Antiypertensive action of ethanolic extract of Imperata cylindrica leaves in animal models.

This work was carried out to determine antihypertensive effect of ethanolic extract of Imperata cylindrical leaves using cat and rabbit models. A freeze dried 70% ethanolic extract was prepared and increasing concentrations from 10 to 320 mg/ml were administered in vivo to anaesthetized cats and in vitro to rabbit jejunum. Adrenaline and phentolamine were used as control drugs. The extract exhibited a significant dose-dependent reduction in amplitude of contraction of smooth muscle cells of rabbit jejunum in comparison with standard antihypertensive drug, adrenaline. The heart pressure of the cats was significantly reduced with 160 and 320 mg/ml of the extract from 266 to 180 mmHg (p = 0.012) but there was no effect on the heart rate. The minimum effective dose EC50 was 0.013. Ethanolic leaf extract of I. cylindrica exhibited vasodilative antihypertensive properties similar to mechanism of action of adrenaline. The extract could be used to manage hypertension.   Key words: Imperata cylindrical, antihypertensive, ethanolic extract, β-blockers.