Determination of zearalenone by liquid chromatography/tandem mass spectrometry and application to a pharmacokinetic study

Toxicokinetics of Zearalenone following Oral Administration in Female Dezhou Donkeys

Zearalenone (ZEN) is a mycotoxin produced by various Fusarium strains, that is present in food and feed raw materials worldwide, causing toxicity effects in animals and humans. This research aimed to explore the toxicokinetics of ZEN on female Dezhou donkeys following a single oral exposure dosage of 2 mg/kg BW (body weight). The sample collection of donkeys plasma was carried out at 0, 5, 10, 15, 20, 30, 45, 60, 90 min, 2 h, 2.5 h, 3 h, 3.5 h, 4 h, 4.5 h, 6 h, 9 h, 12 h, 24 h, 48 h, 72 h, 96 h and 120 h via intravenous catheter, and fecal and urinary samples were severally collected at 0 h and every 6 h until 120 h. The concentrations of ZEN, α-zearalenol (α-ZOL), β-zearalenol (β-ZOL), α-zearalanol (α-ZAL), β-zearalanol (β-ZAL), zearalanone (ZAN) in plasma, urine, and feces were detected by UPLC-MS/MS. Only ZEN was detected in plasma, and the maximum was 15.34 ± 5.12 µg/L occurred at 0.48 h after gavage. The total plasma clearance (Cl) of ZEN was 95.20 ± 8.01 L·kg·BW-1·h-1. In addition, the volume of distribution (Vd) was up to 216.17 ± 58.71 L/kg. The percentage of total ZEN (ZEN plus the main metabolites) excretion in feces and urine was 2.49% and 2.10%, respectively. In summary, ZEN was fast absorbed and relatively slowly excreted in female donkeys during 120 h after a single gavage, indicating a trend of wider tissue distribution and longer tissue persistence.

Ultrasensitive immunoassay for detection of zearalenone in agro-products using enzyme and antibody co-embedded zeolitic imidazolate framework as labels

Zearalenone (ZEN) has a potential hazard to human health, and is frequently found in agro-products. To minimize ZEN exposure to consumers, a novel metal-organic framework-based immunoassay system using zeolitic imidazolate framework-encapsulated horseradish peroxidase and goat anti-mouse IgG (HRP/Ab@ZIF-L) as labels was proposed for rapid and ultrasensitive detection of ZEN in agro-products. The HRP/Ab@ZIF-L not only maintained recognition ability of antibody and catalytic activity of enzyme, but also protected encapsulated proteins against high temperature, organic solvents and long term storage. Under optimal conditions, the detection limit of HRP/Ab@ZIF-L-based immunoassay reached 0.5 ng/L for ZEN, which was approximately 126-fold lower than that of conventional HRP-based immunoassay. Moreover, the proposed method showed an excellent selectivity, and a good dynamic linear detection for ZEN in the range of 0.5 ng/L to 0.476 μg/L. The recoveries of ZEN from spiked corn and wheat samples ranged from 84.50% to 96.70% with the relative standard deviation under 8.9%. In brief, the proposed immunoassay method has potential application for rapid and ultrasensitive detection of ZEN in agro-products.

Rapid determination of fumonisin (FB1) by syringe SPE coupled with solid-phase fluorescence spectrometry

Fumonisin B₁ is the most prevalent member of a family of toxins, known as fumonisins, which occurs mainly in maize, wheat and other cereals. Due to its hepatotoxic and nephrotoxic in all animal species, very strict regulations have been imposed on the levels of fumonisin B₁ in cereal and cereal-based foods worldwide. In this work, a rapid determination method of fumonisin B₁ by membrane solid phase extraction coupled with solid-phase fluorescence analysis is developed. A rhodamine based fluorescent probe was used for derivatization with fumonisin B₁. After derivatization and extraction by nylon membrane, the enriched fumonisin B₁ can be detected directly on the membrane without further elution process that is placed in a designed spectra collection device. The established method showed a linear relationship in concentration range of 0.5-5.0 μg/L, with the R² = 0.991, and a limit of detection of 0.119 μg/L. Method accuracy was further confirmed using LC-MS method by comparing the detection results of 3 corn powder samples spiked with FB₁, that demonstrated equivalent results. The results of this study indicated that the proposed method was simple, sensitive, reliable and suitable for trace fumonisins B₁ quantitation in corn-based feeds.

