Detoxification of Aflatoxin B1 Contaminated Maize Using Human CYP3A4

Metabolic transformation of cyclopiazonic acid in liver microsomes from different species based on UPLC-Q/TOF-MS

To investigate the metabolic transformation of cyclopiazonic acid (CPA) in the liver of different species and to supplement accurate risk assessment information, the metabolism of CPA in liver microsomes from four animals and humans was studied using the ultra-high-performance liquid chromatography-quadrupole/time-of-flight method. The results showed that a total of four metabolites were obtained, and dehydrogenation, hydroxylation, methylation, and glucuronidation were identified as the main metabolic pathways of CPA. Rat liver microsomes exhibited the highest metabolic capacity for CPA, with dehydrogenated (C20H18N2O3) and glucuronic acid-conjugated (C26H28N2O10) metabolites identified in all liver microsomes except chicken, indicating significant species metabolic differences. Moreover, C20H18N2O3 was only detected in the incubation system with cytochromes P450 3A4 (CYP3A4). The hydroxylated (C20H20N2O4) and methylated (C21H22N2O3) metabolites were detected in all incubation systems except for the CYP2C9, with CYP3A4 demonstrating the strongest metabolic capacity. The "cocktail" probe drug method showed that CPA exhibited a moderate inhibitory effect on the CYP3A4 (IC50 value = 8.658 μM), indicating that the substrate had a negative effect on enzyme activity. Our results provide new insights to understand the biotransformation profile of CPA in animals and humans.

Alanazi M, El Yazidi M. Efficient Synthesis, Structural Characterization, Antibacterial Assessment, ADME-Tox Analysis, Molecular Docking and Molecular Dynamics Simulations of New Functionalized Isoxazoles

This work describes the synthesis, characterization, and in vitro and in silico evaluation of the biological activity of new functionalized isoxazole derivatives. The structures of all new compounds were analyzed by IR and NMR spectroscopy. The structures of 4c and 4f were further confirmed by single crystal X-ray and their compositions unambiguously determined by mass spectrometry (MS). The antibacterial effect of the isoxazoles was assessed in vitro against Escherichia coli, Bacillus subtilis, and Staphylococcusaureus bacterial strains. Isoxazole 4a showed significant activity against E. coli and B. subtilis compared to the reference antibiotic drugs while 4d and 4f also exhibited some antibacterial effects. The molecular docking results indicate that the synthesized compounds exhibit strong interactions with the target proteins. Specifically, 4a displayed a better affinity for E. coli, S. aureus, and B. subtilis in comparison to the reference drugs. The molecular dynamics simulations performed on 4a strongly support the stability of the ligand-receptor complex when interacting with the active sites of proteins from E. coli, S. aureus, and B. subtilis. Lastly, the results of the Absorption, Distribution, Metabolism, Excretion and Toxicity Analysis (ADME-Tox) reveal that the molecules have promising pharmacokinetic properties, suggesting favorable druglike properties and potential therapeutic agents.

Current physical techniques for the degradation of aflatoxins in food and feed: Safety evaluation methods, degradation mechanisms and products

Aflatoxins are the most toxic natural mycotoxins discovered so far, posing a serious menace to the food safety and trading economy of the world, especially developing countries. How to effectively detoxify has persistently occupied a place on the list of "global hot-point" concerns. Among the developed detoxification methods, physical methods, as the authoritative techniques for aflatoxins degradation, could rapidly induce irreversible denaturation of aflatoxins. This review presents a brief overview of aflatoxins detection and degradation product structure identification methods. Four main safety evaluation methods for aflatoxins and degradation product toxicity assessment are highlighted combined with an update on research of aflatoxins decontamination in the last decade. Furthermore, the latest applications, degradation mechanisms and products of physical aflatoxin decontamination techniques including microwave heating, irradiation, pulsed light, cold plasma and ultrasound are discussed in detail. Regulatory issues related to "detoxification" are also explained. Finally, we put forward the challenges and future work in studying aflatoxin degradation based on the existing research. The purpose of supplying this information is to help researchers have a deeper understanding on the degradation of aflatoxins, break through the existing bottleneck, and further improve and innovate the detoxification methods of aflatoxins.

