Abstract:
ntroduction: 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 ߤg/mL. The least potent extract, methanol, had an IC50 of 2.11±0.10 ߤg/mL.
Eriodictyol, being the most active compound had an IC50 of 1.23 ± 0.05 ߤg/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.
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