benzofurans and benfuracarb

Benfuracarb (BEN), a broad-spectrum carbamate insecticide used for crop protection, is considered toxic to humans and aquatic organisms. However, the potential risk level of BEN to aquatic organisms is still unclear. In this study, we exposed zebrafish embryos to BEN (0.08, 0.49, and 0.90 mg/L) from 3 to 96 hours post-fertilization (hpf). The results showed that BEN caused shorter body length in zebrafish larvae. The activity of superoxide dismutase (SOD) was significantly increased after BEN exposure. Furthermore, the transcription levels of marker genes associated with early embryonic development (myoD, nkx2.4b, myh6, and gh) were disrupted after BEN treatment. Taken together, the data indicate that BEN possesses developmental toxicity to zebrafish. The results provide a valuable reference for assessing BEN's potentially harmful effects on aquatic ecosystems.

Topics: Animals; Benzofurans; beta-Alanine; Ecosystem; Embryo, Nonmammalian; Humans; Larva; Oxidative Stress; Water Pollutants, Chemical; Zebrafish

Lycoriella ingenua (Dufour) (Diptera: Sciaridae) and Coboldia fuscipes (Meigen) (Diptera: Scatopsidae) are two of the most economically important insect pests of cultivated mushrooms. The toxicities to the fly larvae of the three phenylpropanoids (methyleugenol, myristicin, and safrole) from aerial parts of Asarum sieboldii Miquel (Aristolochiaceae) were compared with those of the currently available carbamate insecticide benfuracarb. In a contact+fumigant mortality bioassay with L. ingenua and C. fuscipes larvae, methyleugenol (1.46 and 2.33 µg/cm2) was the most toxic compound, followed by safrole (2.03 and 2.59 µg/cm2) and myristicin (3.59 and 4.96 µg/cm2), based on 24-h LC50 values. The phenylpropanoids were less toxic than benfuracarb (LC50, 0.75 and 0.55 µg/cm2). In vapor-phase mortality tests with the larvae, the phenylpropanoids were consistently more toxic in closed versus open containers, indicating that the effect of the compounds was largely a result of vapor action. Global efforts to reduce the level of highly toxic synthetic insecticides in the agricultural environment justify further studies on A. sieboldii plant-derived products as potential fumigants for the control of mushroom fly populations in mushroom houses and mushroom compost.

Topics: Allylbenzene Derivatives; Animals; Asarum; Benzofurans; Benzyl Compounds; beta-Alanine; Dioxolanes; Diptera; Eugenol; Fumigation; Insect Control; Insecticides; Larva; Plant Extracts; Pyrogallol; Safrole; Species Specificity

In vitro metabolism of benfuracarb in liver microsomes from seven species was studied in order to quantitate species-specific metabolic profiles and enhance benfuracarb risk assessment by interspecies comparisons. Using LC-MS/MS, a total of seven phase-I-metabolites were detected from the extracted chromatograms and six of them were unequivocally identified. Benfuracarb was metabolized via two metabolic pathways, the sulfur oxidation pathway and nitrogen sulfur bond cleavage, yielding carbofuran, which metabolized further. Analysis of the metabolic profiles showed that benfuracarb was extensively metabolized with roughly similar profiles in different species in vitro. In vitro intrinsic clearance rates as well as calculated in vivo hepatic clearances indicated that all seven species metabolize benfuracarb via the carbofuran metabolic pathway more rapidly than the sulfoxidation pathway. The highest interspecies differences in hepatic clearance rate values were for mouse and rat liver microsomes compared to human, i.e. 4.8 and 4.1-fold higher, as illustrated by in vivo hepatic clearance of carbofuran. Overall, there are quantitative interspecies differences in the metabolic profiles and kinetics of benfuracarb biotransformation. These findings illustrate that in vitro studies of benfuracarb metabolite profiles and toxicokinetics are helpful for the proper selection and interpretation of animal models for toxicological evaluation and chemical risk assessment.

