Novel triazole derivatives as potential rodenticides against the Norway rat, R. norvegicus: histology, biochemical alternations, and field application

Economically speaking, rodents possess a serious threat to the agriculture sector. One of these organisms that directly threaten agriculture, stocks, and others is the Norway rat, Rattus norvegicus (R. norvegicus). The 2-cyano-N-(1H-1,2,4-triazol-3-yl) acetamide (1) was used as a precursor to give 2-cyano-3-(dimethylamino)-N-(1H-1,2,4-triazol-3-yl) acrylamide (2) and ethyl 2-amino-5-cyano-1,6-dihydro-6-oxo-1-(1H-1,2,4-triazol-3-yl) pyridine-3-carboxylate (3). Infra-red, ¹H-NMR, ¹³C-NMR, MS, and elemental analysis were done for the precise structure elucidation of the applied synthons. The prepared compounds were tested as potential rodenticides against the Norway rat, Rattus norvegicus. Toxicity analysis using four serial doses of both prepared compounds revealed that the LD₅₀ values were 160.6 and 391.7 mg/kg body weight, for ethyl 2-amino-5-cyano-1,6-dihydro-6-oxo-1-(1H-1,2,4-triazol-3-yl) pyridine-3-carboxylate (3) and 2-cyano-N-(1H-1,2,4-triazol-3-yl) acetamide (1), respectively. Several biological variables, such as alanine transaminase (ALT), aspartate transaminase (AST), serum urea, creatinine, and total protein, have been assessed and evaluated as biological response indicators. Analysis revealed a highly significant increase in both AST, ALT, urea, and creatinine levels, while the total protein level showed a considerable reduction in treated rats exposed to 2-cyano-N-(1H-1,2,4-triazol-3-yl) acetamide (1) and ethyl 2-amino-5-cyano-1,6-dihydro-6-oxo-1-(1H-1,2,4-triazol-3-yl) pyridine-3-carboxylate (3) when compared to the control treatment. Liver histological examination showed structural changes in the form of congestion in the central vein, necrosis in some hepatic regions, and pyknotic nuclei, while kidney histological examination showed vacuolar degeneration of the epithelial cells of some convoluted tubules and the disappearance of some glomeruli and other marked atrophies. Necrosis in some areas was noticed. Field application through bait consumption took place with a satisfactory reduction of 68.4% for ethyl 2-amino-5-cyano-1,6-dihydro-6-oxo-1-(1H-1,2,4-triazol-3-yl) pyridine-3-carboxylate (3), while it was 61.9% for 2-cyano-N-(1H-1,2,4-triazol-3-yl) acetamide (1) when compared to the recommended Zinc phosphide commercial rodenticide that poses an 81% reduction.

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