Effects of chlorophyll and chlorophyllin on low-dose aflatoxin B(1) pharmacokinetics in human volunteers

Application of EFSA EU menu database and R computing language to calculate the green chlorophyll intake in the European population

The growing evidence of the health benefits of chlorophyll pigments and the claims that could arise from industry and academia require data on their common dietary intakes. This study presents data on the chronic intake of green chlorophyll in 23 European countries using standardised methodologies to manage food consumption data within the EU Menu methodology. A mean intake of 207.12 mg of green chlorophylls/(d × person) for the adult population was calculated, considering significant covariates. The hierarchical cluster and partial least squares discriminant analysis (PLS-DA) techniques were applied to analyse intake disparities by region and age groups, identifying common food sources of green chlorophylls, such as olive oil, kale, and spinach. This paper presents a modern mathematical approach for obtaining novel information from existing databases of food composition data. Future challenges include building a comprehensive chlorophyll composition database for foods and extending the estimation to non-green chlorophyll pigments and metallo-chlorophyll food colourants.

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.

Impact of phenanthrene co-administration on the toxicokinetics of benzo[a]pyrene in humans. UPLC-accelerator mass spectrometry following oral microdosing

Current risk assessments for environmental carcinogens rely on animal studies utilizing doses orders of magnitude higher than actual human exposures. Epidemiological studies of people with high exposures (e.g., occupational) are of value, but rely on uncertain exposure data. In addition, exposures are typically not to a single chemical but to mixtures, such as polycyclic aromatic hydrocarbons (PAHs). The extremely high sensitivity of accelerator mass spectrometry (AMS) allows for dosing humans with known carcinogens with de minimus risk. In this study UPLC-AMS was used to assess the toxicokinetics of [14C]-benzo[a]pyrene ([14C]-BaP) when dosed alone or in a binary mixture with phenanthrene (Phe). Plasma was collected for 48 h following a dose of [14C]-BaP (50 ng, 5.4 nCi) or the same dose of [14C]-BaP plus Phe (1250 ng). Following the binary mixture, Cmax of [14C]-BaP significantly decreased (4.4-fold) whereas the volume of distribution (Vd) increased (2-fold). Further, the toxicokinetics of twelve [14C]-BaP metabolites provided evidence of little change in the metabolite profile of [14C]-BaP and the pattern was overall reduction consistent with reduced absorption (decrease in Cmax). Although Phe was shown to be a competitive inhibitor of the major hepatic cytochrome P-450 (CYP) responsible for metabolism of [14C]-BaP, CYP1A2, the high inhibition constant (Ki) and lack of any increase in unmetabolized [14C]-BaP in plasma makes this mechanism unlikely to be responsible. Rather, co-administration of Phe reduces the absorption of [14C]-BaP through a mechanism yet to be determined. This is the first study to provide evidence that, at actual environmental levels of exposure, the toxicokinetics of [14C]-BaP in humans is markedly altered by the presence of a second PAH, Phe, a common component of environmental PAH mixtures.

Research update on aflatoxins toxicity, metabolism, distribution, and detection: A concise overview

Serious health risks associated with the consumption of food products contaminated with aflatoxins (AFs) are worldwide recognized and depend predominantly on consumed AF concentration by diet. A low concentration of aflatoxins in cereals and related food commodities is unavoidable, especially in subtropic and tropic regions. Accordingly, risk assessment guidelines established by regulatory bodies in different countries help in the prevention of aflatoxin intoxication and the protection of public health. By assessing the maximal levels of aflatoxins in food products which are a potential risk to human health, it's possible to establish appropriate risk management strategies. Regarding, a few factors are crucial for making a rational risk management decision, such as toxicological profile, adequate information concerning the exposure duration, availability of routine and some novel analytical techniques, socioeconomic factors, food intake patterns, and maximal allowed levels of each aflatoxin in different food products which may be varied between countries.

Building a Human Physiologically Based Pharmacokinetic Model for Aflatoxin B1 to Simulate Interactions with Drugs

Mycotoxins such as aflatoxin B1 (AFB1) are secondary fungal metabolites present in food commodities and part of one’s daily exposure, especially in certain regions, e.g., sub-Saharan Africa. AFB1 is mostly metabolised by cytochrome P450 (CYP) enzymes, namely, CYP1A2 and CYP3A4. As a consequence of chronic exposure, it is interesting to check for interactions with drugs taken concomitantly. A physiologically based pharmacokinetic (PBPK) model was developed based on the literature and in-house-generated in vitro data to characterise the pharmacokinetics (PK) of AFB1. The substrate file was used in different populations (Chinese, North European Caucasian and Black South African), provided by SimCYP® software (v21), to evaluate the impact of populations on AFB1 PK. The model’s performance was verified against published human in vivo PK parameters, with AUC ratios and Cmax ratios being within the 0.5–2.0-fold range. Effects on AFB1 PK were observed with commonly prescribed drugs in South Africa, leading to clearance ratios of 0.54 to 4.13. The simulations revealed that CYP3A4/CYP1A2 inducer/inhibitor drugs might have an impact on AFB1 metabolism, altering exposure to carcinogenic metabolites. AFB1 did not have effects on the PK of drugs at representative exposure concentrations. Therefore, chronic AFB1 exposure is unlikely to impact the PK of drugs taken concomitantly.

Benzo[a]pyrene toxicokinetics in humans following dietary supplementation with 3,3'-diindolylmethane (DIM) or Brussels sprouts

Utilizing the atto-zeptomole sensitivity of UPLC-accelerator mass spectrometry (UPLC-AMS), we previously demonstrated significant first-pass metabolism following escalating (25-250 ng) oral micro-dosing in humans of [14C]-benzo[a]pyrene ([14C]-BaP). The present study examines the potential for supplementation with Brussels sprouts (BS) or 3,3'-diindolylmethane (DIM) to alter plasma levels of [14C]-BaP and metabolites over a 48-h period following micro-dosing with 50 ng (5.4 nCi) [14C]-BaP. Volunteers were dosed with [14C]-BaP following fourteen days on a cruciferous vegetable restricted diet, or the same diet supplemented for seven days with 50 g of BS or 300 mg of BR-DIM® prior to dosing. BS or DIM reduced total [14C] recovered from plasma by 56-67% relative to non-intervention. Dietary supplementation with DIM markedly increased Tmax and reduced Cmax for [14C]-BaP indicative of slower absorption. Both dietary treatments significantly reduced Cmax values of four downstream BaP metabolites, consistent with delaying BaP absorption. Dietary treatments also appeared to reduce the T1/2 and the plasma AUC(0,∞) for Unknown Metabolite C, indicating some effect in accelerating clearance of this metabolite. Toxicokinetic constants for other metabolites followed the pattern for [14C]-BaP (metabolite profiles remained relatively consistent) and non-compartmental analysis did not indicate other significant alterations. Significant amounts of metabolites in plasma were at the bay region of [14C]-BaP irrespective of treatment. Although the number of subjects and large interindividual variation are limitations of this study, it represents the first human trial showing dietary intervention altering toxicokinetics of a defined dose of a known human carcinogen.

