Aflatoxin: a 50-year odyssey of mechanistic and translational toxicology

Adsorptive potential of two natural enterosorbents for removing aflatoxin B1 under simulated gastric and small intestinal conditions

A viable strategy for addressing the aflatoxin issue using two enterosorbents prepared from marigold petals and guava leaves was validated. The enterosorbents were characterized via Fourier transform infrared spectroscopy (FTIR), field-emission scanning electron microscopy (FESEM), energy dispersive X-ray fluorescence spectroscopy (EDS), and X-ray diffraction (XRD) to obtain information about the surface functional groups, microstructure, multi-elemental composition, degree of crystallinity, and phase analysis. The potential of the enterosorbents in decreasing aflatoxin uptake and bioavailability under simulated gastrointestinal conditions (including the replication of chemical and enzymatic factors) was estimated using the isotherm models of Langmuir, Freundlich, Temkin, and Dubinin-Radushkevich. Under the simulated gastric and intestinal conditions, marigold removed almost all the mycotoxin at doses of 0.25 and 0.125% (w/w); however, guava leaves efficiently adsorbed the toxin when using doses up to 0.5 and 0.25% (w/w), respectively. Equilibrium adsorption data followed preferentially the Freundlich model, the values of the Freundlich constant (KF) for marigold were 37.3 and 7.1 times higher than those of guava leaves, respectively. Additionally, the n value was > 1, indicative that adsorption was mainly dominated by physical mechanisms. Overall, this research provides insights into the practical application of natural enterosorbents offering a promising approach for AFB1 removal.

Toxicokinetics of a Single Oral Dose of Aflatoxin B1 in Plasma, Feces, and Urine of Male Donkeys

Aflatoxin B1 (AFB1) is widely present in raw materials for food and feedstock, posing a significant threat to the health of humans and animals. This study explored the toxicokinetics of a single oral administration of AFB1 at a dose of 100 µg·kg-1 BW (body weight). Donkey blood samples were gathered at 0, 5, 10, 15, 20, 30, 45, and 60 min and at 1.5 h, 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 through jugular vein sampling needles at intervals. Fecal and urinary samples were collected at 0 h and every 6 h thereafter until 120 h. The concentrations of AFB1 and AFM1 in plasma, urine, and feces were quantitatively analyzed using LC-MS/MS. The maximum concentrations of AFB1 and AFM1 in plasma were 13.10 ± 6.35 µg·L-1 and 0.72 ± 0.33 µg·L-1, occurring at 1.38 ± 0.89 h and 2.25 ± 1.57 h after oral administration, respectively. The AFB1 and AFM1 elimination half-lives (T1/2Elim) were 6.65 ± 2.84 h and 5.85 ± 3.00 h, respectively. The total clearances (CL) of AFB1 and AFM1 were 163 ± 52.2 L·kg-1 BW-1·h-1 and 3210 ± 2450 L·kg-1 BW-1·h-1, and the volumes of distribution (Vd) for AFB1 were 1440 ± 417 L·kg-1·BW and 22,400 ± 14,800 L·kg-1·BW, respectively. In addition, the total amounts of AFB1 and AFM1 excreted over 120 h through urine and feces accounted for 3.38 ± 0.92% and 3.44 ± 1.45% of the total intake, respectively (calculated by material mass). Furthermore, the research showed that the absorption and metabolism of AFB1 were rapid in male donkeys, with the tissue exhibiting a wide distribution and long duration.

Role of NEIL1 in genome maintenance

Phylogenetic analyses of DNA glycosylases that function in the initiation step of base excision repair reveal a high degree of conservation within the genes encoding Nei-like DNA glycosylase 1 (NEIL1). In concert with other glycosylases, this enzyme is an important player in cleansing both nuclear and mitochondrial genomes of a wide variety of damaged DNA bases. The relative efficiency of NEIL1 to catalyze release of ring-opened formamido-pyrimidines (Fapy) and alkylated-Fapy adducts, multiple ring-saturated pyrimidines, secondary oxidation products of 8-oxoguanine, and psoralen-derived crosslinks is augmented by pre-mRNA editing at codon 242, resulting in cells containing both NEIL1-Lys242 and edited Arg242. The biological significance of NEIL1 was revealed through investigations of mutagenesis and carcinogenesis in murine models, primarily using aflatoxin B1 (AFB1) as a genotoxicant challenge, which forms stable AFB1-FapyGua adducts. Specifically, Neil1 knockout mice were > 3-fold more susceptible to AFB1-induced carcinogenesis as compared to either wild-type or nucleotide excision repair-deficient Xpa-/- mice. These data are well-supported by duplex sequencing analyses that showed increased AFB1-induced mutagenesis in Neil1-/- mice relative to wild-type or Xpa-/- mice. Given the biological impact of Neil1 deficiencies in cancer, metabolic syndrome, and neurodegeneration, extrapolation to humans carrying single nucleotide polymorphisms (SNPs) in NEIL1 may suggest that deleterious variants could increase disease risk following various genotoxicant exposures. To address this hypothesis, we have undertaken a systematic characterization of human NEIL1 SNP variants that are distributed throughout the world. The goal of this review is to provide comprehensive analyses of the biochemistry and biology of NEIL1.

Aflatoxin B1 exposure induces Alzheimer's disease like pathology by disrupting redox homeostasis and activating ferroptotic signals in C57BL/6 J mice

Aflatoxin B1 (AFB1) is one of the most toxic mycotoxins with neurotoxicity. Human exposure to AFB1 via contaminated foodstuffs has been linked to the risk of cognitive impairment, which may contribute to the progression of Alzheimer's disease (AD). However, the mechanism underlying the pathogenesis of AD in relation to AFB1 exposure is not clear. Herein, C57BL/6 J mice were exposed to 1.5 mg/L AFB1 in drinking water for 8 weeks. It was found that AFB1 damaged blood-brain barrier function, accumulated in the brain, and led to cognitive impairments and AD-like pathology in the hippocampus. Impaired cognitive function was indicated by the significant alterations in Morris' water maze and Y-maze tests at 8 weeks after AFB1 exposure. Concurrently, AD-like pathology was evinced by a marked neuronal loss and the up-regulated AD related gene and protein expressions in the hippocampus. AFB1 exposure remarkably disrupted redox homeostasis and induced ferroptosis both in the hippocampus at 8 weeks after AFB1 exposure and in cultured hippocampal neuron in vitro as indicated by the suppressions on SOD and CAT activities, the down-regulation of Slc7a11/Gpx4 expressions, the decline in GSH content, the increase in MDA and the lipid peroxidation. AFB1 exposure also increased Fe2+ content significantly at 8 weeks after exposure. In addition, we demonstrated that ferroptosis inhibition by Fer-1 obviously alleviated AFB1 neurotoxicity in HT22 cells. These results revealed an unknown pivotal role of ferroptosis in AFB1 neurotoxicity in relation to AD pathogenesis and emphasized the importance to reduce the health risk of AFB1 exposure as an etiology of AD in humans.

Peanuts (Arachis hypogaea L.) and Mycotoxins: Analytical Approaches, Prevalence, and Innovative Detoxification

Mycotoxins are secondary metabolites originating from several species of fungi that have proven to demonstrate high toxicity. In addition, potential contamination sources can promote increased human exposure to the adverse effects of these toxins. For this reason, it was necessary to develop several analytical methods that allow detection with the highest possible sensitivity for these toxic metabolites. Furthermore, since these methods involve high cost, are lengthy, and have sensitivity requirements, the development of multi-analyte detection methods is indispensable. The increasing consumption of groundnuts (legumes) as well as nuts (such as almonds, walnuts, and pistachios) and dried fruit (raisins and dried figs) has increased the risk of poisoning and the harmful effects of mycotoxins, which has encouraged studies for the creation of these methods. This review addresses the most representative methods applied to analyze and quantify mycotoxins in groundnuts (peanuts) together with decontamination techniques. The methodologies presented in this review are primarily based on analytical techniques for nuts and dried fruits. However, each of these methodologies can also be applied to peanut analysis for comparison and use. It is also relevant to highlight the importance of the development of multi-analyte methods in order to identify multiple mycotoxins using a single method, saving time, costs, and resources.

Aflatoxin B1-induced DNA adduct formation in murine kidney and liver

Aflatoxicosis is a life-threatening nephrotoxic condition arising from eating foods highly contaminated with aflatoxin-producing molds. Additionally, chronic aflatoxin exposures are linked to enhanced hepatocellular carcinomas. Using recent advances in mass spectrometry for the detection of aflatoxin B1 (AFB1) DNA adducts, we present data which show generation of these adducts in the kidney, albeit at ≈ 100-fold lower levels than in the liver of the same animal. This result is consistent with tissue-specific differences in the expression of cytochrome P450s implicated in the activation of AFB1. Although the mechanisms underlying aflatoxin-induced nephrotoxicity had been postulated to be driven by the generation of high levels of reactive oxygen species, measurement of oxidatively-induced DNA base damage did not reveal evidence for genotoxic induction of these lesions. Overall, this investigation provides evidence of the formation of aflatoxin-specific adducts in kidney tissue and challenges the hypothesis of acute aflatoxin exposures generating reactive oxygen-mediated DNA damage.

