ethiprole and fipronil

The phenylpyrazole chiral insecticides, including the widely used fipronil, ethiprole, and flufiprole, have generated a worldwide interest due to their environmental toxicity. However, up to now,only few studies focused on their their potential endocrine-disrupting effects (EDEs). In this study, we investigated the endocrine hormonal disorder caused by the fipronil, ethiprole, and flufiprole enantiomers in vitro and in silico approach. Results of the luciferase reporter assay indicated that the enantiomers of fipronil, ethiprole, or flufiprole have shown stereoselective endocrine-disrupting effects. S-(-)-ethiprole and S-(-)-flufiprole have anti-thyroidal disorder effects whereas R-(-)-fipronil, R-(+)-ethiprole, and R-(+)-flufiprole showed anti-estrogenic disorder effects. The results of the molecular dynamics simulations revealed that the happened EDEs could be partially attributed to the enantioselective specific receptor binding affinities. It also suggested that Vander Waals interactions plays an important role in the binding procedure. This study could provide helpful information for the explanation of enantioselectivity in the EDEs of chiral phenylpyrazole pesticides at the molecular level.

Topics: Animals; Computer Simulation; Endocrine Disruptors; Insecticides; Pesticides; Pyrazoles; Stereoisomerism

The objective of this research was to investigate the potential damage caused by the residual concentrations of the insecticides Regent

Topics: Animals; Cell Death; Cichlids; Environmental Biomarkers; Fish Proteins; HSP70 Heat-Shock Proteins; Insecticides; Liver; Pesticide Residues; Pyrazoles; Water Pollutants, Chemical

An equilibrium passive sampler based on polyoxymethylene (POM) was used to determine the freely dissolved concentrations (C

Topics: Charcoal; Environmental Monitoring; Geologic Sediments; Pyrazoles; Resins, Synthetic; Water Pollutants, Chemical

Topics: 2-Propanol; Chromatography, High Pressure Liquid; Hexanes; Pesticides; Pyrazoles; Stereoisomerism; Temperature; Thermodynamics

Cross-resistance to two fipronil analogs, butene-fipronil and ethiprole, was detected in fipronil-resistant field populations and a resistant laboratory strain of the planthopper Nilaparvata lugens (Stål) (Hemiptera: Delphacidae), although the two analogs have not been used widely in rice-growing areas in China. The results showed that six field populations with 23.8-43.3-fold resistance to fipronil had reached a higher level of cross-resistance to ethiprole (resistance ratio [RR] = 47.1-100.9-fold) and had a minor level of cross-resistance (RR = 3.4- 8.1-fold) to butene-fipronil. After 10 generations of selection, the RR to fipronil increased from 7.3-fold to 41.3-fold. At the same time, the insect increased cross-RR to ethiprole from 16.3-fold to 65.6-fold, whereas it had only minor increase in cross-resistance to butene-fipronil from 2.8-fold to 4.0-fold. These results confirmed that fipronil-resistant N. lugens could develop a higher level of cross-resistance to ethiprole, although it still maintained a lower level cross-resistance to butene-fipronil. Our data suggest that ethiprole is not a suitable alternative for controlling N. lugens, once the insect has developed a high level resistance to fipronil. Further investigation is necessary to understand the cross-resistance mechanisms in N. lugens.

Topics: Animals; Hemiptera; Hydrocarbons, Halogenated; Insecticide Resistance; Insecticides; Molecular Structure; Pyrazoles

Phenylpyrazoles are relatively new insecticides designed to manage problematic insect resistance and public health hazards encountered with older pesticide families. In vitro cytotoxicity induced by the phenylpyrazole insecticides, Ethiprol and Fipronil, and Fipronil metabolites, sulfone and sulfide, was studied in Caco-2 cells. This cellular model was chosen because it made possible to mimic the primary site of oral exposure to xenobiotics, the intestinal epithelium. Assessment of the barrier function of Caco-2 epithelium was assessed by TEER measurement and showed a major loss of barrier integrity after exposure to Fipronil and its metabolites, but not to Ethiprol. The disruption of the epithelial barrier was attributed to severe ATP depletion independent of cell viability, as revealed by LDH release. The origin of energetic metabolism failure was investigated and revealed a transient enhancement of tetrazolium salt reduction and an increase in lactate production by Caco-2 cells, suggesting an increase in glucose metabolism by pesticides. Cellular symptoms observed in these experiments lead us to hypothesize that phenylpyrazole insecticides interacted with mitochondria.

Topics: Adenosine Triphosphate; Caco-2 Cells; Cell Proliferation; Dose-Response Relationship, Drug; Electric Impedance; Energy Metabolism; Epithelial Cells; Humans; Insecticides; L-Lactate Dehydrogenase; Lactic Acid; Mitochondria; Pyrazoles

Ethiprole differs from fipronil, the major phenylpyrazole insecticide, only in an ethylsulfinyl substituent replacing the trifluoromethylsulfinyl moiety. This study compares their photochemistry, metabolism, action at the gamma-aminobutyric acid (GABA) receptor, and insecticidal potency. On exposure to sunlight as a thin film, ethiprole undergoes oxidation (major), reduction, and desethylsulfinylation but not desulfinylation whereas the major photoreaction for fipronil is desulfinylation. Metabolic sulfone formation is more rapid with ethiprole than fipronil in human expressed CYP3A4 in vitro and mouse brain and liver in vivo. High biological activity is observed for the sulfide, sulfoxide, sulfone, and desulfinyl derivatives in both the ethiprole and the fipronil series in GABA receptor assays (human recombinant beta3 homomer and house fly head membranes) with [(3)H]EBOB and in topical toxicity to house flies with and without the P450-inhibiting synergist piperonyl butoxide. On an overall basis, the ethiprole series is very similar in potency to the fipronil series.

Topics: Animals; Brain; Chromatography, High Pressure Liquid; Cytochrome P-450 CYP3A; Cytochrome P-450 Enzyme System; Gas Chromatography-Mass Spectrometry; Houseflies; Humans; Insecticides; Liver; Male; Mice; Oxidation-Reduction; Photochemistry; Pyrazoles; Receptors, GABA; Recombinant Proteins; Sulfones