Molluscicidal activity of fatty acids in the kernel of Chimonanthus praecox cv. Luteus against the golden apple snail Pomacea canaliculata

Novel insights into the glucose metabolic alterations of freshwater snails: a pathway to molluscicide innovation and snail control strategies

As ecosystem disruptors and intermediate hosts for various parasites, freshwater snails have significant socioeconomic impacts on human health, livestock production, and aquaculture. Although traditional molluscicides have been widely used to mitigate these effects, their environmental impact has encouraged research into alternative, biologically based strategies to create safer, more effective molluscicides and diminish the susceptibility of snails to parasites. This review focuses on alterations in glucose metabolism in snails under the multifaceted stressors of parasitic infections, drug exposure, and environmental changes and proposes a novel approach for snail management. Key enzymes within the glycolytic pathway, such as hexokinase and pyruvate kinase; tricarboxylic acid (TCA) cycle; and electron transport chains, such as succinate dehydrogenase and cytochrome c oxidase, are innovative targets for molluscicide development. These targets can affect both snails and parasites and provide an important direction for parasitic disease prevention research. For the first time, this review summarises the reverse TCA cycle and alternative oxidase pathway, which are unique metabolic bypasses in invertebrates that have emerged as suitable targets for the formulation of low-toxicity molluscicides. Additionally, it highlights the importance of other metabolic pathways, including lactate, alanine, glycogenolysis, and pentose phosphate pathways, in snail energy supply, antioxidant stress responses, and drug evasion mechanisms. By analysing the alterations in key metabolic enzymes and their products in stressed snails, this review deepens our understanding of glucose metabolic alterations in snails and provides valuable insights for identifying new pharmacological targets.

Screening the Efficacy and Safety of Molluscicides from Three Leaf Extracts of Chimonanthus against the Invasive Apple Snail, Pomacea canaliculata

Pomacea canaliculata, the invasive snail, is a host of the parasitic nematode Angiostrongylus cantonensis, which has adverse effects on the agriculture system and human health. This work evaluated the molluscicidal activity of petroleum ether extracts (PEEs) from three species of Chimonanthus against the snail P. canaliculate. Pcp (PEE of C. praecox) showed the most effective molluscicide activity. Sixty-one compounds were identified by GC-MS and the main components were terpenoids and fatty acids. The half-lethal concentration (LC50) of Pcp at 24 h (0.27 mg/mL) and 48 h (0.19 mg/mL) was used to evaluate the biochemical alterations in snail tissue. These sublethal concentrations caused the levels of alkaline phosphatase (ALP), alanine aminotransferase (ALT), and aspartate aminotransferase (AST) activity to increase, while acetylcholinesterase (AChE) activity decreased. Also, under LC50 treatment, several histological changes were observed in the hepatopancreas and foot of the snail compared with the control group. Moreover, the toxic test in rice demonstrated that Pcp has low toxicity. These results suggest that Pcp could be developed as an effective molluscicide for P. canaliculata control.

Activities of pumpkin seed oil against Biomphalaria alexandrina snails and the infective stages of Schistosoma mansoni with special emphasis on genotoxic and histopathological alterations

Schistosomiasis is a serious health issue in tropical regions, and natural compounds have gained popularity in medical science. This study investigated the potential effects of pumpkin seed oil (PSO) on Biomphalaria [B.] alexandrina snails (Ehrenberg, 1831), Schistosoma [S.] mansoni (Sambon, 1907) miracidium, and cercariae. The chemical composition of PSO was determined using gas chromatography/mass spectrometry. A bioassay was performed to evaluate the effects of PSO on snails, miracidia, and cercariae. The results showed no significant mortality of B. alexandrina snails after exposure to PSO, but it caused morphological changes in their hemocytes at 1.0 mg/ml for 24 hours. PSO exhibited larvicidal activity against miracidia after 2 hours of exposure at a LC50 of 618.4 ppm. A significant increase in the mortality rate of miracidia was observed in a dose- and time-dependent manner, reaching a 100% death rate after 10 minutes at LC90 and 15 minutes at LC50 concentration. PSO also showed effective cercaricidal activity after 2 hours of exposure at a LC50 of 290.5 ppm. Histological examination revealed multiple pathological changes in the digestive and hermaphrodite glands. The PSO had genotoxic effects on snails, which exhibited a significant increase [p≤0.05] in comet parameters compared to the control. The findings suggest that PSO has potential as a molluscicide, miracidicide, and cercaricide, making it a possible alternative to traditional molluscicides in controlling schistosomiasis.

