Interactions of Mycotoxin Alternariol with Cyclodextrins and its Removal from Aqueous Solution by Beta-Cyclodextrin Bead Polymer

Active and Intelligent Packaging: A Review of the Possible Application of Cyclodextrins in Food Storage and Safety Indicators

Natural cyclodextrins (CDs) can be formed by 6, 7, or 8 glucose molecules (α-, β-, and γ-, respectively) linked in a ring, creating a cone shape. Its interior has an affinity for hydrophobic molecules, while the exterior is hydrophilic and can interact with water molecules. This feature has been used to develop active packaging applied to food, interacting with the product or its environment to improve one or more aspects of its quality or safety. It also provides monitoring information when food is optimal for consumption, as intelligent packaging is essential for the consumer and the merchant. Therefore, this review will focus on discerning which packaging is most appropriate for each situation, solubility and toxicological considerations, characterization techniques, effect on the guest properties, and other aspects related to forming the inclusion complex with bioactive molecules applied to packaging.

Probing the Interactions of 31 Mycotoxins with Xanthine Oxidase: Alternariol, Alternariol-3-Sulfate, and α-Zearalenol Are Allosteric Inhibitors of the Enzyme

Mycotoxins are frequent toxic contaminants in foods and beverages, causing a significant health threat. Interactions of mycotoxins with biotransformation enzymes (e.g., cytochrome P450 enzymes, sulfotransferases, and uridine 5'-diphospho-glucuronosyltransferases) may be important due to their possible detoxification or toxic activation during enzymatic processes. Furthermore, mycotoxin-induced enzyme inhibition may affect the biotransformation of other molecules. A recent study described the strong inhibitory effects of alternariol and alternariol-9-methylether on the xanthine oxidase (XO) enzyme. Therefore, we aimed to test the impacts of 31 mycotoxins (including the masked/modified derivatives of alternariol and alternariol-9-methylether) on XO-catalyzed uric acid formation. Besides the in vitro enzyme incubation assays, mycotoxin depletion experiments and modeling studies were performed. Among the mycotoxins tested, alternariol, alternariol-3-sulfate, and α-zearalenol showed moderate inhibitory actions on the enzyme, representing more than tenfold weaker impacts compared with the positive control inhibitor allopurinol. In mycotoxin depletion assays, XO did not affect the concentrations of alternariol, alternariol-3-sulfate, and α-zearalenol in the incubates; thus, these compounds are inhibitors but not substrates of the enzyme. Experimental data and modeling studies suggest the reversible, allosteric inhibition of XO by these three mycotoxins. Our results help the better understanding of the toxicokinetic interactions of mycotoxins.

Probing Serum Albumins and Cyclodextrins as Binders of the Mycotoxin Metabolites Alternariol-3-Glucoside, Alternariol-9-Monomethylether-3-Glucoside, and Zearalenone-14-Glucuronide

Mycotoxins are toxic metabolites of molds. Chronic exposure to alternariol, zearalenone, and their metabolites may cause the development of endocrine-disrupting and carcinogenic effects. Alternariol-3-glucoside (AG) and alternariol-9-monomethylether-3-glucoside (AMG) are masked derivatives of alternariol. Furthermore, in mammals, zearalenone-14-glucuronide (Z14Glr) is one of the most dominant metabolites of zearalenone. In this study, we examined serum albumins and cyclodextrins (CDs) as potential binders of AG, AMG, and Z14Glr. The most important results/conclusions were as follows: AG and AMG formed moderately strong complexes with human, bovine, porcine, and rat albumins. Rat albumin bound Z14Glr approximately 4.5-fold stronger than human albumin. AG–albumin and Z14Glr–albumin interactions were barely influenced by the environmental pH, while the formation of AMG–albumin complexes was strongly favored by alkaline conditions. Among the mycotoxin–CD complexes examined, AMG–sugammadex interaction proved to be the most stable. CD bead polymers decreased the mycotoxin content of aqueous solutions, with moderate removal of AG and AMG, while weak extraction of Z14Glr was observed. In conclusion, rat albumin is a relatively strong binder of Z14Glr, and albumin can form highly stable complexes with AMG at pH 8.5. Therefore, albumins can be considered as affinity proteins with regard to the latter mycotoxin metabolites.