HPLC–MS/MS method for the simultaneous determination of aflatoxins in blood: toxicokinetics of aflatoxin B1 and aflatoxin M1 in rats

Mycotoxins are highly toxic fungal metabolites that can pose health threats to humans and animals. Aflatoxins are a type of mycotoxin produced mainly by Aspergillus flavus and A. parasiticus. A sensitive high performance liquid chromatography–tandem mass spectrometry (HPLC–MS/MS) method with multiple reaction monitoring (MRM) modes was developed for the determination of aflatoxins in blood after acetonitrile precipitation extraction. The limits of quantification of aflatoxins ranged from 0.05 to 0.2 ng/mL. Intra-day accuracy ranged from 92 to 111.0%, and intra-day precision (n = 6) ranged from 1 to 8%. Inter-day accuracy and precision were 94.0–102.0% and 2.0–8.0%, respectively. The toxicokinetics of AFB1 and its metabolite AFM1 after a single oral administration (AFB1 1 mg/kg body weight) were studied in male Sprague–Dawley rats. The blood AFB1 and AFM1 profiles could be adequately described by a noncompartmental model. The highest concentration of AFB1 (Cmax 93.42 ± 23.01 ng/mL) was observed with Tmax at 0.15 ± 0.034 h. AFB1 was rapidly metabolized to AFM1 which reached its peak blood concentration (Cmax 53.86 ± 12.12 ng/mL) at 0.33 ± 0.11 h. The HPLC–MS/MS method was simple and sensitive, appropriate for studying the in vivo toxicokinetics of aflatoxins.

Unravelling the pharmacokinetics of aflatoxin B1: In vitro determination of Michaelis–Menten constants, intrinsic clearance and the metabolic contribution of CYP1A2 and CYP3A4 in pooled human liver microsomes

Mycotoxins, fungal secondary metabolites, are ubiquitously present in food commodities. Acute exposure to high levels or chronic exposure to low levels has an impact on the human body. The phase I metabolism in the human liver, performed by cytochrome P450 (CYP450) enzymes, is accountable for more than 80% of the overall metabolism of exogenous and endogenous compounds. Mycotoxins are (partially) metabolized by CYP450 enzymes. In this study, in vitro research was performed on CYP450 probes and aflatoxin B1 (AFB1), a carcinogenic mycotoxin, to obtain pharmacokinetic data on AFB1, required for further experimental work. The CYP450 probes of choice were a CYP3A4 substrate, midazolam (MDZ) and a CYP1A2 substrate, phenacetin (PH) since these are the main metabolizing phase I enzymes of AFB1. Linearity experiments were performed on the three substrates indicating that linear conditions were achieved at a microsomal protein concentration and incubation time of 0.25 mg/ml and 5 min, 0.50 mg/ml and 20 min and 0.25 mg/ml and 5 min for MDZ, PH and AFB1, respectively. The K_m was determined in human liver microsomes and was estimated at 2.15 μM for MDZ, 40.0 μM for PH and 40.9 μM for AFB1. The associated V_max values were 956 pmol/(mg.min) (MDZ), 856 pmol/(mg.min) (PH) and 11,536 pmol/(mg.min) (AFB1). Recombinant CYP systems were used to determine CYP450-specific Michaelis–Menten values for AFB1, leading to a CYP3A4 K_m of 49.6 μM and an intersystem extrapolation factor (ISEF) corrected V_max of 43.6 pmol/min/pmol P450 and a CYP1A2 K_m of 58.2 μM and an ISEF corrected V_max of 283 pmol/min/pmol P450. An activity adjustment factor (AAF) was calculated to account for differences between microsome batches and was used as a correction factor in the determination of the human in vivo hepatic clearance for MDZ, PH and AFB1. The hepatic blood clearance corrected for the AAF CL_H,B,MDZ,AAF, CL_H,B,PH,AAF CL_{H,B,AFB1,AAF(CYP3A4)} and CL_{H,B,AFB1,AAF(CYP1A2)} were determined in HLM at 44.1 L/h, 21.7 L/h, 40.0 L/h and 38.5 L/h. Finally, inhibition assays in HLM showed that 45% of the AFB1 metabolism was performed by CYP3A4/3A5 enzymes and 49% by CYP1A2 enzymes.

Development and characterization of chlorophyll-amended montmorillonite clays for the adsorption and detoxification of benzene

After disasters, such as forest fires and oil spills, high levels of benzene (> 1 ppm) can be detected in the water, soil, and air surrounding the disaster site, which poses a significant health risk to human, animal, and plant populations in the area. While remediation methods with activated carbons have been employed, these strategies are limited in their effectiveness due to benzene's inherent stability and limited retention to most surfaces. To address this problem, calcium and sodium montmorillonite clays were amended with a mixture of chlorophyll (a) and (b); their binding profile and ability to detoxify benzene were characterized using in vitro, in silico, and well-established ecotoxicological (ecotox) bioassay methods. The results of in vitro isothermal analyses indicated that chlorophyll-amended clays showed an improved binding profile in terms of an increased binding affinity (Kf = 668 vs 67), increased binding percentage (52% vs 11%), and decreased rates of desorption (28% vs 100%), compared to the parent clay. In silico simulation studies elucidated the adsorption mechanism and validated that the addition of the chlorophyll to the clays increased the adsorption of benzene through Van der Waals forces (i.e., aromatic π-π stacking and alkyl-π interactions). The sorbents were also assessed for their safety and ability to protect sensitive ecotox organisms (Lemna minor and Caenorhabditis elegans) from the toxicity of benzene. The inclusion of chlorophyll-amended clays in the culture medium significantly reduced benzene toxicity to both organisms, protecting C. elegans by 98-100% from benzene-induced mortality and enhancing the growth rates of L. minor. Isothermal analyses, in silico modeling, and independent bioassays all validated our proof of concept that benzene can be sequestered, tightly bound, and stabilized by chlorophyll-amended montmorillonite clays. These novel sorbents can be utilized during disasters and emergencies to decrease unintentional exposures from contaminated water, soil, and air.

The Ability of Chlorophyll to Trap Carcinogen Aflatoxin B1: A Theoretical Approach

The coordination of one and two aflatoxin B1 (AFB1, a potent carcinogen) molecules with chlorophyll a (chl a) was studied at a theoretical level. Calculations were performed using the M06-2X method in conjunction with the 6-311G(d,p) basis set, in both gas and water phases. The molecular electrostatic potential map shows the chemical activity of various sites of the AFB1 and chl a molecules. The energy difference between molecular orbitals of AFB1 and chl a allowed for the establishment of an intermolecular interaction. A charge transfer from AFB1 to the central cation of chl a was shown. The energies of the optimized structures for chl a show two configurations, unfolded and folded, with a difference of 15.41 kcal/mol. Chl a appeared axially coordinated to the plane (α-down or β-up) of the porphyrin moiety, either with the oxygen atom of the ketonic group, or with the oxygen atom of the lactone moiety of AFB1. The complexes of maximum stability were chl a 1-α-E-AFB1 and chl a 2-β-E-AFB1, at -36.4 and -39.2 kcal/mol, respectively. Additionally, with two AFB1 molecules were chl a 1-D-2AFB1 and chl a 2-E-2AFB1, at -60.0 and -64.8 kcal/mol, respectively. Finally, biosorbents containing chlorophyll could improve AFB1 adsorption.

