Molluscicidal activity

The molluscicidal activity of imidazo[2,l-/][l,3,4]thiadiazoles and imidazo[2,l-/][l,3,4]oxadiazoles, such as compounds 112 and 109 (Figure 25), have been evaluated against the snail Lymnaea acumiata, which is a vector of the giant liver flukes, Fasciola gigantica and Fasciola hepatica <2004IJC(B)901>. 

Previous work with extracts of various plant species containing isobutylamide compounds indicated the larvicidal effects of the extracts against several species of mosquito.Other work has shown the molluscicidal activity of some unsaturated aliphatic isobutylamides against Physa occidentalis. 

The lethal activity of the isobutylamides on B. glabratus is shown in Table III. Molluscicidal activity was monitored as described previously.Briefly, snails of uniform sizes (average diameter of the shell 9 mm) were placed 2 snails/ concentration into deionized water solutions containing known concentrations of the isobutylamides. Unlike the relative activities of the isobutylamides on the tested insect species, fagaramide (1 ) and N-isobutyl-2E,4E -octadienamide ( ) were more potent molluscicides than were pellitorine (4) or piperlongumine (2). 

Meepagala KM, Sturtz G, Mischke CC, Wise D, Duke SO, Molluscicidal activity of vulgarone B against ram s horn snail Planorbella trivolvis), Pest Manag Sci 60 479-482, 2004. 

Bringmann, G., Holenz, J., Assi, L. A., Zhao, C. and Hostettmann, K. 1996. Molluscicidal activity of naphthylisoquinoline alkaloids from Triphyophyllum and Ancistrocladus species. Planta Medica, 61 556-557. 

Vieira, J. E. V., G. S. G. Barros, M. C. Medeiros, F. J. A. Matos, M. P. Souza and M. J. Medeiros. Pharmacologic screening of plants from Northeast Brazil. II. Rev Brasil Farm 1968 49 67-75. Dixit, V. P., V. N. Sharma and N. K. Lohiya. The effect of chronically administered cannabis extract on the testicular function of mice. Eur J Pharmacol 1974 26 111-114. Pinheiro de Sousa, M. and M. Z. Rouquayrol. Molluscicidal activity of plants from Northeast Brazil. Rev Bras... 

Mitotic effect. STE, administered to the buccal mucosa of 15 female HMT rats, 6 months of age, weekly for 1 year, produced hyperorthokeratosis, acanthosis, numerous binucleate spinous cells, and subepithelial connective tissue hyalinization. Verrucous carcinoma and squamous cell carcinoma were not seen. Karyotyping revealed that lymphocytes of tobacco-treated, as well as control rats, had normal chromosome number and morphology. However, approx 25% of buccal epithelial cells of the tobacco-treated rats were tetraploid and 5% octa-ploid, compared with only 11% tetraploid and no octaploid in the controls. Results indicated that the mitotic process could be disturbed by tobacco treatment b Molluscicidal activity. Water extract of the dried leaf, at a concentration of 168 ppm, produced equivocal effect on Lymnaea luteola . 

Molluscicidal activity. Methanol extract of the leaf, at a concentration of 2000 ppm for 2 hours of exposure, was active on Biomphalaria glabraw . 

El-Sawi reported the molluscicidal activity of alcoholic extracts from aerial parts of Acacia saligna, which exhibited strong activity against Biomphalaria alexandrina, the intermediate host of Schistosoma mansoni. These extracts were particularly rich in flavonoids and more especially in a new compound identified as 8-C-glucosyldihydrokaempferol. 

Saponins have been variously attributed with a diverse range of properties, some of which include both beneficial and detrimental effects on human health, piscidical, insecticidal and molluscicidal activity, allelopathic action, antinutri-tional effects, sweetness and bitterness, and as phytoprotectants that defend plants against attack by microbes and herbivores [2-11]. A more detailed understanding of the biochemical pathways and enzymes involved in saponin... 

Table 7. Molluscicidal activity of Licania genus plant extracts. ...

Dysidenin (419) has been shown to have inhibition activity of the iodide transfer in thyroid cells through a different mechanism than ouabain [332]. Dysideathiazoles (420-424) were strongly deterrent in fish-feeding experiments [326] and barbamide (426) has shown molluscicidal activity [328]. 

Orjala J, Gerwick WH (1996) Barbamide, a Chlorinated Metabolite with Molluscicidal Activity from the Caribbean Cyanobacterium Lyngbya majuscula. J Nat Prod 59 427... 

The first exploitation of this relationship in a biological context was by Boyce and Milbarrow [28], who showed a relationship between the molluscicidal activity of some A -alkyltritylamines and their Rm values on TLC plates. Many publications have reported the application of TLC to determine the relative lipophilicity of compounds. The first chapter of the book Chromatographic Determination of Molecular Interactions Applications in Biochemistry, Chemistry, and Biology [29[ summarises the theory and presents the major application fields of the TLC method. The advantage of the method for the determination of lipophilicity is that the layers can be easily covered by octanol and by using an aqueous buffer the retention parameter would be directly proportional to the octanol-water partition coefficients. The drawbacks of this method are the limited reproducibility and precision. 

Extracts from tamarind fruit pulp have shown molluscicidal activity against Bulinus trancatus snails. This is probably due to the presence of saponins in the fruit (Imbabi and Abu-Al-Futuh, 1992a, cited in (5)). 

In measuring the AKj values in eq 19, Green and Marcinkiewicz used tri-gol and diisopropyl ether in reversed-phased, tankless flat-bed chromatography. Boyce and Milborrow have shown that % values correlate the molluscicidal activity of a series of N-n-alkyltritylamines assuming a parabolic reaction exists between log LD50 and Rjj. Thus or ARj values can be used in eq 15 in place of log P or ir. 

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