Modified hydra bioassay to evaluate the toxicity of multiple mycotoxins and predict the detoxification efficacy of a clay-based sorbent

Green-Engineered Barrier Creams with Montmorillonite-Chlorophyll Clays as Adsorbents for Benzene, Toluene, and Xylene

Dermal exposures to hazardous environmental chemicals in water can significantly affect the morphology and integrity of skin structure, leading to enhanced and deeper penetration. Organic solvents, such as benzene, toluene, and xylene (BTX), have been detected in humans following skin exposure. In this study, novel barrier cream formulations (EVB™) engineered with either montmorillonite (CM and SM) or chlorophyll-amended montmorillonite (CMCH and SMCH) clays were tested for their binding efficacy for BTX mixtures in water. The physicochemical properties of all sorbents and barrier creams were characterized and were shown to be suitable for topical application. In vitro adsorption results indicated that EVB-SMCH was the most effective and favorable barrier for BTX, as supported by the high binding percentage (29-59% at 0.05 g and 0.1 g), stable binding at equilibrium, low desorption rates, and high binding affinity. Pseudo-second-order and the Freundlich models best fit the adsorption kinetics and isotherms, and the adsorption was an exothermic reaction. Ecotoxicological models using L. minor and H. vulgaris that were submersed in aqueous culture media showed that the inclusion of 0.05% and 0.2% EVB-SMCH reduced BTX concentration. This result was further supported by the significant and dose-dependent increase in multiple growth endpoints, including plant frond number, surface area, chlorophyll content, growth rate, inhibition rate, and hydra morphology. The in vitro adsorption results and in vivo plant and animal models indicated that green-engineered EVB-SMCH can be used as an effective barrier to bind BTX mixtures and interrupt their diffusion and dermal contact.

Adsorption and detoxification of glyphosate and aminomethylphosphonic acid by montmorillonite clays

The co-occurrence of mixtures of glyphosate (GLP) and aminomethylphosphonic acid (AMPA) in contaminated water, soil, sediment, and plants is a cause for concern due to potential threats to the ecosystem and human health. Major routes of exposure include contact with contaminated water and soil and through consumption of crops containing GLP and AMPA residues. Calcium montmorillonite (CM) and acid-processed montmorillonite (APM) clays were investigated for their ability to tightly sorb and detoxify GLP and AMPA mixtures. In vitro adsorption and desorption isotherms and thermodynamic analysis indicated saturable Langmuir binding of both chemicals with high capacities, affinities, enthalpies, and free energies of sorption and low desorption rates. In silico computational modeling indicated that both GLP and AMPA can be readily absorbed onto clay surfaces through electrostatic interactions and hydrogen bonding. The safety and efficacy of the clays were confirmed using well-established living organisms, including an aquatic cnidarian (Hydra vulgaris), a soil nematode (Caenorhabditis elegans), and a floating plant (Lemna minor). Low levels of clay inclusion (0.05% and 0.2%) in the culture medium resulted in increased growth and protection against chemical mixtures based on multiple endpoints. Results indicated that montmorillonite clays may be used to bind mixtures of GLP and AMPA in water, soil, and plants.

Application of Edible Montmorillonite Clays for the Adsorption and Detoxification of Microcystin

