotic-like behaviors induced by ketamine including locomotor activity and stereotypy in the open field test, immobility duration in the forced swim test, and memory impairment using the Y- maze test. The acute antipsychotic effect of EFTM was evaluated on apomorphine climbing test, while woodblock test was performed to assess its extrapyramidal side effects. The LD50 was found to be 3807 mg/kg p.o. which is considered safe. EFTM (100, 200 and 400 mg/kg) exhibited significant antipsychotic effect by reducing ketamine-induced hyperactivity, immobility, and memory deficit in mice, EFTM also suppressed stereotypic climbing behavior due to apomorphine. Accordingly, the antipsychotic activity of EFTM was not associated with extrapyramidal side effects as evidenced by lack of catalepsy. The study revealed that EFTM ameliorated psychotic-like symptoms and is devoid of extrapyramidal side effects in mice, underscoring its antipsychotic-like effect.