No abstract

Aim: An earlier study has demonstrated the in-vivo antidepressant effect of methanol stem bark extract of Adansonia digitata, using soxhlet extraction protocol, but there is a lack of scientific data on its neurobehavioural mechanism of action. This study, therefore, investigated its antidepressant potentials, using cold maceration method, and determined the probable neurobehavioural mechanism of its antidepressant-like effect. Methodology: The antidepressant-like effect of the extract was evaluated in tail suspension test, at graded doses in mice. Subsequently, the probable neurobehavioural mechanism of the antidepressant-like effect of the extract was investigated by intraperitoneal pretreatment with adrenergic, serotonergic, dopaminergic, and muscarinic cholinergic receptor antagonists; GABA agonist; nitric oxide precursor and inhibitors; and using a putative neuromodulator at NMDA receptors prior to the extract administration. Results and discussion: The extract at all the doses used, significantly (p<0.05) and dose-dependently decreased the immobility time in tail suspension test without significant (p>0.05) alteration on locomotor behaviour in mice. However, the anti-immobility potential of the extract was significantly (p<0.05) reversed by prazosin, yohimbine, sulpiride, methylene blue, L-arginine and baclofen, suggesting the involvement of adrenergic, dopaminergic, GABAerargic and nitergic pathways. Conclusion: This study, therefore, concluded that the extract may possess antidepressant effect and its mechanism may involve multiple pathways.

Aim: Milicia excelsa stem bark is used as sedative and for treating mental illnesses among the Hausa tribe of Northern Nigeria, but there is no scientific rationale for its use. Hence, this study investigated the oral acute toxicity and sedative potential of ethanol stem bark extract, n-hexane, ethylacetate, n-butanol and aqueous fractions of the stem bark extract in mice. The phytoconstituents in the extract and fractions were quantified. Methodology: The acute toxicity of the extract and fractions were investigated using OECD guidelines 425 of 2008. The sedative effects of the extract and fractions were investigated using pentobarbital-, and ketamine-induced sleep tests. Results and discussion: The results obtained showed that the acute toxicity of the extract and fractions were > 5000 mg/kg, suggesting that the extract and fractions may be safe. The extract, n-hexane, ethylacetate and aqueous fractions significantly (p<0.05) reduced sleep latencies, indicative of sedative effects, effective for sleep induction, while the extract and all the fractions significantly (p<0.05) prolonged the sleep durations, suggesting sedative effects, effective for sleep maintenance. Conclusion: This study therefore, concluded that the extract and fractions may be safe. The study further concluded that the sedative effect of the extract and fractions may be due to the abundance of flavonoids in the extract and fractions. Thus, providing scientific rationale for its ethnomedicinal use. However, further study may be warranted to isolate and characterize the sleep promoting bioactive principles as well as carry out GABA binding assay of the isolated compound(s) in ESB and its various fractions.

Objective: We investigated the anti-amnesic

Milicia excelsa (Moraceae) is used to treat mental illnesses, among other traditional uses in Africa, but no scientific supports for its use. Hence, this study investigated the antihypoxic potential of the ethanol leaf extract of Milicia excelsa in mice, as well as determined quantitatively the phytoconstituents present in the extract. Hypoxia was induced by sodium nitrite (360 mg/kg, i.p., a haemic hypoxic model) and sodium fluoride (150 mg/kg, i.p., a circulatory hypoxic model) in mice. The phytocompounds were estimated using standard methods. The extract at 500 and 1000 mg/kg, per oral significantly (p<0.05) prolonged the death latency in the haemic hypoxic mouse model while the extract at all the doses (250, 500 and 1000 mg/kg, p.o.) significantly (p<0.05) prolonged the death latency in the circulatory hypoxic mouse model suggesting antihypoxic effect. Total alkaloid was the most abundant of the phytochemicals assayed. This study therefore, concluded that the extract has an antihypoxic effect. The observed antihypoxic effect might be due to the abundance of total alkaloids which may either in synergy or additive with other plant secondary metabolites in the extract be responsible for the observed effect.