Exposure to microcystins (MCs) in humans and animals commonly occurs through the consumption of drinking water and food contaminated with cyanobacteria. Although studies have focused on developing water filtration treatments for MCs using activated carbon, dietary sorbents to reduce the bioavailability of MCs from the stomach and intestines have not been reported. To address this need, edible calcium and sodium montmorillonite clays were characterized for their ability to bind MC containing leucine and arginine (MC-LR) under conditions simulating the gastrointestinal tract and compared with a medical-grade activated carbon. Results of in vitro adsorption isotherms and thermodynamics showed that binding plots for MC-LR on montmorillonites fit the Langmuir model with high binding capacity, affinity, Gibbs free energy, and enthalpy. The in silico results from molecular modeling predicted that the major binding mechanisms involved electrostatics and hydrogen bonds, and that interlayers were important binding sites. The safety and detoxification efficacy of the sorbents against MC-LR were validated in a battery of living organisms, including Hydra vulgaris, Lemna minor, and Caenorhabditis elegans. The inclusion of 0.05% and 0.1% montmorillonite clays in hydra media significantly reduced MC-LR toxicity and protected hydra by 60-80%, whereas only slight protection was shown with the heat-collapsed clay. In the Lemna minor assay, montmorillonites significantly enhanced the growth of lemna, as supported by the increase in frond number, surface area, chlorophyll content, and growth rate, as well as the decrease in inhibition rate. Similar results were shown in the C. elegans assay, where montmorillonite clays reduced MC-LR effects on body length and brood size. All 3 bioassays confirmed dose-dependent protection from MC-LR, validated the in vitro and in silico findings, and suggested that edible montmorillonites are safe and efficacious binders for MC-LR. Moreover, their inclusion in diets during algal blooming seasons could protect vulnerable populations of humans and animals.

Combining Experimental Isotherms, Minimalistic Simulations, and a Model to Understand and Predict Chemical Adsorption onto Montmorillonite Clays

An attractive approach to minimize human and animal exposures to toxic environmental contaminants is the use of safe and effective sorbent materials to sequester them. Montmorillonite clays have been shown to tightly bind diverse toxic chemicals. Due to their promise as sorbents to mitigate chemical exposures, it is important to understand their function and rapidly screen and predict optimal clay-chemical combinations for further testing. We derived adsorption free-energy values for a structurally and physicochemically diverse set of toxic chemicals using experimental adsorption isotherms performed in the current and previous studies. We studied the diverse set of chemicals using minimalistic MD simulations and showed that their interaction energies with calcium montmorillonite clays calculated using simulation snapshots in combination with their net charge and their corresponding solvent's dielectric constant can be used as inputs to a minimalistic model to predict adsorption free energies in agreement with experiments. Additionally, experiments and computations were used to reveal structural and physicochemical properties associated with chemicals that can be adsorbed to calcium montmorillonite clay. These properties include positively charged groups, phosphine groups, halide-rich moieties, hydrogen bond donor/acceptors, and large, rigid structures. The combined experimental and computational approaches used in this study highlight the importance and potential applicability of analogous methods to study and design novel advanced sorbent systems in the future, broadening their applicability for environmental contaminants.

Decreased bioavailability of aminomethylphosphonic acid (AMPA) in genetically modified corn with activated carbon or calcium montmorillonite clay inclusion in soil

The widespread use of pesticides has resulted in detectable residues throughout the environment, sometimes at concentrations well above regulatory limits. Therefore, the development of safe, effective, field-practical, and economically feasible strategies to mitigate the effects of pesticides is warranted. Glyphosate is an organophosphorus herbicide that is degraded to aminomethylphosphonic acid (AMPA), a toxic and persistent metabolite that can accumulate in soil and sediment and translocate to plants. In this study, we investigated the binding efficacy of activated carbon (AC) and calcium montmorillonite (CM) clay to decrease AMPA bioavailability from soil and AMPA translocation to plants. Adsorption isotherms and thermodynamic studies on AC and CM were conducted and showed tight binding (enthalpy values >-20 kJ/mol) for AMPA with high capacities (0.25 mol/kg and 0.38 mol/kg, respectively), based on derivations from the Langmuir model. A hydra assay was utilized to indicate toxicity of AMPA and the inclusion of 1% AC and CM both resulted in 90% protection of the hydra (**p ≤ 0.01). Further studies in glyphosate-contaminated soil showed that AC and CM significantly reduced AMPA bioavailability by 53% and 44%, respectively. Results in genetically modified (GM) corn showed a conversion of glyphosate to AMPA in roots and sprouts over a 10-day exposure duration. Inclusion of AC and CM reduced AMPA residues in roots and sprouts by 47%-61%. These studies collectively indicate that AC and CM are effective sorbents for AMPA and could be used to reduce AMPA bioavailability from soil and AMPA residues in GM corn plants.

