cyadox and olaquindox

The aim of this article is to get an overview of the metabolism of quinoxaline 1,4-di-N-oxides (QdNOs) used in food animals. The derivatives of QdNOs (carbadox, olaquindox, mequindox, quinocetone, and cyadox) are the potent synthetic antimicrobial agents that are used for improving the feed efficiency and controlling dysentery in food-producing animals. Studies have demonstrated that the toxicity of QdNOs is closely associated with the production of their metabolism, especially with the production of their reduced metabolites. To the best of our knowledge, no one has systematically compiled the metabolism data of QdNOs. Therefore, the metabolism of QdNOs in animals has been discussed in the review for the first time. These drugs undergo extensive metabolism prior to excretion. N-oxide group reduction is the major metabolic pathway of QdNOs. Moreover, the N1- and N4-oxide reductions of QdNOs by different reducing mechanisms are also described. Obvious differences in metabolic pathways for QdNOs were observed owing to the differences on the side chain of these drugs. Therefore, understanding the metabolic pathways of QdNOs in animals will provide the guides for further studies of metabolism and toxicology of these drugs, and will also provide abundant information for the food safety assessment.

Topics: Animals; Carbadox; Humans; Quinoxalines

A 2 x 3 factorial arrangement of treatments was used to determine the effects of olaquindox and cyadox on the intestinal mucosal immune response and on fecal shedding of Escherichia coli in Landrace x Large White barrows that had been orally given 10(10) cfu of E. coli (O139:K88). Factors included 1) E. coli inoculation or no inoculation, and 2) no antimicrobial, 100 mg of olaquindox/kg, and 100 mg of cyadox/kg in the basal diet, respectively. The effects of cyadox and olaquindox were assessed in terms of fecal shedding of E. coli, the number of intraepithelial lymphocytes (IEL), immunoglobulin A-positive cells (APC) in the intestinal lamina propria, and ADG. There was no difference in the fecal shedding of total E. coli or the inoculated E. coli between olaquindox-supplemented pigs and cyadox-supplemented pigs during the experiment. However, fecal shedding of the inoculated E. coli in olaquindox- or cyadox-supplemented pigs was less (P < 0.05) than that in nonsupplemented pigs. Escherichia coli inoculation increased IEL and APC in the jejunum and ileum, but olaquindox or cyadox decreased IEL and APC (P < 0.05). Jejunal APC in cyadox-supplemented pigs was less (P < 0.05) than that in olaquindox-supplemented pigs. Escherichia coli inoculation reduced (P < 0.05) ADG, whereas the supplementations improved ADG (P < 0.01) during the experiment. Average daily gain in cyadox-supplemented pigs was greater (P < 0.05) than that in olaquindox-supplemented pigs. The data indicated that olaquindox and cyadox reduced the number of intestinal E. coli and suppressed E. coli-induced immune activation, which might be responsible for the enhanced growth that was observed.

Topics: Animals; Escherichia coli; Feces; Immunity, Mucosal; Immunologic Factors; Intestinal Mucosa; Male; Quinoxalines; Swine

Olaquindox, carbadox, and cyadox are chemically synthesised antibacterial and growth-promoting agents for animals. At high doses they may exert mutagenicity and hepatic and adrenal toxicities in animals. Regrettably, these substances are frequently abused or misused when added into animal feeds. Thus, developing a sensitive and reliable method for simultaneous determination of olaquindox, carbadox, and cyadox in different kinds of animal feeds is crucially important for food safety monitoring. In this paper we optimised instrumental conditions, extraction solvents, solid phase extraction cartridges, and pH of the loading solvents on the Oasis HLB cartridge. Under the optimal conditions, mean recoveries ranged from 74.1 to 111%, and intra-day and inter-day variations were lower than 14.6% and 10.8%, respectively. The limits of quantification for olaquindox, carbadox, and cyadox were 0.05 mg kg

Topics: Animal Feed; Animals; Anti-Bacterial Agents; Carbadox; Chromatography, High Pressure Liquid; Hydrogen-Ion Concentration; Quinoxalines; Solid Phase Extraction; Tandem Mass Spectrometry

