There is evidence of major species-dependent differences in the extent of de-epoxidation of nivalenol in non-ruminants, which may occur in the lower parts of the gastrointestinal tract in some species. The de-epoxy metabolite has been detected in feces of rats, pigs and laying hens, but not in mice or broiler chickens and, based on in vitro studies, it is unlikely to be formed in humans.
来源:Hazardous Substances Data Bank (HSDB)
代谢
在反刍动物中，与其他三线菌素一样，吸收前在瘤胃中可能会发生大量的去环氧化反应。
In ruminants, it is likely that, as for other trichothecenes, extensive de-epoxidation of nivalenol may occur in the rumen prior to absorption.
来源:Hazardous Substances Data Bank (HSDB)
代谢
Nivalenol is metabolized to de-epoxy nivalenol.
尼瓦连醇被代谢为脱环氧尼瓦连醇。
The cytotoxicity of the de-epoxy metabolites of trichothecenes nivalenol (NIV) and deoxynivalenol (DON) was determined and compared with the cytotoxicity of the respective toxin with an intact epoxy group and their acetylated derivatives. The cytotoxic effects was determined by using the 5-bromo-2'-deoxyuridine (BrdU) incorporation assay assessing DNA-synthesis. The toxicity of NIV and DON expressed as the concentration inhibiting 50% of the DNA synthesis (IC(50)), was occurring at similar micromolar concentrations (1.19+/-0.06 and 1.50+/-0.34 uM). The toxicity of fusarenon X (4-acetyl NIV) in the assay was similar to the toxicity of NIV, and the toxicity of 15-AcDON was equal to the toxicity of DON. 3-AcDON was less toxic than DON and 15-AcDON. The IC(50) value for de-epoxy DON was 54 times higher in the assay than the IC(50) for DON, while the IC(50) of de-epoxy NIV was 55 times higher than the IC(50) for NIV. The results verify previous findings that the de-epoxidation is a detoxification reaction.
Evaluation: There is inadequate evidence in humans for the carcinogenicity of toxins derived from Fusarium graminearum. No data were available on the carcinogenicity to humans of toxins derived from F. crookwellense and F. culmorum. ... There is inadequate evidence in experimental animals for the carcinogenicity of nivalenol. ... Overall evaluation: Toxins derived from Fusarium graminearum, F. culmorum and F. crookwellense are not classifiable as to their carcinogenicity to humans (Group 3).
来源:Hazardous Substances Data Bank (HSDB)
毒理性
副作用
Dermatotoxin - 皮肤烧伤。
Dermatotoxin - Skin burns.
来源:Haz-Map, Information on Hazardous Chemicals and Occupational Diseases
A feeding trial was conducted in order to determine the effects of a Fusarium poae extract on the health and performances of broiler chickens and the possible protective effect of a natural zeolite. The F. poae extract contained nivalenol, T-2 toxin and diacetoxyscirpenol and demonstrated high toxicity when administered i.p. to rats. One-day-old broiler chickens were fed ad libitum over a period of 28 days with the following diets: group I - control; group II - 0.5% zeolite; group III -F. poae extract; group IV-0.5% zeolite andF. poae extract. Broilers were sacrificed at 28 days for the measurement of relative organs weights, leukocyte counts and serum biochemical values. No mortality was recorded over the experiment. Body weight gains, feed intake, feed utilization and water consumption were depressed by the F. poae extract (p<0.05). A decrease of these parameters was also observed in group IV which received the diet with zeolite and the F. poae extract. No significant differences were seen in group II when compared to control. In groups III and IV the relative weights of liver, kidney, heart and gizzard were significantly increased (p<0.05), while in group II only the relative liver weight was increased. F. poae extract, administered singly or in combination with zeolite, significantly decreased leukocytes count, serum total protein and serum albumin. Zeolite and F. poae extract, singly or combined, increased serum creatinine and uric acid concentrations (p<0.05). These findings indicate that sublethal doses of F. poae extract can affect adversely the performances and the health in broiler chickens. By adding zeolite these impairments could not be diminished and for some parameters the zeolite additive increased the adverse effects of the F. poae extract.
Deoxynivalenol (DON) and nivalenol (NIV) are toxic Fusarium secondary trichothecene metabolites that often co-occur regularly in cereal grains. These compounds were compared for their toxicity towards C57BL/6 mice on several parameters including alteration in plasma biochemistry, immune system reactivity and hepatic drug metabolism capacity. Mice received individual or combined oral doses of each toxin: 0.071 or 0.355 mg/kg of body weight, administrated three days a week for 4 weeks. Food consumption was altered by the single administration of 0.355 mg/kg of NIV, although no noticeable change of body and organ weights or liver protein contents was detected. NIV administration did cause also significant changes in total CO2 and uric acid concentrations in plasma. Individual toxin exposures led to increases in plasma IgA without no detectable change in the ex vivo production of cytokine by splenocytes. The liver ethoxyresorufin O-deealkylase, pentoxyresorufin O-depenthylase and glutathione S-transferase activities were increased in concert with cytochrome P4501a and P4502b subfamily expression. Administration of combinations of DON and NIV resulted in responses similar to that observed using individual doses of each toxin. However, depending on the ratio of toxin doses and biochemical parameters, some responses could be also additive (plasma IgA and hepatic DCNB conjugation) or synergistic (plasma uric acid).
