In vitro effects of four tropical plants on the activity and development of the parasitic nematode, Trichostrongylus colubriformis

The in vitro effects of extracts of four tropical plants (Zanthoxylum zanthoxyloides, Newbouldia laevis, Morinda lucida and Carica papaya) on the egg, infective larvae and adult worms of Trichostrongylus colubriformis were screened for potential anthelmintic properties. Significant effects were observed with the four plants on T. colubriformis but they differed depending on the stage of the parasite. Extracts of each plant induced a dose-dependent inhibition of egg hatching. Using a larval inhibition migration test, the effects on the infective larvae were also detected with the four plant extracts. In contrast, for adult worms, the effects were statistically significant only for N. laevis and C. papaya. No significant activity was shown for M. lucida and Z. zanthoxyloides. These in vitro results suggest the presence of some anthelmintic properties associated with these four plants, which are traditionally used by small farmers in western Africa. These effects need to be studied under in vivo conditions.