Metabolomic Profiling, Antibacterial, and Molluscicidal Properties of the Medicinal Plants Calotropis procera and Atriplex halimus: In Silico Molecular Docking Study

The potential of plant-based natural compounds in the creation of new molluscicidal and antimicrobial medications has gained attention in recent years. The current study compared the metabolic profiles, antibacterial, and molluscicidal properties of the medicinal plants Calotropis procera (C. procera) and Atriplex halimus (A. halimus). In both plants, 118 metabolites were identified using gas chromatography-mass spectrometry. Palmitic acid, stigmasterol, and campesterol were the most prevalent constituents. C. procera extract showed stronger antibacterial activity than A. halimus against Escherichia coli and Proteus mirabilis. Both extracts exhibited molluscicidal activity against Biomphalaria alexandrina, with LC₅₀ values of C. procera (135 mg/L) and A. halimus (223.8 mg/L). Survival rates of snails exposed to sub-lethal concentrations (LC₂₅) of C. procera and A. halimus extracts were 5% and 20%, respectively. The hatchability of snail eggs exposed to both extracts has been dramatically reduced. Both extracts significantly decreased the levels of alkaline phosphatase, acid phosphatase, total protein, and albumin in snails, as well as causing DNA damage and resulting in numerous hermaphrodite and digestive gland damages and distortions. Molecular docking showed palmitic acid binding with acid, alkaline, and alanine aminotransferases in treated digestive gland snails. In conclusion, C. procera and A. halimus have antibacterial and molluscicidal properties.

Evaluation of the molluscicidal activities of arylpyrrole on Oncomelania hupensis, the intermediate host of Schistosoma japonicum

The snail Oncomelania hupensis is the only intermediate host of the highly invasive parasite Schistosoma japonicum. Molluscicide is often used to curb transmission of S. japonicum. Niclosamide, the only World Health Organization (WHO) recognized molluscicide, presents major drawbacks, including high cost and toxicity towards aquatic animals. In the present study, a number of aryl pyrrole derivatives (ADs) were synthesized to serve as potential molluscicides and were tested on O. hupensis. To uncover the underlying mechanisms, adenosine triphosphate (ATP) and adenosine diphosphate (ADP) levels were assessed in the soft body of ADs-exposed O. hupensis, using high performance liquid chromatography (HPLC). The effect of C6 on key points of energy metabolism (the activities of complexes I, III, IV and the membrane potential) was determined. We demonstrated that the Compound 6 (C6, 4-bromo-1-(bromomethyl)-2-(4-chlorophenyl)-5-(trifluoromethyl)-1H-pyrrole-3-carbonitrile) exerted the strongest molluscicidal activity against adult O. hupensis at LC₅₀ of 0.27, 0.19, and 0.13 mg/L for 24, 48, and 72 h respectively. Moreover, we found that the bromide on the pyrrole ring of C6 was essential for molluscicidal activity. Furthermore, the ATP content reduced from 194.46 to 139.75 μg/g after exposure to 1/2 LC₅₀, and reduced to 93.06 μg/g after exposure to LC₅₀. ADP, on the other hand, remained the same level before and after C6 exposure. We found that C6, at 1/2 LC_50, reduced the membrane potential of O. hupensis, while no significant changes were observed in the activities of complexes I, III, and IV. C6 was identified with excellent activities on O. hupensis. The obtained structure−activity relationship and action mechanism study results should be useful for further compound design and development.