Deoxynivalenol (DON) is the most prevalent trichothecene mycotoxin in crops in Europe and North America. DON is often present with other type B trichothecenes such as 3-acetyldeoxynivalenol (3-ADON), 15-acetyldeoxynivalenol (15-ADON), nivalenol (NIV) and fusarenon-X (FX). Although the cytotoxicity of individual mycotoxins has been widely studied, data on the toxicity of mycotoxin mixtures are limited. The aim of this study was to assess interactions caused by co-exposure to Type B trichothecenes on intestinal epithelial cells. Proliferating Caco-2 cells were exposed to increasing doses of Type B trichothecenes, alone or in binary or ternary mixtures. The MTT test and neutral red uptake, respectively linked to mitochondrial and lysosomal functions, were used to measure intestinal epithelial cytotoxicity. The five tested mycotoxins had a dose-dependent effect on proliferating enterocytes and could be classified in increasing order of toxicity: 3-ADON<15-ADON =~ DON<NIV << FX. Binary or ternary mixtures also showed a dose-dependent effect. At low concentrations (cytotoxic effect between 10 and 30-40%), mycotoxin combinations were synergistic; however DON-NIV-FX mixture showed antagonism. At higher concentrations (cytotoxic effect around 50%), the combinations had an additive or nearly additive effect. These results indicate that the simultaneous presence of low doses of mycotoxins in food commodities and diet may be more toxic than predicted from the mycotoxins alone. Considering the frequent co-occurrence of trichothecenes in the diet and the concentrations of toxins to which consumers are exposed, this synergy should be taken into account.
After long term oral administration of nivalenol to male rats, the dose was recovered as fecal nivalenol (7%), fecal de-epoxy nivalenol (80%), urinary nivalenol (1%) and urinary de-epoxy nivalenol (1%).
In order to investigate the comparative fates of nivalenol (NIV) and 4-acetyl derivative of NIV (fusarenon-X, FX) in mice, (3)H-FX or (3)H-NIV was given p.o. to mice. Radioactivity was excreted mainly via the urine in mice given (3)H-FX, but mainly via the feces in mice given (3)H-NIV. The plasma radioactivity reached a peak at 30 or 60 min after the administration of (3)H-FX or (3)H-NIV, respectively. The plasma peak level was 5 times higher, and the area under curve (AUC) was 10 times higher, in (3)H-FX-administered than (3)H-NIV-administered mice. These findings clearly demonstrate that FX is absorbed from the gastrointestinal tract more rapidly and efficiently than NIV. The HPLC profile of radioactivity of acetonitrile extracts of urine and feces indicated that FX is rapidly metabolized to NIV after being absorbed from the gastrointestinal tract. In vitro incubation of tissue homogenates with (3)H-FX demonstrated that the liver and kidney are the organs responsible for the FX-to-NIV conversion. Thus this study demonstrated that the higher oral toxicity of FX than NIV that has been observed in mice and rats is due to the efficient absorption of FX than NIV from the gastrointestinal tract, followed by its rapid conversion to NIV by the liver and kidney.
In the biosynthesis of Fusarium trichothecenes, the C-3 hydroxyl group of isotrichodermol must be acetylated by TRI101 for subsequent pathway genes to function. Despite the importance of this 3-O-acetylation step in biosynthesis, Tri101 is both physically and evolutionarily unrelated to other Tri genes in the trichothecene gene cluster. To gain insight into the evolutionary history of the cluster, we purified recombinant TRI3 (rTRI3), one of the two cluster gene-encoded trichothecene O-acetyltransferases, and examined to determine whether this 15-O-acetyltransferase can add an acetyl to the C-3 hydroxyl group of isotrichodermol. When a high concentration of rTRI3 was used in the assay (final concentration, 50 μm), we observed 3-O-acetylation activity against isotrichodermol that was more than 105 times less efficient than the known 15-O-acetylation activity against 15-deacetylcalonectrin. The rTRI3 protein also exhibited 4-O-acetylation activity when nivalenol was used as a substrate; in addition to 15-acetylnivalenol, di-acetylated derivatives, 4,15-diacetylnivalenol, and, to a lesser extent, 3,15-diacetylnivalenol, were also detected at high enzyme concentrations. The significance of the trace trichothecene 3-O-acetyltransferase activity detected in rTRI3 is discussed in relation to the evolution of the trichothecene gene cluster.
