Evaluating the enantioselective degradation and novel metabolites following a single oral dose of metalaxyl in mice

Zhang, Ping; Zhu, Wentao; Qiu, Jing; Wang, Dezhen; Wang, Xinru; Wang, Yao; Zhou, Zhiqiang

doi:10.1016/j.pestbp.2014.09.008

Cited by 16 publications

(9 citation statements)

References 30 publications

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“…The concentration of S‐metalaxyl in tomato fruits from Heilongjiang and Hunan reached a maximum level of 22.5 and 6.2 ng/g (days 7 and 3), respectively, and then decreased to 12.1 and 1.5 ng/g (day 40). It was reported that S‐metalaxyl (t 1/2 = 2.2 d) degraded significantly faster than R‐metalaxyl (t 1/2 = 3.0 d) in tomato fruits under field conditions; however, S‐metalaxyl (t 1/2 = 4.03 d) degraded more slowly than the R‐metalaxyl (t 1/2 = 3.68 d) in tomato fruits under greenhouse conditions . In this study, for the application of enantiopure R‐metalaxyl, the half‐lives of S‐metalaxyl (43.3 and 19.3 d) were longer than R‐metalaxyl (8.7 and 1.6 d) (Table ).…”

Section: Resultsmentioning

confidence: 69%

“…In rabbits and mice, the S-enantiomer in plasma, liver, and kidney decreased more rapidly than the R-enantiomer. 19,20 Similarly, S-metalaxyl eliminated preferentially in Tubifex tubifex and rat hepatic microsomes. [21][22][23] The different stereoselectivity of metalaxyl enantiomers was also found in plants.…”

mentioning

confidence: 99%

“…Animal experiments have demonstrated significant enantioselectivity. In rabbits and mice, the S‐enantiomer in plasma, liver, and kidney decreased more rapidly than the R‐enantiomer . Similarly, S‐metalaxyl eliminated preferentially in Tubifex tubifex and rat hepatic microsomes .…”

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confidence: 99%

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Enantioselective Degradation and Chiral Stability of Metalaxyl‐M in Tomato Fruits

et al. 2016

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Metalaxyl is an important chiral acetanilide fungicide, and the activity almost entirely originates from the R-enantiomer. Racemic metalaxyl has been gradually replaced by the enantiopure R-enantiomer (metalaxyl-M). In this study a chiral residue analysis method for metalaxyl and the metabolite metalaxyl acid was set up based on high-performance liquid chromatography tandem mass spectroscopy (HPLC-MS/MS). The enantioselective degradation and chiral stability of metalaxyl-M in tomato fruits in two geographically distinct regions of China (Heilongjiang and Hunan Province) were evaluated and the enantioselectivity of metalaxyl acid was also investigated. Tomato plants grew under field conditions with a one-time spray application of metalaxyl-M wettable powder. It was found that R-metalaxyl was not chirally stable and the inactive S-metalaxyl was detected in tomato fruits. At day 40, S-metalaxyl derived from R-metalaxyl accounted for 32% and 26% of the total amount of metalaxyl, respectively. The metabolites R-metalaxyl acid and S-metalaxyl acid were both observed in tomato, and the ratio of S-metalaxyl acid to the sum of S- and R-metalaxyl acid was 36% and 28% at day 40, respectively. For both metalaxyl and metalaxyl acid, the half-life of the S-enantiomer was longer than the R-enantiomer. The results indicated that the enantiomeric conversion should be considered in the bioactivity evaluation and environmental pollution assessment. Chirality 28:382-386, 2016. © 2016 Wiley Periodicals, Inc.

