Fumonisin B1 -induced mitochondrial toxicity and hepatoprotective potential of rooibos: An update

Gold nanoparticles-doped MXene heterostructure for ultrasensitive electrochemical detection of fumonisin B1 and ampicillin

Early transition metal carbides (MXene) hybridized by precious metals open a door for innovative electrochemical biosensing device design. Herein, we present a facile one-pot synthesis of gold nanoparticles (AuNPs)-doped two-dimensional (2D) titanium carbide MXene nanoflakes (Ti3C2Tx/Au). Ti3C2Tx MXene exhibits high electrical conductivity and yields synergistic signal amplification in conjunction with AuNPs leading to excellent electrochemical performance. Thus Ti3C2Tx/Au hybrid nanostructure can be used as an electrode platform for the electrochemical analysis of various targets. We used screen-printed electrodes modified with the Ti3C2Tx/Au electrode and functionalized with different biorecognition elements to detect and quantify an antibiotic, ampicillin (AMP), and a mycotoxin, fumonisin B1 (FB1). The ultralow limits of detection of 2.284 pM and 1.617 pg.mL-1, which we achieved respectively for AMP and FB1 are far lower than their corresponding maximum residue limits of 2.8 nM in milk and 2 to 4 mg kg-1 in corn products for human consumption set by the United States Food and Drug Administration. Additionally, the linear range of detection and quantification of AMP and FB1 were, respectively, 10 pM to 500 nM and 10 pg mL-1 to 1 µg mL-1. The unique structure and excellent electrochemical performance of Ti3C2Tx/Au nanocomposite suggest that it is highly suitable for anchoring biorecognition entities such as antibodies and oligonucleotides for monitoring various deleterious contaminants in agri-food products.

Advances in investigating microcystin-induced liver toxicity and underlying mechanisms

Microcystins (MCs) are a class of biologically active cyclic heptapeptide pollutants produced by the freshwater alga Microcystis aeruginosa. With increased environmental pollution, MCs have become a popular research topic. In recent years, the hepatotoxicity of MCs and associated effects and mechanisms have been studied extensively. Current epidemiological data indicate that long-term human exposure to MCs can lead to severe liver toxicity, acute toxicity, and death. In addition, current toxicological studies on the liver, a vital target organ of MCs, indicate that MC contamination is associated with the development of liver cancer, nonalcoholic fatty liver, and liver fibrosis. MCs produce hepatotoxicity that affects the metabolic homeostasis of the liver, induces apoptosis, and acts as a pro-cancer factor, leading to liver lesions. MCs mainly mediate the activation of signaling pathways, such as the ERK/JNK/p38 MAPK and IL-6-STAT3 pathways, which leads to oxidative damage and even carcinogenesis. Moreover, MCs can act synergistically with other pollutants to produce combined toxicity. However, few systematic reviews have been performed on these new findings. This review systematically summarizes the toxic effects and mechanisms of MCs on the liver and discusses the combined liver toxicity effects of MCs and other pollutants to provide reference for subsequent research. The toxicity of different MC isomers deserves further study. The detection methods and limit standards of MCs in agricultural and aquatic products will represent important research directions in the future. Standard protocols for fish sampling during harmful algal blooms or to evaluate the degree of MC toxicity in nature are lacking. In future, bioinformatics can be applied to offer insights into MC toxicology research and potential drug development for MC poisoning. Further research is essential to understand the molecular mechanisms of liver function damage in combined-exposure toxicology studies to establish treatment for MC-induced liver damage.