Testing Serum Albumins and Cyclodextrins as Potential Binders of the Mycotoxin Metabolites Alternariol-3-Sulfate, Alternariol-9-Monomethylether and Alternariol-9-Monomethylether-3-Sulfate

Alternaria mycotoxins, including alternariol (AOH), alternariol-9-monomethylether (AME), and their masked/modified derivatives (e.g., sulfates or glycosides), are common food contaminants. Their acute toxicity is relatively low, while chronic exposure can lead to the development of adverse health effects. Masked/modified metabolites can probably release the more toxic parent mycotoxin due to their enzymatic hydrolysis in the intestines. Previously, we demonstrated the complex formation of AOH with serum albumins and cyclodextrins; these interactions were successfully applied for the extraction of AOH from aqueous matrices (including beverages). Therefore, in this study, the interactions of AME, alternariol-3-sulfate (AS), and alternariol-9-monomethylether-3-sulfate (AMS) were investigated with albumins (human, bovine, porcine, and rat) and with cyclodextrins (sulfobutylether-β-cyclodextrin, sugammadex, and cyclodextrin bead polymers). Our major results/conclusions are the following: (1) The stability of mycotoxin-albumin complexes showed only minor species dependent variations. (2) AS and AMS formed highly stable complexes with albumins in a wide pH range, while AME-albumin interactions preferred alkaline conditions. (3) AME formed more stable complexes with the cyclodextrins examined than AS and AMS. (4) Beta-cyclodextrin bead polymer proved to be highly suitable for the extraction of AME, AS, and AMS from aqueous solution. (5) Albumins and cyclodextrins are promising binders of the mycotoxins tested.

Testing the protective effects of cyclodextrins vs. alternariol-induced acute toxicity in HeLa cells and in zebrafish embryos

Alternariol (AOH) is a mycotoxin produced by Alternaria fungi, it appears as a contaminant in tomatoes, grains, and grapes. The chronic exposure to AOH may cause carcinogenic and xenoestrogenic effects. Cyclodextrins (CDs) are cyclic oligosaccharides, they form host-guest complexes with apolar molecules. In this study, the interactions of AOH with CD monomers and polymers were examined employing fluorescence spectroscopy. Thereafter, the protective effects of certain CDs vs. AOH-induced toxicity were investigated on HeLa cells and on zebrafish embryos. Our major observations are the following: (1) Sugammadex forms highly stable complex with AOH (K = 4.8 ×10⁴ L/mol). (2) Sugammadex abolished the AOH-induced toxicity in HeLa cells, while native β-CD did not show relevant protective effect. (3) Each CD tested decreased the AOH-induced mortality and sublethal adverse effects in zebrafish embryos: Interestingly, native β-CD showed the strongest protective impact in this model. (4) CD technology may be suitable to relieve AOH-induced toxicity.

Testing the Protective Effects of Sulfobutylether-Βeta-Cyclodextrin (SBECD) and Sugammadex against Chlorpromazine-Induced Acute Toxicity in SH-SY5Y Cell Line and in NMRI Mice

Chlorpromazine (CPZ) is an antipsychotic drug which can cause several adverse effects and drug poisoning. Recent studies demonstrated that CPZ forms highly stable complexes with certain cyclodextrins (CDs) such as sulfobutylether-β-CD (SBECD) and sugammadex (SGD). Since there is no available antidote in CPZ intoxication, and considering the good tolerability of these CDs even if when administered parenterally, we aimed to investigate the protective effects of SBECD and SGD against CPZ-induced acute toxicity employing in vitro (SH-SY5Y neuroblastoma cells) and in vivo (zebrafish embryo) models. Our major findings and conclusions are the following: (1) both SBECD and SGD strongly relieved the cytotoxic effects of CPZ in SH-SY5Y cells. (2) SGD co-treatment did not affect or increase the CPZ-induced 24 h mortality in NMRI mice, while SBECD caused a protective effect in a dose-dependent fashion. (3) The binding constants of ligand–CD complexes and/or the in vitro protective effects of CDs can help to estimate the in vivo suitability of CDs as antidotes; however, some other factors can overwrite these predictions.