Determination of Trace Zearalenone and Its Metabolites in Human Serum by a High-Throughput UPLC-MS/MS Analysis

This paper described an improved method for high-throughput and sensitive determination of zearalenone and its five metabolites (zearalanone, α-zearalenol, β-zearalenol, α-zearalanol and β-zearalanol) in human serum. Serum samples were measured both before and after enzyme hydrolysis to assess the free and total amount of each compound by ultra-performance liquid chromatography–tandem mass spectrometry (UPLC-MS/MS) in multi reaction monitoring (MRM) mode following off-line 96-well μElution solid-phase extraction (SPE). All the analytes were completely separated on a C18 column within 6 min. It enabled multi-sample preparation at the same time eliminating tedious evaporation and reconstitution steps, allowing 96 (one plate) samples to be processed and analyzed within 24 h. Using an isotope labelled internal standard (13C-ZEN), high recoveries were achieved for all the compounds in the range 91.6%–119.5%, with intra-day and inter-day relative standard deviations (RSDs) of less than 8%. The limits of detection (LOD) and the limits of quantification (LOQ) were 0.02–0.06 ng mL−1 (0.6–2 fmol) and 0.1–0.2 ng mL−1 (3–6 fmol), respectively, demonstrating a notable enhancement in sensitivity compared to the existing methods. The validated method was applied to the analysis of paired urine and serum samples collected from 125 healthy individuals in Henan Province, locating in the middle area of China. ZEN metabolites in human serum were significantly lower than those in urine. Only one serum sample was positive for ZEN after enzyme digestion, whereas at least one of ZEN biomarkers was detected in 75.2% of the paired urine samples. Some comparison and discussion were also included in this paper.

High-throughput and sensitive determination of urinary zearalenone and metabolites by UPLC-MS/MS and its application to a human exposure study

Biomarker-based strategies to assess human exposure to mycotoxins have gained increased acceptance in recent years. In this study, an improved method based on UPLC-MS/MS following 96-well μElution solid-phase extraction was developed and validated for the sensitive and high-throughput determination of zearalenone (ZEN) and its five metabolites α-zearalenol (α-ZEL), β-zearalenol (β-ZEL), α-zearalanol (α-ZAL), β-zearalanol (β-ZAL), and zearalanone (ZAN) in human urine samples, using ¹³C-ZEN as an internal standard for accurate quantification. Two plates of samples (n = 192) could be processed within 2 h, and baseline separation of all the analytes was achieved in a total runtime of 6 min. The proposed method allowed ZEN and its metabolites to be sensitively determined in a high-throughput way for the first time, and with significantly improved efficiency and accuracy with respect to existing methods. The limits of detection (LODs) and limits of quantitation (LOQs) ranged from 0.02 to 0.06 ng mL^-1 and from 0.05 to 0.2 ng mL^-1, respectively. The recoveries for the spiked samples were from 87.9 to 100%, with relative standard deviations (RSDs) of less than 7%. 301 urine samples collected from healthy volunteers aged 0-84 years in China were analyzed with and without enzyme hydrolysis to determine total and free ZEN biomarkers, respectively. ZEN, ZAN, α-ZEL, and β-ZEL were detected in 71.4% of the samples at levels of 0.02-3.7 ng mL^-1 after enzyme hydrolysis. The estimated mean probable daily intake (PDI) was much lower than the tolerable daily intake (TDI). Adolescents had higher exposure than children, adults, and the elderly. Graphical abstract ᅟ.

