naphthoquinones and luteoskyrin

Mycotoxin problems are one of great concern to health scientists. Toxic fungal metabolites such as aflatoxins, trichothecenes, zearalenone and others are contaminated in our environments and induce various diseases. In this manuscript, the author will summarize the recent advances on toxicology of mycotoxins in special references to toxicological characters, cytotoxicity, genotoxicity (mutagenicity and carcinogenicity), metabolism, and biochemical mode of action. Interaction of mycotoxins with cellular components will be reviewed in order to clarify the toxicological characteristics of mycotoxins such as aflatoxins, trichothecenes, zearalenone, toxic peptides, and anthraquinoid mycotoxins.

Topics: Adenosine Triphosphatases; Aflatoxin B1; Aflatoxins; Animals; Aurovertins; Biotransformation; Carcinogens; Chemical Phenomena; Chemistry; Cyclobutanes; Cytochalasins; Electron Transport; Energy Metabolism; Gene Expression Regulation; Griseofulvin; Humans; Immunosuppressive Agents; Mutagens; Mycotoxins; Naphthoquinones; Ochratoxins; Peptides, Cyclic; Protein Biosynthesis; Trichothecenes; Xanthenes; Xanthones; Zearalenone

Penicillium islandicum produces luteoskyrin (LUT), a yellow rice toxin that has been found frequently in rice. However, conventional analytical methods for determining LUT are limited, are complicated, and exhibit low sensitivity. In this study, an analytical method more sensitive and simple based on high-performance liquid chromatography combined with electrospray ionization mass spectrometry was developed. The cleanup procedure of the method was one step, using a solid-phase extraction cartridge. An isocratic mobile-phase system, consisting of acetonitrile-water-acetic acid (50:49:1 [vol/vol/vol]) at a flow rate of 0.2 ml/min, was utilized to obtain the best resolution. Our method showed good linearity (r = 0.9993, 0.5 to 50 ng/g) and high repeatability (relative standard deviation = 8.9 and 5.1% at levels of 0.5 and 10 ng/g, respectively) in the fortification test. The detection and quantification limits for the method in multiple-reaction monitoring mode were 0.1 and 0.3 ng/g, respectively. The average recovery of LUT in spiked rice at 0.5 and 10 ng/g was 80.7 and 85.2%, respectively. The method developed in this study should be applicable to survey LUT in rice, with high sensitivity, selectivity, and rapidity.

Topics: Chromatography, High Pressure Liquid; Food Contamination; Naphthoquinones; Oryza; Reproducibility of Results; Sensitivity and Specificity; Solid Phase Extraction; Spectrometry, Mass, Electrospray Ionization

Fungi growing on domestic rice were examined from April to June, 2003. One hundred samples of rice, which had been harvested in the autumn of 2002, were collected from the local market, and 15 samples of stored rice, which had been harvested in 2001 and stored in warehouses under government control, were used as samples. From each sample, 50 grains (100 grains in total) were plated on potato-dextrose agar (PDA) and malt yeast 40% sucrose agar (M40YA) containing chloramphenicol after being washed with sterile distilled water to remove any microorganisms on the surface, and incubated at 25 degrees C for a week. For most of the rice samples harvested in the preceding year, the proportion of grains infected with fungi was less than 20% of the total grains tested. In about half the samples of rice stored for one and half years, more than 80% of the grains were infected with fungi that grew on M40YA. The major genera of fungi isolated from the rice harvested in the preceding year were Penicillium and Alternaria, and those from the rice stored for one and a half years were Aspergillus, Penicillium and Eurotium. P. islandicum, A. versicolor, A. ochraceus and others were isolated as possible mycotoxin-producers in the mycoflora of domestic rice. P. islandicum was isolated from 3 samples, and 82% of the grains were infected with this fungus in one sample. All three isolates from these samples appeared to produce luteoskyrin on Czapek yeast extract agar, based on TLC and HPLC analysis.