Supramolecular Complexes of Plant Neurotoxin Veratridine with Cyclodextrins and Their Antidote-like Effect on Neuro-2a Cell Viability

Veratridine (VTD) is a plant neurotoxin that acts by blocking the voltage-gated sodium channels (VGSC) of cell membranes. Symptoms of VTD intoxication include intense nausea, hypotension, arrhythmia, and loss of consciousness. The treatment for the intoxication is mainly focused on treating the symptoms, meaning there is no specific antidote against VTD. In this pursuit, we were interested in studying the molecular interactions of VTD with cyclodextrins (CDs). CDs are supramolecular macrocycles with the ability to form host–guest inclusion complexes (ICs) inside their hydrophobic cavity. Since VTD is a lipid-soluble alkaloid, we hypothesized that it could form stable inclusion complexes with different types of CDs, resulting in changes to its physicochemical properties. In this investigation, we studied the interaction of VTD with β-CD, γ-CD and sulfobutyl ether β-CD (SBCD) by isothermal titration calorimetry (ITC) and nuclear magnetic resonance (NMR) spectroscopy. Docking and molecular dynamics studies confirmed the most stable configuration for the inclusion complexes. Finally, with an interest in understanding the effects of the VTD/CD molecular interactions, we performed cell-based assays (CBAs) on Neuro-2a cells. Our findings reveal that the use of different amounts of CDs has an antidote-like concentration-dependent effect on the cells, significantly increasing cell viability and thus opening opportunities for novel research on applications of CDs and VTD.

Testing the extraction of 12 mycotoxins from aqueous solutions by insoluble beta-cyclodextrin bead polymer

Mycotoxins are toxic metabolites of filamentous fungi; they are common contaminants in numerous foods and beverages. Cyclodextrins are ring-shaped oligosaccharides, which can form host-guest type complexes with certain mycotoxins. Insoluble beta-cyclodextrin bead polymer (BBP) extracted successfully some mycotoxins (e.g., alternariol and zearalenone) from aqueous solutions, including beverages. Therefore, in this study, we aimed to examine the ability of BBP to remove other 12 mycotoxins (including aflatoxin B1, aflatoxin M1, citrinin, dihydrocitrinone, cyclopiazonic acid, deoxynivalenol, ochratoxin A, patulin, sterigmatocystin, zearalanone, α-zearalanol, and β-zearalanol) from different buffers (pH 3.0, 5.0, and 7.0). Our results showed that BBP can effectively extract citrinin, dihydrocitrinone, sterigmatocystin, zearalanone, α-zearalanol, and β-zearalanol at each pH tested. However, for the removal of ochratoxin A, BBP was far the most effective at pH 3.0. Based on these observations, BBP may be a suitable mycotoxin binder to extract certain mycotoxins from aqueous solutions for decontamination and/or for analytical purposes.

Effects of Microenvironmental Changes on the Fluorescence Signal of Alternariol: Magnesium Induces Strong Enhancement in the Fluorescence of the Mycotoxin

Alternariol (AOH) is an emerging mycotoxin produced by Alternaria molds. It occurs as a contaminant e.g., in oilseeds, cereals, grapes, and tomatoes. Chronic exposure to AOH may cause genotoxic and endocrine disruptor effects. Our recent studies demonstrated that the fluorescence signal of AOH can be strongly affected by the environmental pH as well as by the presence of serum albumin or cyclodextrins. In the current study, we aimed to characterize the most optimal circumstances regarding the highly sensitive fluorescent detection of AOH. Therefore, the further detailed investigation of the microenvironment on the fluorescence signal of the mycotoxin has been performed, including the effects of different buffers, organic solvents, detergents, and cations. Organic solvents (acetonitrile and methanol) caused only slight increase in the emission signal of AOH, while detergents (sodium dodecyl sulfate and Triton-X100) and Ca²⁺ induced considerably higher enhancement in the fluorescence of the mycotoxin. In addition, Mg²⁺ proved to be a superior fluorescence enhancer of the AOH. Spectroscopic and modeling studies suggest the formation of low-affinity AOH-Mg²⁺ complexes. The effect of Mg²⁺ was also tested in two HPLC assays: Our results show that Mg²⁺ can considerably increase the fluorescence signal of AOH even in a chromatographic system.