Quinoxaline 1,4-di-N-oxides (QdNOs) are widely known as potent antibacterial agents, but their antibacterial mechanisms are incompletely understood. In this study, the transcriptomic and proteomic profiles of Escherichia coli exposed to QdNOs were integratively investigated, and the results demonstrated that QdNOs mainly induced an SOS response and oxidative stress. Moreover, genes and proteins involved in the bacterial metabolism, cellular structure maintenance, resistance and virulence were also found to be changed, conferring bacterial survival strategies. Biochemical assays showed that reactive oxygen species were induced in the QdNO-treated bacteria and that free radical scavengers attenuated the antibacterial action of QdNOs and DNA damage, suggesting an oxidative-DNA-damage action of QdNOs. The QdNO radical intermediates, likely carbon-centered and aryl-type radicals, as identified by electron paramagnetic resonance, were the major radicals induced by QdNOs, and xanthine oxidase was one of the QdNO-activating enzymes. This study provides new insights into the action of QdNOs in a systematic manner and increases the current knowledge of bacterial physiology under antibiotic stresses, which may be of great value in the development of new antibiotic-potentiating strategies.

Topics: Anti-Bacterial Agents; Cell Survival; DNA Damage; Dose-Response Relationship, Drug; Escherichia coli; Gene Expression Regulation, Bacterial; Microbial Sensitivity Tests; Molecular Sequence Annotation; Oxidation-Reduction; Oxidative Stress; Protein Biosynthesis; Proteomics; Quinoxalines; Reactive Oxygen Species; SOS Response, Genetics; Structure-Activity Relationship; Tirapazamine; Triazines

Quinocetone (QCT) and Cyadox (CYA) are important derivative of heterocyclic N-oxide quinoxaline (QdNO), used actively as antimicrobial feed additives in China. Here, we tested and compared the genotoxic potential of QCT and CYA with olaquindox (OLA) in Ames test, HGPRT gene mutation (HGM) test in V79 cells, unscheduled DNA synthesis (UDS) assay in human peripheral lymphocytes, chromosome aberration (CA) test, and micronucleus (MN) test in mice bone marrow. OLA was found genotoxic in all 5 assays. In Ames test, QCT produced His(+) mutants at 6.9 μg/plate in Salmonella typhimurium TA 97, at 18.2 μg/plate in TA 100, TA 1535, TA 1537, and at 50 μg/plate in TA 98. CYA produced His(+) mutants at 18.2 μg/plate in TA 97, TA 1535, and at 50 μg/plate in TA 98, TA 100 and TA 1537. QCT was found positive in HGM and UDS assay at concentrations ≥10 μg/ml while negative results were reported in CA test and MN test. Collectively, we found that OLA was more genotoxic than QCT and CYA. Genotoxicity of QCT was found at higher concentration levels in Ames test, HGM and UDS assays while CYA showed weak mutagenic potential to bacterial cells in Ames test.

Topics: Animals; Anti-Infective Agents; Bone Marrow Cells; Cell Line; Cells, Cultured; Cricetinae; Cricetulus; DNA Replication; Dose-Response Relationship, Drug; Humans; Lymphocytes; Male; Mice; Mice, Inbred Strains; Micronuclei, Chromosome-Defective; Mutagens; Mutation; Quinoxalines; Random Allocation; Salmonella typhimurium