Fluoroimmunoassays for the detection of zearalenone in maize using CdTe/CdS/ZnS quantum dots

CdTe/CdS/ZnS quantum dots (QDs) were synthesized in aqueous phase and conjugated with a new anti-zearalenone (ZEN) monoclonal antibody. Using this novel fluorescent probe, a fluoroimmunoassay (FLISA) and a rapid immunochromatographic strip (ICTS) were developed for the detection of ZEN in maize. Our proposed FLISA allowed for ZEN determination in the range of 0.038-0.977 ng/mL with an IC₅₀ of 0.162 ng/mL and a limit of detection (LOD) of 0.012 ng/mL occurring in maize. The rapid ICTS had a visual LOD of 1.0 ng/mL in buffer solution and 1.5 ng/mL in maize extract. These two QDs-based immunoassays were all successfully verified by commercial ELISA kits. The results confirmed that: firstly, the FLISA can be used as a robust method for the sensitive detection of ZEN; and secondly, the ICTS is ideally suited for rapidly screening large numbers of samples.

Studies on the Presence of Mycotoxins in Biological Samples: An Overview

Mycotoxins are fungal secondary metabolites with bioaccumulation levels leading to their carry-over into animal fluids, organs, and tissues. As a consequence, mycotoxin determination in biological samples from humans and animals has been reported worldwide. Since most mycotoxins show toxic effects at low concentrations and considering the extremely low levels present in biological samples, the application of reliable detection methods is required. This review summarizes the information regarding the studies involving mycotoxin determination in biological samples over the last 10 years. Relevant data on extraction methodology, detection techniques, sample size, limits of detection, and quantitation are presented herein. Briefly, liquid-liquid extraction followed by LC-MS/MS determination was the most common technique. The most analyzed mycotoxin was ochratoxin A, followed by zearalenone and deoxynivalenol—including their metabolites, enniatins, fumonisins, aflatoxins, T-2 and HT-2 toxins. Moreover, the studies were classified by their purpose, mainly focused on the development of analytical methodologies, mycotoxin biomonitoring, and exposure assessment. The study of tissue distribution, bioaccumulation, carry-over, persistence and transference of mycotoxins, as well as, toxicokinetics and ADME (absorption, distribution, metabolism and excretion) were other proposed goals for biological sample analysis. Finally, an overview of risk assessment was discussed.

Role of mycotoxins in the pathobiology of autism: A first evidence

Objectives: Gene-environment interaction is an emerging hypothesis to expound not only the autism pathogenesis but also the increased incidence of neurodevelopmental disorders (such as autistic spectrum disorder, attention-deficit, hyperactivity disorder). Among xenobiotics, mycotoxins are worldwide contaminants of food that provoke toxicological effects, crucially resembling several symptoms associated with autism such as oxidative stress, intestinal permeability, and inflammation. Here, we focused on a group of mycotoxins to test their role in the manifestation of autism, try to explain their mechanism of action, and discuss possible preventive and therapeutic interventions. Methods: Autistic children (n = 52) and healthy children [n = 58 (31 siblings and 27 unrelated subjects)] were recruited and body fluids and clinical data collected. The diagnosis of autism was made according to DSM V criteria, then with GMDS 0-2, WPPSI, and ADOS. Ochratoxin A (OTA), gliotoxin, zearalenone, and sphingosine/sphinganine ratio were determined by LC analysis in sera and urines. Statistical analysis was performed by the Wilcoxon Rank Sum (Mann-Whitney) test and Spearman test. Results: By comparing the results of autistic patients with those of unrelated controls, a significant association was found for OTA levels in urines (P = 0.0002) and sera (P = 0.0017), and also comparing patients with siblings and unrelated controls together (P = 0.0081). Discussion: Our results are the first describing a possible role of OTA in the pathobiology of autism. Recalling the male prevalence of ASD (male/female = 4-5/1), it is noted that, in animal models, OTA exerts its neurotoxicity especially in males. Moreover, in vitro, OTA increases microRNA-132 that is dysregulated in autistic patients and involved in reciprocal regulation of the autism-related genes MeCP2 and PTEN. A personalized diet coupled with probiotic administration, especially OTA adsorbing Lactobacillus, could ameliorate autistic symptoms in OTA-positive patients.