Structurally Similar Mycotoxins Aflatoxin B1 and Sterigmatocystin Trigger Different and Distinctive High-Resolution Mutational Spectra in Mammalian Cells

Aflatoxin B1 (AFB1) and sterigmatocystin (ST) are mycotoxins that pose significant threats to human and animal health owing to their mutagenic, carcinogenic, and toxic properties. They are structurally similar and widely believed to exert their biological effects via the generation of DNA-damaging epoxides at their respective terminal furan rings. Despite structural identity in the warhead portion of each toxin, this work shows that distal parts of each molecule are responsible for the distinctive mutational fingerprints seen in gptΔ C57BL/6J mouse embryo fibroblasts (MEFs). The two toxins differ structurally in the puckered cyclopentenone ring of AFB1 and in the planar xanthone functionality of ST. While both toxins mainly induce GC→TA mutations, the aforementioned differences in structure apparently trigger unique patterns of mutations, as revealed by high-resolution duplex sequencing of MEF genomes. AFB1 is more mutagenic than ST and displays its transversion mutations in a pattern with primary and secondary hotspots (underscored) in 5'-CGC-3' and 5'-CGG-3' contexts, respectively. ST displays a modest 5'-CGG-3' hotspot while its other GC→TA transversions are more uniformly distributed in a pattern resembling established oxidative stress mutational spectra. This research delineates the mutational spectra of AFB1 and ST, establishing these patterns as possible early-onset biomarkers of exposure.

Prevalence and Concentration of Aflatoxin M1 in Mother Milk: A Meta-analysis, Meta-regression, and Infants' Health Risk Assessment

Breast milk is a complete and nutritious food for newborns and infants, but it may be contaminated with Aflatoxin M1 (AFM1), which endangers consumers' health. Several studies from various regions have determined the concentration and prevalence of AFM1 in mother milk. In this study, an attempt was made to meta-analyze the concentration and prevalence of AFM1 and estimate the health risk of infants. The concentration and prevalence of AFM1 in the countries subgroup were meta-analyzed in the random effects model (REM), and also the effect over time on the prevalence of AFM1 was determined by meta-regression. Finally, the human risk in infants was estimated via the margin of exposure (MOES) in different countries. The five countries with the highest prevalence of AFM1 in mother milk were observed in Jordan (100.00), Tanzania (100.00), Mexico (97.00%), Lebanon (93.69%), and Colombia (90.00%). The pooled prevalence of AFM1 in mother milk was 54.48%, 95% CI (42.99-65.73). The five countries with the highest concentration of AFM1 in mother milk were observed: Egypt (570 µg/l), Sudan (413 µg/l), Cameroon (315.00 µg/l), Serbia (175 µg/l), and Tanzania (70 µg/l). The pooled prevalence of AFM1 in mother milk was 6.00, 95% CI (5.80-6.90(. Except for Egypt, infants in other countries are at an acceptable health risk (MOEs > 10,000). Considering the unacceptable risk due to the consumption of milk containing AFM1 in Egypt, it is suggested that programs be carried out to control the quality of mother milk.

A High-Affinity and Selective DNA Aptamer for the N-Linked C8-Deoxyguanosine Adduct Produced by the Arylamine Carcinogen 4-Aminobiphenyl

4-Aminobiphenyl (4-ABP) is a known human carcinogen that is implicated in the development of bladder cancers in smokers. The amine substituent undergoes bioactivation to generate nitrenium ions capable of covalently modifying DNA nucleobases. The primary adduct of 4-ABP, N-(deoxyguanosin-8-yl)-4-aminobiphenyl (dG-C8-ABP), is a bulky N-linked C8-dG adduct that serves as a biomarker for assessing the cancer risk associated with aromatic amine exposure. In this study, the capture-SELEX method was utilized to isolate DNA aptamers for dG-C8-ABP with high affinity and specificity. Using thioflavin T fluorescence spectroscopy and isothermal titration calorimetry, the parent aptamer PdG-1 has a Kd value below 100 nM and over 50-fold selectivity for dG-C8-ABP against competing analytes. A turn-on fluorescent sensor for dG-C8-ABP diagnostics, developed using a strand displacement assay, is also presented with a limit of detection of 68 nM. Our work represents the first selection of a DNA aptamer for a bulky DNA adduct produced by a known human carcinogen and sets the stage for the creation of ultrasensitive aptasensor platforms to meet the challenge of dG-C8-ABP detection in clinical settings.

Profound primary prevention of liver cancer following a natural experiment in China: A 50-year perspective and public health implications

Liver cancer causes upwards of 1 million cancer deaths annually and is projected to rise by at least 55% over the next 15 years. Two of the major risk factors contributing to liver cancer have been well documented by multiple epidemiologic studies and the hepatitis B virus (HBV) and aflatoxin show a synergy that increases by more than 8-fold the risk of liver cancer relative to HBV alone. Using the population-based cancer registry established by the Qidong Liver Cancer Institute in 1972 and aflatoxin-specific biomarkers, we document that reduction of aflatoxin exposure has likely contributed to a nearly 70% decline in age-standardized liver cancer incidence over the past 30 years despite an unchanging prevalence of HBV infection in cases. A natural experiment of economic reform in the 1980s drove a rapid switch from consumption of heavily contaminated corn to minimally, if any, contaminated rice and subsequent dietary diversity. Aflatoxin consumption appears to accelerate the time to liver cancer diagnosis; lowering exposure to this carcinogen adds years of life before a cancer diagnosis. Thus, in 1990 the median age of diagnosis was 48 years, while increasing to 67 years by 2021. These findings have important translational public health implications since up to 5 billion people worldwide might be routinely exposed to dietary aflatoxin, especially in societies using corn as the staple food. Interventions against aflatoxin are an achievable outcome leading to a reduction in liver cancer incidence and years of delay of its nearly always fatal diagnosis.

Phylogenetic studies and distinction of aflatoxin-producing Aspergillus species in section Flavi, Ochraceorosei and Nidulantes: A review

Aspergillus species produce polyketides, which form the basis of aflatoxins, some of the most significant mycotoxins in agriculture. Aflatoxins contaminate cereals, oilseeds, and nuts, both in the field and during storage. Of the 13 naturally occurring aflatoxins, the most potent are aflatoxins B1, B2, G1, and G2. The primary aflatoxigenic species are A. flavus, A. parasiticus, and A. nomius, while A. arachidicola, A. minisclerotigenes, and A. saccharicola also documented. These aflatoxin producers belong to three sections- 'Flavi', 'Ochraceorosei', and 'Nidulantes.' Aspergillus flavus, within section Flavi, shows morphological diversity, classified into Group I (S- and L- strains) and Group II (S- strains), with S-strains producing higher levels of aflatoxins. Aflatoxin biosynthesis is primarily regulated by the aflR gene, though other genes like aflS, aflP, aflQ, aflC, and aflM are also associated. However, presence of the aflR gene does not guarantee aflatoxin production across species. Sterigmatocystin serves as a precursor molecule within the pathway leading to aflatoxin production. Phylogenetic assessment, using ITS, BenA, CaM, and RBP2 gene sequences, reveals distinct clusters within Aspergillus sections and highlights the co-evolution of aflatoxigenic and non-aflatoxigenic species. Aspergillus ochraceoroseus and A. rambellii diverged out of aflatoxin-producing species earlier in evolutionary history, before splitting from a shared ancestor with A. fumigatus, which neither produces aflatoxins nor sterigmatocystin. Non-aflatoxigenic species like A. oryzae may evolve from aflatoxigenic species like A. flavus due to variations in evolutionary rates, telomere deletions, and mutations in aflatoxin biosynthesis genes. Comparative genomic analysis of AF, AF/ST and ST gene cluster shows that A. flavus has a larger aflatoxin gene cluster, while A. ochraceoroseus lacks the genes aflP and aflQ. Additionally, A. ochraceoroseus and A. rambellii possess a smaller genome, suggesting that genetic drift and deletions have refined their genomes for more efficient aflatoxin production.

Fifty Years of Aflatoxin Research in Qidong, China: A Celebration of Team Science to Improve Public Health

The Qidong Liver Cancer Institute (QDLCI) and the Qidong Cancer Registry were established in 1972 with input from doctors, other medical practitioners, and non-medical investigators arriving from urban centers such as Shanghai and Nanjing. Medical teams were established to quantify the extent of primary liver cancer in Qidong, a corn-growing peninsula on the north side of the Yangtze River. High rates of liver cancer were documented and linked to several etiologic agents, including aflatoxins. Local corn, the primary dietary staple, was found to be consistently contaminated with high levels of aflatoxins, and bioassays using this corn established its carcinogenicity in ducks and rats. Observational studies noted a positive association between levels of aflatoxin in corn and incidence of liver cancer across townships. Biomarker studies measuring aflatoxin B1 and its metabolite aflatoxin M1 in biofluids reflected the exposures. Approaches to decontamination of corn from aflatoxins were also studied. In 1993, investigators from Johns Hopkins University were invited to visit the QDLCI to discuss chemoprevention studies in some townships. A series of placebo-controlled clinical trials were conducted using oltipraz (a repurposed drug), chlorophyllin (an over-the-counter drug), and beverages prepared from 3-day-old broccoli sprouts (rich in the precursor phytochemical for sulforaphane). Modulation of biomarkers of aflatoxin DNA and albumin adducts established proof of principle for the efficacy of these agents in enhancing aflatoxin detoxication. Serendipitously, by 2012, aflatoxin exposures quantified using biomarker measurements documented a many hundred-fold reduction. In turn, the Cancer Registry documents that the age-standardized incidence rate of liver cancer is now 75% lower than that seen in the 1970s. This reduction is seen in Qidongese who have never received the hepatitis B vaccination. Aflatoxin mitigation driven by economic changes switched the dietary staple of contaminated corn to rice coupled with subsequent dietary diversity leading to lower aflatoxin exposures. This 50-year effort to understand the etiology of liver cancer in Qidong provides the strongest evidence for aflatoxin mitigation as a public health strategy for reducing liver cancer burden in exposed, high-risk populations. Also highlighted are the challenges and successes of international team science to solve pressing public health issues.