Research Progress on Synthesis and Application of Cyclodextrin Polymers

Cyclodextrins (CDs) are a series of cyclic oligosaccharides formed by amylose under the action of CD glucosyltransferase that is produced by Bacillus. After being modified by polymerization, substitution and grafting, high molecular weight cyclodextrin polymers (pCDs) containing multiple CD units can be obtained. pCDs retain the internal hydrophobic-external hydrophilic cavity structure characteristic of CDs, while also possessing the stability of polymer. They are a class of functional polymer materials with strong development potential and have been applied in many fields. This review introduces the research progress of pCDs, including the synthesis of pCDs and their applications in analytical separation science, materials science, and biomedicine.

Construction of a sustainable/controlled-release nano-container of non-toxic corrosion inhibitors for the water-based siliconized film: Estimating the host-guest interactions/desorption of inclusion complexes of cerium acetylacetonate (CeA) with beta-cyclodextrin (β-CD) via detailed electronic/atomic-scale computer modeling and experimental methods

Utilization of the coatings with self-healing anti-corrosion activities is one of the most promising routes for the development of advanced anti-corrosion coatings. In the present work, the green/sustainable corrosion inhibitive compounds based on the cerium acetylacetonate (CeA) was loaded into a beta-cyclodextrin (β-CD) nano-container (with negligible hazardous impacts) and through combined computer modeling and experimental approaches, the host-guest interactions/desorptions of the inclusion complexes of CeA with beta-cyclodextrin (β-CD) were assessed. The inhibition performance of the β-CD-CeA inclusion complex was investigated by electrochemical and surface experiments in a saline solution (NaCl, 3.5 wt.%). The particles were analyzed by Raman, XRD, FT-IR, and UV-vis spectroscopies. Additionally, the thermal properties in the 30-600 °C temperature range were examined by employing TGA/DTG test, and via the ICP analysis, the concentration of the released inorganic compounds in the electrolyte was studied. Achievements demonstrated 24 ppm Ce element existence after introducing β-CD-CeA inclusion complexes (during 24 h) in NaCl 3.5 wt.% solution. The analysis of Tafel curves proved that the prepared β-CD-CeA inclusion complex could inhibit the metallic substrate corrosion following the mixed cathodic and anodic mechanisms. The EIS investigation disclosed about 82 % inhibition degree after 48 h of metal immersion in the solution containing β-CD-CeA extract. The EIS analysis clarified that the silane coating (SC) resistance was enhanced noticeably by introducing the β-CD-CeA particles into the SC matrix. Using detailed-level (i.e., electronic and atomic) computer modeling techniques applying density functional theory (DFT), Mote Carlo (MC) and molecular dynamics (MD), the active sites, and the adsorption propensity of CeA complexes over the steel-based metallic adsorbents were explored. These modelings evidenced the CeA complexes interfacial adsorption on the steel.

The use of plant extracts and their phytochemicals for control of toxigenic fungi and mycotoxins

Mycotoxins present a great concern to food safety and security due to their adverse health and socio-economic impacts. The necessity to formulate novel strategies that can mitigate the economic and health effects associated with mycotoxin contamination of food and feed commodities without any impact on public health, quality and nutritional value of food and feed, economy and trade industry become imperative. Various strategies have been adopted to mitigate mycotoxin contamination but often fall short of the required efficacy. One of the promising approaches is the use of bioactive plant components/metabolites synergistically with mycotoxin-absorbing components in order to limit exposure to these toxins and associated negative health effects. In particular, is the fabrication of β-cyclodextrin-based nanosponges encapsulated with bioactive compounds of plant origin to inhibit toxigenic fungi and decontaminate mycotoxins in food and feed without leaving any health and environmental hazard to the consumers. The present paper reviews the use of botanicals extracts and their phytochemicals coupled with β-cyclodextrin-based nanosponge technology to inhibit toxigenic fungal invasion and detoxify mycotoxins.

