EFFECTS OF LEAF AQUEOUS EXTRACT OF BIDENS-PILOSA (ASTERACEAE) ON KCL-INDUCED AND NOREPINEPHRINE-INDUCED CONTRACTIONS OF RAT AORTA

The effect of leaf aqueous extract of Bidens pilosa Linn. on KCl- and norepinephrine-induced contractions of rat aortic strips was studied. In aortic strips with endothelium intact, contractions induced using 6 0 mM KCl and 10(-5) M norepinephrine were dose-dependently relaxed by the extract, a more significant effect being seen with norepinephrine- induced contractions. Following mechanical damage to the aortic endoth elium, inhibition of contractions was more prominent (105%) with the n orepinephrine-induced contractions compared with KCl-induced contracti ons (15%) when the maximal dose (8 mg/mI) of the extract was used. The results suggest that the relaxation effect of the extract may be due to the blockade of the influx of extracellular Ca2+ into the cell. (C) 1998 Elsevier Science Ireland Ltd. All rights reserved.