Molluscicidal Activity of Camellia Sinensis (green tea) and Camellia Sinensis var. Assamica (purple tea) extracts against Biomphalaria pfeifferi; the Major Vector Snail of Human Schistosomiasis in Sub-Saharan Africa

Abstract

Freshwater pulmonate snails are prevalent across Kenya and act as intermediate hosts for trematode parasites, which cause schistosomiasis in humans. Chemical molluscicides have rarely been used routinely to control snail-borne parasitic infections due to high costs of manufacture and the subsequent environmental concerns associated with their use. This study tested raw extracts from green tea and purple tea plant, Camellia sinensis, which are widely grown in Kenyan highland areas against the freshwater pulmonate snail, Biomphalaria pfeifferi. Snails were exposed to five different concentrations (10, 20, 50, 100 and 150 ppm) of the water extracts. All quantitative data analysis was done in R version 4.4.0. The Kruskal-Wallis test was used to test the difference in mortality across the different extract concentrations. Kaplan-Meier survival analysis was used to examine the survival rates of snails. Survival curves were compared using the log-rank test. A p-value of less than 0.05 was considered significant. Phytochemical analysis of the extracts was done using Liquid Chromatography and Gas Chromatography with mass spectrophotometry. Analysis of the raw extracts by LCMS showed that the compounds present in the extracts were epicatechin, epigallocatechin, caffeine, which was the most, theobromine as well assamsaponin C. The compounds Identified by GCMS are hexadecanoic acid, caffeine, octadecenoic acid-methyl and octadec-1-ene. The crude extracts from the Kenyan tea plant Camellia sinensis (both green and purple tea) induced mortality of the Biomphalaria pfeifferi snails. Therefore, they can be explored as alternative plant-based molluscicides against the vector snails of intestinal schistosomiasis.