Quinoxaline 1, 4-dioxides (QdNOs) has been used in animals as antimicrobial agents and growth promoters for decades. However, the resistance to QdNOs in pathogenic bacteria raises worldwide concern but it is barely known. To explore the molecular mechanism involved in development of QdNOs resistance in Escherichia coli, 6 strains selected by QdNOs in vitro and 21 strains isolated from QdNOs-used swine farm were subjected to MIC determination and PCR amplification of oqxA gene. A conjugative transfer was carried out to evaluate the transfer risk of QdNOs resistant determinant. Furthermore, the transcriptional profile of a QdNOs-resistant E. coli (79O4-2) selected in vitro with its parent strain 79-161 was assayed with a prokaryotic suppression subtractive hybridization (SSH) PCR cDNA subtraction. The result showed that more than 95% (20/21) clinical isolates were oqxA positive, while all the 6 induced QdNOs-resistant strains carried no oqxA gene and exhibited low frequency of conjugation. 44 fragments were identified by SSH PCR subtraction in the QdNOs-resistant strain 79O4-2. 18 cDNAs were involved in biosynthesis of Fe-S cluster (narH), protein (rpoA, trmD, truA, glyS, ileS, rplFCX, rpsH, fusA), lipoate (lipA), lipid A (lpxC), trehalose (otsA), CTP(pyrG) and others molecular. The 11 cDNAs were related to metabolism or degradation of glycolysis (gpmA and pgi) and proteins (clpX, clpA, pepN and fkpB). The atpADG and ubiB genes were associated with ATP biosynthesis and electron transport chain. The pathway of the functional genes revealed that E. coli may adapt the stress generated by QdNOs or develop specific QdNOs-resistance by activation of antioxidative agents biosynthesis (lipoate and trehalose), protein biosynthesis, glycolysis and oxidative phosphorylation. This study initially reveals the possible molecular mechanism involved in the development of QdNOs-resistance in E. coli, providing with novel insights in prediction and assessment of the emergency and horizontal transfer of QdNOs-resistance in E. coli.

Topics: Animals; Anti-Bacterial Agents; Base Sequence; DNA Primers; DNA, Complementary; Drug Resistance, Bacterial; Escherichia coli; Escherichia coli Proteins; Glycolysis; Microbial Sensitivity Tests; Models, Genetic; Molecular Sequence Data; Nucleic Acid Hybridization; Oxides; Phenotype; Phosphorylation; Polymerase Chain Reaction; Quinoxalines; Swine

To investigate the chronic toxicity of cyadox, a growth promoting agent, five groups of Wistar rats (30 rats/group/sex) were fed with the diets containing cyadox (0, 100, 400 and 2000 mg/kg) or olaquindox (400 mg/kg) for 78weeks. There were significant decreases in body weights in both genders during most of the study period in 2000 mg/kg cyadox and 400 mg/kg olaquindox rats. Significant decreases in serum alkaline aminotransferase in the 2000 mg/kg cyadox rats at weeks 26, 52 and 78 were observed. Relative weights of liver and kidney were significantly increased in 2000 mg/kg cyadox and 400 mg/kg olaquindox rats at weeks 26, 52 and 78. A significant increase in relative brain and heart weights in 2000 mg/kg cyadox males was observed. The histopathological examinations revealed that 2000 mg/kg cyadox diet or 400 mg/kg olaquindox diet could induce proliferation of bile canaliculi in the portal area of liver and swelling and fatty degeneration of the proximal renal tubular epithelial cells in kidneys. In conclusion, the target organs of cyadox for rats were liver and kidney. The no-observed-adverse-effect level of cyadox in this study was estimated to be 400 mg/kg diet.

Topics: Animals; Body Weight; Eating; Female; Kidney; Liver; Male; No-Observed-Adverse-Effect Level; Organ Size; Quinoxalines; Random Allocation; Rats; Rats, Wistar; Toxicity Tests, Chronic; Transaminases

To investigate the teratogenic potential and reproductive toxicity of cyadox, a growth promoting agent, Wistar rats (F(0)) were fed with diets containing cyadox (0, 50, 150 and 2500 mg/kg) or olaquindox (150 mg/kg), approximately equivalent to cyadox 5, 15, 250 or olaquindox 15 mg/kg b.w./day across two generations. Half of the pregnant rats (F(0), F(1b)) were subjected to caesarean section on gestational day 20 for teratogenic examination and the other half produced pups F(1a) and F(2a), respectively. At the 250 mg/kg b.w./day cyadox group, body weights of F(1b) pregnant rats and F(2a) on day 21 after birth decreased; fetal body lengths and tail lengths decreased; the number of fetal resorptions increased significantly; litter weights, number of viable fetuses decreased; number of embryo resorptions increased significantly; number of liveborn F(1a), F(1b) and F(2a) decreased. No macroscopic or microscopic change of any significance was found in the reproductive organs. Significant increases in the incidence of cervical ribs or lumbar ribs in F(2a) pups and significant increases of relative organ weight of testis and epididymis in F(1b) were observed at the 250 mg/kg b.w./day cyadox group. The NOAEL for reproduction/development of cyadox for rats was estimated to be 150 mg/kg diet, which was equivalent to approximately 15 mg/kg b.w./day.

