A novel molluscicide: investigating the efficacy of the Penicillium aurantiocandidum Z12 strain in controlling the schistosome-transmitting snail Oncomelania hupensis

Oncomelania hupensis, the sole intermediate host for Schistosoma japonicum, is a barrier to schistosomiasis elimination. Currently, chemical molluscicides are widely used; however, they can lead to environmental residues and toxicity problems. Molluscicides derived from microorganisms offer the advantages of mass production and environmental compatibility. Building on the molluscicidal activity of Penicillium aurantiocandidum Z12, we fractionated its fermentation broth via centrifugation and solvent extraction to identify active components. Ethyl acetate extract (EAE) and n-butanol extract (BE) demonstrated molluscicidal effects in toxicity tests. EAE (LC50 = 1.40 g/L, 95% Cl = 1.21-1.60; LC90 = 2.92 g/L, 95% Cl = 2.44-3.78) was significantly more potent than BE (LC50 = 2.17 g/L, 95% Cl = 1.96-2.39; LC90 = 3.31 g/L, 95% Cl = 2.93-4.07). ANOVA/Kruskal–Wallis analysis showed specific concentrations of EAE (0.4, 0.7 g/L) and BE (3.2 g/L) significantly reduced snails’ total hepatic protein content after 72 h. Treatment with EAE and BE at LC50 values also significantly suppressed superoxide dismutase (SOD) and peroxidase (POD) activities in head-foot tissue after 72 h. In conclusion, molluscicidal components concentrate in EAE and BE. Their mechanism involves inhibiting hepatic protein synthesis and suppressing SOD/POD activity, leading to snail death. More research is needed to further explore the specific effective constituents and their mechanisms.