Tight sorption of arsenic, cadmium, mercury, and lead by edible activated carbon and acid-processed montmorillonite clay

Heavy metal exposure in humans and animals commonly occurs through the consumption of metal-contaminated drinking water and food. Although many studies have focused on the remediation of metals by purification of water using sorbents, limited therapeutic sorbent strategies have been developed to minimize human and animal exposures to contaminated water and food. To address this need, a medical grade activated carbon (MAC) and an acid processed montmorillonite clay (APM) were characterized for their ability to bind heavy metals and mixtures. Results of screening and adsorption/desorption isotherms showed that binding plots for arsenic, cadmium, and mercury sorption on surfaces of MAC (and lead on APM) fit the Langmuir model. The highest binding percentage, capacity, and affinity were shown in a simulated stomach model, and the lowest percentage desorption (< 18%) was shown in a simulated intestine model. The safety and protective ability of MAC and APM were confirmed in a living organism (Hydra vulgaris) where 0.1% MAC significantly protected the hydra against As, Cd, Hg, and a mixture of metals by 30-70%. In other studies, APM showed significant reduction (75%) of Pd toxicity, compared with MAC and heat-collapsed APM, suggesting that the interlayer of APM was important for Pb sorption. This is the first report showing that edible sorbents can bind mixtures of heavy metals in a simulated gastrointestinal tract and prevent their toxicity in a living organism. Graphical abstract.

Sphinganine-Analog Mycotoxins (SAMs): Chemical Structures, Bioactivities, and Genetic Controls

Sphinganine-analog mycotoxins (SAMs) including fumonisins and A. alternata f. sp. Lycopersici (AAL) toxins are a group of related mycotoxins produced by plant pathogenic fungi in the Fusarium genus and in Alternaria alternata f. sp. Lycopersici, respectively. SAMs have shown diverse cytotoxicity and phytotoxicity, causing adverse impacts on plants, animals, and humans, and are a destructive force to crop production worldwide. This review summarizes the structural diversity of SAMs and encapsulates the relationships between their structures and biological activities. The toxicity of SAMs on plants and animals is mainly attributed to their inhibitory activity against the ceramide biosynthesis enzyme, influencing the sphingolipid metabolism and causing programmed cell death. We also reviewed the detoxification methods against SAMs and how plants develop resistance to SAMs. Genetic and evolutionary analyses revealed that the FUM (fumonisins biosynthetic) gene cluster was responsible for fumonisin biosynthesis in Fusarium spp. Sequence comparisons among species within the genus Fusarium suggested that mutations and multiple horizontal gene transfers involving the FUM gene cluster were responsible for the interspecific difference in fumonisin synthesis. We finish by describing methods for monitoring and quantifying SAMs in food and agricultural products.

Trial for reduction of Ochratoxin A residues in fish feed by using nano particles of hydrated sodium aluminum silicates (NPsHSCAS) and copper oxide

This paper was designed to analyze the effect of ochratoxin A (OTA) contaminated feed on the growth outcomes, certain serum biochemical, histopathology, and OTA residue in the dorsal muscle, liver, and kidney in Nile tilapia. Also, to improve the drastic effect of OTA through dietary supplementation of hydrated sodium aluminum silicates nanoparticles or nano copper. For performing the present study, 270 fish were randomly allotted into 6 equal groups according to ochratoxin and nanoparticles of hydrated sodium aluminum silicates or copper oxide. The results indicated that supplementation of two levels of both nanoparticles (aluminum silicate or copper) as a mycotoxin adsorbent could prevent ochratoxicosis in Nile tilapia fish. In addition, they maintained optimal growth performance, feed efficiency without bad effect on serum profiles and vital organs function of fish in a dose-dependent manner. Histopathologically, the most interesting finding was the precipitation of calcium salts known as nephrocalcinosis, within the tubules, upon the degenerative tubules and tunica intima and media of the blood vessels in the control positive group. These pathological lesions were mitigated by nanoparticle supplementation. Thus increase the safety of fish products.