Topics: Abnormalities, Drug-Induced; Administration, Oral; Analysis of Variance; Animal Feed; Animals; Animals, Newborn; Body Weight; Disease Models, Animal; Dose-Response Relationship, Drug; Epididymis; Female; Fetal Development; Male; Maternal Exposure; No-Observed-Adverse-Effect Level; Organ Size; Pregnancy; Quinoxalines; Rats; Rats, Wistar; Reproduction; Teratogens; Testis

Quinoxaline 1,4-dioxides (QdNOs) derivatives, the potent synthetic antibacterial group used in food-producing animals, are assumed to have pro-oxidant properties. However, how oxidative stress mediated their adrenal toxicity is far from clear. The aim of this study was to assess the ability of three QdNOs, i.e. olaquindox (OLA), mequindox (MEQ), and cyadox (CYA), to produce reactive oxygen species (ROS) and oxidative cell damage in porcine adrenocortical cells. Multiple approaches such as cell activity assay, biochemical detectation, flow cytometry and fluorescent were used to study the integrated role of ROS homeostasis, mitochondrial redox metabolism and cell apoptosis as well as chemical stability of these drugs. The results showed that OLA and MEQ treatment evoked a significant dose and time-dependent cell damage in adrenocortical cells, well CYA displayed much less toxicity. As for the intracellular ROS production, OLA irritated a persistent and utmost release of ROS while MEQ made a similar but weaker reaction. CYA, however, had a short and unstable release of intracellular ROS. On the other hand, quinoxalinine-2-carboxylie acid (QCA), one of the metabolites of OLA and MEQ, did not cause any significant production of ROS and showed relatively lower toxicity than its parents. Moreover, an imbalance in the redox metabolism and mitochondrial membrane damage has been implicated in adrenal toxicity of QdNOs. ROS scavengers partially reversed QdNOs-induced mitochondrial damage, indicating that mitochondria may be a major target and critical for ROS-mediated cell death. In a word, these results suggested that ROS is a key mediator of QdNOs-induced cell death via mitochondria-dependent pathway in adrenocortical cells. The results provide a mechanism approach in understanding the characterize of adrenal damage caused by QdNOs in vitro, which would in turn, help in designing the appropriate therapeutic strategies of these kind of feed additives.

Topics: Adrenal Cortex; Animals; Apoptosis; Cell Death; Cell Survival; Cells, Cultured; Dose-Response Relationship, Drug; Mitochondria; Molecular Structure; Oxidation-Reduction; Quinoxalines; Reactive Oxygen Species; Swine; Time Factors

To investigate the potential subchronic toxicity of cyadox, groups of 15 male and 15 female Wistar rats were fed with diets containing cyadox (0, 50, 150 or 2500 mg/kg) or olaquindox (150 mg/kg), approximately equivalent to cyadox 5, 15, 250 or olaquindox 15 mg/kg b.w./day, for 13 weeks. Five rats/sex/group were sacrificed on days 30, 60 and 90. No test-material-related changes were seen in mortality, clinical signs, hematology, clinical chemistry, organ weight data and macroscopic examinations. Except that body weights of both sexes of the 2500 mg/kg cyadox group were significantly lower than controls beginning after the second week of treatment. Body weights of females of 150 mg/kg olaquindox group were significantly lower than those of the control group at weeks 3 and 4. Other groups were unaffected by treatments. Histopathological observations revealed that 2500 mg/kg cyadox or 150 mg/kg olaquindox induced swelling and fatty degeneration of the hepatocytes and proximal renal tubular epithelial cells. It was for the first time that changes were found in the liver and kidneys of rats fed 2500 mg/kg cyadox. The no-observed-adverse-effect level (NOAEL) of cyadox for rats was estimated to be 150 mg/kg dietary dose level.