Effects of Chlorophyll a and b in Reducing Genotoxicity of 2-Amino-3,8-dimethylimidazo[4,5-F]quinoxaline (MeIQx)

In this study, the protective effects of chlorophyll a and chlorophyll b (0.5 and 1 µM) against the heterocyclic amine compound 2-amino-3,8-dimethylimidazo[4,5-f]quinoxaline (MeIQx, 4.69 µM, 9.38 µM, 23.45 µM) with somatic mutation and recombination test in Drosophila melanogaster are investigated. Chronic applications are performed to transheterozygous larvae with respect to two recessive genes, mwh (multiple wing hair) and flr3 (flare), by using Drosophila strains. The genotoxic effects of MeIQx are primarily determined for third instars larvae. In antigenotoxicity studies, two different application groups are constituted. While for the first group doses of chlorophyll a, b, and MeIQx are given to the third instars larvae simultaneously, for the second group doses of MeIQx are applied at the third instars after doses of chlorophyll a and b are given to at the second instars larvae. Chlorophyll a and b are effective in reducing genotoxic effects of MeIQx by both applications on individuals and it is observed that the pretreatment method is much more effective than the simultaneous one. There are similar results for chlorophyll a and b in efficacy.

Dietary spinach reshapes the gut microbiome in an Apc-mutant genetic background: mechanistic insights from integrated multi-omics

Complex interrelationships govern the dynamic interactions between gut microbes, the host, and exogenous drivers of disease outcome. A multi-omics approach to cancer prevention by spinach (SPI) was pursued for the first time in the polyposis in rat colon (Pirc) model. SPI fed for 26 weeks (10% w/w, freeze-dried in the diet) exhibited significant antitumor efficacy and, in the Apc-mutant genetic background, β-catenin remained highly overexpressed in adenomatous polyps. However, in both wild type and Apc-mutant rats, increased gut microbiome diversity after SPI consumption coincided with reversal of taxonomic composition. Metagenomic prediction implicated linoleate and butanoate metabolism, tricarboxylic acid cycle, and pathways in cancer, which was supported by transcriptomic and metabolomic analyses. Thus, tumor suppression by SPI involved marked reshaping of the gut microbiome along with changes in host RNA-miRNA networks. When colon polyps were compared with matched normal-looking tissues via metabolomics, anticancer outcomes were linked to SPI-derived linoleate bioactives with known anti-inflammatory/ proapoptotic mechanisms, as well as N-aceto-2-hydroxybutanoate, consistent with altered butanoate metabolism stemming from increased α-diversity of the gut microbiome. In colon tumors from SPI-fed rats, L-glutamate and N-acetylneuraminate also were reduced, implicating altered mitochondrial energetics and cell surface glycans involved in oncogenic signaling networks and immune evasion. In conclusion, a multi-omics approach to cancer prevention by SPI provided mechanistic support for linoleate and butanoate metabolism, as well as tumor-associated changes in L-glutamate and N-acetylneuraminate. Additional factors, such as the fiber content, also warrant further investigation with a view to delaying colectomy and drug intervention in at-risk patients.

Potential of Kale and Lettuce Residues as Natural Adsorbents of the Carcinogen Aflatoxin B1 in a Dynamic Gastrointestinal Tract-Simulated Model

Adsorption of the carcinogen aflatoxin B1 (AFB1) onto agro-waste-based materials is a promising alternative over conventional inorganic binders. In the current study, two unmodified adsorbents were eco-friendly prepared from kale and lettuce agro-wastes. A dynamic gastrointestinal tract-simulated model was utilized to evaluate the removal efficiency of the sorptive materials (0.5%, w/w) when added to an AFB1-contaminated diet (100 µg AFB1/kg). Different characterization methodologies were employed to understand the interaction mechanisms between the AFB1 molecule and the biosorbents. Based on adsorption results, the biosorbent prepared from kale was the best; its maximum adsorption capacity was 93.6%, which was significantly higher than that of the lettuce biosorbent (83.7%). Characterization results indicate that different mechanisms may act simultaneously during adsorption. Non-electrostatic (hydrophobic interactions, dipole-dipole interactions, and hydrogen bonding) and electrostatic interactions (ionic attractions) together with the formation of AFB1-chlorophyll complexes appear to be the major influencing factors driving AFB1 biosorption.

A one-pot ring-closure and ring-opening sequence for the cascade synthesis of dihydrofurofurans and functionalized furans

We have developed a simple novel ring-closure and ring-opening pathway using an organo-base system for the synthesis of highly substituted dihydrofurofuran and furan frameworks via a triethylamine-catalyzed one-pot three-component reaction. The protocol involved a Knoevenagel and Michael adduct via Paal-Knorr cyclization with aromatic/aliphatic glyoxal and 2-cyanoacetophenone under mild and heating conditions with excellent yields through a simple filtration method. The merits of this methodology, including the use of easily available feedstocks and an inexpensive catalyst, Gram-scale synthesis, wide functional group tolerance, an open-air reaction setup, and no need for workup and column-chromatography procedures, make the developed methodology a practical way to access dihydrofurofurans and functionalized furans.

Light-Activated Biomedical Applications of Chlorophyll Derivatives

Tetrapyrroles are the basis of essential physiological functions in most living organisms. These compounds represent the basic scaffold of porphyrins, chlorophylls, and bacteriochlorophylls, among others. Chlorophyll derivatives, obtained by the natural or artificial degradation of chlorophylls, present unique properties, holding great potential in the scientific and medical fields. Indeed, they can act as cancer-preventing agents, antimutagens, apoptosis inducers, efficient antioxidants, as well as antimicrobial and immunomodulatory molecules. Moreover, thanks to their peculiar optical properties, they can be exploited as photosensitizers for photodynamic therapy and as vision enhancers. Most of these molecules, however, are highly hydrophobic and poorly soluble in biological fluids, and may display undesired toxicity due to accumulation in healthy tissues. The advent of nanomedicine has prompted the development of nanoparticles acting as carriers for chlorophyll derivatives, facilitating their targeted administration with demonstrated applicability in diagnosis and therapy. In this review, the chemical and physical properties of chlorophyll derivatives that justify their usage in the biomedical field, with particular regard to light-activated dynamics are described. Their role as antioxidants and photoactive agents are discussed, introducing the most recent nanomedical applications and focusing on inorganic and organic nanocarriers exploited in vitro and in vivo.

