Molluscicidal Activity of Extracts and Fractions From Hagenia abyssinica, Rosa abyssinica, and Cucumis ficifolius Against Biomphalaria and Bulinus Snails.

Background: Schistosomiasis continues to be a major public health concern in Ethiopia. Eliminating the intermediate host snails is an effective and cost-efficient strategy for preventing and controlling schistosomiasis transmission. However, chemical molluscicides have limitations due to their toxicity to nontarget aquatic organisms, environmental concerns, and the development of resistance. Plant-based molluscicides are biodegradable, less toxic, safe, and cost-effective. Objective: This study is aimed at evaluating the molluscicidal activity of Hagenia abyssinica flowers, Rosa abyssinica fruits, and Cucumis ficifolius roots against Biomphalaria and Bulinus species. Methods: Adult Biomphalaria and Bulinus species were subjected to varying concentrations of aqueous and 70% ethanol extracts and solvent partitions from H. abyssinica, R. abyssinica, and C. ficifolius for 24, 48, and 72 h. The investigation involved conducting a phytochemical analysis using standard screening methods. Female mice were subjected to an acute oral toxicity test using a 70% ethanol extract of H. abyssinica, R. abyssinica, and C. ficifolius. The mortality data were then determined using GraphPad Prism 9 software. Results: Aqueous and 70% ethanol extracts of R. abyssinica and C. ficifolius did not exhibit molluscicidal activities against Biomphalaria and Bulinus species. However, aqueous, 70% ethanol, and chloroform extracts of H. abyssinica showed significant molluscicidal activities against Biomphalaria species with 24-h LC₅₀ values of 39.05, 11.93, and 5.52 mg/L, respectively. Similarly, the LC₅₀ values of the same extracts against Bulinus species after 24 h of exposure were 40.08, 12.23, and 6.13 mg/L, respectively. The plant extract's LD₅₀ for acute toxicity against mice was found to be over 2000 mg/kg of body weight. Conclusion: H. abyssinica demonstrated potent molluscicidal activity, making it a potential candidate for application. Further isolation of active ingredients and field trials are necessary to determine the optimal conditions for its use in snail control.