Environmental exposures and the risk of hepatocellular carcinoma

The global epidemiology of HCC is shifting due to changes in both established and emerging risk factors. This transformation is marked by an emerging prevalence of metabolic dysfunction-associated steatotic liver disease (MASLD) and type 2 diabetes, alongside traditional risks such as viral hepatitis (HBV and HCV), and exposure to chemical agents like aflatoxin, alcohol, tobacco, and air pollution. This review examines how environmental exposures and evolving liver pathology, exacerbated by lifestyle and metabolic conditions, are contributing to the rising worldwide incidence of HCC. Effective prevention strategies must not only address traditional risk factors through vaccination and therapeutic measures but also confront metabolic and socioeconomic disparities through comprehensive public health efforts. As the burden of liver cancer continues to grow, particularly in resource-limited settings, an expansive and inclusive approach is vital for mitigating its impact across diverse populations.

Alterations in the proteomes of HepG2 and IHKE cells inflicted by six selected mycotoxins

Toxic fungal secondary metabolites, referred to as mycotoxins, emerge in moldy food and feed and constitute a potent but often underestimated health threat for humans and animals. They are structurally diverse and can cause diseases after dietary intake even in low concentrations. To elucidate cellular responses and identify cellular targets of mycotoxins, a bottom-up proteomics approach was used. We investigated the effects of the mycotoxins aflatoxin B1, ochratoxin A, citrinin, deoxynivalenol, nivalenol and penitrem A on the human hepatoblastoma cell line HepG2 and of ochratoxin A and citrinin on the human kidney epithelial cell line IHKE. Incubations were carried out at sub-cytotoxic concentrations to monitor molecular effects before acute cell death mechanisms predominate. Through these experiments, we were able to detect specific cellular responses that point towards the mycotoxins' mode of action. Besides very well-described mechanisms like the ribotoxicity of the trichothecenes, we observed not yet described effects on different cellular mechanisms. For instance, trichothecenes lowered the apolipoprotein abundance and aflatoxin B1 affected proteins related to inflammation, ribogenesis and mitosis. Ochratoxin A and citrinin upregulated the minichromosomal maintenance complex and nucleotide synthesis in HepG2 and downregulated histones in IHKE. Penitrem A reduced enzyme levels of the sterol biosynthesis. These results will aid in the elucidation of the toxicodynamic properties of this highly relevant class of toxins.

Engineered S. cerevisiae-pYD1-ScFv-AFB1 mitigates aflatoxin B1 toxicity via bio-binding and intestinal microenvironment repair

The highly toxic aflatoxin B1 (AFB1) is considered one of the primary risk factors for hepatocellular carcinoma, while effective measures after AFB1 exposure remain to be optimized. This study utilized cell-surface-display technique to construct an engineered S. cerevisiae-pYD1-ScFv-AFB1 (S.C-AF) that specifically binds AFB1, and verified the potential mechanism of S.C-AF in vivo through AFB1-induced (gastric perfused with 0.3 mg/kg/d AFB1 per day) liver injury mouse model. In this experiment, the C57BL/6 mouse model of AFB1-induced liver injury was treated with S.C (gastric perfused with 1 × 109 CFU/mL S.C per day) and S.C-AF (gastric perfused with 1 × 109 CFU/mL S.C-AF per day) for 4 weeks, respectively. With probiotic properties optimized, S.C.-AF achieved an in vitro AFB1 binding capacity 1.7 times higher than S. cerevisiae. Furthermore, S.C-AF could alleviate AFB1-induced liver injury by reducing proinflammatory cytokine secretion and apoptotic protein expression, enhancing antioxidative capacity via Nrf2 activation, and simultaneously reversing intestinal tight junction protein deficiency, increasing intestinal barrier permeability, and improving intestinal dysbiosis caused by AFB1 exposure. S.C-AF alleviates AFB1-induced liver lesions, which might be a novel intervention to mitigate aflatoxin toxicity.

Mechanistic insights into ferroptosis and apoptosis pathways: Synergistic effects of multi-organ toxicity and transgenerational effects induced by co-exposure of epoxiconazole and aflatoxin B1 in zebrafish

INTRODUCTION

In the environment, mycotoxins and fungicides frequently coexist, potentially causing synergistic risks to organisms. Epoxiconazole (EPO) and aflatoxin B1 (AFB1) are a common fungicide and mycotoxins, respectively, which are widely present in the environment and have toxic effects on multiple organs once entering the organism, but it is still unclear whether the co-exposure has a synergistic toxic effect.

OBJECTIVES

This study delves into the molecular mechanisms underlying the co-exposure to EPO and AFB1, emphasizing multi-organ toxicity in female zebrafish (F0 generation) and potential transgenerational impacts on the offspring embryos (F1 generation) through multi-omics approaches.

RESULTS

Findings indicate that exposure to either EPO or AFB1, individually or combined, intensified intestinal pathological damage, decreased the expression of tight junction proteins, altered gut microbiota composition, and induced intestinal inflammation, with co-exposure causing more severe effects. RNA-seq analysis revealed an enrichment of ferroptosis and apoptosis pathways in the liver and ovaries of F0 zebrafish. Co-exposure markedly altered the expression of associated molecules, exacerbating pathological damage in these organs. Molecular docking studies revealed that AFB1 exhibited lower binding energies to Caspase3, GPX4 and IL-1β compared to EPO, suggesting that it may have a higher binding capacity. Furthermore, both single and combined exposures modified the expression of molecules related to apoptosis, inflammatory response, and ferroptosis in unexposed F1 embryos, with co-exposure demonstrating more significant biological effects, thereby confirming transgenerational toxicity.

CONCLUSION

The present study provides preliminary evidence on the potential mechanisms of combined exposure-induced multi-organ toxicity, highlighting ferroptosis of the liver and apoptosis of the ovary as key pathways. These findings provide new perspectives and methods for risk assessment of multiple environmental pollutants.

Species Differences in the Biotransformation of Aflatoxin B1: Primary Determinants of Relative Carcinogenic Potency in Different Animal Species

It has been known since the early days of the discovery of aflatoxin B1 (AFB1) that there were large species differences in susceptibility to AFB1. It was also evident early on that AFB1 itself was not toxic but required bioactivation to a reactive form. Over the past 60 years there have been thousands of studies to delineate the role of ~10 specific biotransformation pathways of AFB1, both phase I (oxidation, reduction) and phase II (hydrolysis, conjugation, secondary oxidations, and reductions of phase I metabolites). This review provides a historical context and substantive analysis of each of these pathways as contributors to species differences in AFB1 hepatoxicity and carcinogenicity. Since the discovery of AFB1 as the toxic contaminant in groundnut meal that led to Turkey X diseases in 1960, there have been over 15,000 publications related to aflatoxins, of which nearly 8000 have addressed the significance of biotransformation (metabolism, in the older literature) of AFB1. While it is impossible to give justice to all of these studies, this review provides a historical perspective on the major discoveries related to species differences in the biotransformation of AFB1 and sets the stage for discussion of other papers in this Special Issue of the important role that AFB1 metabolites have played as biomarkers of exposure and effect in thousands of human studies on the toxic effects of aflatoxins. Dr. John Groopman has played a leading role in every step of the way-from initial laboratory studies on specific AFB1 metabolites to the application of molecular biomarkers in epidemiological studies associating dietary AFB1 exposure with liver cancer, and the design and conduct of chemoprevention clinical trials to reduce cancer risk from unavoidable aflatoxin exposures by alteration of specific AFB1 biotransformation pathways. This article is written in honor of Dr. Groopman's many contributions in this area.

Potential mutagenicity of aflatoxin B1 in Egyptian spices

The current study aimed to detect the mutagenic impacts of aflatoxin B1 (AFB1), which is produced by Aspergillus group fungi, via a high-plant genotoxicity test. Different durations of treatment (3 h, 6 h, and 12 h) were used to treat the Vicia faba root tips with varying concentrations of Aflatoxin B1 (AFB1) following the approved protocol for plant assays published by the International Program on Chemical Safety (IPCS) and the World Health Organization (WHO). The data obtained indicated that AFB1 not only has the ability to induce various alterations in the process of mitosis, ranging from increasing to decreasing mitotic and phase indices but also leads to many mitotic aberrations. The abnormalities observed varied on the basis of the ratio of AFB1 to treatment time. The aberrations included micronuclei in interphase, stickiness; two groups ring star disturbed and oblique metaphase late separation diagonal bridge and laggard and disturbed. anaphase and telophase. This study showed that biomonitoring Vicia faba is a sustainable method for estimating the cytotoxicity and genotoxicity of applied AFB1. Additionally, AFB1 caused changes in the protein profile detected by SDS‒PAGE, with each treated sample displaying a unique electrophoretic pattern due to the formation and disappearance of certain bands. The ISSR and RAPD assays changes in band numbers in all samples compared with the untreated control, and a decrease in genetic template stability (GTS) ratios was observed with higher levels of AFB1. The image cytometric data revealed a correlation between the dosage of AFB1 and its impact on cell cycle components in the meristematic cells of Vicia faba roots. Furthermore, an increase in AFB1 concentrationled to a decrease in B-cell lymphoma 2 (Bcl2) levels, an increase in chromatin condensation levels, and an increase in poly ADP‒ribose polymorphism (PARP) levels.