Subcellular spatio-temporal intravital kinetics of aflatoxin B1 and ochratoxin A in liver and kidney

Local accumulation of xenobiotics in human and animal tissues may cause adverse effects. Large differences in their concentrations may exist between individual cell types, often due to the expression of specific uptake and export carriers. Here we established a two-photon microscopy-based technique for spatio-temporal detection of the distribution of mycotoxins in intact kidneys and livers of anesthetized mice with subcellular resolution. The mycotoxins ochratoxin A (OTA, 10 mg/kg b.w.) and aflatoxin B1 (AFB1, 1.5 mg/kg b.w.), which both show blue auto-fluorescence, were analyzed after intravenous bolus injections. Within seconds after administration, OTA was filtered by glomeruli, and enriched in distal tubular epithelial cells (dTEC). A striking feature of AFB1 toxicokinetics was its very rapid uptake from sinusoidal blood into hepatocytes (t1/2 ~ 4 min) and excretion into bile canaliculi. Interestingly, AFB1 was enriched in the nuclei of hepatocytes with zonal differences in clearance. In the cytoplasm of pericentral hepatocytes, the half-life (t1/2~ 63 min) was much longer compared to periportal hepatocytes of the same lobules (t1/2 ~ 9 min). In addition, nuclear AFB1 from periportal hepatocytes cleared faster compared to the pericentral region. These local differences in AFB1 clearance may be due to the pericentral expression of cytochrome P450 enzymes that activate AFB1 to protein- and DNA-binding metabolites. In conclusion, the present study shows that large spatio-temporal concentration differences exist within the same tissues and its analysis may provide valuable additional information to conventional toxicokinetic studies.

Ability of low contents of biosorbents to bind the food carcinogen aflatoxin B1in vitro

In vitro experiments were conducted to evaluate the effectiveness of two new biosorbents (lettuce and field horsetail) in removing aflatoxin B1 (AFB1). Formosa firethorn was used as reference material. The adsorption of AFB1 (190 ng/mL) was investigated at two sorbent contents (0.5% and 0.1% w/v) and three pHs (2, 5, and 7). Batch experiments were performed at 40 °C for 2 h. Several methodologies were used to characterize the nature of the biosorbent-AFB1 interaction. In general, when using biosorbents at 0.5% w/v, AFB1 was well adsorbed by the three tested biomaterials (70 to 100%). Furthermore, with the lowest biosorbent content (0.1% w/v), significant AFB1 adsorption efficiencies were attained at pH 5 (33 to 50%). Nevertheless, at pH 7, lettuce showed the highest ability against AFB1 removal (95%). Further characterization of the AFB1-loaded biosorbents demonstrated that chemical and physical mechanisms were involved in the adsorption process.

Implementing a risk-risk analysis framework to evaluate the impact of food intake shifts on risk of illness: a case study with infant cereal

In food safety, process pathway risk assessments usually estimate the risk of illness from a single hazard and a single food and can inform food safety decisions and consumer advice. To evaluate the health impact of a potential change in diet, we need to understand not only the risk posed by the considered hazard and food but also the risk posed by the substitution food and other potential hazards. We developed a framework to provide decision-makers with a multi-faceted evaluation of the impact of dietary shifts on risk of illness. Our case study explored exposure to inorganic arsenic (iAs) and aflatoxins through consumption of infant cereals and the risk of developing lung, bladder and liver cancer over a lifetime. The estimated additional Disability-Adjusted Life Year (DALY) in the U.S. from exposure to iAs and aflatoxin based on available contamination and consumption patterns of infant rice and oat cereal is 4,921 (CI 90% 414; 9,071). If all infant cereal consumers shift intake (maintaining equivalent serving size and frequency) to only consuming infant rice cereal, the predicted DALY increases to 6,942 (CI 90% 326; 12,931). If all infant cereal consumers shift intake to only consuming infant oat cereal, the predicted DALY decreases to 1,513 (CI 90% 312; 3,356). Changes in contaminant concentrations or percent consumers, that could occur in the future, also significantly impact the predicted risk. Uncertainty in these risk predictions is primarily driven by the dose-response models. A risk-risk analysis framework provides decision-makers with a nuanced understanding of the public health impact of dietary changes and can be applied to other food safety and nutrition questions.

Cancer interception by interceptor molecules: mechanistic, preclinical and human translational studies with chlorophylls

Before 'cancer interception' was first advocated, 'interceptor molecules' had been conceived as a sub-category of preventive agents that interfered with the earliest initiation steps in carcinogenesis. Three decades ago, a seminal review cataloged over fifty synthetic agents and natural products that were known or putative interceptor molecules. Chlorophylls and their derivatives garnered much interest based on the potent antimutagenic activity in the Salmonella assay, and the subsequent mechanistic work that provided proof-of-concept for direct molecular complexes with planar aromatic carcinogens. As the 'interceptor molecule' hypothesis evolved, mechanistic experiments and preclinical studies supported the view that chlorophylls can interact with environmental heterocyclic amines, aflatoxins, and polycyclic aromatic hydrocarbons to limit their uptake and bioavailability in vivo. Support also came from human translational studies involving ultralow dose detection in healthy volunteers, as well as intervention in at-risk subjects. Antimutagenic and antigenotoxic effects of natural and synthetic chlorophylls against small alkylating agents also highlighted the fact that non-interceptor mechanisms existed. This gave impetus to investigations broadly related to free radical scavenging, anti-inflammatory effects, immune modulation and photodynamic therapy. Therapeutic aspects of chlorophylls also were investigated, with evidence for cell cycle arrest and apoptosis in human cancer cells. As the science has evolved, new mechanistic leads continue to support the use and development of chlorophylls and their porphyrin derivatives for cancer interception, beyond the initial interest as interceptor molecules.

Stability of Chlorophyll a Monomer Incorporated into Cremophor EL Nano-Micelles under Dark and Moderate Light Conditions

In this paper, stability of chlorophyll a monomers encapsulated into the Cremophor EL nano-micelles was studied under dark and moderate light conditions, typical of a room with natural or artificial lighting, in the presence of oxygen. The pigment stability against visible light was determined using the dynamic light scattering and molecular spectroscopy (UV-Vis absorption and stationary fluorescence) methods. Chlorophyll a, at the molar concentration of 10-5 M, was dissolved in the 5 wt% Cremophor emulsion for comparison in the ethanolic solution. The stability of such a self-assembly pigment-detergent nano-system is important in the light of its application on the commercial-scale. The presented results indicate the high stability of the pigment monomeric molecular organization in the nano-emulsion. During the storage in the dark, the half-lifetime was calculated as about 7 months. Additionally, based on the shape of absorption and fluorescence emission spectra, chlorophyll aggregation in the Cremophor EL aqueous solution along with the time was excluded. Moreover, the average size of detergent micelles as chlorophyll carriers was not affected after 70 days of the nano-system storage. Pigment stability against the moderate white light (0.1 mW) did not differ significantly from storage conditions in the dark. The photooxidation products, detected by occurrence of new absorption and fluorescence emission bands, was estimated on the negligible level. The stability of such a self-assembly pigment-detergent nano-system would potentially broaden the field of chlorophyll a (chl a) application in the food industry, medicine or artificial photosynthesis models.