Topics: Adult; Animals; Benzofurans; beta-Alanine; Dogs; Female; Humans; Insecticides; Macaca fascicularis; Male; Mice; Mice, Inbred DBA; Microsomes, Liver; Middle Aged; Rabbits; Rats; Risk Assessment; Species Specificity

Human responses to the toxicological effects of chemicals are often complicated by a substantial interindividual variability in toxicokinetics, of which metabolism is often the most important factor. Therefore, we investigated human variation and the contributions of human-CYP isoforms to in vitro metabolism of benfuracarb. The primary metabolic pathways were the initial sulfur oxidation to benfuracarb-sulfoxide and the nitrogen-sulfur bond cleavage to carbofuran (activation). The Km, Vmax, and CL(int) values of carbofuran production in ten individual hepatic samples varied 7.3-, 3.4-, and 5.4-fold, respectively. CYP2C9 and CYP2C19 catalyzed benfuracarb sulphur oxidation. Carbofuran formation, representing from 79% to 98% of the total metabolism, was catalyzed predominantly by CYP3A4. The calculated relative contribution of CYP3A4 to carbofuran formation was 93%, while it was 4.4% for CYP2C9. The major contribution of CYP3A4 in benfuracarb metabolism was further substantiated by showing a strong correlation with CYP3A4-selective markers midazolam-1'-hydroxylation and omeprazole-sulfoxidation (r=0.885 and 0.772, respectively). Carbofuran formation was highly inhibited by the CYP3A inhibitor ketoconazole. Moreover, CYP3A4 marker activities were relatively inhibited by benfuracarb. These results confirm that human CYP3A4 is the major enzyme involved in the in vitro activation of benfuracarb and that CYP3A4-catalyzed metabolism is the primary source of interindividual differences.

Topics: Adult; Benzofurans; beta-Alanine; Biotransformation; Cytochrome P-450 CYP3A; Cytochrome P-450 Enzyme System; Female; Humans; Insecticides; Isoenzymes; Ketoconazole; Male; Metabolic Networks and Pathways; Microsomes, Liver; Middle Aged

Sorption-desorption processes govern the movement of pesticides in soil. These processes determine the potential hazard of the pesticide in a given environment for groundwater contamination and need to be investigated.. In the present study, sorption-desorption processes of benfuracarb were investigated using a batch method in two mollisols. The kinetics of benfuracarb sorption in mollisols conformed to two-compartment (1 + 1) first-order kinetics. The fast sorption rate constant was about 3 times higher for silt loam than for loam soil. However, the slow sorption rate constants were statistically similar for both soils. The concentration-dependent sorption-desorption isotherms of benfuracarb could not closely conform to the Freundlich isotherm in mollisols of high organic C content. The computed values of both the sorption (log K) and desorption (log K') capacities were higher for silt loam than for loam soil. The desorption index (n'/n) values in the range 30.0-41.3 indicated poor reversibility of sorbed benfuracarb in mollisols.. In view of the strong sorption of benfuracarb in mollisols with only partial desorption, the possibility of the leaching of soil-applied benfuracarb to contaminate groundwaters appears to be low.

Topics: Adsorption; Benzofurans; beta-Alanine; Insecticides; Kinetics; Soil; Soil Pollutants

The fate of benfuracarb was studied under field conditions in brinjal fruits and soil following foliar spray application at 0.25 and 0.50 microg g(-1) by HPLC. At 0.25 microg g(-1), benfuracarb persisted up to 7 days both in soil and brinjal but at 0.50 microg g(-1), benfuracarb residues persisted up to 10 and 12 days in soil and brinjal fruits, respectively. The persistence of benfuracarb residues, both in soil and brinjal, followed first-order kinetics. The half-life values of benfuracarb in soil and brinjal fruit were found to be 3.54 and 3.90 days at 0.25 microg g(-1) and 3.75 and 4.73 days at 0.50 microg g(-1), respectively.