Strong Adsorption of Dieldrin by Parent and Processed Montmorillonite Clays

Widespread use of pesticides has resulted in the accumulation of pesticide residues in the environment due to their persistence and stability. To reduce potential exposures, we have developed broad-acting clay-based sorbents that can be included in the diet as enterosorbents to reduce the bioavailability and toxicity of chemicals. In the present study, parent and acid-processed calcium montmorillonite clays (CM and APM, respectively) were used to determine their potential as sorbents of the organochlorine insecticide dieldrin. We used adsorption isotherms, thermodynamics, and dosimetry studies to determine the capacities and affinities of the clays, the enthalpies of the binding reactions, and potential doses of sorbent that could protect against high exposures. Adsorption isotherms for APM fit a Langmuir model with high enthalpy (suggesting chemisorption) and high capacity (Qmax value = 0.45 mol kg-1 ), indicating tight binding of dieldrin. Cultures of Hydra vulgaris were used to determine the ability of sorbents to protect a living organism from dieldrin toxicity. The inclusion of acid-processed clays resulted in the highest reduction of dieldrin toxicity (70%) in the hydra. Further work indicated that both CM and APM can significantly reduce the bioavailability of dieldrin from soil (p ≤ 0.01). These results suggest that APM (and similar clays) can be effective sorbents of dieldrin and may be included in the diet and/or soil to protect against environmental exposures. Environ Toxicol Chem 2020;39:517-525. © 2019 SETAC.

A high capacity bentonite clay for the sorption of aflatoxins

Previously a calcium bentonite clay (CB) has been shown to tightly bind aflatoxins in vitro, significantly reduce mortality and morbidity in animals, and decrease molecular biomarkers of aflatoxin exposure in humans and animals. Extensive studies have shown that CB is safe for human and animal consumption. In further work, we have investigated a highly active sodium bentonite (SB) clay (SB-E) with enhanced aflatoxin sorption efficacy compared to CB and other clays. Computational models and isothermal analyses were used to characterise toxin/clay surface interactions, predict mechanisms of toxin sorption, and gain insight into: 1) surface capacities and affinities, and 2) thermodynamics and sites of toxin/surface interactions. We have also used a toxin-sensitive living organism (Hydra vulgaris) to confirm the safety and predict the efficacy of SB-E against aflatoxin toxicity. Compared to CB, SB-E had a higher capacity for aflatoxin B1 (AfB1) at pH 2 and 6.5. Results from this work suggest that high capacity clays such as SB-E can be used as effective aflatoxin enterosorbents to decrease short-term exposures in humans and animals when included in food and/or water during extended droughts and outbreaks of aflatoxicosis.

Potential Applications of Clay-Based Therapy for the Reduction of Pesticide Exposures in Humans and Animals

The risk of pesticide exposure in humans and animals may be magnified following natural and man-made disasters such as hurricanes and floods that can result in mobilization and redistribution of contaminated sediments. To develop broad-acting sorbents for mixtures of diverse toxins, we have processed calcium and sodium montmorillonite clays with high concentrations of sulfuric acid. These acid-processed montmorillonite clays (APMs) have shown limited hydration and swelling in water, higher surface areas, and lower trace metal levels than the parent clays, prior to processing. Isothermal analyses have indicated that newly developed APMs are highly active sorbents, with significantly increased binding capacities for a wide range of pesticides, including pentachlorophenol (PCP), 2,4,6-trichlorophenol (2,4,6-TCP), lindane, diazinon, linuron, trifluralin and paraquat. The safety and protective effects of APMs, against pesticide design mixtures, were confirmed in a living organism (Hydra vulgaris). Further work is planned to confirm the safety of the APMs in long-term rodent studies. This is the first report of a sorbent material (other than carbon) with high binding efficacy for mixtures of these pesticides. Based on our results, APMs (and similar clays), may be able to decrease human and animal pesticide exposures during disasters and emergencies.