In vivo AFB1 detoxification by Lactobacillus fermentum LC5/a with chlorophyll and immunopotentiating activity in albino mice

The potential Aflatoxin B₁ (AFB₁) binding Lactobacillus fermentum (LC5/a) was used for in vivo AFB₁ binding and detoxification in presence of chlorophyll (CL) in male Swiss albino mice. Mice were randomly divided into seven groups. The control groups (CL, AFB₁ and LC5/a) received chlorophyll (250 μg/kg b.w), AFB₁ (100 μg/kg b.w) and LC5/a (1 × 10⁸ CFU) for 21 days. The treatment group (AFB₁+LC5/a) received 100 μl of lyophilized bacterial suspension (1 × 10⁸ CFU) 2 h before the AFB₁ dosage (100μg/kg b.w). The chlorophyll mice group (CL + AFB₁) was given single oral dose of CL (250 μg/kg b.w) before AFB₁ dosage and last mice group received the combination of CL + LC5/a before the AFB₁ dosage over a period of 21 days. Ballooning of cytoplasm and necrosis in liver was evident in histopathological examination of AFB₁ mice group, while, marked improvement and nearly normal histology were seen in LC5/a and CL treated mice group. The levels of AST, ALT, GST, and SOD were increased in AFB₁ mice group compared to LC5/a and CL treated mice group. Elevated levels of pro-inflammatory cytokines, TNF-α, IL-12, IL-6 (324, 506, 117.25 pg/ml) were observed in AFB₁ treated mice serum compared to LC5/a and CL treated mice (249.54, 322.01 and 82.35 pg/ml). Thus, Lactobacillus fermentum LC5/a has certainly sequestered AFB₁ from gastrointestinal tract besides regulating the production of pro-inflammatory cytokines.

Predicting the Acute Liver Toxicity of Aflatoxin B1 in Rats and Humans by an In Vitro-In Silico Testing Strategy

SCOPE

High-level exposure to aflatoxin B1 (AFB1) is known to cause acute liver damage and fatality in animals and humans. The intakes actually causing this acute toxicity have so far been estimated based on AFB1 levels in contaminated foods or biomarkers in serum. The aim of the present study is to predict the doses causing acute liver toxicity of AFB1 in rats and humans by an in vitro-in silico testing strategy.

METHODS AND RESULTS

Physiologically based kinetic (PBK) models for AFB1 in rats and humans are developed. The models are used to translate in vitro concentration-response curves for cytotoxicity in primary rat and human hepatocytes to in vivo dose-response curves using reverse dosimetry. From these data, the dose levels at which toxicity would be expected are obtained and compared to toxic dose levels from available rat and human case studies on AFB1 toxicity. The results show that the in vitro-in silico testing strategy can predict dose levels causing acute toxicity of AFB1 in rats and human.

CONCLUSIONS

Quantitative in vitro in vivo extrapolation (QIVIVE) using PBK modeling-based reverse dosimetry can predict AFB1 doses that cause acute liver toxicity in rats and human.

Diet and Dermatology: The Role of a Whole-food, Plant-based Diet in Preventing and Reversing Skin Aging-A Review

BACKGROUND: Previous studies have demonstrated that a whole-food, plant-based (WFPB) diet can aid in the prevention, and in some cases reversal, of some of the leading chronic diseases in the United States. The medical literature on the relationship between diet and disease is steadily growing. Over the last decade, the possible connection between diet and many dermatological conditions has been studied, including skin aging. OBJECTIVE: As patients are increasingly seeking dietary advice from their dermatologist related to preventing and reversing the aging of skin, dermatologists need an evidence-based approach to tackle this challenging topic. This review focuses on dietary factors that contribute to telomere length, a marker for cellular aging. Although various factors contribute to accelerating telomere shortening, this review focuses on dietary factors that contribute to telomere length, specifically gerontotoxins and antioxidants. These can be measured in the blood, making them biomarkers of accelerated cellular skin aging. Included in this discussion is an evidence-based approach to increase the amount of antioxidants and decrease the amount of gerontotoxins in the diet, resulting in healthier skin. METHODS: A comprehensive MEDLINE (PubMed) literature review search was performed. Keywords used included: WFPB, telomerase, coronary artery disease, cellular aging, cigarette smoke, photoaging, telomeres, antioxidants, gerontotoxins, intrinsic cutaneous aging, extrinsic cutaneous aging, advanced glycation end products (AGEs), vitamin E, vitamin C, vitamin E, CoQ10, polyphenols, chlorophyll, zeaxanthin, polyunsaturated fatty acids, eicosapentaenoic acid, docosahexaenoic acid, alpha-linolenic acid, and monounsaturated fatty acids. Inclusion criteria included the above stated keywords and access to full text. RESULTS: A WFPB diet maximizes the antioxidant potential within our cells by providing essential vitamins, including vitamins A, C, and E. It also helps to eliminate harmful carcinogens and gerontotoxins within our bloodstream and has been shown to lengthen telomeres, which prevents cellular damage. CONCLUSION: Evidence obtained within this literature review supports a WFPB diet for preventing skin aging. .

Engineered algae: A novel oxygen-generating system for effective treatment of hypoxic cancer

Microalgae, a naturally present unicellular microorganism, can undergo light photosynthesis and have been used in biofuels, nutrition, etc. Here, we report that engineered live microalgae can be delivered to hypoxic tumor regions to increase local oxygen levels and resensitize resistant cancer cells to both radio- and phototherapies. We demonstrate that the hypoxic environment in tumors is markedly improved by in situ-generated oxygen through microalgae-mediated photosynthesis, resulting in notably radiotherapeutic efficacy. Furthermore, the chlorophyll from microalgae produces reactive oxygen species during laser irradiation, further augmenting the photosensitizing effect and enhancing tumor cell apoptosis. Thus, the sequential combination of oxygen-generating algae system with radio- and phototherapies has the potential to create an innovative treatment strategy to improve the outcome of cancer management. Together, our findings demonstrate a novel approach that leverages the products of photosynthesis for treatment of tumors and provide proof-of-concept evidence for future development of algae-enhanced radio- and photodynamic therapy.