Pentahydroxyscirpene, a novel trichothecene-type compound, was isolated from Fusarium-inoculated rice. The structure of pentahydroxyscirpene was elucidated by 1D and 2D NMR spectroscopy and X-ray single-crystal diffraction. The conformation in solution was determined by NOESY experiments supported by quantum chemical calculations. In vitro toxicity tests showed that pentahydroxyscirpene inhibits protein
Pentahydroxyscirpene 是一种新型的单端孢霉烯类化合物，是从接种镰刀菌的水稻中分离出来的。通过一维和二维核磁共振光谱和 X 射线单晶衍射阐明了五羟基芘的结构。溶液中的构象由量子化学计算支持的 NOESY 实验确定。体外毒性试验表明，五羟基鼠尾草烯与其他单端孢霉烯一样抑制蛋白质合成。
Preparation of Monoclonal Antibodies Specifically Reacting with the Trichothecene Mycotoxins Nivalenol and 15-Acetylnivalenol via the Introduction of a Linker Molecule into Its C-15 Position
Nivalenol (NIV) is a trichothecene mycotoxin that is more toxic than deoxynivalenol. It accumulates in grains due to infection with Fusarium species, which are the causative agents of scab or Fusarium head blight. An immunoassay, which is a rapid and easy analytical method, is necessary for monitoring NIV in grains. However, a specific antibody against NIV has not been prepared previously. To establish an immunoassay, we prepared NIV, introduced a linker, and generated antibodies against it. NIV was prepared from a culture of Fusarium kyushuense obtained from pressed barley through chromatographic procedures with synthetic adsorbents and silica gel. NIV was reacted with glutaric anhydride, and the reaction was stopped before mono-hemiglutaryl-NIV was changed to di-hemiglutaryl-NIV. 15-O-Hemiglutaryl-NIV was isolated via preparative HPLC and bound to keyhole limpet hemocyanin (KLH) using the active ester method. Two different monoclonal antibodies were prepared by immunizing mice with the NIV-KLH conjugate. The 50% inhibitory concentration values were 36 and 37 ng/mL. These antibodies also showed high reactivity in a direct competitive enzyme-linked immunosorbent assay and specifically reacted with NIV and 15-acetyl-NIV but not with deoxynivalenol and 4-acetyl-NIV.
Structure−Activity Relationships of Trichothecene Toxins in an <i>Arabidopsis thaliana</i> Leaf Assay
作者：Anne E. Desjardins、Susan P. McCormick、Michael Appell
DOI：10.1021/jf0709193
日期：2007.8.1
Many Fusarium species produce trichothecenes, sesquiterpene epoxides that differ in patterns of oxygenation and esterification at carbon positions C-3, C-4, C-7, C-8, and C-15. For the first comprehensive and quantitative comparison of the effects of oxygenation and esterification on trichothecene phytotoxicity, we tested 24 precursors, intermediates, and end products of the trichothecene biosynthetic pathway in an Arabidopsis thaliana detached leaf assay. At 100 mu M, the highest concentration tested, only the trichothecene precursor trichodiene was nontoxic. Among trichothecenes, toxicity varied more than 200-fold. Oxygenation at C-4, C-8, C-7/8, or C-15 was, on average, as likely to decrease as to increase toxicity. Esterification at C-4, C-8, or C-15 generally increased toxicity. Esterification at C-3 increased toxicity in one case and decreased toxicity in three of eight cases tested. Thus, the increase in structural complexity along the trichothecene biosynthetic pathway in Fusarium is not necessarily associated with an increase in phytotoxicity.
Preparation, Purification, and NMR Spectra of Some Mono- and Dihemisuccinates of the Trichothecene Mycotoxin Nivalenol
作者：Denis R. Lauren、Wendy A. Smith、Alistair L. Wilkins
DOI：10.1021/jf00039a046
日期：1994.3
4,15-Diacetylnivalenol (DANIV) was produced in liquid culture and purified by fractionation over silica followed by preparative liquid chromatography. Hydrolysis gave nivalenol (NIV), a trichothecene mycotoxin found as a common contaminant in grain grown in the North Island of New Zealand. Reaction of NIV with succinic anhydride in the presence of n-butylboronic acid and (dimethylamino)pyridine produced a mixture of three mono-and two dihemisuccinates. These were separated by semipreparative HPLC. The major product was 3-hemisuccinyl-NIV (3-HS-NIV). Other products were 4-HS-NIV, 15-HS-NIV, 3,4-diHS-NIV, and 3,15-diHS-NIV. 3-HS-NIV was also produced by enzymatic hydrolysis of 3-HS-DANIV.