B-Type Fumonisins in Post-Fermented Tea: Occurrence and Consumer Dietary Exposure in Guangxi, China

Post-fermented tea (PFT), a commonly consumed beverage worldwide, is characterized by the rapid growth of its microbial groups and the substantial changes they undergo. Consequently, PFT may contain mycotoxins such as B-type fumonisins (FBs). This study aimed to assess the intake of FBs through the consumption of PFT among consumers in Guangxi, China. A novel quantitative method using high-performance liquid chromatography-mass spectrometry was used to determine the FB concentration in PFT products. Additionally, a PFT consumption survey was conducted using a face-to-face questionnaire, recording their body weight and PFT consumption patterns based on a three-day dietary recall method. Finally, hazard index was calculated to estimate the health risk of FBs from the consumption of PFT products in Guangxi. The results revealed that the occurrence of FBs in PFT was 20% (24/120), with a concentration ranging from 2.14 to 18.28 μg/kg. The results of the survey showed that the average daily consumption of PFT by consumers was 9.19 ± 11.14 g. The deterministic risk assessment revealed that only 0.026% of the provisional maximum tolerable daily intake of FBs was consumed through PFT, indicating that FB contamination in PFT is not a public health risk.

New insights into the combined toxicity of aflatoxin B1 and fumonisin B1 in HepG2 cells using Seahorse respirometry analysis and RNA transcriptome sequencing

Aflatoxin B1 (AFB1) and fumonisin B1 (FB1) are widely (co-)detected in food and known for their hepatotoxicity in humans. Still, their combined toxicity needs to be investigated, especially the impact on mitochondria. In our previous work, we examined the effect of short-term exposure to different doses of AFB1, FB1, and their binary mixture (MIX) on the bioenergetic status of HepG2 cells, a well-recognized in vitro model system for studying liver cell function. In the current work, we further investigated the (combined) effect of AFB1 and FB1 on the mitochondrial and glycolytic activity of HepG2 cells using Seahorse respirometry analysis and RNA transcriptome sequencing. The results showed that the co-exposure, especially at high doses, is more toxic due to a more inhibition of all parameters of mitochondrial respiration. However, FB1 contributes more to the MIX effects than AFB1. RNA transcriptome sequencing showed that the p53 signaling pathway, a major orchestrator of mitochondrial apoptosis, was differentially expressed. Moreover, the co-exposure significantly downregulated the genes encoding for Complexes I, II, III, and IV, representing the onset of the suppressed mitochondrial respiration in HepG2 cells.

Fumonisin B1 disrupts mitochondrial function in oxidatively poised HepG2 liver cells by disrupting oxidative phosphorylation complexes and potential participation of lincRNA-p21

Fumonisin B₁ (FB₁) is etiologically linked to cancer, yet the underlying mechanisms remain largely unclear. It is also not known if mitochondrial dysfunction is involved as a contributor to FB₁-induced metabolic toxicity. This study investigated the effects of FB₁ on mitochondrial toxicity and its implications in cultured human liver (HepG2) cells. HepG2 cells poised to undergo oxidative and glycolytic metabolism were exposed to FB₁ for 6 h. We determined mitochondrial toxicity, reducing equivalent levels and mitochondrial sirtuin activity using luminometric, fluorometric and spectrophotometric methods. Molecular pathways involved were determined using western blots and PCR. Our data confirm that FB₁ is a mitochondrial toxin capable of disrupting the stability of complexes I and V of the mitochondrial electron transport and decreasing the NAD:NADH ratio in galactose supplemented HepG2 cells. We further showed that in cells treated with FB₁, p53 acts as a metabolic stress-responsive transcription factor that induces the expression of lincRNA-p21, which plays a crucial role in stabilising HIF-1α. The findings provide novel insights into the impact of this mycotoxin in the dysregulation of energy metabolism and may contribute to the growing body of evidence of its tumor promoting effects.