Topics: Aspergillus; Mycotoxins; Naphthoquinones; Oryza; Penicillium

Rubroskyrin, a modified bis-anthraquinone pigment from Penicillium islandicum Sopp, was studied on the redox interaction with NADH-linked redox system of rat liver microsomes, comparing with luteoskyrin and rugulosin. It was found that rubroskyrin was enzymatically reduced by NADH/microsomes and was immediately autoxidized by dissolved oxygen, producing hydrogen peroxide (H2O2). Luteoskyrin and rugulosin did not exhibit such a redox reaction, consuming dissolved oxygen and producing H2O2. The H2O2 production was significantly accelerated by superoxide dismutase (SOD), suggesting the production of superoxide anion during the reduction-autoxidation cycles of rubroskyrin. The thin layer chromatographic (TLC) and spectrophotometric analyses revealed that rubroskyrin was biotransformed by the NADH/microsomes system to stable product(s) which was no longer enzymatically reduced by the NADH/microsome system. From these results it was speculated that the mutagenicity of rubroskyrin might result from the generation of active oxygen by the NADH/microsome-catalyzed redox reaction, and that the redox reaction-linked biotransformation might lead to the elimination of cytotoxicity of rubroskyrin, showing significantly less toxicity than those of luteoskyrin and rugulosin in vivo.

Topics: Animals; Anthraquinones; Biotransformation; Chromatography, Thin Layer; Cytochrome Reductases; Cytochrome-B(5) Reductase; Microsomes, Liver; Mycotoxins; Naphthoquinones; Oxidation-Reduction; Penicillium; Rats; Superoxide Dismutase

Luteoskyrin is a hepatotoxic and hepatocarcinogenic bisdihydroanthraquinone produced by Penicillium islandicum Sopp. By observing the EPR spectra of DMPO-spin adducts and luteoskyrin semiquinone radical, we investigated in vitro whether luteoskyrin is reduced to its semiquinone radical leading to the generation of active oxygen species in redox systems catalyzed by NADPH-dependent cytochrome reductases of the liver. We found (1) the formation of luteoskyrin semiquinone radical in the NADPH-cytochrome P-450 reductase system under anaerobic conditions, (2) the generation of O2- in the systems composed of luteoskyrin, NAD(P)H, and either rat liver microsomal NADPH-cytochrome P-450 reductases or submitochondrial particles and (3) dicoumarol showed no effect on the O2- generation in the case of submitochondrial particles. From these results we proposed that luteoskyrin liver injuries are induced by the active oxygen species generated in the process of autoxidation of luteoskyrin semiquinone radical which is produced in the one-electron redox systems catalyzed by the liver NAD(P)H-dependent cytochrome reductases.

Topics: Animals; Carcinogenicity Tests; Chemical and Drug Induced Liver Injury; Electron Spin Resonance Spectroscopy; Free Radicals; Liver; Liver Neoplasms; Mycotoxins; NADH, NADPH Oxidoreductases; Naphthoquinones; Oxidation-Reduction; Penicillium; Rats; Rats, Sprague-Dawley; Superoxides

Luteoskyrin is a bis-dihydroanthraquinone mycotoxin produced by Penicillium islandicum Sopp. By using EPR spin-trap techniques we investigated whether .OH is formed in a model system containing ascorbic acid and the toxin. In the presence of DMSO and DMPO, we found signals of DMPO-CH3, a more specific and reliable signature of .OH than DMPO-OH, together with the signals of ascorbyl radical. DMPO-CH3 signals increased with time of incubation up to 5.5 min. The DMPO-CH3 formation depended completely on both luteoskyrin and ascorbic acid, and deferoxamine, an iron-chelator, inhibited its formation. The signals disappeared in the presence of excess amount of catalase whereas SOD showed no effect. These results suggest that .OH is formed from ferrous ion present in the mixture of H2O2 generated from ascorbic acid and luteoskyrin.

