Abstract

Livestock production is hampered to a great extent by helminth parasites throughout the world. Plant derived drugs have been used for ages against these parasites; however, there is limited scientific knowledge on their efficacy against helminths. In this study, established techniques were used to detect anthelmintic activity of extract and fractions of Combretum molle R. Br. x. G. Don (Combretaceae) using a bioassay-guided purification approach. Two kilograms of powdered stem bark of C. molle were extracted with 10 L of absolute methanol. The crude methanol extract was dissolved in water and partitioned successively in petroleum ether, chloroform and n-butanol to obtain the petroleum ether (PE), chloroform (CP), n-butanol (BP) and aqueous methanol (AMF) fractions. The AMF was further subjected to liquid column chromatography (LCC) to obtain 12 different fractions that were pooled together into 3 major fractions based on the similarity of their relative front (Rf) values. Fractions I, II, and III obtained during the column chromatographic separation and the AMF were tested for activity against the eggs of Haemonchus contortus using the egg hatch inhibition assay (EHIA). Column fractions I, II and AMF demonstrated activity that is comparable to levamisole (standard anthelmintic), and inhibited helminth egg hatching by 91.7, 91 and 92%, respectively in vitro. The refined fraction of C. molle and the separated components of the fraction showed promising effect against H. contortus eggs and could serve as potential anthelmintics.

Key words: Combretum molle, anthelmintic activity, Haemonchus contortus, medicinal plant.