The natural occurrence, toxicity mechanisms and management strategies of Fumonisin B1：A review

Fumonisin B1 (FB1) contaminates various crops, causing huge losses to agriculture and livestock worldwide. This review summarizes the occurrence regularity, toxicity, toxic mechanisms and management strategies of FB1. Specifically, FB1 contamination is particularly serious in developing countries, humid and hot regions. FB1 exposure can produce different toxic effects on the nervous system, respiratory system, digestive system and reproductive system. Furthermore, FB1 can also cause systemic immunotoxicity. The mechanism of toxic effects of FB1 is to interfere with the normal pathway of sphingolipid de novo biosynthesis by acting as a competitive inhibitor of ceramide synthase. Meanwhile, the toxic products of sphingolipid metabolic disorders can cause oxidative stress and apoptosis. FB1 also often causes feed contamination by mixing with other mycotoxins, and then exerts combined toxicity. For detection, lateral flow dipstick technology and enzyme linked immunosorbent assay are widely used in the detection of FB1 in commercial feeds, while mainstream detection methods such as high performance liquid chromatography and liquid chromatography-mass spectrometry are widely used in the laboratory theoretical study of FB1. For purification means of FB1, some natural plant extracts (such as Zingiber officinale and Litsea Cubeba essential oil) and their active compounds have been proved to inhibit the toxic effects of FB1 and protect livestock due to their antifungal and antioxidant effects. Natural plant extract has the advantages of high efficiency, low cost and no contamination residue. This review can provide information for comprehensive understanding of FB1, and provide reference for formulating reasonable treatment and management strategies in livestock production.

Recent Research on Fusarium Mycotoxins in Maize—A Review

Maize (Zea mays L.) is one of the most susceptible crops to pathogenic fungal infections, and in particular to the Fusarium species. Secondary metabolites of Fusarium spp.—mycotoxins are not only phytotoxic, but also harmful to humans and animals. They can cause acute or chronic diseases with various toxic effects. The European Union member states apply standards and legal regulations on the permissible levels of mycotoxins in food and feed. This review summarises the most recent knowledge on the occurrence of toxic secondary metabolites of Fusarium in maize, taking into account modified forms of mycotoxins, the progress in research related to the health effects of consuming food or feed contaminated with mycotoxins, and also the development of biological methods for limiting and/or eliminating the presence of the same in the food chain and in compound feed.

Bioenergetic Status of the Intestinal and Hepatic Cells after Short Term Exposure to Fumonisin B1 and Aflatoxin B1

Fumonisin B1 (FB1) and aflatoxin B1 (AFB1) are frequent contaminants of staple foods such as maize. Oral exposure to these toxins poses health hazards by disrupting cellular signaling. However, little is known regarding the multifaced mitochondrial dysfunction-linked toxicity of FB1 and AFB1. Here, we show that after exposure to FB1 and AFB1, mitochondrial respiration significantly decreased by measuring the oxygen consumption rate (OCR), mitochondrial membrane potential (MMP) and reactive oxygen species (ROS). The current work shows that the integrity of mitochondria (MMP and ROS), that is the central component of cell apoptosis, is disrupted by FB1 and AFB1 in undifferentiated Caco-2 and HepG2 cells as in vitro models for human intestine and liver, respectively. It hypothesizes that FB1 and AFB1 could disrupt the mitochondrial electron transport chain (ETC) to induce mitochondrial dysfunction and break the balance of transferring H⁺ between the mitochondrial inner membrane and mitochondrial matrix, however, the proton leak is not increasing and, as a result, ATP synthesis is blocked. At the sub-toxic exposure of 1.0 µg/mL for 24 h, i.e., a viability of 95% in Caco-2 and HepG2 cells, the mitochondrial respiration was, however, stimulated. This suggests that the treated cells could reserve energy for mitochondrial respiration with the exposure of FB1 and AFB1, which could be a survival advantage.

Toxic Mechanism and Biological Detoxification of Fumonisins

Food safety is related to the national economy and people’s livelihood. Fumonisins are widely found in animal feed, feed raw materials, and human food. This can not only cause economic losses in animal husbandry but can also have carcinogenicity or teratogenicity and can be left in animal meat, eggs, and milk which may enter the human body and pose a serious threat to human health. Although there are many strategies to prevent fumonisins from entering the food chain, the traditional physical and chemical methods of mycotoxin removal have some disadvantages, such as an unstable effect, large nutrient loss, impact on the palatability of feed, and difficulty in mass production. As a safe, efficient, and environmentally friendly detoxification technology, biological detoxification attracts more and more attention from researchers and is gradually becoming an accepted technique. This work summarizes the toxic mechanism of fumonisins and highlights the advances of fumonisins in the detoxification of biological antioxidants, antagonistic microorganisms, and degradation mechanisms. Finally, the future challenges and focus of the biological control and degradation of fumonisins are discussed.