Risk assessment of aflatoxins in food

EFSA was asked to deliver a scientific opinion on the risks to public health related to the presence of aflatoxins in food. The risk assessment was confined to aflatoxin B1 (AFB1), AFB2, AFG1, AFG2 and AFM1. More than 200,000 analytical results on the occurrence of aflatoxins were used in the evaluation. Grains and grain-based products made the largest contribution to the mean chronic dietary exposure to AFB1 in all age classes, while 'liquid milk' and 'fermented milk products' were the main contributors to the AFM1 mean exposure. Aflatoxins are genotoxic and AFB1 can cause hepatocellular carcinomas (HCCs) in humans. The CONTAM Panel selected a benchmark dose lower confidence limit (BMDL) for a benchmark response of 10% of 0.4 μg/kg body weight (bw) per day for the incidence of HCC in male rats following AFB1 exposure to be used in a margin of exposure (MOE) approach. The calculation of a BMDL from the human data was not appropriate; instead, the cancer potencies estimated by the Joint FAO/WHO Expert Committee on Food Additives in 2016 were used. For AFM1, a potency factor of 0.1 relative to AFB1 was used. For AFG1, AFB2 and AFG2, the in vivo data are not sufficient to derive potency factors and equal potency to AFB1 was assumed as in previous assessments. MOE values for AFB1 exposure ranged from 5,000 to 29 and for AFM1 from 100,000 to 508. The calculated MOEs are below 10,000 for AFB1 and also for AFM1 where some surveys, particularly for the younger age groups, have an MOE below 10,000. This raises a health concern. The estimated cancer risks in humans following exposure to AFB1 and AFM1 are in-line with the conclusion drawn from the MOEs. The conclusions also apply to the combined exposure to all five aflatoxins.

Human Biomonitoring of Mycotoxins in Blood, Plasma and Serum in Recent Years: A Review

This manuscript reviews the state-of-the-art regarding human biological monitoring (HBM) of mycotoxins in plasma serum and blood samples. After a comprehensive and systematic literature review, with a focus on the last five years, several aspects were analyzed and summarized: a) the biomarkers analyzed and their encountered levels, b) the analytical methodologies developed and c) the relationship between biomarker levels and some illnesses. In the literature reviewed, aflatoxin B1-lysine (AFB1-lys) and ochratoxin A (OTA) in plasma and serum were the most widely studied mycotoxin biomarkers for HBM. Regarding analytical methodologies, a clear increase in the development of methods for the simultaneous determination of multiple mycotoxins has been observed. For this purpose, the use of liquid chromatography (LC) methodologies, especially when coupled with tandem mass spectrometry (MS/MS) or high resolution mass spectrometry (HRMS), has grown. A high percentage of the samples analyzed for OTA or aflatoxin B1 (mostly as AFB1-lys) in the reviewed papers were positive, demonstrating human exposure to mycotoxins. This review confirms the importance of mycotoxin human biomonitoring and highlights the important challenges that should be faced, such as the inclusion of other mycotoxins in HBM programs, the need to increase knowledge of mycotoxin metabolism and toxicokinetics, and the need for reference materials and new methodologies for treating samples. In addition, guidelines are required for analytical method validation, as well as equations to establish the relationship between human fluid levels and mycotoxin intake.

Behavioural and biochemical effects of one-week exposure to aflatoxin B1 and aspartame in male Wistar rats

Food products are susceptible to contamination by mycotoxins, and aflatoxin B1 (AFB1) stands as the most toxic among them. AFB1 intoxication results in distinct signs, including widespread systemic toxicity. Aspartame (ASP) is an artificial sweetener used as a sugar substitute in many products, and compelling evidence indicates ASP can be toxic. Interestingly, mechanisms underlying ASP and AFB1 toxicity involve oxidative stress. In this context, concomitant use of ASP and AFB1 in a meal may predispose to currently unidentified behavioural and biochemical changes. Therefore, we evaluated the effect of AFB1 (250 μg/kg, intragastrically (i.g.)) and/or ASP (75 mg/kg, i.g.) exposure for 7 days on behavioural and biochemical markers of oxidative stress in male Wistar rats. AFB1 and/or ASP increased hepatic glutathione S-transferase (GST) activity when compared to controls. In the kidneys, increased GST activity was detected in AFB1 and AFB1+ASP groups. In addition, AFB1 and or ASP elicited behavioural changes in the open field, marble burying and splash tests, however no additive effects were detected. Altogether, present data suggest AFB1 and ASP predispose to anxiety- and obsessive-compulsive-like symptoms, as well as to enzymatic defence system imbalance in liver and kidney of Wistar rats.

Toxicokinetics of benzo[a]pyrene in humans: Extensive metabolism as determined by UPLC-accelerator mass spectrometry following oral micro-dosing

Benzo[a]pyrene (BaP), is a known human carcinogen (International Agency for Research on Cancer (IARC) class 1). The remarkable sensitivity (zepto-attomole ¹⁴C in biological samples) of accelerator mass spectrometry (AMS) makes possible, with de minimus risk, pharmacokinetic (PK) analysis following [¹⁴C]-BaP micro-dosing of humans. A 46 ng (5 nCi) dose was given thrice to 5 volunteers with minimum 2 weeks between dosing and plasma collected over 72 h. [¹⁴C]-BaP_eq PK analysis gave plasma T_max and C_max values of 1.25 h and 29-82 fg/mL, respectively. PK parameters were assessed by non- compartment and compartment models. Intervals between dosing ranged from 20 to 420 days and had little impact on intra-individual variation. DNA, extracted from peripheral blood mononuclear cells (PBMCs) of 4 volunteers, showed measurable levels (LOD ~ 0.5 adducts/10¹¹ nucleotides) in two individuals 2-3 h post-dose, approximately three orders of magnitude lower than smokers or occupationally-exposed individuals. Little or no DNA binding was detectable at 48-72 h. In volunteers the allelic variants CYP1B1^*1/*⁎1, ^*1/*3 or ^*3/*3 and GSTM1^*0/0 or ^*1 had no impact on [¹⁴C]-BaP_eq PK or DNA adduction with this very limited sample. Plasma metabolites over 72 h from two individuals (one CYP1B1^*1/*1 and one CYP1B1^*3/*3) were analyzed by UPLC-AMS. In both individuals, parent [¹⁴C]-BaP was a minor constituent even at the earliest time points and metabolite profiles markedly distinct. AMS, coupled with UPLC, could be used in humans to enhance the accuracy of pharmacokinetics, toxicokinetics and risk assessment of environmental carcinogens.

Silage review: Mycotoxins in silage: Occurrence, effects, prevention, and mitigation

Ensiled forage, particularly corn silage, is an important component of dairy cow diets worldwide. Forages can be contaminated with several mycotoxins in the field pre-harvest, during storage, or after ensiling during feed-out. Exposure to dietary mycotoxins adversely affects the performance and health of livestock and can compromise human health. Several studies and surveys indicate that ruminants are often exposed to mycotoxins such as aflatoxins, trichothecenes, ochratoxin A, fumonisins, zearalenone, and many other fungal secondary metabolites, via the silage they ingest. Problems associated with mycotoxins in silage can be minimized by preventing fungal growth before and after ensiling. Proper silage management is essential to reduce mycotoxin contamination of dairy cow feeds, and certain mold-inhibiting chemical additives or microbial inoculants can also reduce the contamination levels. Several sequestering agents also can be added to diets to reduce mycotoxin levels, but their efficacy varies with the type and level of mycotoxin contamination. This article gives an overview of the types, prevalence, and levels of mycotoxin contamination in ensiled forages in different countries, and describes their adverse effects on health of ruminants, and effective prevention and mitigation strategies for dairy cow diets. Future research priorities discussed include research efforts to develop silage additives or rumen microbial innocula that degrade mycotoxins.