Topics: Benzofurans; beta-Alanine; Biodegradation, Environmental; Fruit; Half-Life; Insecticides; Kinetics; Pesticide Residues; Soil; Soil Pollutants; Solanum melongena; Spectrophotometry, Ultraviolet; Weather

N-methylcarbamate insecticides are widely used chemicals for crop protection. This study examines the hydrolytic and photolytic cleavage of benfuracarb, carbosulfan and carbofuran under natural conditions. Their toxicity and that of the corresponding main degradation products toward aquatic organisms were evaluated.. Suspensions of benfuracarb, carbosulfan and carbofuran in water were exposed to sunlight, with one set of dark controls, for 6 days, and analyzed by 1H-NMR and HPLC. Acute toxicity tests were performed on Brachionus calyciflorus, Daphnia magna, and Thamnocefalus platyurus. Chronic tests were performed on Pseudokirchneriella subcapitata, and Ceriodaphnia dubia.. Under sunlight irradiation, benfuracarb and carbosulfan gave off carbofuran and carbofuran-phenol, while only carbofuran was detected in the dark experiments. The latter was degraded to phenol by exposure to sunlight. Effects of pH, humic acid and KNO3 were evaluated by kinetics on dilute solutions in the dark and by UV irradiation, which evidenced the lability of the pesticide at pH 9. All three pesticides and phenol exhibited acute and higher chronic toxicity towards the aquatic organisms tested.. Investigation on the hydrolysis and photolysis of benfuracarb and carbosulfan under natural conditions provides evidence concerning the selective decay to carbofuran and/or phenol. Carbofuran is found to be more persistent and toxic.. The decay of benfuracarb and carbosulfan to carbofuran and the relative stability of this latter pesticide account for many papers that report the detection of carbofuran in water, fruits and vegetables.

Topics: Animals; Benzofurans; beta-Alanine; Carbamates; Carbofuran; Daphnia; Insecticides; Lethal Dose 50; Rotifera; Water Pollutants, Chemical

Topics: Adsorption; Benzofurans; beta-Alanine; Carbofuran; China; Insecticides; Soil Microbiology; Soil Pollutants

In order to complete previous studies conducted on Blattella germanica, three insecticides from different groups were evaluated: boric acid, an inorganic compound, benfuracarb, a carbamate, and halofenozide, a non-steroidal ecdysone agonist. Boric acid (8.20%, LD50) and benfuracarb (2%, LD50) were incorporated into the diet and orally administrated to newly emerged adults of both sexes, while halofenozide (0.33%, LD50) was applied topically. Hydrocarbons extracts was made on bidistilled pentane from control and treated series sampled 6 days following treatment. Extracts was analyzed by gas chromatography. Data showed that cuticular profiles of control and treated series were qualitatively similar with thirteen major compounds; however, significant quantitative differences were noted. Boric acid seemed to feminize the cuticular profile in males with a significant reduction of the two first cuticular compounds detected. Halofenozide and benfuracarb reduced cuticular compounds in both sexes.

Topics: Administration, Oral; Administration, Topical; Animals; Benzoates; Benzofurans; beta-Alanine; Blattellidae; Boric Acids; Chromatography, Gas; Female; Hydrazines; Hydrocarbons; Insecticides; Lethal Dose 50; Male; Time Factors

Blatta germanica is the more prevalent cockroach species in Algeria. In the present study, we tested the effect on reproduction in B. germanica of two insect growth regulators, RH-0345, a benzoylhydrazine analogue that mimics the action of 20-hydroxyecdysone, and methoprene, one of the most commercially important juvenile hormone analogues, and a novel carbamate insecticide, benfuracarb. The compounds were applied topically (10 and 20 microg/insect for RH-0345, and 1 and 10 microg/insect for methoprene) or orally administrated (at 2% for benfuracarb) on newly emerged females and evaluated on reproductive events during the adult life (2, 4 and 6 days). Treatment with RH-0345 and benfuracarb reduced significantly the number of oocytes, the size and the volume of the basal oocyte during the experimental period. Methoprene distorted the ovarian development since it caused a significant reduction in the number of oocytes at 2, 4 and 6 days for the two tested doses, and an increase in oocyte size at 2, 4 and 6 days with 1 microg and a decrease with 10 microg. In a second series of experiments, the effects of these compounds were assayed on the ovarian proteins. Data from biochemical analysis revealed that RH-0345 and benfuracarb reduced the ovarian amounts of proteins, while treatment with methoprene increased it during the sexual maturation.