Antioxidant, Volatile Compounds; Antimicrobial, Anti-Inflammatory, and Dermatoprotective Properties of Cedrus atlantica (Endl.) Manetti Ex Carriere Essential Oil: In Vitro and In Silico Investigations

Cedrus atlantica (Endl.) Manetti ex Carriere is an endemic tree possessing valuable health benefits which has been widely used since time immemorial in international traditional pharmacopoeia. The aim of this exploratory investigation is to determine the volatile compounds of C. atlantica essential oils (CAEOs) and to examine their in vitro antimicrobial, antioxidant, anti-inflammatory, and dermatoprotective properties. In silico simulations, including molecular docking and pharmacokinetics absorption, distribution, metabolism, excretion, and toxicity (ADMET), and drug-likeness prediction were used to reveal the processes underlying in vitro biological properties. Gas chromatography-mass spectrophotometry (GC-MS) was used for the chemical screening of CAEO. The antioxidant activity of CAEO was investigated using four in vitro complementary techniques, including ABTS and DPPH radicals scavenging activity, ferric reductive power, and inhibition of lipid peroxidation (β-carotene test). Lipoxygenase (5-LOX) inhibition and tyrosinase inhibitory assays were used for testing the anti-inflammatory and dermatoprotective properties. GC-MS analysis indicated that the main components of CAEO are β-himachalene (28.99%), α-himachalene (14.43%), and longifolene (12.2%). An in vitro antimicrobial activity of CAEO was examined against eleven strains of Gram-positive bacteria (three strains), Gram-negative bacteria (four strains), and fungi (four strains). The results demonstrated high antibacterial and antifungal activity against ten of them (>15 mm zone of inhibition) using the disc-diffusion assay. The microdilution test showed that the lowest values of MIC and MBC were recorded with the Gram-positive bacteria in particular, which ranged from 0.0625 to 0.25 % v/v for MIC and from 0.5 to 0.125 % v/v for MBC. The MIC and MFC of the fungal strains ranged from 0.5 to 4.0% (MIC) and 0.5 to 8.0% v/v (MFC). According to the MBC/MIC and MFC/MIC ratios, CAEO has bactericidal and fungicidal activity. The results of the in vitro antioxidant assays revealed that CAEO possesses remarkable antioxidant activity. The inhibitory effects on 5-LOX and tyrosinase enzymes was also significant (p < 0.05). ADMET investigation suggests that the main compounds of CAEO possess favorable pharmacokinetic properties. These findings provide scientific validation of the traditional uses of this plant and suggest its potential application as natural drugs.

Molecular docking and in vitro evaluations reveal the role of human cytochrome P450 3A4 in the cross-coupling metabolism of phenolic xenobiotics

Metabolism generally transforms xenobiotics into more polar and hydrophilic products, facilitating their elimination from the body. Recently, a new metabolic pathway that transforms phenolic xenobiotics into more lipophilic and bioactive dimer products was discovered. To elucidate the role of cytochrome P450 (CYP) enzymes in mediating this cross-coupling metabolism, we used high-throughput screening to identify the metabolites generated from the coupling of 20 xenobiotics with four endogenous metabolites in liver microsomes. Endogenous vitamin E (VE) was the most reactive metabolite, as VE reacted with seven phenolic xenobiotics containing various structures (e.g., an imidazoline ring or a diphenol group) to generate novel lipophilic ethers such as bakuchiol-O-VE, phentolamine-O-VE, phenylethyl resorcinol-O-VE, 2-propanol-O-VE, and resveratrol-O-VE. Seven recombinant CYP enzymes were successfully expressed and purified in Escherichia coli. Integration of the results of recombinant human CYP incubation and molecular docking identified the central role of CYP3A4 in the cross-coupling metabolic pathway. Structural analysis revealed the π-π interactions, hydrogen bonds, and hydrophobic interactions between reactive xenobiotics and VE in the malleable active sites of CYP3A4. The consistency between the molecular docking results and the in vitro human cytochrome P450 evaluation shows that docking calculations can be used to screen molecules participating in cross-coupling metabolism. The results of this study provide supporting evidence for the overlooked toxicological effects induced by direct reactions between xenobiotics and endogenous metabolites during metabolic processes.