Roles of cytochromes P450 and ribosome inhibition in the interaction between two preoccupying mycotoxins, aflatoxin B1 and deoxynivalenol

Mycotoxins are a threat to human and animal health. Climate change increases their occurrence and our dietary exposure. Although humans and animals are concomitantly exposed to several mycotoxins, their combined effects are poorly characterised. This study investigated the interaction between aflatoxin B1 (AFB1), the most potent natural carcinogen, and deoxynivalenol (DON), which is among the most prevalent mycotoxins. AFB1 is associated with hepatocellular carcinoma through its bioactivation by cytochrome P450 (CYP450) enzymes; while DON induces ribotoxic stress leading to an alteration of intestinal, immune and hepatic functions. Analysis of DNA damage biomarkers γ-H2AX and 53BP1 revealed that DON reduces the genotoxicity of AFB1. This effect was mimicked with cycloheximide (CHX), another ribosome inhibitor; moreover DOM-1, a DON-derivative lacking ribosome inhibition, did not affect DNA damage. Exposure to DON, alone or in combination with AFB1, decreased the protein levels and/or activities of CYP1A2 and CYP3A4 in a time- and dose-dependent manner. A similar reduction of CYP1A2 and CYP3A4 activities was also observed with CHX. Altogether, these results revealed an original interaction between DON and AFB1, DON inhibiting the genotoxicity of AFB1. The underlying mechanism involves ribosome inhibition by DON and the subsequent impairment of CYP450s, responsible for the bioactivation of AFB1. This work highlights the importance of studying mycotoxins not only individually but also in mixture and of considering food contaminants as part of the exposome.

Biomonitoring and determinants of mycotoxin exposures from pregnancy until post-lactation in HIV-infected and HIV-uninfected women from Harare, Zimbabwe

The human immunodeficiency virus (HIV) heavily affects women from resource-limited settings who are vulnerable to potentially harmful mycotoxins including aflatoxin B1 (AFB1), fumonisin B1 (FB1) and ochratoxin A (OTA). We aimed to conduct biomonitoring and ascertain the determinants of maternal mycotoxin exposure in pregnancy, lactation and post-lactation periods. We conducted a retrospective longitudinal study in HIV-infected and HIV-uninfected women from Harare, Zimbabwe. 175 and 125 random urine samples in pregnancy and 24 months after delivery (post-lactation) respectively were analysed for aflatoxin M1 (AFM1) and FB1 by ELISA. 6 weeks after delivery (lactation), 226 and 262 breast milk (BM) samples were analysed for AFM1 and OTA respectively by ELISA. The association of demographics and food consumption with mycotoxins was evaluated using multivariable logistic regression. In HIV-infected, urinary AFM1 was detected in 46/94 (Median: 0.05; Range: 0.04-0.46 ng mL-1) in pregnancy and 47/66 (Median: 0.05; Range: 0.04-1.01 ng mL-1) post-lactation. Urinary FB1 was detected in 86/94 (Median: 1.39; Range: 0.17-6.02 ng mL-1) in pregnancy and 56/66 (Median: 0.72; Range: 0.20-3.81 ng mL-1) post-lactation. BM AFM1 was detected in 28/110 (Median: 7.24; Range: 5.96-29.80 pg mL-1) and OTA in 11/129 (Median: 0.20; Range: 0.14-0.65 ng mL-1). In HIV-uninfected, urinary AFM1 was detected in 48/81 (Median: 0.05; Range: 0.04-1.06 ng mL-1) in pregnancy and 41/59 (Median: 0.05; Range: 0.04-0.52 ng mL-1) post-lactation. Urinary FB1 was detected in 74/81 (Median: 1.15; Range: 0.17-6.16 ng mL-1) in pregnancy and 55/59 (Median: 0.96; Range: 0.20-2.82 ng mL-1) post-lactation. BM AFM1 was detected in 38/116 (Median: 7.70; Range: 6.07-31.75 pg mL-1) and OTA in 4/133 (Median: 0.24; Range: 0.18-0.83 ng mL-1). Location, wealth, and peanut butter consumption were determinants of AFB1 exposure. HIV infection, BMI, location, rainy season, unemployment, and age were determinants of FB1 exposure. Women especially those pregnant and/or HIV-infected are at risk of adverse effects of mycotoxins.

65 Years on-Aflatoxin Biomarkers Blossoming: Whither Next?

Aflatoxins are mycotoxins produced by Aspergillus flavus and several other related organisms and are common contaminants of numerous grains and nuts, especially maize (corn) and peanuts. Although, undoubtedly, aflatoxins have been present in the food of humans for millennia, their toxic effects were not discovered until 1960, first becoming evident as a non-infectious outbreak of poisoning of turkeys (Turkey X disease) arising from contaminated groundnut meal. The elucidation of specific chemical structures in 1963 led to the rapid characterization of aflatoxins as among the most potent chemical carcinogens of natural origin ever discovered. As a frontispiece to the Special Issue "65 Years on from Aflatoxin Discovery-A Themed Issue in Honor of Professor John D. Groopman", we highlight many of Professor Groopman's important contributions utilizing urinary (aflatoxin-N7-guanine) and, especially, serum (aflatoxin-albumin adducts) biomarkers; this work focused on over 40+ years of the development of analytical methods to measure biomarkers of aflatoxin exposure and their application in experimental and clinical studies. Collectively, this work serves as a template for using chemical-specific biomarkers as key tools to probe 'exposure-disease relationships'-in this instance, dietary aflatoxins and liver cancer. New approaches to measuring carcinogen biomarkers will build upon this 'aflatoxin paradigm' to inform the public health implications of diverse exposures around the world.

Dietary Mycotoxins: An Overview on Toxicokinetics, Toxicodynamics, Toxicity, Epidemiology, Detection, and Their Mitigation with Special Emphasis on Aflatoxicosis in Humans and Animals

Mycotoxins are secondary metabolites of filamentous fungi and ubiquitous dietary contaminants. Aflatoxins, a group of mycotoxins with high prevalence and toxicity, have raised a high level of public health concern, the most prevalent and toxic being aflatoxin B1 (AFB1). Many aspects appertaining to AFB1 poisoning are not well understood. Yet this information is necessary to devise appropriate surveillance and mitigation strategies against human and animal aflatoxicosis. This review provides an in-depth update of work carried out on mycotoxin poisoning, particularly aflatoxicosis in humans and animals, to identify gaps in knowledge. Hypotheses explaining the functional significance of mycotoxins in fungal biology and their dietary epidemiological data are presented and briefly discussed. The toxicology of aflatoxins and the challenges of their mitigation are discussed in depth. It was concluded that the identification of potential mycotoxin-hazard-prone food items and quantification of the associated risk of cancer ailments in humans is a prime priority. There is a dearth of reliable sampling methodologies for estimating AFB1 in animal feed. Data update on AFB1 in animal feed and its implication in animal production, mitigation strategies, and elucidation of risk factors to this hazard is required. To reduce the burden of aflatoxins, surveillance employing predictive technology, and biocontrol strategies seem promising approaches.

Aflatoxin M1 in milk and dairy products: The state of the evidence for child growth impairment

Aflatoxin M1 (AFM1) is a metabolite of the more toxic aflatoxin B1 (AFB1) a mycotoxin produced by the fungi Aspergillus flavus and A. parasiticus; which contaminates maize, peanuts, tree nuts, and oilseeds, among other crops in warm regions of the world. When mammals consume AFB1 in these foods, they secrete AFM1 in milk. A recent analysis indicated negligible cancer risk associated with AFM1 exposure, but whether AFM1 impairs children's growth is important to understand because children consume relatively more milk than adults worldwide. Our paper reviews the evidence on the link between AFM1 exposure and child growth impairment. We find that the existing studies are contradictory and necessitates further studies on this question; in particular, those that control for potentially confounding factors such as household socioeconomic status, children's overall diets, hygienic factors, and agroecological zone. Though many nations have policies for maximum AFM1 limits in dairy foods, they are not based on an explicit health risk analysis of AFM1 but on conversion rates of AFB1 levels to AFM1 in dairy products. Future studies on AFM1's potential harmful effects on child growth will help to better inform policies on maximum allowable AFM1 in milk and other dairy products.

A smartphone-enabled visual platform for detecting aflatoxins in peanut oil using colorimetric analysis coupled with magnetic imprinted solid-phase extraction

The study aimed to develop a rapid and sensitive colorimetric platform based on the Emerson reaction to visualize and determine total aflatoxins (AFs) in peanut oil. This method offers the advantage of fast screening for AFs (AFB1, AFB2, AFG1, and AFG2), eliminating the need for specific antibodies. The proposed approach combined colorimetric detection with magnetic dummy imprinted solid-phase extraction and purification, enhancing sensitivity and selectivity. The oxidizer aided the colorless AFs in reacting with 4-aminoantipyrine, producing green condensates. Thus, a dual-mode approach was developed for AFs detection, employing both UV-vis colorimetric and smartphone-based colorimetry. Both methods showed a good linear relationship with the concentration of AFs. Notably, the smartphone-based method demonstrated a detection range of 0.5-57 μg/kg, with a detection limit as low as 0.21 μg/kg. The suggested colorimetric methods present a promising potential for onsite detection and fast screening of AFs in actual samples.

Liver Cancer: Progress and Priorities

Liver cancer, the sixth most frequently occurring cancer in the world and the third most common cause of cancer mortality, has wide geographical variation in both incidence and mortality rates. At the end of the 20th century, incidence rates began declining in some high-rate areas and increasing in some lower-rate areas. These trends were undoubtedly driven by the shifting contributions of both well-established and more novel risk factors. While notable strides have been made in combating some major risk factors, such as hepatitis B virus and hepatitis C virus, the emergence of metabolic conditions as important drivers of liver cancer risk indicates that much work remains to be done in prevention. As liver cancer is strongly associated with economic and social deprivation, research, early-diagnosis, and treatment among disadvantaged populations are of paramount importance.