Topics: Administration, Oral; Animals; Anti-Infective Agents; Body Weight; Diet; Dose-Response Relationship, Drug; Epithelial Cells; Female; Hepatocytes; Kidney Tubules, Proximal; Male; No-Observed-Adverse-Effect Level; Quinoxalines; Rats; Rats, Wistar

One hundred and fifty piglets were randomly allotted to one of six treatments to determine the effects of olaquindox and cyadox on growth and intestinal immune response including the number of intraepithelial lymphocytes and immunoglobulin A secreting cells (ASCs) during the three-week period. A 2 x 3 factorial arrangement of treatments was employed with the following factors: (1) Escherichia coli (O(139):K(88), 10(10) CFU) inoculation or control and (2) no antimicrobials, 100 mg/kg olaquindox and 100 mg/kg cyadox in the basal diet respectively. The antimicrobial supplementations improved (p < 0.01) average daily gain and feed conversion ratio (FCR) during the experiment. Average daily gain and FCR in the cyadox-supplemented pigs were higher (p < 0.05) than those in the olaquindox-supplemented pigs. Intraepithelial lymphocytes and ASCs decreased (p < 0.05) when the diets were supplemented. Jejunal ASCs in the cyadox-supplemented pigs were lower (p < 0.05) than those in the olaquindox-supplemented pigs. Olaquindox and cyadox suppressed E. coli-induced intestinal immune activation, which may be involved in the observed growth promotion.

Topics: Animal Feed; Animal Nutritional Physiological Phenomena; Animals; Anti-Bacterial Agents; Colony Count, Microbial; Energy Intake; Escherichia coli; Immunoglobulin A; Intestinal Mucosa; Lymphocyte Count; Quinoxalines; Random Allocation; Swine; Weight Gain

An experiment was designed to study the clinical effects of different levels of carbadox, cyadox and olaquindox in the ration on health, weekly weight gain and feed conversion in pigs. Four different carbadox and olaquindox (25, 50, 100 and 200 ppm) levels and five different cyadox (25, 50, 100, 200 and 400 ppm) levels were tested in groups of 6 pigs during 6 weeks. The 13 groups were compared with a control group fed on the same diet with only vehicle. After one week the first clinical sign, a high faecal dry matter (FDM) content, was observed in the 200 ppm carbadox group, followed by the 100 and 50 ppm carbadox, the 400 and 100 ppm cyadox, and the 200 and 100 ppm olaquindox groups two weeks later. A second clinical sign, urine drinking from the floor or from pen-mates, was observed in the same pens, occurring in the same sequence. The third important clinical sign, a decreased abdominal volume, was also observed in almost the same sequence, however, in the 50 ppm olaquindox and cyadox groups this clinical sign was not observed. Average weekly weight gain was significantly decreased in the higher carbadox and olaquindox groups. Weight gain was significantly increased in the 200 ppm cyadox group. Hematocrit values were significantly increased in the 200 and 100 ppm carbadox groups only. From this study one may conclude that, within the dosages used, carbadox is more harmful than olaquindox for pigs, and it seems that cyadox is harmless for pigs in dosages up to 400 ppm.

Topics: Animals; Anti-Bacterial Agents; Carbadox; Female; Hematocrit; Male; Quinoxalines; Swine; Weight Gain

Quindoxin (quinoxaline-1,4-dioxide), a former 'growth promoter' used in animal husbandry, has been taken from the market because of its photoallergic properties. Nowadays its derivatives olaquindox, carbadox and cyadox are frequently applied for the same purpose. Recent reports show that olaquindox too, can induce photoallergic skin reactions in stockmen. From the present investigation it appeared that all compounds mentioned, form a reactive oxaziridine upon exposure to light, just like many other imino-N-oxides. Photoreactivity with protein, which is considered as an important condition for a compound to be a potential photoallergen, was also studied. Quindoxin and olaquindox proved to meet this condition, as was expected. But carbadox and cyadox also react and were shown to be even more reactive towards human serum albumin.