Degradation of Aflatoxin B1 by recombinant laccase extracellular produced from Escherichia coli

Bioenzymatic degradation of aflatoxin B1 (AFB1) is a safe, efficient and environmentally friendly detoxification technology. In this work, AFB1 was successfully degraded by recombinant laccase (fmb-rL103) in the absence of a mediator. The laccase gene was cloned from Bacillus vallismortis fmb-103, and was expressed in heterologous host Escherichia coli after codon optimization. The extracellular production of fmb-rL103 could be induced by adding methanol (6 %, v/v), and the maximum yield was 1545.6 U/L. In the 10 L bioreactor, the extracellular yield increased to 50,950.6 U/L after 20 h of induction, accounting for three quarters of the total yield. The mechanism of methanol-induced extracellular secretion was further studied by measuring acetate content, lac103 gene expression and cell membrane permeability. Furthermore, we explored the biochemical properties of fmb-rL103 and its degradation conditions on AFB1. The degradation efficiency increased constantly with increase in incubation pH and temperature, and exceeded 60 % at pH 7.0 and 37 °C. This work provides new insight into developing the large-scale production of laccase and its application to degrade AFB1.

Curcumin activates the Nrf2 Pathway to alleviate AFB1-induced immunosuppression in the spleen of ducklings

Ducklings is one of the most susceptible poultry to Aflatoxin B1 (AFB1) which widely existed in duckling products will also in turn affect human health. Curcumin (CUR) has significant effects on immune regulation and anti-oxidation. But whether CUR alleviates toxic effects on duckling spleen induced by AFB1 remains largely unknown. In this study we treated duckings with AFB1 and CUR for 21 days before harvesting serum and spleen tissue for analyses. The results showed that AFB1 damaged the spleen tissue of ducklings by activating the NF-κB signaling pathway. And the addition of CUR not only promoted the growth of ducklings, but also enhanced the immune function of the spleen and reduced the damage of AFB1 to the spleen tissue. At the same time, CUR activated the Nrf2 signaling pathway, upregulated the expression of related antioxidant enzymes, inhibited the NF-kB signaling pathway, and ultimately reducing the inflammation of the duckling spleen induced by AFB1. It has been suggested from these results that Nrf2 pathway might be a potential therapeutic target for CUR to treat AFB1-induced immunosuppression in ducklings.

A Portable, Cost-Effective and User-Friendly Instrument for Colorimetric Enzyme-Linked Immunosorbent Assay and Rapid Detection of Aflatoxin B1

Food analysis based on the enzyme-linked immunosorbent assay (ELISA) is simple, sensitive and rapid, but requires a costly colorimetric instrument. The aim of this work was to develop a portable, low-cost and user-friendly colorimetric instrument for colorimetric ELISA and aflatoxin B₁ (AFB₁) detection. The principle of the developed instrument was employing a light-emitting diode to generate the signal light and using a light-dependent resistor to measure the signal light absorbed by the oxidized 3,3′,5,5′-tetramethyl benzidine. The absorption spectra revealed that the solution absorbed signal light more strongly after reaction with H₂SO₄, and blue light would be favorably absorbed. Evaluations on the stability and accuracy of the instrument and interference from ambient light showed that the fabricated instrument was stable, accurate, capable of quantitative detection and insensitive to ambient light changes. In addition, this instrument is user-friendly since it could calculate and report the final amount of AFB₁ to the operator. Measurements of maize and peanuts showed that the instrument provided as accurate results as the professional equipment. With the low fabrication cost (about RMB 129 or USD 20), portability, and user-friendliness, this instrument presents attractive potential in the rapid detection of AFB₁.

Cytochrome P450-mediated mycotoxin metabolism by plant-feeding insects

Mycotoxins are secondary metabolites produced primarily by filamentous fungi that when consumed cause pathological responses in animal hosts or consumers. Defined functionally rather than structurally, mycotoxins derive from numerous primary metabolic pathways. Through opportunistic or mutualistic associations, insect herbivores inflict damage that can predispose plants to infection by mycotoxin-producing phytopathogens, resulting in economically significant contamination. The few cytochrome P450 subfamilies implicated in mycotoxin detoxification by insects, including CYP6 and CYP9, are also known to detoxify phytochemicals. Some insect P450s bioactivate, rather than detoxify, mycotoxins, suggestive of an 'escalation' in arms-race interactions between these herbivores and fungi. Characterizing insect P450s that detoxify mycotoxins can be useful for developing biological remediation technologies and for ensuring the safety of insects reared for human or livestock consumption.