In vitro anthelminthic activities of four medicinal plants against Haemonchus contortus

In vitro experiments were conducted to determine the anthelmintic effects of crude aqueous extracts of the leaves of Carissa spinarum and Azadrichta indica, fruits ofPhytolacca dodecandra and stem bark of Acacia tortilis on eggs and adults ofHaemonchus contortus using egg hatch assay and mortality of adult parasite. Extracts of the leaves of C. spinarum and A. indica inhibited hatching of egg at concentration less than or equal to 1 mg/ml. Low egg hatch inhibition were observed for extracts of A. tortilis(100%) and P. dodecandra (99.4%) at the maximum concentration tested (2 mg/ml). Of the plants tested, extracts of C. spinarum and A. indica showed very good activity against the adult worms of H. contortus, mortality raised to the levels of 96.8 and 93.9%, respectively, at concentration of 4 mg/ml. P. dodecandra and A. tortilis produced mortality of 68.1 and 53.03% of adult H. contortus at 4 mg/ml concentration, respectively. Albendazole killed the parasites in a dose dependant manner and all the worms were dead at a concentration of 0.5 mg/kg within 24 h. The overall findings of the current study indicated that most of the plants have potential anthelmintic effect warranting further in vitro and in vivo evaluation.   Key words: Anthelmintic, Haemonchus contortus, in vitro experiment, plant extracts.