Anthelmintic action of plant cysteine proteinases against the rodent stomach nematode,Protospirura muricola,in vitroandin vivo

Abstract

Cysteine proteinases from the fruit and latex of plants, including papaya, pineapple and fig, were previously shown to have a rapid detrimental effect,in vitro, against the rodent gastrointestinal nematodes,Heligmosomoides polygyrus(which is found in the anterior small intestine) andTrichuris muris(which resides in the caecum). Proteinases in the crude latex of papaya also showed anthelmintic efficacy against both nematodesin vivo. In this paper, we describe thein vitroandin vivoeffects of these plant extracts against the rodent nematode,Protospirura muricola, which is found in the stomach. As in earlier work, all the plant cysteine proteinases examined, with the exception of actinidain from the juice of kiwi fruit, caused rapid loss of motility and digestion of the cuticle, leading to death of the nematodein vitro. In vivo, in contrast to the efficacy againstH. polygyrusandT. muris, papaya latex only showed efficacy againstP. muricolaadult female worms when the stomach acidity had been neutralized prior to administration of papaya latex. Therefore, collectively, our studies have demonstrated that, with the appropriate formulation, plant cysteine proteinases have efficacy against nematodes residing throughout the rodent gastrointestinal tract.