High-performance liquid chromatographic determination of multi-mycotoxin in cereals and bean foodstuffs using interference-removal solid-phase extraction combined with optimized dispersive liquid-liquid microextraction

A novel pre-treatment was proposed for the simultaneous determination of aflatoxins, ochratoxin A and zearalenone in foodstuffs using high-performance liquid chromatography with fluorescence detection. The analytical procedure was based on a first step using a quick, easy, cheap, effective, rugged, and safe based extraction procedure, followed by salting out and purification with a C₁₈ solid-phase extraction column as interference removal clean-up. Subsequently, collected supernatant was subjected to dispersive liquid-liquid microextraction. Response surface methodology based on central composite design was employed to optimize conditions in the microextraction procedure. Under the optimum conditions, satisfactory analytical performance with recoveries ranging from 63.22 to 107.6% were achieved in different types of cereals and beans, as well as desirable precisions (0.81-8.13%). Limits of detections and quantifications for these six mycotoxins ranging from 0.03 to 13 μg/kg and 0.22 to 44 μg/kg, respectively, were obtained. Finally, the established method was successfully validated by four certified reference materials (P = 0.897 > 0.05) and applied to 79 samples from local markets.

Development of a liquid chromatography tandem mass spectrometry method for the simultaneous determination of zearalenone, deoxynivalenol and their metabolites in pig serum

A sensitive and selective liquid chromatography tandem mass spectrometry method using negative electrospray ionisation (LC-ESI-MS/MS) was developed for the simultaneous determination of zearalenone (ZEN), deoxynivalenol (DON) and their metabolites α-zearalenol, β-zearalenol, zearalanone, α-zearalanol, β-zearalanol and de-epoxy-deoxynivalenol in pig serum. For method development, different sample preparation columns were tested for their suitability for extraction and clean up. Finally, preparation of serum samples was carried out using Oasis™ HLB solid-phase extraction (SPE) columns. The analyte concentrations were determined by the use of isotopically labelled internal standards (IS). The method was in-house validated for all analytes. Calibration graphs (0.3-480 ng/ml) were prepared and high degree of linearity was achieved (r ≥ 0.99). Results for method precision ranged between 2.7 and 21.5 % for inter-day and between 1.1 and 11.1 % for intra-day. The recoveries were in the range of 82-131 %. Limits of detection and quantification ranged 0.03-0.71 and 0.08-2.37 ng/ml, respectively. The method has been successfully used for quantitative determination of ZEN, DON and their metabolites in pig serum from a feeding trial with practically relevant ZEN and DON concentrations. This method is precise and reproducible and can be used as a multi-biomarker method to assess animal exposure to these mycotoxins and for diagnosis of intoxications.

Rapid simultaneous quantification of zearalenone and fumonisin B1 in corn and wheat by lateral flow dual immunoassay

A lateral flow dual immunoassay (LFDIA) was developed for rapid quantitative detection of zearalenone (ZEN) and fumonisin B1 (FB1) in corn and wheat samples on a single test strip. Two test lines and the control line on the nitrocellulose membrane were coated with ZEN and FB1 conjugates and goat anti-mouse IgG, respectively. Colloidal gold nanoparticles were conjugated with monoclonal antibodies against ZEN or FB1. The intensity of the test lines was analyzed by a photometric strip reader to determine the concentrations of ZEN and FB1 based on the calibration curves of known concentrations versus intensity readings. Test parameters such as types of buffers, ratio of the two gold-labeled antibodies, and dilution of the sample extracts and the gold-labeled antibodies were optimized. The detection limit was 0.35 and 5.23 ng/mL for ZEN and FB1, respectively, and the corresponding detection ranges were 0.94-7.52 and 9.34-100.45 ng/mL, respectively. Spiked and natural samples were analyzed using both LFDIA and liquid chromatography-tandem mass spectrometry. The two methods had a good correlation (R(2) = 0.96). The dual quantitative LFDIA is sensitive, rapid, and easy-to-use for on-site testing of a large number of samples.