Effects of inoculation of corn silage with Saccharomyces cerevisiae on silage fermentation characteristics, nutrient digestibility, mycoflora and aflatoxin production

In the present study, fresh whole corn plants along with half milk kernels line were treated with live and hydrolysed yeast with different concentrations before ensiling and kept in airtight bags and then into mini silos in order to achieve anaerobic conditions for proper fermentation. The buckets were opened after different time intervals to characterise the material, quick acidification, dry matter recovery, and aerobic stability of silage respectively. Moreover, mycoflora and aflatoxin contamination were also analysed. The overall result reported that the silage quality was improved by the application of live and hydrolysed yeast. The best result was reported by the application of live yeast (T2: 10 g/kg) which significantly improved the fermentative, proximate, and digestibility parameters and reduced the mycoflora and aflatoxin contamination. Our results present promising new options for the use of natural compounds that may help to improve silage quality and reduce aflatoxin contamination.

Pathogen producing aflatoxin in contaminated sandwich: Identification and preservation

The toxicity of the contaminated powder contributed to toxic aflatoxins has been well-known in the literature. However, before this study, the specific fungal strain behind aflatoxin production remained unidentified. Our research aimed to isolate and identify fungi from the tainted sandwiches while also assessing the preservation of sandwiches in ambient conditions. The study pinpointed Aspergillus flavus as the fungus responsible for aflatoxin production. Analysis revealed that the sandwich samples contaminated with pure A. flavus exhibited a significant Aflatoxin B1 (AFB1) concentration of 55.2 ± 0.21 ng/g, accompanied by a spore count of 2 × 106 Colony-Forming Unit (CFU)/g after ten days. In contrast, sandwich samples contaminated with the unspecified fungi displayed a lower AFB1 content of 16.21 ± 0.42 ng/g, with a spore count of 2.2 × 102 CFU/g after the same duration. In the prevention study, the efficacy of the ethanol spray method for inhibiting aflatoxin from A. flavus was investigated. Results demonstrated that a 70 % ethanol concentration at a ratio of 2.0 % total weight of the sandwich proved highly effective, significantly impeding fungal growth. This method extended the preservation time by sevenfold compared to the control. Importantly, tests at 2.0 % ethanol of the sandwich weight did not detect aflatoxin presence.

Comparative analysis of the genomes and aflatoxin production patterns of three species within the Aspergillus section Flavi reveals an undescribed chemotype and habitat-specific genetic traits

Aflatoxins are the most dangerous mycotoxins for food safety. They are mainly produced by Aspergillus flavus, A. parasiticus, and A. minisclerotigenes. The latter, an understudied species, was the main culprit for outbreaks of fatal aflatoxicosis in Kenya in the past. To determine specific genetic characteristics of these Aspergillus species, their genomes are comparatively analyzed. Differences reflecting the typical habitat are reported, such as an increased number of carbohydrate-active enzymes, including enzymes for lignin degradation, in the genomes of A. minisclerotigenes and A. parasiticus. Further, variations within the aflatoxin gene clusters are described, which are related to different chemotypes of aflatoxin biosynthesis. These include a substitution within the aflL gene of the A. parasiticus isolate, which leads to the translation of a stop codon, thereby switching off the production of the group 1 aflatoxins B1 and G1. In addition, we demonstrate that the inability of the A. minisclerotigenes isolates to produce group G aflatoxins is associated with a 2.2 kb deletion within the aflF and aflU genes. These findings reveal a relatively high genetic homology among the three Aspergillus species investigated. However, they also demonstrate consequential genetic differences that have an important impact on risk-assessment and food safety.

Some relevant mitigating agents of chronic aflatoxin exposure: a treatise

Aflatoxins, a group of toxic secondary metabolites produced by Aspergillus species, pose significant threats to human health due to their potent carcinogenic, mutagenic, and immunosuppressive properties. Chronic exposure to these contaminants, commonly found in staple foods such as maize and groundnuts, has been linked to an increased risk of liver cancer, growth impairment, and immune dysfunction. Several agents, such as calcium montmorillonite clay and Lactobacillus rhamnosus GG, have shown promise in reducing aflatoxin bioavailability and alleviating its toxic effects. Additionally, dietary supplements such as chlorophyllin, selenium, and N-acetylcysteine have demonstrated potential as adjuvants to counteract aflatoxin-induced oxidative stress and support liver function. In this treatise, some of the most discussed approaches to mitigating aflatoxin effects are explored in terms of their efficacy, safety, and potential mechanisms of action, which include direct aflatoxin binding, detoxification, cellular antioxidative, and hepatocellular protection properties. However, the effectiveness of these strategies can be influenced by various factors, such as dose, duration of exposure, and individual susceptibility. Therefore, further research is needed to optimize these interventions and develop new, targeted therapies for the prevention and treatment of aflatoxin-related diseases. This review aims to provide a comprehensive analysis of 18 pharmaceutical, nutraceutical, supplement, and probiotic strategies currently available for mitigating the deleterious effects of chronic aflatoxin exposure in humans and animal models.

Occurrence of aflatoxin M1 in cheese products commonly available in Sri Lankan market

Aflatoxins (AFs) are a group of mycotoxins produced by certain fungi of Aspergillus spp. AFs of major concern are B1 (AFB1), B2 (AFB2), G1 (AFG1), G2 (AFG2), and M1 (AFM1). AFM1 is a hydroxylated metabolite of AFB1 formed inside the animal's body which is excreted into milk of cows that consumed AFB1 contaminated feed. Consumption of AFM1-contaminated milk and subsequent dairy products causes negative health effects in consumers. This study was conducted to determine the occurrence and levels of AFM1 in cheese products available in the Sri Lankan market where AFM1 is not regularly monitored in milk while having an outdated regulatory limit of 1 ppb established for dairy products. Processed cheese (n = 28), hard cheese (n = 14), semi-hard cheese (n = 5), and soft cheese (n = 3) representing seven popular brands were collected. The samples were analyzed by Ultra High-Performance Liquid Chromatography Fluorescence Detection. AFM1 was detected in 40 samples (80 %), while 17 (34 %) and 37 (74 %) of the samples had AFM1 levels exceeding the maximum permitted limit set by Codex Alimentarius Commission (0.5 ppb) and the Netherlands (0.2 ppb). Further, 10 samples violated the Sri Lankan maximum limit of 1 ppb. Thirteen out of the 14 hard cheese (92.9 %, 0.11-14.43 ppb) and all semi-hard cheese samples (100 %, 0.29-0.65 ppb) contained AFM1. Most of the soft (66.7 %, 0.35-0.45 ppb) and processed (71.4 %, 0.11-1.35 ppb) cheese samples had AFM1. Most of the locally manufactured cheese products in Sri Lankan market may pose health risks to consumers. The results highlight the significance of regular monitoring of AFM1 in dairy products and the importance of updating regulations on par with international standards concurrently to ensure consumer safety.

Synergistic antifungal mechanism of cinnamaldehyde and nonanal against Aspergillus flavus and its application in food preservation

Aspergillus flavus colonization on agricultural products during preharvest and postharvest results in tremendous economic losses. Inspired by the synergistic antifungal effects of essential oils, the aims of this study were to explore the mechanism of combined cinnamaldehyde and nonanal (SCAN) against A. flavus and to evaluate the antifungal activity of SCAN loading into diatomite (DM). Shriveled mycelia were observed by scanning electron microscopy, especially in the SCAN treatment group. Calcofluor white staining, transmission electron microscopy, dichloro-dihydro-fluorescein diacetate staining and the inhibition of key enzymes in tricarboxylic acid cycle indicated that the antifungal mechanism of SCAN against A. flavus was related to the cell wall damage, reactive oxygen species accumulation and energy metabolism interruption. RNA sequencing revealed that some genes involved in antioxidation were upregulated, whereas genes responsible for cell wall biosynthesis, oxidative stress, cell cycle and spore development were significantly downregulated, supporting the occurrence of cellular apoptosis. In addition, compared with the control group, conidia production in 1.5 mg/mL DM/cinnamaldehyde, DM/nonanal and DM/SCAN groups were decreased by 27.16%, 48.22% and 76.66%, respectively, and the aflatoxin B1 (AFB1) contents decreased by 2.00%, 73.02% and 84.15%, respectively. These finding suggest that DM/SCAN complex has potential uses in food preservation.

Functional characterization of single nucleotide polymorphic variants of DNA repair enzyme NEIL1 in South Asian populations

The base excision repair (BER) pathway is a precise and versatile mechanism of DNA repair that is initiated by DNA glycosylases. Endonuclease VIII-like 1 (NEIL1) is a bifunctional glycosylase/abasic site (AP) lyase that excises a damaged base and subsequently cleaves the phosphodiester backbone. NEIL1 is able to recognize and hydrolyze a broad range of oxidatively-induced base lesions and substituted ring-fragmented guanines, including aflatoxin-induced 8,9-dihydro-8-(2,6-diamino-4-oxo-3,4-dihydropyrimid-5-yl-formamido)-9-hydroxyaflatoxin B1 (AFB1-FapyGua). Due to NEIL1's protective role against these and other pro-mutagenic lesions, it was hypothesized that naturally occurring single nucleotide polymorphic (SNP) variants of NEIL1 could increase human risk for aflatoxin-induced hepatocellular carcinoma (HCC). Given that populations in South Asia experience high levels of dietary aflatoxin exposures and hepatitis B viral infections that induce oxidative stress, investigations on SNP variants of NEIL1 that occur in this region may have clinical implications. In this study, the most common South Asian variants of NEIL1 were expressed, purified, and functionally characterized. All tested variants exhibited activities and substrate specificities similar to wild type (wt)-NEIL1 on high-molecular weight DNA containing an array of oxidatively-induced base lesions. On short oligodeoxynucleotides (17-mers) containing either a site-specific apurinic/apyrimidinic (AP) site, thymine glycol (ThyGly), or AFB1-FapyGua, P206L-NEIL1 was catalytically comparable to wt-NEIL1, while the activities of NEIL1 variants Q67K and T278I on these substrates were ≈2-fold reduced. Variant T103A had a greatly diminished ability to bind to 17-mer DNAs, limiting the subsequent glycosylase and lyase reactions. Consistent with this observation, the rate of excision by T103A on 17-mer oligodeoxynucleotides containing ThyGly or AFB1-FapyGua could not be measured. However, the ability of T103A to excise ThyGly was improved on longer oligodeoxynucleotides (51-mers), with ≈7-fold reduced activity compared to wt-NEIL1. Our studies suggest that NEIL1 variant T103A may present a pathogenic phenotype that is limited in damage recognition, potentially increasing human risk for HCC.

