Transformations of Selected Fusarium Toxins and Their Modified Forms During Malt Loaf Production

Lamium album Flower Extracts: A Novel Approach for Controlling Fusarium Growth and Mycotoxin Biosynthesis

Lamium album is a medicinal flowering plant that is rich in bioactive compounds with various biological properties. Fusarium species, known for causing significant crop losses and mycotoxin contamination, pose threats to food safety and human health. While synthetic fungicides are commonly employed for fungal management, their environmental impact prompts the ongoing development of alternative methods. This study aimed to evaluate the efficacy of L. album flower extracts in inhibiting the in vitro growth and biosynthesis of mycotoxins by Fusarium culmorum and F. proliferatum strains. The extracts were obtained by supercritical fluid extraction using CO2 (SC-CO2). The effects of various concentrations (2.5, 5, 7.5, and 10%) were assessed on a potato dextrose agar (PDA) medium using the "poisoning" technique. L. album flower extracts reduced mycelium growth by 0 to 30.59% for F. culmorum and 27.71 to 42.97% for F. proliferatum. Ergosterol content was reduced by up to 88.87% for F. culmorum and 93.17% for F. proliferatum. Similarly, the amounts of synthesized mycotoxins produced by both strains were also lower compared to control cultures. These findings are a preliminary phase for further in vivo tests planned to determine the fungistatic effect of L. album flower extracts on cereal substrates as seedlings incubated in controlled environments and under field conditions. Their phytotoxicity and biological stability, as well as the possibility of formulating a bio-preparation to protect cereals against Fusarium infections, will be evaluated.

Zearalenone-14-glucoside specifically promotes dysplasia of Gut-Associated Lymphoid Tissue: A natural product for constructing intestinal nodular lymphatic hyperplasia model

INTRODUCTION

Zearalenone-14-glucoside (Z14G) is a modified mycotoxin that widely contaminates food across the world. Our preliminary experiment showed that Z14G degrades to zearalenone (ZEN) in the intestine exerting toxicity. Notably, oral administration of Z14G in rats induces intestinal nodular lymphatic hyperplasia.

OBJECTIVES

To investigate the mechanism of Z14G intestinal toxicity and how it differs from ZEN toxicity. We conducted a precise toxicology study on the intestine of rats exposed to Z14G and ZEN using multi-omics technology.

METHODS

Rats were exposed to ZEN (5 mg/kg), Z14G-L (5 mg/kg), Z14G-H (10 mg/kg), and pseudo germ free (PGF)-Z14G-H (10 mg/kg) for 14 days. Histopathological studies were performed on intestines from each group and compared. Metagenomic, metabolomic, and proteomic analyses were performed on rat feces, serum, and intestines, respectively.

RESULTS

Histopathological studies showed that Z14G exposure resulted in dysplasia of gut-associated lymphoid tissue (GALT) compared to ZEN exposure. The elimination of gut microbes in the PGF-Z14G-H group alleviated or eliminated Z14G-induced intestinal toxicity and GALT dysplasia. Metagenomic analysis revealed that Z14G exposure significantly promoted the proliferation of Bifidobacterium and Bacteroides compared to ZEN. Metabolomic analysis showed that Z14G exposure significantly reduced bile acid, while proteomic analysis found that Z14G exposure significantly reduced the expression of C-type lectins compared to ZEN.

CONCLUSIONS

Our experimental results and previous research suggest that Z14G is hydrolyzed to ZEN by Bifidobacterium and Bacteroides promoting their co-trophic proliferation. This leads to inactivation of lectins by hyperproliferative Bacteroides when ZEN caused intestinal involvement, resulting in abnormal lymphocyte homing and ultimately GALT dysplasia. It is noteworthy that Z14G is a promising model drug to establish rat models of intestinal nodular lymphatic hyperplasia (INLH), which is of great significance for studying the pathogenesis, drug screening and clinical application of INLH.

Zearalenone and Its Masked Forms in Cereals and Cereal-Derived Products: A Review of the Characteristics, Incidence, and Fate in Food Processing

Zearalenone (ZEA) is known as a Fusarium-produced mycotoxin, representing a risk to cereal food safety with repercussions for economies and worldwide trade. Recent studies have reported the co-occurrence of ZEA and masked ZEA in a variety of cereals and cereal-based products, which may exert adverse effects on public health due to additive/synergistic interactions. However, the co-contamination of ZEA and masked ZEA has received little attention. In order to minimize the threats of co-contamination by ZEA and masked ZEA, it is necessary to recognize the occurrence and formation of ZEA and masked ZEA. This review focuses on the characteristics, incidence, and detection of ZEA and its masked forms. Additionally, the fate of ZEA and masked ZEA during the processing of bread, cake, biscuits, pasta, and beer, as well as the ZEA limit, are discussed. The incidence of masked ZEA is lower than that of ZEA, and the mean level of masked ZEA varies greatly between cereal samples. Published data showed a considerable degree of heterogeneity in the destiny of ZEA during cereal-based food processing, mostly as a result of the varying contamination levels and complicated food processing methods. Knowledge of the fate of ZEA and masked ZEA throughout cereal-based food processing may reduce the likelihood of severe detrimental market and trade ramifications. The revision of legislative limits of masked ZEA may become a challenge in the future.