Development of enterosorbents that can be added to food and water to reduce toxin exposures during disasters

Humans and animals can be exposed to mixtures of chemicals from food and water, especially during disasters such as extended droughts, hurricanes and floods. Drought stress facilitates the occurrence of mycotoxins such as aflatoxins B1 (AfB1) and zearalenone (ZEN), while hurricanes and floods can mobilize toxic soil and sediments containing important pesticides (such as glyphosate). To address this problem in food, feed and water, we developed broad-acting, clay-based enterosorbents that can reduce toxin exposures when included in the diet. In this study, we processed sodium and calcium montmorillonite clays with high concentrations of sulfuric acid to increase surface areas and porosities, and conducted equilibrium isothermal analyses and dosimetry studies to derive binding parameters and gain insight into: (1) surface capacities and affinities, (2) potential mechanisms of sorption, (3) thermodynamics (enthalpy) of toxin/surface interactions and (4) estimated dose of sorbent required to maintain toxin threshold limits. We have also used a toxin-sensitive living organism (Hydra vulgaris) to predict the safety and efficacy of newly developed sorbents. Our results indicated that acid processed montmorillonites were effective sorbents for AfB1, ZEN and glyphosate, with high capacity and tight binding, and effectively protected hydra against individual toxins, as well as mixtures of mycotoxins.

Development of broad-acting clays for the tight adsorption of benzo[a]pyrene and aldicarb

People and animals can be unintentionally exposed to complex mixtures of hazardous chemicals that can threaten the safety of food and water supplies following natural and man-made disasters and emergencies. Our research has focused on the development of broad-acting adsorbents that will tightly bind environmental contaminants in the gastrointestinal tract and decrease their bioavailability to humans and animals during these events. In this study, benzo[a]pyrene (BaP) and aldicarb were used as representative chemicals due to their high toxicity and extensive distribution in the environment. Both chemicals have been commonly detected in water and sediments in the US, and their distribution and concentrations can be enhanced during disasters. To address this problem, we have amended and functionalized montmorillonite clays with the nutrients, L-carnitine and choline to enhance their attraction for lipophilic toxins, such as BaP and aldicarb. Based on equilibrium isothermal analyses, we have demonstrated a significantly increased binding capacity (Qmax) and affinity (Kd) for BaP and aldicarb compared to the parent clay. Adsorption isotherms also showed that talc bound strongly to BaP with the highest Qmax, which was twice that of activated carbon. Additionally, cultures of adult hydra with a metabolism activation package were used as an in vivo toxicity indicator to confirm the ability of test adsorbents to protect against toxicity at low inclusion levels. We anticipate that the optimal adsorbents developed can be delivered in food and flavored water, or administered by sachet or capsule during emergencies and disasters to decrease human and animals exposures to environmental toxins.

NovaSil clay for the protection of humans and animals from aflatoxins and other contaminants

Aflatoxin contamination of diets results in disease and death in humans and animals. The objective of the present paper was to review the development of innovative enterosorption strategies for the detoxification of aflatoxins. NovaSil clay (NS) has been shown to decrease exposures to aflatoxins and prevent aflatoxicosis in a variety of animals when included in their diets. Results have shown that NS clay binds aflatoxins with high affinity and high capacity in the gastrointestinal tract, resulting in a notable reduction in the bioavailability of these toxins without interfering with the utilization of vitamins and other micronutrients. This strategy is already being utilized as a potential remedy for acute aflatoxicosis in animals, and as a sustainable intervention via diet. Animal and human studies have confirmed the apparent safety of NS and refined NS clay (with uniform particle size). Studies in Ghanaians at high risk of aflatoxicosis have indicated that NS (at a dose level of 0.25% w/w) is effective at decreasing biomarkers of aflatoxin exposure and does not interfere with levels of serum vitamins A and E, or iron or zinc. A new spinoff of this strategy is the development and use of broad-acting sorbents for the mitigation of environmental chemicals and microbes during natural disasters and emergencies. In summary, enterosorption strategies/therapies based on NS clay are promising for the management of aflatoxins and as sustainable public health interventions. The NS clay remedy is novel, inexpensive, and easily disseminated.

