Current Knowledge of Individual and Combined Toxicities of Aflatoxin B1 and Fumonisin B1 In Vitro

Abstract

Mycotoxins are considered the most threating natural contaminants in food. Among these mycotoxins, aflatoxin B1 (AFB1) and fumonisin B1 (FB1) are the most prominent fungal metabolites that represent high food safety risks, due to their widespread co-occurrence in several food commodities, and their profound toxic effects on humans. Considering the ethical and more humane animal research, the 3Rs (replacement, reduction, and refinement) principle has been promoted in the last few years. Therefore, this review aims to summarize the research studies conducted up to date on the toxicological effects that AFB1 and FB1 can induce on human health, through the examination of a selected number of in vitro studies. Although the impact of both toxins, as well as their combination, were investigated in different cell lines, the majority of the work was carried out in hepatic cell lines, especially HepG2, owing to the contaminants’ liver toxicity. In all the reviewed studies, AFB1 and FB1 could invoke, after short-term exposure, cell apoptosis, by inducing several pathways (oxidative stress, the mitochondrial pathway, ER stress, the Fas/FasL signaling pathway, and the TNF-α signal pathway). Among these pathways, mitochondria are the primary target of both toxins. The interaction of AFB1 and FB1, whether additive, synergistic, or antagonistic, depends to great extent on FB1/AFB1 ratio. However, it is generally manifested synergistically, via the induction of oxidative stress and mitochondria dysfunction, through the expression of the Bcl-2 family and p53 proteins. Therefore, AFB1 and FB1 mixture may enhance more in vitro toxic effects, and carry a higher significant risk factor, than the individual presence of each toxin.

Toxicity Screening of Fungal Extracts and Metabolites, Xenobiotic Chemicals, and Indoor Dusts with In Vitro and Ex Vivo Bioassay Methods

“…It has been demanded that animal experiments should be replaced by cell tests in toxicological research [ 8 , 38 ], but it is controversial how well cell-based bioassays replace the in vivo exposures in animal experiments. This is specifically true for the risk assessment of respiratory toxins, e.g., T-2 toxin was over 10 times more toxic when inhaled than after systemic administration [ 38 , 39 ]. Several mycotoxins produced by molds (e.g., ochratoxin and fumonisins) are very toxic in vivo [ 38 , 40 ], but there is no sensitive in vitro biotest to measure their true bioactivity.…”

“…This is specifically true for the risk assessment of respiratory toxins, e.g., T-2 toxin was over 10 times more toxic when inhaled than after systemic administration [ 38 , 39 ]. Several mycotoxins produced by molds (e.g., ochratoxin and fumonisins) are very toxic in vivo [ 38 , 40 ], but there is no sensitive in vitro biotest to measure their true bioactivity. Methanol, commonly used in the extraction of toxic compounds, is a non-toxic solvent in cell tests, but its metabolic product, formic acid, is toxic to humans and monkeys [ 41 ].…”

Quantitative Determination of Aflatoxin B1 in Maize and Feed by ELISA and Time-Resolved Fluorescent Immunoassay Based on Monoclonal Antibodies

“…AFTs are secondary metabolites mainly produced by Aspergillus flavus and A. parasiticus, which are teratogenic and mutagenic [2]. Among them, aflatoxin B 1 (AFB 1 ) is considered a carcinogenic agent (group 1 carcinogens) due to its potent hepatocellular carcinoma (HCC) in humans, as well as its immunotoxic, mutagenic, and teratogenic properties in humans [3]. Cereals become contaminated by AFTs during their growth, harvesting, transportation, and storage [4].…”