Safe and effective degradation of aflatoxins by food-grade culture broth of Aspergillus oryzae

Aflatoxins (AFs) are carcinogenic fungal toxins contaminating up to 25% of the global food supply. Over half of the world's population is exposed to unmonitored levels of AFs, mostly aflatoxin B1 (AFB1). Despite numerous efforts over the past 60 years, there are no solutions to remove AFs safely from food. Here, we present a safe and effective AF-degrading product called "D-Tox", a filtered culture broth of Aspergillus oryzae grown in a food-grade liquid medium. When 5 ppm of AFB1 is added to D-Tox, ∼90% is degraded at 48 and 24 hr at room temperature and 50°C, respectively. Moreover, when varying amounts (0.1 ppm ∼ 100 ppm) of AFB1 are added to D-Tox at 100°C, over 95% of AFB1 is degraded in 1 hr, suggesting a nonenzymatic process. Examining degradation of 100 ppm AFB1 reveals that aflatoxin D1 (AFD1) is the major transient degradant of AFB1, indicating that degradation occurs irreversibly by lactone ring hydrolysis followed by decarboxylation. D-Tox further degrades AFD1 to unknown fragmented products. Importantly, the practical application of D-Tox is also demonstrated, as more than 70% of AFB1 is degraded when wheat, corn, and peanuts naturally contaminated with high levels of AFB1 (0.3 ∼ 4.5 ppm) are boiled in D-Tox for 1 hr. Additionally, D-Tox can degrade other lactone-ring containing mycotoxins, including patulin and ochratoxin. D-Tox exhibits no cytotoxicity under the conditions tested in MCF-7 breast cancer cell lines. In summary, D-Tox is a safe and effective AF-detoxifying product that can enhance global food safety.

Exploring the Impact of Efavirenz on Aflatoxin B1 Metabolism: Insights from a Physiologically Based Pharmacokinetic Model and a Human Liver Microsome Study

Physiologically based pharmacokinetic (PBPK) models were utilized to investigate potential interactions between aflatoxin B1 (AFB1) and efavirenz (EFV), a non-nucleoside reverse transcriptase inhibitor drug and inducer of several CYP enzymes, including CYP3A4. PBPK simulations were conducted in a North European Caucasian and Black South African population, considering different dosing scenarios. The simulations predicted the impact of EFV on AFB1 metabolism via CYP3A4 and CYP1A2. In vitro experiments using human liver microsomes (HLM) were performed to verify the PBPK predictions for both single- and multiple-dose exposures to EFV. Results showed no significant difference in the formation of AFB1 metabolites when combined with EFV (0.15 µM) compared to AFB1 alone. However, exposure to 5 µM of EFV, mimicking chronic exposure, resulted in increased CYP3A4 activity, affecting metabolite formation. While co-incubation with EFV reduced the formation of certain AFB1 metabolites, other outcomes varied and could not be fully attributed to CYP3A4 induction. Overall, this study provides evidence that EFV, and potentially other CYP1A2/CYP3A4 perpetrators, can impact AFB1 metabolism, leading to altered exposure to toxic metabolites. The results emphasize the importance of considering drug interactions when assessing the risks associated with mycotoxin exposure in individuals undergoing HIV therapy in a European and African context.

Understanding How Chemical Pollutants Arise and Evolve in the Brewing Supply Chain: A Scoping Review

In this study, a critical review was carried out using the Web of ScienceTM Core Collection database to analyse the scientific literature published to date to identify lines of research and future perspectives on the presence of chemical pollutants in beer brewing. Beer is one of the world's most popular drinks and the most consumed alcoholic beverage. However, a widespread challenge with potential implications for human and animal health is the presence of physical, chemical, and/or microbiological contaminants in beer. Biogenic amines, heavy metals, mycotoxins, nitrosamines, pesticides, acrylamide, phthalates, bisphenols, microplastics, and, to a lesser extent, hydrocarbons (aliphatic chlorinated and polycyclic aromatic), carbonyls, furan-derivatives, polychlorinated biphenyls, and trihalomethanes are the main chemical pollutants found during the beer brewing process. Pollution sources include raw materials, technological process steps, the brewery environment, and packaging materials. Different chemical pollutants have been found during the beer brewing process, from barley to beer. Brewing steps such as steeping, kilning, mashing, boiling, fermentation, and clarification are critical in reducing the levels of many of these pollutants. As a result, their residual levels are usually below the maximum levels allowed by international regulations. Therefore, this work was aimed at assessing how chemical pollutants appear and evolve in the brewing process, according to research developed in the last few decades.

MicroRNA (miRNA) profiling of maize genotypes with differential response to Aspergillus flavus implies zma-miR156-squamosa promoter binding protein (SBP) and zma-miR398/zma-miR394-F -box combinations involved in resistance mechanisms

Maize (Zea mays), a major food crop worldwide, is susceptible to infection by the saprophytic fungus Aspergillus flavus that can produce the carcinogenic metabolite aflatoxin (AF) especially under climate change induced abiotic stressors that favor mold growth. Several studies have used "-omics" approaches to identify genetic elements with potential roles in AF resistance, but there is a lack of research identifying the involvement of small RNAs such as microRNAs (miRNAs) in maize-A. flavus interaction. In this study, we compared the miRNA profiles of three maize lines (resistant TZAR102, moderately resistant MI82, and susceptible Va35) at 8 h, 3 d, and 7 d after A. flavus infection to investigate possible regulatory antifungal role of miRNAs. A total of 316 miRNAs (275 known and 41 putative novel) belonging to 115 miRNA families were identified in response to the fungal infection across all three maize lines. Eighty-two unique miRNAs were significantly differentially expressed with 39 miRNAs exhibiting temporal differential regulation irrespective of the maize genotype, which targeted 544 genes (mRNAs) involved in diverse molecular functions. The two most notable biological processes involved in plant immunity, namely cellular responses to oxidative stress (GO:00345990) and reactive oxygen species (GO:0034614) were significantly enriched in the resistant line TZAR102. Coexpression network analysis identified 34 hubs of miRNA-mRNA pairs where nine hubs had a node in the module connected to their target gene with potentially important roles in resistance/susceptible response of maize to A. flavus. The miRNA hubs in resistance modules (TZAR102 and MI82) were mostly connected to transcription factors and protein kinases. Specifically, the module of miRNA zma-miR156b-nb - squamosa promoter binding protein (SBP), zma-miR398a-3p - SKIP5, and zma-miR394a-5p - F-box protein 6 combinations in the resistance-associated modules were considered important candidates for future functional studies.

Dietary aflatoxins exposure, environmental enteropathy, and their relation with childhood stunting

Childhood stunting is a global phenomenon affecting more than 149 million children under the age of 5 worldwide. Exposure to aflatoxins (AFs) in utero, during breastfeeding, and consumption of contaminated food affect the gut microbiome, resulting in intestinal dysfunction and potentially contributing to stunting. This review explores the potential relationship between AF exposure, environmental enteropathy and childhood stunting. AFs bind to DNA, disrupt protein synthesis and elicit environmental enteropathy (EE). An EE alters the structure of intestinal epithelial cells, impairs nutrient uptake and leads to malabsorption. This article proposes possible intervention strategies for researchers and policymakers to reduce AF exposure, EE and childhood stunting, such as exposure reduction, the implementation of good agricultural practices, dietary diversification and improving environmental water sanitation and hygiene.

Macrophage AHR-TLR4 cross-talk drives p-STAT3 (Ser727)-mediated mitochondrial oxidative stress and upregulates IDO/ICAM-1 in the steatohepatitis induced by aflatoxin B1

Aflatoxin B1 (AFB1) is a major mycotoxin contaminant showing in the environment and foods. In this study, the molecular initiating events (MIEs) of AFB1-induced steatohepatitis were explored in mice and human cell model. We observed dose-dependent steatohepatitis in the AFB1-treated mice, including triglyceride accumulation, fibrotic collagen secretion, enrichment of CD11b + and F4/80+ macrophages/Kupffer cells, cell death, lymphocytes clusters and remarkable atrophy areas. The gut barrier and gut-microbiota were also severely damaged after the AFB1 treatment and pre-conditioned colitis in the experimental mice aggravated the steatohepatitis phenotypes. We found that macrophages cells can be pro-inflammatorily activated to M1-like phenotype by AFB1 through an AHR/TLR4/p-STAT3 (Ser727)-mediated mitochondrial oxidative stress. The phenotypes can be rescued by AHR inhibitors in the mice model and human cell model. We further showed that this signaling axis is based on the cross-talk interaction between AHR and TLR4. Gene knock-up experiment found that the signaling is dependent on AFB1 ligand-binding with AHR, but not protein expressions of TLR4. The signaling elevated NLRP3 and two immune metabolic enzymes ICAM-1 and IDO that are associated with macrophage polarization. Results from intervention experiments with natural anti-oxidant and AHR inhibitor CH223191 suggest that the macrophage polarization may rely on AHR and ROS. Our study provides novel and critical references to the food safety and public health regulation of AFB1.

