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.