Topics: Ascorbic Acid; Electron Spin Resonance Spectroscopy; Ferrous Compounds; Free Radicals; Hydroxides; Mycotoxins; Naphthoquinones; Penicillium

When cultured Reuber hepatoma H4-II-E and fibroblast Balb/3T3 cells were exposed to various concentrations of 5 derivatives of anthraquinones, luteoskyrin, a bis-anthraquinoid hepatocarcinogenic mycotoxin, exhibited the highest cytotoxicity to these cell lines. The content of 8-hydroxydeoxyguanine residues in the DNA of H4-II-E cells was dose- and time-dependently increased by luteoskyrin. The tumorigenic anthraquinones such as rugulosin and danthron also slightly elevated the level of this modified DNA base, while no such modification was observed with chrysophanol and emodin. Detailed experiments with luteoskyrin have demonstrated the formation of 8-hydroxydeoxyguanine and the degradation of deoxyribose into thiobarbituric acid-reactive products in the presence of ascorbic acid. These findings suggest the possible involvement of anthraquinone-derived hydroxy radicals for the modification of DNA base and deoxyribose.

Topics: 3T3 Cells; 8-Hydroxy-2'-Deoxyguanosine; Animals; Anthraquinones; Cell Survival; Deoxyguanosine; Deoxyribose; Hydroxides; Hydroxyl Radical; Mice; Naphthoquinones

HPLC analysis revealed that luteoskyrin administered orally to male mice accumulated selectively in the liver, with minor distribution to the serum and kidneys. Elevation of serum GOT and GPT values was maximal 3 days after administration. In mice administered this mycotoxin intravenously, selective accumulation was also observed in the liver, and the half-life of hepatic luteoskyrin in males was significantly longer than that in females. Increment of serum transaminases was also marked in males with maximum accumulation at 24 h after administration. Histopathologically, cellular membrane damage was an early effect of luteoskyrin on cell necrosis, and these morphological changes were also marked in males. Luteoskyrin also elevated hepatic lipid peroxides, the maximum elevation being 8 h after injection; this increase was suppressed by alpha-tocopherol and Bi(NO3)3. HPLC-ECD analysis indicated that the level of 8-hydroxy-deoxyguanosine, one of the markers of hydroxy-radical-mediated modification of DNA guanine residues, was increased in hepatic DNA. These findings indicate that luteoskyrin has a high affinity for the liver, resulting in induction of lipid peroxidation, hepatocellular membrane damage, and elevation of serum transaminase activities. It is suggested that the hydroxy radicals derived from this anthraquinone contribute to these toxicological changes.

Topics: 8-Hydroxy-2'-Deoxyguanosine; Alanine Transaminase; Animals; Aspartate Aminotransferases; Chromatography, High Pressure Liquid; Deoxyguanosine; Free Radical Scavengers; Hydroxylation; Lipid Peroxides; Liver; Male; Mice; Naphthoquinones; Necrosis; Time Factors

The transforming activity of luteoskyrin (LS), a bis-anthraquinoid mycotoxin produced by Penicillium islandicum Sopp., and a hepatocarcinogen in rodents, was examined by an in vitro transformation assay using mouse embryonal Balb/3T3 A31-1-1 cells. The results revealed that LS induced type III foci at 0.5 micrograms/ml, and that the cells selected from these foci by soft-agar cloning grew with a high saturation density. Thus, it was confirmed that LS not only induces hepatic tumours in laboratory animals, but also transforms in vitro cultured mammalian cells. The tumorigenicity of the transformants obtained was confirmed by transplantation into nude mice and by image analysis with IIIIn. A transfection assay, using calcium phosphate co-precipitation, demonstrated that the DNA of the cloned cells transformed NIH3T3 cells. Northern blot also revealed transcriptional activation of c-myc and c-Ha-ras oncogenes. The possible participation of LS-derived hydroxy radicals in the formation of genetic lesions was discussed.

