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Aim: This study investigated the acute toxicity (LD50) and antipsychotic potentials of ethanol leaf extract of Milicia excelsa (EME), hexane (HF), ethyl acetate (EAF), butanol (BF) and aqueous (AF) fractions in mice.
Study Design: This study used experimental mice models predictive of human psychosis.
Place and Duration of Study: Department of Pharmacology, Faculty of Pharmacy, Obafemi Awolowo University, Ile-Ife, Osun State, Nigeria, between January 2014 to February 2015.
Methodology: The antipsychotic effect was assessed using swim-induced grooming; apomorphine-induced climbing and ketamine-induced hyperlocomotion behaviours in mice.
Results: The results showed that the LD50 of the ethanol extract and its various fractions were greater than 5000 mg/kg. EME and all its fractions significantly (P < 0.05) decreased the number of grooming while the duration of grooming was significantly (P < 0.05) reduced by EME, EAF and AF in swim-induced grooming. EME and EAF significantly (P < 0.05) inhibited climbing behaviour in apomorphine-induced climbing. EME and all the fractions significantly (P < 0.05) inhibited the hypermotility induced by ketamine while the number of ataxia was significantly (P < 0.05) reduced by EME, EAF and AF in ketamine-induced hyperlocomotion, with AF producing a stronger ataxia reducing effect compared to haloperidol, a reference antipsychotic drug. EME and EAF showed consistent antipsychotic activities in all the models used.
Conclusion: This study concludes that EME and all its fractions may be safe and contain antipsychotic principles, thus, providing scientific evidence for the suggested ethnomedicinal use of the leaf in treating insanity in traditional medicine.