In vitro Cercaricidal Activity of Fractions and Isolated Compounds of Erythrophleum ivorense (Fabaceae) Root Bark against Schistosoma haematobium

Abstract

Introduction: Schistosoma haematobium is one of the species of Schistosoma responsible for schistosomiasis in humans, a major public health problem worldwide. Praziquantel, the most effective drug against all adult stages of human schistosomiasis, faces the threat of resistance and also has sub-optimal efficacy against cercaria, an immature form of schistosomiasis. This underscores the need to search for an alternative anti-schistosomal drug with pronounced activity particularly against cercaria. Aim: This study investigated anti-cercarial activity of total crude (70% ethanolic extract), fractions (methanolic, ethyl acetate and petroleum ether) and isolated bioactive compounds from the root bark of Erythrophleum ivorense. Study Design: In vitro anti-cercarial activity was evaluated using 20 freshly shed cercariae from Schistosoma haematobium species transferred into 20 well plates. Cercaricidal effect of the various concentrations (15.6, 31.3, 62.5, 125.0, 250.0 and 500.0 µg/mL) of test extracts and compounds were observed for 3 hours using an inverted microscopy. The results showed that extracts and compounds of the plant decreased percentage viability of cercariae in a dose-dependent manner. Results: Within two hours of incubation, all cercariae died at the various concentrations of test compounds and extracts with the exception of methanol extract and the bioactive compound erythroivorensin at 15.6 g/mL. The least potent extract, methanol, had an IC50 of 2.11±0.10 g/mL. Eriodictyol, being the most active compound had an IC50 of 1.23 ± 0.05 g/mL. Conclusion: It is evident from the results obtained that fractions and isolated bioactive compounds of Erythrophleum ivorense can be a potential cercaricidal agent and therefore should be investigated further.