Fumonisin B1 Inhibits Cell Proliferation and Decreases Barrier Function of Swine Umbilical Vein Endothelial Cells

The fumonisins are a group of common mycotoxins found around the world that mainly contaminate maize. As environmental toxins, they pose a threat to human and animal health. Fumonisin B₁ (FB₁) is the most widely distributed and the most toxic. FB₁ can cause pulmonary edema in pigs. However, the current toxicity mechanism of fumonisins is still in the exploratory stage, which may be related to sphingolipid metabolism. Our study is designed to investigate the effect of FB₁ on the cell proliferation and barrier function of swine umbilical vein endothelial cells (SUVECs). We show that FB₁ can inhibit the cell viability of SUVECs. FB₁ prevents cells from entering the S phase from the G1 phase by regulating the expression of the cell cycle-related genes cyclin B1, cyclin D1, cyclin E1, Cdc25c, and the cyclin-dependent kinase-4 (CDK-4). This results in an inhibition of cell proliferation. In addition, FB₁ can also change the cell morphology, increase paracellular permeability, destroy tight junctions and the cytoskeleton, and reduce the expression of tight junction-related genes claudin 1, occludin, and ZO-1. This indicates that FB₁ can cause cell barrier dysfunction of SUVECs and promote the weakening or even destruction of the connections between endothelial cells. In turn, this leads to increased blood vessel permeability and promotes exudation. Our findings suggest that FB₁ induces toxicity in SUVECs by affecting cell proliferation and disrupting the barrier function.

Epiphytic Acampe ochracea orchid relieves paracetamol-induced hepatotoxicity by inhibiting oxidative stress and upregulating antioxidant genes in in vivo and virtual screening

Orchids are basically ornamental, and biological functions are seldom evaluated. This research investigated the effects of Acampe ochracea methanol extract (AOME) in ameliorating the paracetamol (PCM) induced liver injury in Wistar albino rats, evaluating its phytochemical status through UPLC-qTOF-MS analysis. With molecular docking and network pharmacology, virtual screening verified the inevitable interactions between the UPLC-qTOF-MS-characterized compounds and hepatoprotective drug receptors. The AOME has explicit a dose-dependent decrease of liver enzymes acid phosphatase (ACP), aspartate aminotransferase (AST), alanine aminotransferase (ALT), alkaline phosphatase (ALP), gamma-glutamyl transferase (GGT), lactate dehydrogenase (LDH), total bilirubin, as well as an increase of serum total protein and antioxidant enzymes catalase (CAT), superoxide dismutase (SOD), glutathione reductase (GSH) with a virtual normalization (p < 0.05-p < 0.001) and the values were almost equivalent to the reference drug silymarin. After pretreatment with AOME, PCM-induced malondialdehyde (MDA) levels were considerably decreased (p < 0.001). Histopathological examinations corroborated the functional and biochemical findings. The AOME upregulated the genes involved in antioxidative (CAT, SOD, β-actin, PON1, and PFK1) and hepatoprotective mechanisms in PCM intoxicated rats. An array of 103 compounds has been identified from AOME through UPLC-qTOF-MS analysis. The detected compounds were substantially related to the targets of several liver proteins and antioxidative enzymes, according to an in silico study. Virtual prediction by SwissADME and admetSAR showed that AOME has drug-like, non-toxic, and potential pharmacological activities in hepatic damage. Furthermore, VEGFA, CYP19A1, MAPK14, ESR1, and PPARG genes interact with target compounds impacting the significant biological actions to recover PCM-induced liver damage.

