Some central nervous system and blood pressure lowering effects of methanol extract of the leaves of Spondias mombin (Anarcadiaceae) in albino wistar rats and mice
The methanol extract of the leaves of Spondias mombin (SP) was evaluated for some central nervous system and blood pressure lowering effect in albino wistar rats and mice. The extract was administered to pre-weighed mice (20-35 g), divided into five groups of five mice each at the doses of 50, 100 and 200 mg/kg for the first three groups, while the fourth and the fifth groups were administered 30 mg/kg phenobarbitone and 1 ml/kg of 0.2% tween-20 which served as the standard reference drug and control respectively for the maximal electroshock (MES)-induced seizure and motor co-ordination screening. Similar grouping was done for the evaluation of pentylene tetrazol-induced convulsion, and the animals were administered the same doses of extract as used for the maximal electroshock induced convulsion. Pentylenetetrazol (70 mg/kg) was used as the convulsant agent, and was administered to the animals 40minutes after the administration of the extract and reference drugs respectively. Blood pressure lowering effect was evaluated in normotensive wistar albino rats at the dose range of 0.625-5.0 mg/kg of extract. Atropine (0.01mg/kg) was administered to the normotensive rats purposefully to block the hypotensive effect of the extract. The extract protected the mice against both MES (100%) and 20, 40, and 80% for PTZ-induced seizures at the doses of 50, 100, and 200 mg/kg respectively, and there was significant impairment of motor co-ordination ability of the mice on the rotating Ugo Basile rotarod for mice. The extract caused dose-dependent (0.625- 5mg/kg) reduction in the mean systolic, diastolic and mean arterial blood pressure, from the basal level of 136.67±21.86; 71.67±6.0 and 87.78±5.55 mmHg, to 101.67±; 59.0±4.93 and 73.22±4.30 mmHg respectively for 0.625mg/kg, and 67.50±2.5; 56.0±14.0 and 47.84±1.84 mmHg for 5 mg/kg respectively. The results of the experiments showed that the methanol extract of the leaves of Spondias mombin has some pharmacologicaly active principles that have effect on the central nervous system and also reduces blood pressure in normotensive rats.
Key words: Spondias mombin, methanol-extract, seizures, motor co-cordination, central nervous system depression hypotensive effect.