Evaluating the Antischistosomal Activity of Crude Extracts of Carica Papaya against Schistosoma Mansoni: the Interplay of Cellular and Humoral Immunity

Abstract

Carica papaya is widely used in different parts of Kenya for the treatment of intestinal helminthes. The present study was designed to evaluate the anti-schistosomal effect of a methanolic and aqueous extract of Carica papaya seeds in schistosoma infected mice. Laboratory mice were infected with a single dose of Schistosoma mansoni cercariae. The extracts were administered orally at a dose of 300 mg/kg body weight in 200µl suspension to infected mice two days apart. Praziquantel was the reference drug used in the experiments.Two weeks post-treatment; all animals were sacrificed to evaluate the efficacy of Carica papaya in treatment of the infection.  Significant effect of the extracts was observed against schistosomal infected mice. Carica papaya methanol extract was found more effective against schistosomes recording more less recovery while Carica papaya aqueous extract recorded more recovery. Detectable levels of cytokines were also recorded during infection and after treatment with a marked rise in SWAP specific IL5. These data support the use of Carica papaya based medicines as antischistosomal agents where acces to commercial drugs is restricted. These findings provide solid scientific evidence to support the traditional medicinal uses of these extracts and indicate a promising potential of this plant for medicinal purposes. There is also need for detailed scientific study of traditional medicinal practices to ensure that valuable therapeutic knowledge of this plant is preserved and also to provide scientific evidence for their efficacy.

KEY WORDS: Plant extract, Antischstosomal activity, Schistosoma mansoni, Carica papaya