Topics: Administration, Topical; Animals; Benzoates; Benzofurans; beta-Alanine; Blattellidae; Female; Hydrazines; Insecticides; Juvenile Hormones; Methoprene; Oocytes; Ovary; Reproduction

A simultaneous analytical method was examined for carbofuran and its derivative pesticides in water. Since carbofuran derivatives are hydrolyzed to carbofuran in water, the liquid-liquid extraction method was used to obtain an accurate concentration value. Moreover, since these compounds are easily decomposed at the GC/MS injection port, temperature programmable inlet on-column injection was used. By combining the two methods, a sensitive analytical method was established without hydrolysis and thermal decomposition. As a result of recovery experiments using distilled water, river water and tap water, acceptable recovery rates and favorable reproducibility were obtained. This method was used in a field investigation to determine carbofuran and its derivative pesticides in river water taken from three points of the Y river over a period of one year. Carbofuran, benfuracarb, and carbosulfan were detected and corresponded to the period when these pesticides were used in the area. Although benfuracarb and carbosulfan using traditional methods are believed to easily hydrolyze and thermally decompose during the analytical process, by using our method they can be detected.

Topics: Automation; Benzofurans; beta-Alanine; Carbamates; Carbofuran; Fresh Water; Gas Chromatography-Mass Spectrometry; Japan; Pesticides; Rivers; Temperature; Water Pollutants

We describe four fatal cases due to ingestion of carbofuran, a carbamate insecticide. Carbofuran was detected in the gastric contents using thin layer chromatography (TLC) and gas chromatography/mass spectrophotometry (GC/MS), and quantified in the blood using a gas chromatograph equipped with nitrogen-phosphorus detector (NPD). Fatal concentrations of carbofuran in blood ranged from 0.32 to 11.6 microg/ml.

Topics: Adult; Benzofurans; beta-Alanine; Carbofuran; Chromatography, Thin Layer; Fatal Outcome; Female; Forensic Medicine; Gas Chromatography-Mass Spectrometry; Gastrointestinal Contents; Humans; Insecticides; Male; Suicide; Survival

A multiresidue method based on matrix solid-phase dispersion (MSPD) microextraction was studied to determine the carbamate, benfuracarb, and urea insecticides, diflubenzuron, flufenoxuron hexaflumuron and hexythiazox, used in control of citrus pests. Optimisation of different parameters, such as the type of solid support for matrix dispersion, elution solvents and the clean-up step were carried out. The method used 0.5 g of orange sample, C8 bonded silica as MSPD sorbent and dichloromethane as eluting solvent. Recoveries, at spiked concentrations below the maximum residue levels established by Spanish Government, were between 74 and 84% with relative standard deviations ranging from 2 to 4%. The limits of quantification were from 0.15 to 0.25 microgram/g using high-performance liquid chromatography with UV detection at 200 nm. The method may be useful as a screening protocol for the determination of these newly developed pesticides in citrus samples.

