PHYTOCHEMICAL SCREENING AND PURGATIVE ACTIVITY OF ETHANOLIC EXTRACTS OF VERNONIA AMYGDALINA DEL. LEAF

Vernonia amygdalina has diverse ethno-medical uses including constipation. The aim of this study was to determine the phytochemical component and purgative effect of ethanolic extract of Vernonia amygdalina leaf on rabbit jejunum. Leaves of Vernonia amygdalina were collected, dried, ground and extracted using 95% ethanol. Isolated tissue of rabbit jejunum was challenged with acetylcholine as standard and different strength of the extract at dose ranges of 10 mg to 160 mg in a 50 ml capacity organ bath. The preliminary phytochemical analysis revealed the presence of alkaloids, tannins, phlabotannins, saponins, and anthraquinones. Alkaloids, tannins, and saponins appeared in high quantities, while steroids and flavonoids were absent. The extract at concentrations of 0.2, 0.4, 0.8, 1.6 and 3.2mg/ml produce contractile responses of 3.0, 7.0, 10.2, 15.3 and 15.0 mm respectively which were dose depended. Atropine was able to block the contraction exerted by the extract. These suggest that the extract may be acting on the muscarinic receptors (M3) which are present on the intestine. This study amply justifies the ethno medical claim that the leaves are used as purgatives.