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Section: Resultsmentioning

confidence: 69%

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Enantioselective Degradation and Chiral Stability of Metalaxyl‐M in Tomato Fruits

et al. 2016

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“…Typically, normal-phase HPLC is more widely applied in chiral separation than reversedphase HPLC due to better separation efficiency. [28][29][30][31] Chiral separation of BF and LCT enantiomers was conducted by gas chromatography, 32 HPLC, 14,33 capillary electrochromatography, 18 and cyclodextrin-modified micellar electrokinetic chromatography. Furthermore, reversed-phase HPLC is more compatible for electron spray ionization sources than normal-phase HPLC in mass spectrometry detection.…”

Section: Introductionmentioning

confidence: 99%

Enantiomeric separation of type I and type II pyrethroid insecticides with different chiral stationary phases by reversed‐phase high‐performance liquid chromatography

Zhang

Qian

et al. 2017

Chirality

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The enantiomeric separation of type I (bifenthrin, BF) and type II (lambda-cyhalothrin, LCT) pyrethroid insecticides on Lux Cellulose-1, Lux Cellulose-3, and Chiralpak IC chiral columns was investigated by reversed-phase high-performance liquid chromatography. Methanol/water or acetonitrile/water was used as mobile phase at a flow rate of 0.8 mL/min. The effects of chiral stationary phase, mobile phase composition, column temperature, and thermodynamic parameters on enantiomer separation were carefully studied. Bifenthrin got a partial separation on Lux Cellulose-1 column and baseline separation on Lux Cellulose-3 column, while LCT enantiomers could be completely separated on both Lux Cellulose-1 and Lux Cellulose-3 columns. Chiralpak IC provided no separation ability for both BF and LCT. Retention factor (k) and selectivity factor (α) decreased with the column temperature increasing from 10°C to 40°C for both BF and LCT enantiomers. Thermodynamic parameters including ∆H and ∆S were also calculated, and the maximum R were not always obtained at lowest temperature. Furthermore, the quantitative analysis methods for BF and LCT enantiomers in soil and water were also established. Such results provide a new approach for pyrethroid separation under reversed-phase condition and contribute to environmental risk assessment of pyrethroids at enantiomer level.

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“…Metalaxyl is a chiral pesticide and consists of a pair of enantiomers: (+)-S-metalaxyl and (-) -R-metalaxyl. The enantioselective difference of metalaxyl enantiomers in toxicity, 7 bioactivity, 8,9 and degradation [10][11][12][13][14] has been proven. A sizable quantity of metalaxyl leaches into the soil when it is used, which inevitably causes serious impacts on the soil and groundwater.…”

Section: Introductionmentioning

confidence: 99%

Enantioselective effects of metalaxyl on soil enzyme activity

et al. 2016

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The enantioselective effects of the chiral pesticide metalaxyl on soil enzyme activity were investigated. Incubation experiments were conducted to investigate the effects of metalaxyl enantiomers at different concentrations on the activities of urease, invertase, and catalase as well as the type of activity change (activation vs. inhibition) at different times during incubation. The results indicated that the effects of metalaxyl on the activity of soil enzymes were not only related to the concentration of the enantiomers and soil incubation time, but also to the chiral configuration, suggesting the effects were enantioselective. A pattern of inhibition-recovery-slight stimulation was observed in urease activity of the soil samples treated with metalaxyl enantiomers, but the effects of (-) -R-metalaxyl were stronger than those of (+)-S-metalaxyl at the same concentration. Invertase activity in soil samples treated with metalaxyl enantiomers initially sharply decreased before finally returning to the normal level, and the effects of (+)-S-metalaxyl were stronger than those of (-) -R-metalaxyl at the same concentration. Metalaxyl enantiomers influenced catalase activity in a pattern of slight stimulation-inhibition-recovery, and the effects of (-) -R-metalaxyl were stronger than those of (+)-S-metalaxyl at the same concentration.

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Evaluating the enantioselective degradation and novel metabolites following a single oral dose of metalaxyl in mice

Cited by 16 publications

References 30 publications

Enantioselective Degradation and Chiral Stability of Metalaxyl‐M in Tomato Fruits

Enantioselective Degradation and Chiral Stability of Metalaxyl‐M in Tomato Fruits

Enantiomeric separation of type I and type II pyrethroid insecticides with different chiral stationary phases by reversed‐phase high‐performance liquid chromatography

Enantioselective effects of metalaxyl on soil enzyme activity

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