• Archives of Pharmacal Research
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• v.14 no.3
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• pp.204-206
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• 1991

Arylazomethylene derivatives as molluscicides were synthesized from hetro cyclic amines.

• Journal of Environmental Health Sciences
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• v.6 no.1
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• pp.10-21
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• 1979

In preventing the infection of Clonorchis sinensis, there is one way in which life cycle of Clonorchis sinensis is cut off by eradicating the first intermediate host viz Parafossarulus manchuoricus, with molluscicides or insecticides. This survey was carried out in order to evaluating the molluscicidal effect of several insecticides upon P. manchauricus. In this survey, diazinon, heptachlor, E.P.N., E.M., and malathion was applied as molluscidies. Those insecticides had been generaly used in farming area. The results are summarized as follows. 1) In molluscicidal effect, E.M. showed the higher molluscicidal effect than any other insecticides in all experiment parts, and the order of insecticides upon molluscicidal effect was that of E.M., E.P.N., heptachlor and malathion. 2) $LD_{50}$ values are varied according to the exposure time in insecticide solution, and the longer the exposure time is, the lower the values of $LD_{50}$ is. 3) To take the exposure time in low concentration of insecticide solution for the long time would obtain the more molluscicidal effect. 4) The mortality rate increases in proportion as the concentration of insecticides increases.

• Archives of Pharmacal Research
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• v.26 no.5
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• pp.358-366
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• 2003

Some N-p-substituted phenyl uracil-5-sulphonamide derivatives have been synthesized to be evaluated as molluscicides against Biomphalaria alexandrina snails, the intermediate host of Schistosoma mansoni. Schistosoma mansoni infected mice were treated with hemolymph obtained from pre-treated Biomphalaria alexandrina snails with the products 4a, 10a, 10b and 4b or obtained from non-treated snails. The selection of the concentration based on the predetermined dose which caused mortality of less than 50% of snails/24 h. $LC_{50}$ of compounds 4a, 10a, 10b and 4b was 50, 100, 200 and 50 ppm respectively. The result showed that immuno-stimulatory effect of treated hemolymph with compounds 4a, 10a and 4b was related to significant protective effects (44.4, 34.6 and 50.4% reduction in worm burden respectively). In addition, mean total worm burdens were significantly reduced in non treated hemolymph by 33.8%. The effect of hemolymph obtained from treated or non treated snails on S. mansoni adult worms antigens was studied by indirect immunofluorescence technique using chronic mouse sera (CMS). The results indicated that there was a strong reaction with epitopes in gut epithelium, tubercles, teigument and subtegumental musculature of untreated and treated S. mansoni adult worms antigens. Therefore, treatment of hemolymph obtained from pre-treated snails with compounds 4a, 10a, and 4b can stimulate specific immune response and induce protective effects against S. mansoni infection.

• Parasites, Hosts and Diseases
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• v.51 no.5
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• pp.537-544
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• 2013

The present study was performed to observe histopathological changes in tissues of Bithynia siamensis goniomphalos (Gastropoda, Bithyniidae) incubated in crude extract solutions of camellia (Camellia oleifera) seed and mangosteen (Garcinia mangostana) pericarp, and furthermore to estimate the molluscicidal effects of 2 plant substances. Substantial numbers of bithyniid snails were incubated in various concentrations of 2 plant solution for 24 hr. As the positive control, snails incubated in various concentrations of niclosamide, a chemical molluscicide, were used. The histopathological findings were observed in sectioned snail specimens of each experimental and control groups. The results showed that both camellia and mangosteen extracts had molluscicidal effects at 24 hr with 50% lethal concentration ($LC_{50}$) at concentrations of 0.003 and 0.002 g/ml, respectively, while niclosamide had $LC_{50}$ at concentrations 0.599 ppm. B. siamensis goniomphalos snail tissues (foot, gill, and digestive system) showed disruption of columnar muscle fibers of the foot, reduction of the length and number of gill cilia, numerous mucous vacuoles, and irregularly shaped of epithelial cells. Irregular apical and calciferous cells, dilatation of the digestive gland tubule, and large hemolymphatic spaces, and irregular apical surfaces, detachment of cilia, and enlargement of lysosomal vacuoles of epidermis were also shown in all groups. By the present study, it is confirmed that 2 plants, camellia and mangosteen, are keeping some substance having molluscicidal effects, and histopathological findings obtained in this study will provide some clues in further studies on their action mechanisms to use them as natural molluscicides.