(3S)-14,16-Dihy-droxy-3-methyl-3,4,5,6,9,10,11,12-octa-hydro-1H-2-benzoxacyclo-tetra-decine-1,7(8H)-dione (zearalanone) monohydrate

The absolute configuration of the title compound, C₁₈H₂₄O₅·H₂O, was not been determined by anomalous-dispersion effects, but has been assigned by reference to an unchanging chiral centre in the synthetic procedure. Intra­molecular O—H⋯O hydrogen bonds stabilize the mol­ecular conformation. In the crystal, O—H⋯O hydrogen bonds link the main mol­ecules and the water mol­ecules, forming an infinite three-dimensional network.

Developments in mycotoxin analysis: an update for 2009-2010

This review highlights developments in mycotoxin analysis and sampling over a period between mid-2009 and mid-2010. It covers the major mycotoxins aflatoxins, Alternaria toxins, ergot alkaloids, fumonisins, ochratoxin, patulin, trichothecenes, and zearalenone. New and improved methods for mycotoxins continue to be published. Immunological-based method developments continue to be of wide interest in a broad range of formats. Multimycotoxin determination by LC-MS/MS is now being targeted at the specific ranges of mycotoxins and matrices of interest or concern to the individual laboratory. Although falling outside the main emphasis of the review, some aspects of natural occurrence have been mentioned, especially if linked to novel method developments.

Molecularly imprinted polymer solid-phase extraction for detection of zearalenone in cereal sample extracts

The aim of this work was to develop a method for the clean-up and preconcentration of zearalenone from corn and wheat samples employing molecularly imprinted polymer (MIP) as selective sorbent for solid-phase extraction (SPE). Cereal samples were extracted with acetonitrile/water (75:25, v/v) and the extract was diluted with water and applied to an AFFINIMIP ZON MIP-SPE column. The column was then washed to eliminate the interferences and zearalenone was eluted with methanol and quantified using HPLC with fluorescence detection (lambda(exc)=275/lambda(em)=450 nm). The precision and accuracy of the method were satisfactory for both cereals at the different fortification levels tested and it gave recoveries between 82 and 87% (RSDr 2.5-6.2%, n=3) and 86 and 90% (RSDr 0.9-6.8%, n=3) for wheat and maize, respectively. MIP-SPE column capacity was determined to be not less than 6.6 microg of zearalenone and to be at least four times higher than that of immunoaffinity column (IAC). The application of AFFINIMIP ZON molecularly imprinted polymer as a selective sorbent material for detection of zearalenone fulfilled the method performance criteria required by the Commission Regulation (EC) No. 401/2006, demonstrating the suitability of the technique for the control of zearalenone in cereal samples.

Cleavage of zearalenone by Trichosporon mycotoxinivorans to a novel nonestrogenic metabolite

Zearalenone (ZON) is a potent estrogenic mycotoxin produced by several Fusarium species most frequently on maize and therefore can be found in food and animal feed. Since animal production performance is negatively affected by the presence of ZON, its detoxification in contaminated plant material or by-products of bioethanol production would be advantageous. Microbial biotransformation into nontoxic metabolites is one promising approach. In this study the main transformation product of ZON formed by the yeast Trichosporon mycotoxinivorans was identified and characterized by liquid chromatography-tandem mass spectrometry (LC-MS/MS) and LC-diode array detector (DAD) analysis. The metabolite, named ZOM-1, was purified, and its molecular formula, C(18)H(24)O(7), was established by time of flight MS (TOF MS) from the ions observed at m/z 351.1445 [M-H](-) and at m/z 375.1416 [M+Na](+). Employing nuclear magnetic resonance (NMR) spectroscopy, the novel ZON metabolite was finally identified as (5S)-5-({2,4-dihydroxy-6-[(1E)-5-hydroxypent-1-en-1-yl]benzoyl}oxy)hexanoic acid. The structure of ZOM-1 is characterized by an opening of the macrocyclic ring of ZON at the ketone group at C6'. ZOM-1 did not show estrogenic activity in a sensitive yeast bioassay, even at a concentration 1,000-fold higher than that of ZON and did not interact with the human estrogen receptor in an in vitro competitive binding assay.

