Evaluation of the psychopharmacological properties and neural mechanisms of action of the ethanol extract of leaves of Triumfetta cordifolia in mice

This study was carried out to investigate neurobehavioral properties and the underlying neural mechanisms of action of the ethanol extract of leaves of Triumfetta cordifolia (EETC) on behavioral models in mice. The acute toxicity test of EETC was assessed using Locke’s method. Thereafter, neurobehavioral property of EETC (4.4, 8.8 and 17.5 mg/kg) administered intraperitoneally (i.p.) was evaluated on novelty-induced rearing, grooming and locomotor using open-field test; cognitive enhancing effect was evaluated using Y-maze test. The anxiolytic and sedative effects were assessed using elevated-plus maze and hole board tests respectively. Moreover, the potential underlying neural mechanisms of EETC was carried out using neurotransmitter receptor antagonists: haloperidol (0.2 mg/kg), yohimbine (1 mg/kg), propranolol (0.2 mg/kg), cyproheptadine (0.5 mg/kg) and atropine (0.5 mg/kg) on novelty-induced rearing, grooming, locomotor and hole board tests. Acute toxicity test carried out revealed the LD 50 of the extract was estimated to be 282 mg/kg, i.p. EETC significantly (p < 0.05) reduced rearing, grooming and locomotor activity in the open-field test. Moreover, EETC reduced head dipping activity in the hole board test, suggesting sedation. EETC did not exhibit anxiolytic and memory enhancing effects in comparison to controls. Pretreatments with haloperidol, yohimbine, propranolol, cyproheptadine and atropine significantly potentiated the inhibitory effects of EETC on rearing and grooming, but reversed its effect on locomotion in the open-field test respectively. In conclusion, the findings suggest that EETC possesses central nervous system depressant activity and the effect might be related to modulation of dopaminergic, noradrenergic, serotoninergic and cholinergic neurotransmissions. Keywords: Triumfetta cordifolia ; Toxicity; Rearing; Grooming