Topics: Animals; Anti-Bacterial Agents; Carbadox; Chemical Phenomena; Chemistry; Humans; Organophosphorus Compounds; Photochemistry; Photosensitivity Disorders; Proteins; Quinoxalines; Serum Albumin; Ultraviolet Rays

To study the effects of olaquindox and cyadox on aldosterone, sodium and potassium in the blood in comparison with the effects of carbadox, weaned pigs were fed these compounds in different doses. Pigs treated with 100 and 200 ppm carbadox showed a significant decline of aldosterone after five and three weeks, respectively, compared with control values. In the 200 ppm group treatment was interrupted at week 4. With olaquindox a continuous, significant decline was found from 50 ppm and above after five weeks, and from 25 ppm and above (but excluding the 100 ppm group), after six weeks. In the cyadox groups a significant decline was measured after six weeks in the 50, 200 and 400 ppm groups. Only the 200 ppm group had an earlier response at three and five weeks. A decrease of sodium to hyponatraemic levels in the carbadox groups was seen after three weeks in the 200, and after five weeks in the 100 ppm group. In the olaquindox groups only the 200 ppm dosage showed a consistent decrease to hyponatraemic levels from four weeks treatment. In the cyadox groups the 200 ppm dosage reached a hyponatraemic level after six weeks. An increase of potassium to hyperkalaemic levels occurred at 100 and 200 ppm carbadox dosage after four and three weeks, respectively, and at 200 ppm olaquindox dosage after four weeks. No hyperkalaemic levels were seen in the cyadox groups. It is concluded that the toxic effect of olaquindox, despite minor differences, is comparable with that of carbadox but that cyadox is less toxic.

Topics: Aldosterone; Animal Feed; Animals; Anti-Bacterial Agents; Carbadox; Female; Male; Potassium; Quinoxalines; Sodium; Swine

Topics: Animals; Bone Marrow; Bone Marrow Cells; Carbadox; Chromosome Aberrations; Growth Substances; Male; Mice; Mice, Inbred ICR; Quinoxalines

The growth-promoting agents carbadox and olaquindox were active in the mouse transplacental micronucleus test, whereas cyadox was ineffective. Chemicals were administered p.o. and i.p. at a dose of 100 mg/kg and the effect was observed 18 h after treatment. The effects observed in fetal liver were parallel to those in maternal bone marrow, but fetal tissue was approximately 2-3 times more sensitive.

Topics: Administration, Oral; Animals; Bone Marrow; Carbadox; Cell Nucleus; Female; Fetus; Injections, Intraperitoneal; Liver; Maternal-Fetal Exchange; Mice; Mice, Inbred ICR; Pregnancy; Quinoxalines

The cytogenetic activities of 3 growth-promoting agents carbadox, olaquindox and cyadox were examined by the micronucleus test. These chemicals were administered i.p. to male Wistar rats 30 and 6 h before they were killed. Single-dose levels were 5, 10, 15, 30, 60, 90, 120 and 240 mg/kg for carbadox; 30, 60, 90, 120 and 240 mg/kg for olaquindox; and for cyadox 30, 60, 120 and 240 mg/kg. Over the entire dose range tested, carbadox induced a statistically significant increase in the number of micronucleated polychromatic erythrocytes in the rat bone marrow, whereas similar activity of olaquindox started at a dose of 2 X 60 mg/kg. The effect of cyadox was very low even at the highest dosage tested. Further testing of the genotoxicity of this class of chemicals is required. The genetic activity of the solvent used (dimethyl sulfoxide) is briefly discussed.

Topics: Animals; Anti-Bacterial Agents; Bone Marrow; Carbadox; Cell Nucleus; Erythrocytes; Male; Mutagenicity Tests; Mutagens; Mutation; Quinoxalines; Rats; Rats, Inbred Strains; Structure-Activity Relationship