Nanoparticles as a Solution for Eliminating the Risk of Mycotoxins

Mycotoxins are toxic secondary metabolites produced by certain filamentous fungi. The occurrence of mycotoxins in food and feed causes negative health impacts on both humans and animals. Clay binders, yeast cell walls, or antioxidant additives are the most widely used products for mycotoxin elimination to reduce their impact. Although conventional methods are constantly improving, current research trends are looking for innovative solutions. Nanotechnology approaches seem to be a promising, effective, and low-cost way to minimize the health effects of mycotoxins. This review aims to shed light on the critical knowledge gap in mycotoxin elimination by nanotechnology. There are three main strategies: mold inhibition, mycotoxin adsorption, and reducing the toxic effect via nanoparticles. One of the most promising methods is the use of carbon-based nanomaterials. Graphene has been shown to have a huge surface and high binding capacity for mycotoxins. Attention has also been drawn to polymeric nanoparticles; they could substitute adsorbents or enclose any substance, which would improve the health status of the organism. In light of these findings, this review gives new insights into possible future research that might overcome challenges associated with nanotechnology utilization for mycotoxin elimination from agricultural products.

Development of High Capacity Enterosorbents for Aflatoxin B1 and Other Hazardous Chemicals

Previously, a calcium montmorillonite clay (NovaSil) included in the diet of animals has been shown to bind aflatoxin B1 (AfB1) and reduce the symptoms of aflatoxicosis. To investigate and improve the capacity and efficacy of clay-based materials as aflatoxin sorbents, we developed and tested calcium and sodium montmorillonite clays amended with nutrients including l-carnitine and choline. Also, we determined the sorption of AfB1 by isothermal analysis and tested the ability of these amended sorbents to protect adult hydra from AfB1 toxicity. The results showed that exchanging montmorillonite clays with l-carnitine and choline inhibited swelling of the clays and increased the sorption capacity and efficacy of clay surfaces for AfB1. Results from dehydroxylated and heat-collapsed clays suggested that AfB1 was primarily adsorbed in the clay interlayer, as predicted from thermodynamic calculations and computational modeling. The hydra bioassay further indicated that the modified clays can significantly protect adult hydra from AfB1 with as low as 0.005% clay inclusion. This enterosorbent therapy may also be applied to screen hazardous chemicals such as pesticides and PAHs based on similar sorption mechanisms. Taken together, enterosorbent therapy could be delivered in nutritional supplements, foods that are vulnerable to aflatoxin contamination, flavored liquids and animal feeds during emergencies and outbreaks of acute aflatoxicosis, and as a screening model for hazardous environmental chemicals.

Analysis of T-2 Toxin Removal Factors in a Lactococcus Fermentation System

The objective of this work was to determine the bacterial strains and factors that most efficiently degrade T-2 toxin in foods or animal feed. To determine the most efficient strain and optimal incubation times for degradation of T-2, the rate of T-2 removal by three lactic acid bacteria strains was quantified by liquid chromatography plus tandem mass spectrometry after incubation in de Man Rogosa Sharpe broth with 50 ng mL^-1 T-2 at 37°C for 96 h. Various components of the most efficient degradation strain fermentation systems were extracted, and the ability to remove T-2 was assayed. Lactococcus lactis CAMT22361 was the most efficient degradation strain for removing T-2. Yeast extract powder interfered with L. lactis CAMT22361 in the degradation process. T-2 toxin was removed by various components of the L. lactis CAMT22361 cells in the following order: nonprotein material of the extracellular fraction > protein in the extracellular fraction > whole cell ≈ cell wall > cell intracellular matrix fluid. T-2 removal rates were 54.08% ± 0.79%, 43.65% ± 0.84%, 43.09% ± 0.87%, 41.98% ± 0.8%, and 23.45% ± 0.66%, respectively. The nonprotein fraction in the extracellular fluid was most likely the key component in L. lactis CAMT22361 and hence would be the most desirable cellular component to be used to remove T-2 from food or feed.