Rooibos (Aspalathus linearis) influence on health and ovarian functions

This paper reviews provenance, processing and properties of rooibos (Aspalathus linearis, Brum.f) and its numerous biologically active constituents, as well as the currently available knowledge concerning their physiological and medicinal effects and their possible extra- and intracellular mechanisms of action. Search for literature was performed in agreement with the preferred reporting items for systematic review criteria in Cochrane Library, PubMed, Web of Science and SCOPUS databases between the years 2000 and 2021. The limited number of in vitro studies suggests an influence of rooibos on basic ovarian cell functions, as well as its potential applicability to control female reproduction and prevent the effect of environmental contaminants on ovarian functions. Nevertheless, further studies are required for better understanding of the character and mechanisms of action, as well as of rooibos' application in reproductive biology and medicine.

Hepatotoxicity of food-borne mycotoxins: molecular mechanism, anti-hepatotoxic medicines and target prediction

Mycotoxins are metabolites produced by fungi. The widespread contamination of food and feed by mycotoxins is a global food safety problem and a serious threat to people's health. Most food-borne mycotoxins have strong hepatotoxicity. However, no effective methods have been found to prevent or treat Mycotoxin- Induced Liver Injury (MILI) in clinical and animal husbandry. In this paper, the molecular mechanisms and potential anti-MILI medicines of six food-borne MILI are reviewed, and their targets are predicted by network toxicology, which provides a theoretical basis for further study of the toxicity mechanism of MILI and the development of effective strategies to manage MILI-related health problems in the future and accelerate the development of food safety.

Update on the adverse effects of microcystins on the liver

Microcystins (MCs) are the most common cyanobacteria toxins in eutrophic water, which have strong hepatotoxicity. In the past decade, epidemiological and toxicological studies on liver damage caused by MCs have proliferated, and new mechanisms of hepatotoxicity induced by MCs have also been discovered and confirmed. However, there has not been a comprehensive and systematic review of these new findings. Therefore, this paper summarizes the latest advances in studies on the hepatotoxicity of MCs to reveal the effects and mechanisms of hepatotoxicity induced by MCs. Current epidemiological studies have confirmed that symptoms or signs of liver damage appear after human exposure to MCs, and a long time of exposure can even lead to liver cancer. Toxicological studies have shown that MCs can affect the expression of oncogenes by activating cell proliferation pathways such as MAPK and Akt, thereby promoting the occurrence and development of cancer. The latest evidence shows that epigenetic modifications may play an important role in MCs-induced liver cancer. MCs can cause damage to the liver by inducing hepatocyte death, mainly manifested as apoptosis and necrosis. The imbalance of liver metabolic homeostasis may be involved in hepatotoxicity induced by MCs. In addition, the combined toxicity of MCs and other toxins are also discussed in this article. This detailed information will be a valuable reference for further exploring of MCs-induced hepatotoxicity.

A 65-Day Fumonisin B Exposure at High Dietary Levels Has Negligible Effects on the Testicular and Spermatological Parameters of Adult Rabbit Bucks

A 65-day study was undertaken to test the effects of two doses (10 and 20 mg/kg) of dietary fumonisin Bs (FB) on the rabbit male reproduction system. Body and testicular weight was not affected by the intoxication, neither the fatty acid composition of the testicular total phospholipids; the testis histological analysis failed to reveal any toxic effect. The FBs increased the testicular concentration and activity of reduced glutathione and glutathione peroxidase and decreased initial phase lipid peroxidation (conjugated dienes and trienes) in a dose dependent manner. Sperm morphology and chromatin condensation were monitored on Feulgen-stained smears. No significant differences were observed between the treatment groups and between sampling time points. The live cell ratio in the sperm (as assessed with flow cytometry) was not different among groups at any of the five sampling timepoints and was also identical within groups. Similarly, the spermatozoa membrane lipid profile was also identical in all three groups after the total intoxication period. In summary, it was demonstrated that FBs in an unrealistic and unjustified high dose still do not exert any drastic harmful effect on the leporine, male reproduction system, meanwhile slightly augmenting testicular antioxidant response.

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.