The present work evaluates the cardiovascular activity of the aqueous (AES) and methanol (MES) extracts from S. torvum fruits. The anti-platelet aggregation activity of the AES was also evaluated on platelets isolated from rats. Intravenous administration of AES and MES induced a significant reduction in arterial blood pressure. The intravenous administration of AES at the doses of 1 and 2 mg/kg did not affect the heart rate. In contrast to AES, MES reduced the heart rate at all the doses (1, 2 and 5 mg/kg). Neither atropine (1 mg/kg) nor yohimbine (1 mg/kg) significantly affects the hypotensive activity of AES. Yohimbine almost completely inhibited the cardiac effect of AES. L-NAME (20 mg/kg) significantly potentiated the hypotensive and the cardiac effects of AES. When essayed on the platelet aggregation, induced by either thrombin (0.5 U/ml) or Adenosine diphosphate (5 µM), AES significantly and dose dependently inhibited the aggregation induced by both agents. MES and AES possess hypotensive activity which may partially result from their bradycardic effect. The anti-platelet aggregation effect of AES may be a benefit for its cardiovascular effect. These results support the use of the plant in the treatment of arterial hypertension and haemostatic ailments.
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