Topics: Benzamides; Benzofurans; beta-Alanine; Chromatography, High Pressure Liquid; Diflubenzuron; Fruit; Indicators and Reagents; Insecticides; Pesticide Residues; Phenylurea Compounds; Quality Control; Sensitivity and Specificity

We describe here three cases involving acute fatalities due to benfuracarb ingestion and the forensic toxicological implications. Benfuracarb, a carbamate insecticide and its main metabolite carbofuran, were detected using thin layer chromatography (TLC) and gas chromatography/mass spectrophotometry (GC/MS) after extraction with ethyl acetate and then quantified using gas chromatography (GC) equipped with NPD. The blood levels of benfuracarb and carbofuran were in the range of 0.30-2.32 microg/ml and 1.45-1.47 microg/ml, respectively. Benfuracarb was not detected in urine, but carbofuran was detected in the range of 0.53-2.66 microg/ml.

Topics: Adult; Benzofurans; beta-Alanine; Carbofuran; Chromatography, Gas; Chromatography, Thin Layer; Female; Gas Chromatography-Mass Spectrometry; Humans; Insecticides; Male; Poisoning; Suicide

The antidotal action of atropine sulfate and 2-pyridine aldoxime methiodide (2-PAM) against poisoning attributable to the new procarbamate insecticide benfuracarb [(ethyl N-[2,3-dihydro-2,2-dimethylbenzofuran-7-yloxycarbonyl (methyl) aminothio]-N-isopropyl-beta-alaninate] was compared utilizing rats as our experimental model. Both the intraperitoneal and oral administrations of these antidotes were examined after five, ten, fifteen and thirty minutes exposure periods, following treatment with benfuracarb at dose levels approximating LD50 and LD100. The results obtained demonstrate that both the intraperitoneal and oral administrations of atropine sulfate blocked or significantly reduced the toxic effects of benfuracarb and protected the animals from death. The intraperitoneal administration route appears to be more effective than was the oral route. In addition, the administration of atropine sulfate after the shorter period (up to 15 minutes), following exposure to benfuracarb, improved antidotal action, particularly with the LD100 dose of benfuracarb. It is suggested that atropine sulfate antagonizes benfuracarb poisoning by blocking acetylcholine (ACh) receptors, as many other carbamate insecticides, since benfuracarb was an in vivo cholinesterase (ChE) inhibitor and the toxic effect of benfuracarb was reduced by atropine sulfate. 2-PAM, however, did not significantly block or reduce the toxic effects of benfuracarb.

Topics: Administration, Oral; Animals; Antidotes; Atropine; Benzofurans; beta-Alanine; Carbamates; Cholinesterase Reactivators; Injections, Intraperitoneal; Insecticides; Male; Pralidoxime Compounds; Rats; Rats, Sprague-Dawley

The carbamate insecticides benfuracarb, carbosulfan and furathiocarb were investigated in the mouse bone marrow micronucleus assay to establish whether they show cytogenetic activity in vivo. Two doses of each substance were administered intraperitoneally to NMRI mice. All of the three substances led to a positive micronucleus response in polychromatic erythrocytes of the bone marrow at different expression times. While furathiocarb and carbosulfan showed similar patterns of the time-dependence of the micronucleus formation with maximum values after 72 h, benfuracarb exhibited a different behaviour with the maximum increase taking place within 24 h after substance application. In furathiocarb-treated animals the ratio of normochromatic to polychromatic erythrocytes showed a dose and time depending increase with the highest value obtained after 72 h in animals treated with the upper dose. The two yeast test systems Saccharomyces cerevisiae strains D7 and D61.M were applied in order to evaluate the genetic endpoints gene mutation, gene conversion and aneuploidy induction. None of the three insecticides had an influence on the frequencies of gene conversion and reverse mutation in the yeast S. cerevisiae D7 when tested with and without metabolic activation. In strain D61.M however benfuracarb and furathiocarb led to an increase of chromosome loss in the presence of the S9 metabolizing system.

Topics: Animals; Benzofurans; beta-Alanine; Biotransformation; Bone Marrow Cells; Carbamates; Chromosome Deletion; Dose-Response Relationship, Drug; Erythrocytes; Female; Injections, Intraperitoneal; Insecticides; Male; Mice; Micronucleus Tests; Microsomes, Liver; Mutagenicity Tests; Mutagens; Saccharomyces cerevisiae