Assessment of Aflatoxin and Fumonisin Contamination of Maize in Western Kenya

We conducted a survey of aflatoxin and fumonisin in maize in western Kenya. In a regional survey of aflatoxin conducted in 2009 across three agroecological zones within three administrative regions, milled maize samples were collected from 985 patrons of 26 hammer mills. Aflatoxin contamination was detected in 49% of samples and was above the regulatory (10 ppb) in 15% of the samples overall; 65% of samples from a drought-prone area were over the limit. In a detailed survey in Bungoma County, we investigated aflatoxin and fumonisin contamination in four popular maize varieties at harvest and after 2 and 4 months of storage. We collected whole-grain samples from farmers' storage sheds and milled samples from patrons of local mills. Mean aflatoxin contamination was identical for storage sheds and mills at 2.3 ppb. In all, 41% of the samples from mills had detectable aflatoxin, with 4% over the regulatory limit, whereas 87% had detectable fumonisin, with 50% over the regulatory limit (1 ppm). Mean contamination levels did not change during storage. Maize varieties differed in fumonisin contamination, with the most popular varieties vulnerable to both mycotoxins and weevils, which are potential factors in exacerbating mycotoxin contamination. Mycotoxin surveillance is important not just in areas known previously for aflatoxin contamination and acute poisoning but also is needed in all maize-producing regions.

Calcium montmorillonite clay reduces AFB1 and FB1 biomarkers in rats exposed to single and co-exposures of aflatoxin and fumonisin

Aflatoxins (AFs) and fumonisins (FBs) can co-contaminate foodstuffs and have been associated with hepatocellular and esophageal carcinomas in humans at high risk for exposure. One strategy to reduce exposure (and toxicity) from contaminated foodstuffs is the dietary inclusion of a montmorillonite clay (UPSN) that binds AFs and FBs in the gastrointestinal tract. In this study, the binding capacity of UPSN was evaluated for AFB1, FB1 and a combination thereof in Fischer 344 rats. Rats were pre-treated with different dietary levels of UPSN (0.25% or 2%) for 1 week. Rats were gavaged with a single dose of either 0.125 mg AFB1 or 25 mg FB1 per kg body weight and a combination thereof in the presence and absence of an aqueous solution of UPSN. The kinetics of mycotoxin excretion were monitored by analyzing serum AFB1 -albumin, urinary AF (AFM1) and FB1 biomarkers over a period of 72 h. UPSN decreased AFM1 excretion by 88-97%, indicating highly effective binding. FB1 excretion was reduced, to a lesser extent, ranging from 45% to 85%. When in combination, both AFB1 and FB1 binding occurred, but capacity was decreased by almost half. In the absence of UPSN, the combined AFB1 and FB1 treatment decreased the urinary biomarkers by 67% and 45% respectively, but increased levels of AFB1 -albumin, presumably by modulating its cytochrome metabolism. UPSN significantly reduced bioavailability of both AFB1 and FB1 when in combination; suggesting that it can be utilized to reduce levels below their respective thresholds for affecting adverse biological effects.

Review of the inhibition of biological activities of food-related selected toxins by natural compounds

There is a need to develop food-compatible conditions to alter the structures of fungal, bacterial, and plant toxins, thus transforming toxins to nontoxic molecules. The term 'chemical genetics' has been used to describe this approach. This overview attempts to survey and consolidate the widely scattered literature on the inhibition by natural compounds and plant extracts of the biological (toxicological) activity of the following food-related toxins: aflatoxin B1, fumonisins, and ochratoxin A produced by fungi; cholera toxin produced by Vibrio cholerae bacteria; Shiga toxins produced by E. coli bacteria; staphylococcal enterotoxins produced by Staphylococcus aureus bacteria; ricin produced by seeds of the castor plant Ricinus communis; and the glycoalkaloid α-chaconine synthesized in potato tubers and leaves. The reduction of biological activity has been achieved by one or more of the following approaches: inhibition of the release of the toxin into the environment, especially food; an alteration of the structural integrity of the toxin molecules; changes in the optimum microenvironment, especially pH, for toxin activity; and protection against adverse effects of the toxins in cells, animals, and humans (chemoprevention). The results show that food-compatible and safe compounds with anti-toxin properties can be used to reduce the toxic potential of these toxins. Practical applications and research needs are suggested that may further facilitate reducing the toxic burden of the diet. Researchers are challenged to (a) apply the available methods without adversely affecting the nutritional quality, safety, and sensory attributes of animal feed and human food and (b) educate food producers and processors and the public about available approaches to mitigating the undesirable effects of natural toxins that may present in the diet.