Microfiltration results in the loss of analytes and affects the in vitro genotoxicity of a complex mixture of Alternaria toxins

Alternaria molds produce a variety of chemically diverse secondary metabolites with potentially adverse effects on human health. However, data on occurrence in food and human exposure is inconsistent for some of these mycotoxins. Membrane filtration is a frequent step in many sample preparation procedures for LC-MS-based methods analyzing food contaminants. Yet, little is known about the possibility of adsorptive phenomena that might result in analyte losses. Thus, we treated a complex extract of Alternaria toxins with several types of syringe filters and unraveled the impact on its chemical composition by LC-MS/MS. We observed significant, and in some cases complete, losses of compounds due to filtration. Particularly, two key Alternaria toxins, alternariol (AOH) and its monomethyl ether (AME), were heavily affected. As a comparison with published food surveys indicating a correlation of the type of filtration used with lower incidence reports in food, our results point at a possible underestimation of AME in past exposure assessment. Also, perylene quinones were greatly affected by filtration, underlining the importance to take this into consideration during analytical method development. Furthermore, we applied the comet assay in HT-29 cells to elucidate the impact of filtration on the genotoxicity of the extract. We observed strong coincidences with the loss of epoxide-carrying metabolites and also an intriguing induction of oxidative DNA damage by yet toxicologically uncharacterized Alternaria toxins. In conclusion, we highlight potential issues with sample filtration and call for a critical re-evaluation of previous food occurrence data in the light of the results at hand.

Toxicity of mycotoxins in vivo on vertebrate organisms: A review

Mycotoxins are considered to be a major risk factor affecting human and animal health as they are one of the most dangerous contaminants of food and feed. This review aims to compile the research developed up to date on the toxicological effects that mycotoxins can induce on human health, through the examination of a selected number of studies in vivo. AFB1 shows to be currently the most studied mycotoxin in vivo, followed by DON, ZEA and OTA. Scarce data was found for FBs, PAT, CIT, AOH and Fusarium emerging mycotoxins. The majority of them concerned the investigation of immunotoxicity, whereas the rest consisted in the study of genotoxicity, oxidative stress, hepatotoxicity, cytotoxicity, teratogenicity and neurotoxicity. In order to assess the risk, a wide range of different techniques have been employed across the reviewed studies: qPCR, ELISA, IHC, WB, LC-MS/MS, microscopy, enzymatic assays, microarray and RNA-Seq. In the last decade, the attention has been drawn to immunologic and transcriptomic aspects of mycotoxins' action, confirming their toxicity at molecular level. Even though, more in vivo studies are needed to further investigate their mechanism of action on human health.

Thermodynamic Characterization of the Interaction between the Antimicrobial Drug Sulfamethazine and Two Selected Cyclodextrins

Sulfamethazine is a representative member of the sulfonamide antibiotic drugs; it is still used in human and veterinary therapy. The protonation state of this drug affects its aqueous solubility, which can be controlled by its inclusion complexes with native or chemically-modified cyclodextrins. In this work, the temperature-dependent (298–313 K) interaction of sulfamethazine with native and randomly methylated β-cyclodextrins have been investigated at acidic and neutral pH. Surprisingly, the interaction between the neutral and anionic forms of the guest molecule and cyclodextrins with electron rich cavity are thermodynamically more favorable compared to the cationic guest. This property probably due to the enhanced formation of zwitterionic form of sulfamethazine in the hydrophobic cavities of cyclodextrins. Spectroscopic measurements and molecular modeling studies indicated the possible driving forces (hydrophobic interaction, hydrogen bonding, and electrostatic interaction) of the complex formation, and highlighted the importance of the reorganization of the solvent molecules during the entering of the guest molecule into the host’s cavity.