Molluscicidal activities of Senna alata silver nanoparticles against adult and egg stages of Lymnaea natalensis

Fascioliasis, a significant foodborne parasitic disease, is transmitted via Lymnaea natalensis snails. This study evaluated the molluscicidal activities of Senna alata ethanolic extracts and its green-synthesized silver nanoparticles (AgNPs) against adult L. natalensis and its ova. AgNPs were synthesized using S. alata leaf extract, confirmed by UV-visible spectroscopy with an absorption peak at 362 nm. Characterization via XRD revealed crystalline peaks at 2θ values of 25.50°, 30.50°, and 38.00°, while SEM showed irregularly shaped particles averaging 20.32 nm with an elemental composition of 47.04% silver. FTIR identified key functional groups, including aromatic C-H stretching (3016.39 and 3098.26 cm^-1) and O-H stretching of phenolics. Molluscicidal assays demonstrated that AgNPs achieved 100% snail mortality within 40 min at 0.167 mg/mL, significantly outperforming crude extracts (60% mortality at 5 mg/mL after 24 h; p < 0.05). The green-synthesized molluscicide AgNPs halted embryonic development at the blastula stage at all concentrations, whereas crude extracts showed minimal effects. Oxidative stress markers in snails exposed to AgNPs indicated elevated lipid peroxidation (p < 0.01) and catalase activity (p < 0.05), alongside reduced superoxide dismutase activity (p < 0.05). SDS-PAGE analysis revealed altered protein expression, with new bands at 17-95 kDa in AgNP-exposed snails. These findings highlight S. alata-AgNPs as a potent, eco-friendly molluscicide, effective at low concentrations. Further studies on environmental safety and field applications are recommended.