In vitro Anthelmintic Activity of Bidens pilosa Linn. (Asteraceae) Leaf Extracts against Haemonchus contortus Eggs and Larvae

Haemonchus contortus is a major health and welfare problem for small ruminants, responsible for economic losses through reduced productivity and increased mortality. The in vitro efficacy of Bidens pilosa was determined against this gastrointestinal nematode (GIN). Fresh eggs, embryonated eggs and larvae (L1 and L2) were incubated at room temperature in infused aqueous extract, macerated aqueous and ethanolic leaf extract of B. pilosa at concentrations of 0.625, 1.25, 2.5, 3.75 and 5 mg/ml for 48, 6 and 24 hours, respectively. Distilled water and 1.5% Tween 80 were used as negative controls. They did not affect development of eggs and larvae whereas extracts showed a concentration dependent activity eventhough aqueous extracts exhibited a weak activity on the different developmental stages of H. contortus compared to ethanolic extract. Ethanolic extract was more potent on larvae than on eggs. It inhibited 92.5±7.5% and 67.4±7.4% egg embryonation and egg hatch at 5 mg/ml, with IC50 values of 2.1 mg/ml and 3.3 mg/ml respectively and induced 100±0% and 89.8±3.2% L1 and L2 larvae mortality at 5 mg/ml with LC50 values of 1.8 and 1.96 mg/ml respectively. The overall findings of the current study indicated that the evaluated medicinal plant in occurrence B. pilosa possess potential anthelmintic effect and further in vivo and toxicity evaluation are indispensable to validate its use as anthelmintic for the control of GIN.