Aflatoxin B1 residues in human livers and their relationship with markers of hepatic carcinogenesis in São Paulo, Brazil

In this study, hepatic biopsies from autopsy cases in São Paulo, Brazil, showing hepatocellular carcinoma (HCC, n = 8), cirrhosis associated with viral hepatitis (VC, n = 20), cirrhosis associated with alcoholism (AC, n = 20), and normal livers (NL or controls, n = 10) were subjected to determination of aflatoxin B1 (AFB1) and its main metabolites, and of markers of hepatic carcinogenesis Only non-metabolized AFB1 was detected in 13 samples (27.1%, N = 48) of liver disorders (HCC, VC and AC), at levels between 10.0 and 418.0 pg/g (mean: 76.6 ± 107.7 pg/g). Immuno-labeling of p53, cyclin D1, p21, β-catenin, and Prohibitin (PB) increased mainly in HCC patients, in relation to the controls. AFB1+ samples of HCC presented higher expressions of p53, cyclin D1, p21, and β-catenin compared with AFB1-livers. In contrast, p27, p16, and Rb immuno-labeling decreased in HCC, VC, and AC samples, compared with NL, with lowest values in AFB1+ samples for all liver disorders. Compared with NL, gene expression of cyclin D1 and PB in AFB1+ samples of HCC and AC were also higher, along with higher gene expression of p21 in VC and AC AFB1+ livers. Results indicated that patients with liver disorders were exposed to dietary aflatoxins, and that residual AFB1 in liver negatively affected the p53 and protein Rb pathways in HCC. Moreover, the presence of AFB1 in cirrhotic livers warrants concern about the potential contribution of dietary aflatoxin to disease progression during VC and AC.

Pharmacokinetics of [14C]-Benzo[a]pyrene (BaP) in humans: Impact of Co-Administration of smoked salmon and BaP dietary restriction

Benzo[a]pyrene (BaP), a polycyclic aromatic hydrocarbon (PAH), is a known human carcinogen. In non-smoking adults greater than 95% of BaP exposure is through diet. The carcinogenicity of BaP is utilized by the U.S. EPA to assess relative potency of complex PAH mixtures. PAH relative potency factors (RPFs, BaP = 1) are determined from high dose animal data. We employed accelerator mass spectrometry (AMS) to determine pharmacokinetics of [¹⁴C]-BaP in humans following dosing with 46 ng (an order of magnitude lower than human dietary daily exposure and million-fold lower than animal cancer models). To assess the impact of co-administration of food with a complex PAH mixture, humans were dosed with 46 ng of [¹⁴C]-BaP with or without smoked salmon. Subjects were asked to avoid high BaP-containing diets and a 3-day dietary questionnaire given to assess dietary exposure prior to dosing and three days post-dosing with [¹⁴C]-BaP. Co-administration of smoked salmon, containing a complex mixture of PAHs with an RPF of 460 ng BaP_eq, reduced and delayed absorption. Administration of canned commercial salmon, containing very low amounts of PAHs, showed the impacts on pharmacokinetics were not due to high amounts of PAHs but rather a food matrix effect.

Aflatoxin and viral hepatitis exposures in Guatemala: Molecular biomarkers reveal a unique profile of risk factors in a region of high liver cancer incidence

Liver cancer is an emerging global health issue, with rising incidence in both the United States and the economically developing world. Although Guatemala experiences the highest rates of this disease in the Western hemisphere and a unique 1:1 distribution in men and women, few studies have focused on this population. Thus, we determined the prevalence and correlates of aflatoxin B₁ (AFB₁) exposure and hepatitis virus infection in Guatemalan adults. Healthy men and women aged ≥40 years (n = 461), residing in five departments of Guatemala, were enrolled in a cross-sectional study from May—October of 2016. Serum AFB₁-albumin adducts were quantified using isotope dilution mass spectrometry. Multivariate linear regression was used to assess relationships between AFB₁-albumin adduct levels and demographic factors. Biomarkers of hepatitis B virus and hepatitis C virus infection were assessed by immunoassay and analyzed by Fisher’s exact test. AFB₁-albumin adducts were detected in 100% of participants, with a median of 8.4 pg/mg albumin (range, 0.2–814.8). Exposure was significantly higher (p<0.05) in male, rural, low-income, and less-educated participants than in female, urban, and higher socioeconomic status participants. Hepatitis B and C seropositivity was low (0.9% and 0.5%, respectively). Substantial AFB₁ exposure exists in Guatemalan adults, concurrent with low prevalence of hepatitis virus seropositivity. Quantitatively, AFB₁ exposures are similar to those previously found to increase risk for liver cancer in Asia and Africa. Mitigation of AFB₁ exposure may reduce liver cancer incidence and mortality in Guatemala, warranting further investigation.

A miRNA signature for an environmental heterocyclic amine defined by a multi-organ carcinogenicity bioassay in the rat

Heterocyclic amines (HCAs) produced during high-temperature cooking have been studied extensively in terms of their genotoxic/genetic effects, but recent work has implicated epigenetic mechanisms involving non-coding RNAs. Colon tumors induced in the rat by 2-amino-1-methyl-6-phenylimidazo[4,5-b]pyridine (PhIP) have altered microRNA (miRNA) signatures linked to dysregulated pluripotency factors, such as c-Myc and Krüppel-like factor 4 (KLF4). We tested the hypothesis that dysregulated miRNAs from PhIP-induced colon tumors would provide a "PhIP signature" for use in other target organs obtained from a 1-year carcinogenicity bioassay in the rat. Downstream targets that were corroborated in the rat were then investigated in human cancer datasets. The results confirmed that multiple let-7 family members were downregulated in PhIP-induced skin, colon, lung, small intestine, and Zymbal's gland tumors, and were associated with c-myc and Hmga2 upregulation. PhIP signature miRNAs with the profile mir-21high/mir-126low/mir-29clow/mir-215low/mir-145low were linked to reduced Klf4 levels in rat tumors, and in human pan-cancer and colorectal cancer. It remains to be determined whether this PhIP signature has predictive value, given that more than 20 different genotoxic HCAs are present in the human diet, plus other agents that likely induce or repress many of the same miRNAs. Future studies should define more precisely the miRNA signatures of other HCAs, and their possible value for human risk assessment.