Bacillus licheniformis ameliorates Aflatoxin B1-induced testicular damage by improving the gut-metabolism-testis axis

Global aflatoxin B1 (AFB1) contamination is inevitable, and it can significantly damage testicular development. However, the current mechanism is confusing. Here, by integrating the transcriptome, microbiome, and serum metabolome, we comprehensively explain the impact of AFB1 on testis from the gut-metabolism-testis axis. Transcriptome analysis suggested that AFB1 exposure directly causes abnormalities in testicular inflammation-related signalling, such as tumor necrosis factor (TNF) pathway, and proliferation-related signalling pathways, such as phosphatidylinositide 3-kinases-protein kinase B (PI3K-AKT) pathway, which was verified by immunofluorescence. On the other hand, we found that upregulated inflammatory factors in the intestine after AFB1 exposure were associated with intestinal microbial dysbiosis, especially the enrichment of Bacilli, and enrichment analysis showed that this may be related to NLR family pyrin domain containing 3 (NLRP3)-mediated NOD-like receptor signalling. Also, AFB1 exposure caused blood metabolic disturbances, manifested as decreased hormone levels and increased oxidative stress. Significantly, B. licheniformis has remarkable AFB1 degradation efficiency (> 90%). B. licheniformis treatment is effective in attenuating gut-testis axis damage caused by AFB1 exposure through the above-mentioned signalling pathways. In conclusion, our findings indicate that AFB1 exposure disrupts testicular development through the gut-metabolism-testis axis, and B. licheniformis can effectively degrade AFB1.

Mass Spectrometry-Based Method to Measure Aflatoxin B1 DNA Adducts in Formalin-Fixed Paraffin-Embedded Tissues

Aflatoxin B1 (AFB1) is a potent human liver carcinogen produced by certain molds, particularly Aspergillus flavus and Aspergillus parasiticus, which contaminate peanuts, corn, rice, cottonseed, and ground and tree nuts, principally in warm and humid climates. AFB1 undergoes bioactivation in the liver to produce AFB1-exo-8,9-epoxide, which forms the covalently bound cationic AFB1-N7-guanine (AFB1-N7-Gua) DNA adduct. This adduct is unstable and undergoes base-catalyzed opening of the guanine imidazolium ring to form two ring-opened diastereomeric 8,9-dihydro-8-(2,6-diamino-4-oxo-3,4-dihydropyrimid-5-yl-formamido)-9-hydroxy-aflatoxin B1 (AFB1-FapyGua) adducts. The AFB1 formamidopyrimidine (Fapy) adducts induce G → T transversion mutations and are likely responsible for the carcinogenic effects of AFB1. Quantitative liquid chromatography-mass spectrometry (LC-MS) methods have shown that AFB1-N7-Gua is eliminated in rodent and human urine, whereas ring-opened AFB1-FapyGua adducts persist in rodent liver. However, fresh frozen biopsy tissues are seldom available for biomonitoring AFB1 DNA adducts in humans, impeding research advances in this potent liver carcinogen. In contrast, formalin-fixed paraffin-embedded (FFPE) specimens used for histopathological analysis are often accessible for molecular studies. However, ensuring nucleic acid quality presents a challenge due to incomplete reversal of formalin-mediated DNA cross-links, which can preclude accurate quantitative measurements of DNA adducts. In this study, employing ion trap or high-resolution accurate Orbitrap mass spectrometry, we demonstrate that ring-opened AFB1-FapyGua adducts formed in AFB1-exposed newborn mice are stable to the formalin fixation and DNA de-cross-linking retrieval processes. The AFB1-FapyGua adducts can be detected at levels comparable to those in a match of fresh frozen liver. Orbitrap MS2 measurements can detect AFB1-FapyGua at a quantification limit of 4.0 adducts per 108 bases when only 0.8 μg of DNA is assayed on the column. Thus, our breakthrough DNA retrieval technology can be adapted to screen for AFB1 DNA adducts in FFPE human liver specimens from cohorts at risk of this potent liver carcinogen.

The aflatoxin B1-induced imidazole ring-opened guanine adduct: High mutagenic potential that is minimally affected by sequence context

Dietary exposure to aflatoxin B1 (AFB1) is a recognized risk factor for developing hepatocellular carcinoma. The mutational signature of AFB1 is characterized by high-frequency base substitutions, predominantly G>T transversions, in a limited subset of trinucleotide sequences. The 8,9-dihydro-8-(2,6-diamino-4-oxo-3,4-dihydropyrimid-5-yl-formamido)-9-hydroxyaflatoxin B1 (AFB1-FapyGua) has been implicated as the primary DNA lesion responsible for AFB1-induced mutations. This study evaluated the mutagenic potential of AFB1-FapyGua in four sequence contexts, including hot- and cold-spot sequences as apparent in the mutational signature. Vectors containing site-specific AFB1-FapyGua lesions were replicated in primate cells and the products of replication were isolated and sequenced. Consistent with the role of AFB1-FapyGua in AFB1-induced mutagenesis, AFB1-FapyGua was highly mutagenic in all four sequence contexts, causing G>T transversions and other base substitutions at frequencies of ~80%-90%. These data suggest that the unique mutational signature of AFB1 is not explained by sequence-dependent fidelity of replication past AFB1-FapyGua lesions.

Frequencies and spectra of aflatoxin B1-induced mutations in liver genomes of NEIL1-deficient mice as revealed by duplex sequencing

Increased risk for the development of hepatocellular carcinoma (HCC) is driven by a number of etiological factors including hepatitis viral infection and dietary exposures to foods contaminated with aflatoxin-producing molds. Intracellular metabolic activation of aflatoxin B1 (AFB1) to a reactive epoxide generates highly mutagenic AFB1-Fapy-dG adducts. Previously, we demonstrated that repair of AFB1-Fapy-dG adducts can be initiated by the DNA glycosylase NEIL1 and that male Neil1-/- mice were significantly more susceptible to AFB1-induced HCC relative to wild-type mice. To investigate the mechanisms underlying this enhanced carcinogenesis, WT and Neil1-/- mice were challenged with a single, 4 mg/kg dose of AFB1 and frequencies and spectra of mutations were analyzed in liver DNAs 2.5 months post-injection using duplex sequencing. The analyses of DNAs from AFB1-challenged mice revealed highly elevated mutation frequencies in the nuclear genomes of both males and females, but not the mitochondrial genomes. In both WT and Neil1-/- mice, mutation spectra were highly similar to the AFB1-specific COSMIC signature SBS24. Relative to wild-type, the NEIL1 deficiency increased AFB1-induced mutagenesis with concomitant elevated HCCs in male Neil1-/- mice. Our data establish a critical role of NEIL1 in limiting AFB1-induced mutagenesis and ultimately carcinogenesis.

Integrated data from intravital imaging and HPLC-MS/MS analysis reveal large interspecies differences in AFB1 metabolism in mice and rats

Large interspecies differences between rats and mice concerning the hepatotoxicity and carcinogenicity of aflatoxin B1 (AFB1) are known, with mice being more resistant. However, a comprehensive interspecies comparison including subcellular liver tissue compartments has not yet been performed. In this study, we performed spatio-temporal intravital analysis of AFB1 kinetics in the livers of anesthetized mice and rats. This was supported by time-dependent analysis of the parent compound as well as metabolites and adducts in blood, urine, and bile of both species by HPLC-MS/MS. The integrated data from intravital imaging and HPLC-MS/MS analysis revealed major interspecies differences between rats and mice: (1) AFB1-associated fluorescence persisted much longer in the nuclei of rat than mouse hepatocytes; (2) in the sinusoidal blood, AFB1-associated fluorescence was rapidly cleared in mice, while a time-dependent increase was observed in rats in the first three hours after injection followed by a plateau that lasted until the end of the observation period of six hours; (3) this coincided with a far stronger increase of AFB1-lysine adducts in the blood of rats compared to mice; (4) the AFB1-guanine adduct was detected at much higher concentrations in bile and urine of rats than mice. In both species, the AFB1-glutathione conjugate was efficiently excreted via bile, where it reached concentrations at least three orders of magnitude higher compared to blood. In conclusion, major differences between mice and rats were observed, concerning the nuclear persistence, formation of AFB1-lysine adducts, and the AFB1-guanine adducts.

The Impact of Climate Change, Pollution, and Biodiversity Loss on Digestive Health and Disease

The environment is changing rapidly under pressure from 3 related drivers: climate change, pollution, and biodiversity loss. These environmental changes are affecting digestive health and disease in multiple ways. Heat extremes can cause intestinal and hepatic dysfunction. Access to adequate amounts of food of high nutritional content and to clean water is under threat. Extreme weather is associated with flooding and enteric infections and affects the delivery of care through infrastructure loss. Air, water, and soil pollution from chemicals and plastics are emerging as risk factors for a variety of intestinal diseases including eosinophilic esophagitis, metabolic dysfunction associated fatty liver disease, digestive tract cancers, inflammatory bowel disease, and functional bowel disease. Migration of populations to cities and between countries poses a special challenge to the delivery of digestive care. The response to the threat of environmental change is well underway in the global digestive health community, especially with regard to understanding and reducing the environmental impact of endoscopy. Individuals, and peer societies, are becoming more engaged, and have an important role to play in meeting the challenge.