Topics: Animals; Cell Transformation, Neoplastic; Cells, Cultured; DNA; Mice; Mice, Nude; Mycotoxins; Naphthoquinones; Neoplasms, Experimental; Oncogenes

Following oral administration of luteoskyrin (LS), a bis-anthraquinone and hepatocarcinogenic mycotoxin of Penicillium islandicum Sopp, to ddY male mice, significant increases in serum GOT and GPT activities, 8-hydroxydeoxyguanosine (8-OH-dG) residues in hepatic DNA, and hepatic lipid peroxide level were observed. alpha-Tocopherol (alpha-TP) depressed the hepatic lipid peroxide content but did not decrease the 8-OH-dG level. These findings indicate that hydroxy radicals derived from LS are involved in the peroxidation of hepatic lipids followed by liver injury, and that the hydroxylation reaction of deoxyguanosine (dG) residues of hepatic DNA at the 8-position was unsusceptible to alpha-TP.

Topics: 8-Hydroxy-2'-Deoxyguanosine; Administration, Oral; Animals; Chromatography, High Pressure Liquid; Deoxyguanosine; DNA; Lipid Peroxides; Liver; Male; Mice; Mycotoxins; Naphthoquinones; Vitamin E

Material milled and sampled in 1986 in one Prague flour mill included two flour batches contaminated with a toxicogenic strain of Penicillium islandicum Sopp. P. islandicum, cultivated under experimental conditions, yielded the total of eight grams of chloroform extract containing three grams of luteoskyrin from a kilogram of wheat. The effective dose of chloroform extract was 0.8 microgram (0.5-1.8) for a two-day old chicken embryo, 2.0 microgram (1.7-2.6) for a three-day old embryo and 2.8 micrograms (1.7-4.7) for a four-day old embryo. On all days of administration the chloroform extract had a strong teratogenous action. The most frequent malformations included microophthalmia and anophthalmia, cerebral hernia, bilaterally cleft beak, and reduction deformities of the extremities.

Topics: Abnormalities, Drug-Induced; Animals; Chick Embryo; Flour; Food Contamination; Naphthoquinones; Penicillium; Teratogens

Topics: Alanine Transaminase; Animals; Chemical and Drug Induced Liver Injury; Cobalt; Dibenzylchlorethamine; Drug Synergism; Female; Liver; Male; Mice; Naphthoquinones; Piperonyl Butoxide; Proadifen; Time Factors

Topics: Adenosine Triphosphate; Anthraquinones; Cell Membrane; Cytochromes; Electron Transport Complex II; Kidney; Liver; Magnesium; Mitochondria; Myocardium; Naphthoquinones; Oxidoreductases; Penicillium; Pharmacology; Pigments, Biological; Research; Succinate Dehydrogenase; Tissue Culture Techniques

Topics: Adenosine Triphosphate; Anthraquinones; Benzoates; Calcium Chloride; Chloromercuribenzoates; Cysteine; Glutathione; Liver; Magnesium; Mercury; Mitochondria; Naphthoquinones; Pathology; Penicillium; Pharmacology; Phosphates; Rats; Research; Silver; Silver Compounds; Sucrose; Thyroxine; Toxicology

Topics: Antitoxins; Chlorine; Electrons; HeLa Cells; Hepatocytes; Humans; Liver; Microscopy; Microscopy, Electron; Mycotoxins; Naphthoquinones; Pathology; Penicillium; Peptides; Pharmacology; Research; Tissue Culture Techniques; Toxicology; Toxins, Biological

Topics: Animals; Anthracenes; Humans; Liver Cirrhosis, Experimental; Liver Neoplasms, Experimental; Naphthoquinones; Oryza

Topics: Chlorine; Ions; Naphthoquinones; Penicillium; Peptides

Topics: Anthraquinones; Fungi; Naphthoquinones

Topics: Biological Products; Fungi; Naphthoquinones; Pigments, Biological