In vitro anthelmintic efficacy of essential oils in the control of Neoechinorhynchus buttnerae, an endoparasite of Colossoma macropomum

In this study, we evaluated the chemical composition and the in vitro anthelmintic efficacy of the essential oils (EOs) of the plants Aloysia triphylla, Adenocalymna alliaceum, Allium sativum, Croton cajucara (white and red morphotypes), Curcuma longa, Lippia gracilis, Lippia origanoides, Ocimum gratissimum, Mentha arvensis, and Piper aduncum against the Acantocephalan Neoechinorhynchus buttnerae. The in vitro viability of worms was observed after 24 h-exposure to nine concentrations of EOs from each plant. Lower EC50 values were obtained for M. arvensis, L. origanoides, L. gracilis, C. cajucara (red and white morphotypes), O. gratissimum, and P. aduncum. All EOs showed 100% anthelmintic efficacy in vitro in 24 h. In regard to damage to the integument of helminths, edema in the lacunar spaces with formation of bubbles in the subcuticle, body swelling, increased volume of the pseudocelomatic cavity and degeneration of the reproductive organs were observed after exposure to A. triphylla OE.