Advancing Global Health Surveillance of Mycotoxin Exposures using Minimally Invasive Sampling Techniques: A State-of-the-Science Review

Mycotoxins are a heterogeneous group of toxins produced by fungi that can grow in staple crops (e.g., maize, cereals), resulting in health risks due to widespread exposure from human consumption and inhalation. Dried blood spot (DBS), dried serum spot (DSS), and volumetric tip microsampling (VTS) assays were developed and validated for several important mycotoxins. This review summarizes studies that have developed these assays to monitor mycotoxin exposures in human biological samples and highlights future directions to facilitate minimally invasive sampling techniques as global public health tools. A systematic search of PubMed (MEDLINE), Embase (Elsevier), and CINAHL (EBSCO) was conducted. Key assay performance metrics were extracted to provide a critical review of the available methods. This search identified 11 published reports related to measuring mycotoxins (ochratoxins, aflatoxins, and fumonisins) using DBS/DSS and VTS assays. Multimycotoxin assays adapted for DBS/DSS and VTS have undergone sufficient laboratory validation for applications in large-scale population health and human biomonitoring studies. Future work should expand the number of mycotoxins that can be measured in multimycotoxin assays, continue to improve multimycotoxin assay sensitivities of several biomarkers with low detection rates, and validate multimycotoxin assays across diverse populations with varying exposure levels. Validated low-cost and ultrasensitive minimally invasive sampling methods should be deployed in human biomonitoring and public health surveillance studies to guide policy interventions to reduce inequities in global mycotoxin exposures.

Mass Spectral Library for DNA Adductomics

Endogenous electrophiles, ionizing and non-ionizing radiation, and hazardous chemicals present in the environment and diet can damage DNA by forming covalent adducts. DNA adducts can form in critical cancer driver genes and, if not repaired, may induce mutations during cell division, potentially leading to the onset of cancer. The detection and quantification of specific DNA adducts are some of the first steps in studying their role in carcinogenesis, the physiological conditions that lead to their production, and the risk assessment of exposure to specific genotoxic chemicals. Hundreds of different DNA adducts have been reported in the literature, and there is a critical need to establish a DNA adduct mass spectral database to facilitate the detection of previously observed DNA adducts and characterize newly discovered DNA adducts. We have collected synthetic DNA adduct standards from the research community, acquired MSn (n = 2, 3) fragmentation spectra using Orbitrap and Quadrupole-Time-of-Flight (Q-TOF) MS instrumentation, processed the spectral data and incorporated it into the MassBank of North America (MoNA) database, and created a DNA adduct portal Web site (https://sites.google.com/umn.edu/dnaadductportal) to serve as a central location for the DNA adduct mass spectra and metadata, including the spectral database downloadable in different formats. This spectral library should prove to be a valuable resource for the DNA adductomics community, accelerating research and improving our understanding of the role of DNA adducts in disease.

Key Role of Porcine Cytochrome P450 2A19 in the Bioactivation of Aflatoxin B1 in the Liver

The metabolic transformation of aflatoxin B1 (AFB1) in pigs remains understudied, presenting a gap in our toxicological understanding compared with extensive human-based research. Here, we found that the main products of AFB1 in porcine liver microsomes (PLMs) were AFB1-8,9-epoxide (AFBO), the generation of which correlated strongly with the protein levels and activities of cytochrome P450 (CYP)3A and CYP2A. In addition, we found that porcine CYP2A19 can transform AFB1 into AFBO, and its metabolic activity was stronger than the other CYPs we have reported, including CYP1A2, CYP3A29, and CYP3A46. Furthermore, we stably transfected all identified CYPs in HepLi cells and found that CYP2A19 stable transfected HepLi cells showed more sensitivity in AFB1-induced DNA adducts, DNA damage, and γH2AX formation than the other three stable cell lines. Moreover, the CYP2A19 N297A mutant that lost catalytic activity toward AFB1 totally eliminated AFB1-induced AFB1-DNA adducts and γH2AX formations in CYP2A19 stable transfected HepLi cells. These results indicate that CYP2A19 mainly mediated AFB1-induced cytotoxicity through metabolizing AFB1 into a highly reactive AFBO, promoting DNA adduct formation and DNA damage, and lastly leading to cell death. This study advances the current understanding of AFB1 bioactivation in pigs and provides a promising target to reduce porcine aflatoxicosis.

Aflatoxin B1 induces infertility, fetal deformities, and potential therapies

Aflatoxin B1 (AFB1) is a subsidiary poisonous metabolite, archetypally spawned by Aspergillus flavus and A. parasiticus, which are often isolated in warm or tropical countries across the world. AFB1 is capable of disrupting the functioning of several reproductive endocrine glands by interrupting the enzymes and their substrates that are liable for the synthesis of various hormones in both males and females. In men, AFB1 is capable of hindering testicular development, testicular degeneration, and reduces reproductive capabilities. In women, a direct antagonistic interaction of AFB1 with steroid hormone receptors influencing gonadal hormone production of estrogen and progesterone was responsible for AFB1-associated infertility. AFB1 is potentially teratogenic and is responsible for the development of malformation in humans and animals. Soft-tissue anomalies such as internal hydrocephalus, microphthalmia, cardiac defects, augmented liver lobes, reproductive changes, immune modifications, behavioral changes and predisposition of animals and humans to neoplasm development are AFB1-associated anomalies. Substances such as esculin, selenium, gynandra extract, vitamins C and E, oltipraz, and CDDO-Im are potential therapies for AFB1. Thus, this review elucidates the pivotal pathogenic roles of AFB1 in infertility, fetal deformities, and potential therapies because AFB1 toxicity is a key problem globally.

Aflatoxin M1 Analysis in Urine of Mill Workers in Bangladesh: A Pilot Study

Presence of aflatoxin B1 (AFB1) in food and feed is a serious problem, especially in developing countries. Human exposure to this carcinogenic mycotoxin can occur through dietary intake, but also through inhalation or dermal contact when handling and processing AFB1-contaminated crops. A suitable biomarker of AFB1 exposure by all routes is the occurrence of its hydroxylated metabolite aflatoxin M1 (AFM1) in urine. To assess mycotoxin exposure in mill workers in Bangladesh, we analyzed AFM1 levels in urine samples of this population group who may encounter both dietary and occupational AFB1 exposure. In this pilot study, a total of 76 participants (51 mill workers and 25 controls) were enrolled from the Sylhet region of Bangladesh. Urine samples were collected from people who worked in rice, wheat, maize and spice mills and from controls with no occupational contact to these materials. A questionnaire was used to collect information on basic characteristics and normal food habits of all participants. Levels of AFM1 in the urine samples were determined by a competitive enzyme linked immunosorbent assay. AFM1 was detected in 96.1% of mill workers' urine samples with a range of LOD (40) of 217.7 pg/mL and also in 92% of control subject's urine samples with a range of LOD of 307.0 pg/mL). The mean level of AFM1 in mill workers' urine (106.5 ± 35.0 pg/mL) was slightly lower than that of the control group (123.3 ± 52.4 pg/mL), whilst the mean AFM1 urinary level adjusted for creatinine was higher in mill workers (142.1 ± 126.1 pg/mg crea) than in the control group (98.5 ± 71.2 pg/mg crea). Yet, these differences in biomarker levels were not statistically significant. Slightly different mean urinary AFM1 levels were observed between maize mill, spice mill, rice mill, and wheat mill workers, yet biomarker values are based on a small number of individuals in these subgroups. No significant correlations were found between the study subjects' urine AFM1 levels and their consumption of some staple food items, except for a significant correlation observed between urinary biomarker levels and consumption of groundnuts. In conclusion, this pilot study revealed the frequent presence of AFM1 in the urine of mill workers in Bangladesh and those of concurrent controls with dietary AFB1 exposure only. The absence of a statistical difference in mean biomarker levels for workers and controls suggests that in the specific setting, no extra occupational exposure occurred. Yet, the high prevalence of non-negligible AFM1 levels in the collected urines encourage further studies in Bangladesh regarding aflatoxin exposure.

Antioxidant, anti-inflammatory, and anti-apoptotic effects of genkwanin against aflatoxin B1-induced testicular toxicity

Aflatoxin B1 (AFB1) is the most hazardous aflatoxin that causes significant damage to the male reproductive system. Genkwanin (GNK) is a bioactive flavonoid that shows antioxidant and anti-inflammatory potential. Therefore, the current study was planned to evaluate the effects of GNK against AFB1-induced testicular toxicity. Forty-eight male rats were distributed into four groups (n = 12 rats). AFB1 (50 μg/kg) and GNK (20 mg/kg) were administered to the rats for eight weeks. Results of the current study revealed that AFB1 exposure induced adverse effects on the Nrf2/Keap1 pathway and reduced the expressions and activities of antioxidant enzymes. Additionally, it increased the levels of oxidative stress markers. Furthermore, expressions of steroidogenic enzymes were down-regulated by AFB1 intoxication. Besides, AFB1 exposure reduced the levels of gonadotropins and plasma testosterone, which subsequently reduced the epididymal sperm count, motility, and hypo-osmotic swelled (HOS) sperms, while increasing the number of dead sperms and causing morphological anomalies of the head, midpiece, and tail of the sperms. In addition, AFB1 decreased the activities of testicular function marker enzymes and the levels of inflammatory markers. Moreover, it severely affected the apoptotic profile by up-regulating the expressions of Bax and Casp3, while down-regulating the Bcl2 expression. Besides, AFB1 significantly damaged the histoarchitecture of testicular tissues. However, GNK treatment reversed all the AFB1-induced damages in the rats. Taken together, the current study reports the potential use of GNK as a therapeutic agent to prevent AFB1-induced testicular toxicity due to its antioxidant, anti-inflammatory, and anti-apoptotic properties.