Disposition, oral bioavailability, and tissue distribution of zearalenone in rats at various dose levels

This study was conducted to characterize the disposition, oral bioavailability, and tissue distribution of zearalenone in rats. The pharmacokinetics and tissue distribution of zearalenone were studied after intravenous (i.v.) or oral (p.o.) administration at doses ranging from 1 to 8 mg/kg in intact and bile duct-cannulated rats. Serum, bile, and urine concentrations were determined by liquid chromatography and mass spectroscopy (LC/MS/MS) and tissue concentrations by high-performance liquid chromatography (HPLC)/fluorescence detection assays. Noncompartmental methods were used for pharmacokinetic analysis. Average Cl(s) (range 5.0-6.6 L/h/kg) and V(dss) (range 2-4.7 L/kg) remained unaltered over an i.v. dose range from 1 to 8 mg/kg, and area under the concentration-time curve (AUC) and initial peak concentrations increased linearly with dose. Minimal quantities of zearalenone were excreted unchanged in urine (f(e,urine) 0.5 +/- 0.2%) and bile (f(e,bile) 0.91 +/- 0.64%). After p.o. administration of 8 mg/kg, zearalenone was rapidly absorbed and serum concentration-time profiles showed a distinct second peak. The absolute oral bioavailability was low (2.7%). Comparing bile duct-cannulated to intact rats at a dose of 8 mg/kg, the impact of biliary excretion on overall pharmacokinetics was more pronounced after p.o. than after i.v. administration. Upon i.v. infusion to steady state, the highest zearalenone concentration was found in small intestine, followed by kidneys, liver, adipose tissue, and lung. Zearalenone concentrations in stomach, heart, brain, spleen, muscle, and testes were lower than those found in serum. The pharmacokinetics and tissue distribution data from this study may be useful to develop physiologically based pharmacokinetic (PBPK) models for zearalenone and subsequently to predict the pharmacokinetics and toxicity in humans.

Physiologically based pharmacokinetics of zearalenone

The objectives of this study were to (1) develop physiologically based pharmacokinetic (PBPK) models for zearalenone following intravenous (i.v.) and oral (p.o.) dosing in rats and (2) predict concentrations in humans via interspecies scaling. The model for i.v. dosing consisted of vein, artery, lung, liver, spleen, kidneys, heart, testes, brain, muscle, adipose tissue, stomach, and small intestine. To describe the secondary peak phenomenon observed after p.o. administration, the absorption model was constructed to reflect glucuronidation, biliary excretion, enterohepatic recirculation, and fast and slow absorption processes from the lumenal compartment. The developed models adequately described observed concentration-time data in rats after i.v. or p.o. administration. Upon model validation in rats, steady-state zearalenone concentrations in blood and tissues were simulated for rats after once daily p.o. exposures (0.1 mg/kg/d). The average steady-state blood zearalenone concentration predicted in rat was 0.014 ng/ml. Subsequently, a daily human p.o. dose needed to achieve the same steady-state blood concentration found in rats (0.014 ng/ml) was determined to be 0.0312 mg/kg/d or 2.18 mg/70 kg/d. The steady-state zearalenone concentration-time profiles in blood and tissues were also simulated for human after multiple p.o. administrations (dose 0.0312 mg/kg/d). The developed PBPK models adequately described the pharmacokinetics in rats and may be useful in predicting human blood and tissue concentrations for zearalenone under different p,o, exposure conditions.