Stereoselective degradation of tebuconazole in rat liver microsomes

Shen, Zhigang; Zhu, Wentao; Liu, Donghui; Xu, Xinyuan; Zhang, Ping; Zhou, Zhiqiang

doi:10.1002/chir.21027

Cited by 31 publications

(36 citation statements)

References 21 publications

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“…In addition, there's significant competitive inhibition between S-and R-tebuconazole, and S-isomer was more effective than R-isomer. [10,11] This study can not directly answer the bioaccumulation difference between rac-, R-, and S-tebuconazole, but we assumed that S-tebuconazole may induce more stresses to D. magna during metabolism than rac-tebuconaozle and 458…”

Section: Chronic Toxicitymentioning

confidence: 99%

“…1) have different fungicidal activity against some pathogens, [9] and different degradation characteristics in mammals, vegetables, and soil. [2,10,11] However, little is known about the toxicity of tebuconazole enantiomers. [12] Thus, the aim of this research was to evaluate and compare the toxicity effects of racemic and Stebuconazole on an important non-target aquatic organism, Daphnia magna, at both acute and chronic levels.…”

Section: Introductionmentioning

confidence: 99%

See 1 more Smart Citation

Comparative toxicity of rac- andS-tebuconazole toDaphnia magna

Chen

Liu

et al. 2015

Journal of Environmental Science and Health, Part B

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Tebuconazole is a chiral triazole fungicide used as raceme in a variety of agricultural applications. Earlier studies showed that tebuconazole is toxic to many non-target aquatic organisms but relative data for tebuconazole enantiomers are lacking. Thus, goal of this study was to evaluate and compare the toxicity of rac- and S-tebuconazole with Daphnia magna at both acute and chronic levels according to Organization for Economic Cooperation and Development (OECD) guidelines 202 and 211 respectively, to provide some guidelines for optimizing chiral pesticides application and management. The exposure concentrations were 0.1, 0.5, 1, 2, 4, 8, 10 mg L(-1) for both rac- and S-tebuconazole and their 48-h EC(50) values to D. magna were 3.53 (3.32-3.78) and 2.74 (2.33-3.10) mg L(-1) respectively, indicating that these both are medium toxic to D. magna with no significant toxicity difference at acute level. In chronic test, <24-h old D. magna were exposed to 0.01, 0.05, 0.10, 0.20, and 0.40 mg L(-1) of rac- and S-tebuconazole with one blank and one solvent control for 21 days according to OECD guideline 211. Four developmental (molting rate, days to the 1st and 3rd brood, and body length) and five reproductive (size of the 1st and 3rd brood, number of broods, and number of neonates) parameters for each D. magna were determined. Results showed that both rac- and S-tebuconazole significantly reduced the reproduction and impacted the development of D. magna at concentrations of 0.05 mg L(-1) or higher. Furthermore, S-tebuconazole was more toxic than raceme, and the difference between effects on the same parameters induced by rac- and S-tebuconazole was statistically significant. These results demonstrated that the chronic toxicity of S-tebuconazole might be underestimated in general use, and further studies should focus more on the biological behaviors of enantiomers and not just the raceme of tebuconazole and other chiral pesticides in the environment.

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Section: Chronic Toxicitymentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Comparative toxicity of rac- andS-tebuconazole toDaphnia magna

Chen

Liu

et al. 2015

Journal of Environmental Science and Health, Part B

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“…Its absolute configuration is left-optical (-) rotation of S-enantiomer and rightoptical (+) rotation of R-enantiomer (Kaulen, 1989). The (+)-R-enantiomer shows faster degradation than that of (-)-S-enantiomer in cabbage, rat liver microsomes and rabbit plasma, while (-)-S-enantiomer dissipates faster than (+)-R-form in cucumber fruit and soil (Zhu et al, 2007;Shen et al, 2012;Wang et al, 2012). It is important to further understand the biological behavior of tebuconazole enantiomers in ecosystem.…”

Section: Introductionmentioning

confidence: 99%

Enantioseletive bioaccumulation of tebuconazole in earthworm Eisenia fetida

Zhang

et al. 2012

Journal of Environmental Sciences

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“…45 A simple mean of the values for the two enantiomers was calculated and used in the single compound version of the model. The corresponding constants measured for either the R or the S form as substrate (compound X-TEB) in the presence of the other enantiomer as an inhibitor (compound Y-TEB) were used to derive the inhibition constants (K I ) used in the binary model by the following equation.…”

Section: ■ Introductionmentioning

confidence: 99%

Physicologically Based Toxicokinetic Models of Tebuconazole and Application in Human Risk Assessment

Jónsdóttir

Reffstrup

Petersen

et al. 2016

Chem. Res. Toxicol.

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A series of physiologically based toxicokinetic (PBTK) models for tebuconazole were developed in four species, rat, rabbit, rhesus monkey, and human. The developed models were analyzed with respect to the application of the models in higher tier human risk assessment, and the prospect of using such models in risk assessment of cumulative and aggregate exposure is discussed. Relatively simple and biologically sound models were developed using available experimental data as parameters for describing the physiology of the species, as well as the absorption, distribution, metabolism, and elimination (ADME) of tebuconazole. The developed models were validated on in vivo half-life data for rabbit with good results, and on plasma and tissue concentration-time course data of tebuconazole after i.v. administration in rabbit. In most cases, the predicted concentration levels were seen to be within a factor of 2 compared to the experimental data, which is the threshold set for the use of PBTK simulation results in risk assessment. An exception to this was seen for one of the target organs, namely, the liver, for which tebuconazole concentration was significantly underestimated, a trend also seen in model simulations for the liver after other nonoral exposure scenarios. Possible reasons for this are discussed in the article. Realistic dietary and dermal exposure scenarios were derived based on available exposure estimates, and the human version of the PBTK model was used to simulate the internal levels of tebuconazole and metabolites in the human body for these scenarios. By a variant of the models where the R(-)- and S(+)-enantiomers were treated as two components in a binary mixture, it was illustrated that the inhibition between the two tebuconazole enantiomers did not affect the simulation results for these realistic exposure scenarios. The developed models have potential as an important tool in risk assessment.

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Stereoselective degradation of tebuconazole in rat liver microsomes

Cited by 31 publications

References 21 publications

Comparative toxicity of rac- andS-tebuconazole toDaphnia magna

Comparative toxicity of rac- andS-tebuconazole toDaphnia magna

Enantioseletive bioaccumulation of tebuconazole in earthworm Eisenia fetida

Physicologically Based Toxicokinetic Models of Tebuconazole and Application in Human Risk Assessment

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