Daily uptake of mycotoxins - TDI might not be protective for nursed infants

Exclusive breast feeding is recommended by international bodies for the first six months of life. Because of the presence of contaminants, breast feeding might lead to toxicologically relevant exposure of the nursed child. Exposure towards mycotoxins is of specific interest because of their widespread occurrence in food and of their toxicological profile. We calculated the relationship between maternal intake at the level of the existing TDIs and the exposure in the nursed infants of several mycotoxins to evaluate whether maternal exposure at the TDI is also safe for the nursed infant. If published information was not available we used in silico methods for estimating toxicokinetic parameters and the lactational transfer. A single dose and a continuous daily intake scenario were considered. Maternal intake at the TDI exceeds the age-adjusted TDI (TDI/3) values for infants in case of deoxynivalenol and patulin in the single dose scenario. Exceedance is particularly pronounced for ochratoxin A in the continuous daily intake scenario (29.2 fold above the child adjusted TDI). According to published data in infants impaired kidney function may result from this exceedance. When setting a TDI, the safety of the exclusively nursed infant should be considered in the continuous daily intake scenario.

Survey on Urinary Levels of Aflatoxins in Professionally Exposed Workers

Feed mill workers may handle or process maize contaminated with aflatoxins (AFs). This condition may lead to an unacceptable intake of toxins deriving from occupational exposure. This study assessed the serological and urinary levels of AFs in workers exposed to potentially contaminated dusts in two mills. From March to April 2014, blood and urine samples were collected, on Monday and Friday morning of the same working week from 29 exposed workers and 30 non-exposed controls. AFs (M₁, G₂, G₁, B₁, B₂) and aflatoxicol (AFOH) A were analyzed. Each subject filled in a questionnaire to evaluate potential food-borne exposures to mycotoxins. AFs contamination in environmental dust was measured in both plants. No serum sample was found to be positive. Seventy four percent of urine samples (73.7%) revealed AFM₁ presence. AFM₁ mean concentration was 0.035 and 0.027 ng/mL in exposed and non-exposed workers, respectively (p = 0.432); the concentration was slightly higher in Friday’s than in Monday’s samples, in exposed workers, 0.040 versus (vs.) 0.031 and non-exposed controls (0.030 vs. 0.024, p = 0.437). Environmental AFs contamination ranged from 7.2 to 125.4 µg/kg. The findings of this study reveal the presence of higher AFs concentration in exposed workers than in non-exposed controls, although these differences are to be considered consistent with random fluctuations.

Use of Accelerator Mass Spectrometry in Human Health and Molecular Toxicology

Accelerator mass spectrometry (AMS) has been adopted as a powerful bioanalytical method for human studies in the areas of pharmacology and toxicology. The exquisite sensitivity (10-18 mol) of AMS has facilitated studies of toxins and drugs at environmentally and physiologically relevant concentrations in humans. Such studies include risk assessment of environmental toxicants, drug candidate selection, absolute bioavailability determination, and more recently, assessment of drug-target binding as a biomarker of response to chemotherapy. Combining AMS with complementary capabilities such as high performance liquid chromatography (HPLC) can maximize data within a single experiment and provide additional insight when assessing drugs and toxins, such as metabolic profiling. Recent advances in the AMS technology at Lawrence Livermore National Laboratory have allowed for direct coupling of AMS with complementary capabilities such as HPLC via a liquid sample moving wire interface, offering greater sensitivity compared to that of graphite-based analysis, therefore enabling the use of lower 14C and chemical doses, which are imperative for clinical testing. The aim of this review is to highlight the recent efforts in human studies using AMS, including technological advancements and discussion of the continued promise of AMS for innovative clinical based research.

Tools for Defusing a Major Global Food and Feed Safety Risk: Nonbiological Postharvest Procedures To Decontaminate Mycotoxins in Foods and Feeds

Mycotoxin contamination of foods and animal feeds is a worldwide problem for human and animal health. Controlling mycotoxin contamination has drawn the attention of scientists and other food and feed stakeholders all over the world. Despite best efforts targeting field and storage preventive measures, environmental conditions can still lead to mycotoxin contamination. This raises a need for developing decontamination methods to inactivate or remove the toxins from contaminated products. At present, decontamination methods applied include an array of both biological and nonbiological methods. The targeted use of nonbiological methods spans from the latter half of last century, when ammoniation and ozonation were first used to inactivate mycotoxins in animal feeds, to the novel techniques being developed today such as photosensitization. Effectiveness and drawbacks of different nonbiological methods have been reported in the literature, and this review examines the utility of these methods in addressing food safety. Particular consideration is given to the application of such methods in the developing world, where mycotoxin contamination is a serious food safety issue in staple crops such as maize and rice.

Nondestructive Optical Sensing of Flavonols and Chlorophyll in White Head Cabbage (Brassica oleracea L. var. capitata subvar. alba) Grown under Different Nitrogen Regimens

A multiparametric optical sensor was used to nondestructively estimate phytochemical compounds in white cabbage leaves directly in the field. An experimental site of 1980 white cabbages (Brassica oleracea L. var. capitata subvar. alba), under different nitrogen (N) treatments, was mapped by measuring leaf transmittance and chlorophyll fluorescence screening in one leaf/cabbage head. The provided indices of flavonols (FLAV) and chlorophyll (CHL) displayed the opposite response to applied N rates, decreasing and increasing, respectively. The combined nitrogen balance index (NBI = CHL/FLAV) calculated was able to discriminate all of the plots under four N regimens (0, 100, 200, and 400 kg/ha) and was correlated with the leaf N content determined destructively. CHL and FLAV were properly calibrated against chlorophyll (R(2) = 0.945) and flavonol (R(2) = 0.932) leaf contents, respectively, by using a homographic fit function. The proposed optical sensing of cabbage crops can be used to estimate the N status of plants and perform precision fertilization to maintain acceptable crop yield levels and, additionally, to rapidly detect health-promoting flavonol antioxidants in Brassica plants.

Epigenetic modulation of Chlorella (Chlorella vulgaris) on exposure to polycyclic aromatic hydrocarbons

DNA methylation in promoter region can be a new chemopreventive marker against polycyclic aromatic hydrocarbons (PAHs). We performed a randomized, double blind and cross-over trial (N=12 healthy females) to evaluate chlorella (Chlorella vulgaris)-induced epigenetic modulation on exposure to PAHs. The subjects consumed 4 tablets of placebo or chlorella supplement (total chlorophyll ≈ 8.3mg/tablet) three times a day before meals for 2 weeks. When the subjects consumed chlorella, status of global hypermethylation (5-methylcytosine) was reduced, compared to placebo (p=0.04). However, DNA methylation at the DNMT1 or NQO1 was not modified by chlorella. We observed the reduced levels of urinary 1-hydroxypyrene (1-OHP), a typical metabolite of PAHs, by chlorella intake (p<0.1) and a positive association between chlorella-induced changes in global hypermethylation and urinary 1-OHP (p<0.01). Therefore, our study suggests chlorella works for PAH-detoxification through the epigenetic modulation, the interference of ADME of PAHs and the interaction of mechanisms.