Microbial degradation of aristolochic acid I by endophytic fungus A.h-Fs-1 of Asarum heterotropoides

Asari Radix et Rhizoma is commonly used in classic prescriptions of herbal medicine in several Asian countries for resuscitation, pain relief, and sore treatment, and Asarum heterotropoides (A. heterotropoides) is an important source material of Asari Radix et Rhizoma. However, the plants of the Asari Radix et Rhizoma and some plants in Asarum spp. contain aristolochic acid I (AAI), which is considered as a carcinogen. The objective of the current study is to detoxify Asarum spp. through microbial degradation of AAI in order to ensure drug safety. Based on the observation of the close correlation between endophytic fungi of A. heterotropoides and AAI, we identified an AAI-degrading fungus and screened for candidate genes involved in AAI degradation. Full-length O-demethylase genes (ODMs) were cloned including A.h-ODM-5, Fs-ODM-4, and Fs-ODM-1, and their ability to degrade AAI was tested in vitro. The results showed that the AAI-degrading fungus was identified as Neocosmospora solani (A.h-Fs-1, endophytic fungi of A. heterotropoides), and verified the capability of specific O-demethylation to modify the structure of AAI. We further identified the functional ODMs in A.h-Fs-1 capable of degrading AAI and uncovered the AAI degradation mechanism of A.h-Fs-1. The microbial degradation of AAI demonstrated in the present study offers a new method to detoxify plant materials used for herbal medicine, and would enhance the regulation of toxic ingredients content in herbal medicine source materials.

Zearalenone-14-Glucoside Is Hydrolyzed to Zearalenone by β-Glucosidase in Extracellular Matrix to Exert Intracellular Toxicity in KGN Cells

As one of the most important conjugated mycotoxins, zearalenone-14-glucoside (Z14G) has received widespread attention from researchers. Although the metabolism of Z14G in animals has been extensively studied, the intracellular toxicity and metabolic process of Z14G are not fully elucidated. In this study, the cytotoxicity of Z14G to human ovarian granulosa cells (KGN) and the metabolism of Z14G in KGN cells were determined. Furthermore, the experiments of co-administration of β-glucosidase and pre-administered β-glucosidase inhibitor (Conduritol B epoxide, CBE) were used to clarify the mechanism of Z14G toxicity release. Finally, the human colon adenocarcinoma cell (Caco-2) metabolism model was used to verify the toxicity release mechanism of Z14G. The results showed that the IC₅₀ of Z14G for KGN cells was 420 μM, and the relative hydrolysis rate of Z14G on ZEN was 35% (25% extracellular and 10% intracellular in KGN cells). The results indicated that Z14G cannot enter cells, and Z14G is only hydrolyzed extracellularly to its prototype zearalenone (ZEN) by β-glucosidase which can exert toxic effects in cells. In conclusion, this study demonstrated the cytotoxicity of Z14G and clarified the toxicity release mechanism of Z14G. Different from previous findings, our results showed that Z14G cannot enter cells but exerts cytotoxicity through deglycosylation. This study promotes the formulation of a risk assessment and legislation limit for ZEN and its metabolites.

In Vitro Effects of Lemon Balm Extracts in Reducing the Growth and Mycotoxins Biosynthesis of Fusarium culmorum and F. proliferatum

The objectives of this research were to obtain the extracts of lemon balm (Melissa officinalis) using supercritical CO2 (SC-CO2) and methanol as co-solvent and evaluate the antifungal activity of those extracts against two selected strains of Fusarium species (Fusarium culmorum and Fusarium proliferatum). The extraction conditions were set at 40 and 60 °C and 250 bar. The obtained extracts were characterized in terms of antifungal activity on potato dextrose agar media (PDA). The results showed that the extraction parameters had different effects on mycelium growth and mycotoxins biosynthesis reduction. All studied lemon balm extracts (1, 2.5, 5, 7.5, and 10%) inhibited the growth of F. proliferatum and F. culmorum mycelia compared to the control. The lemon balm extracts significantly reduced ergosterol content and synthesized mycotoxins in both tested strains. These findings support the antifungal activity of lemon balm extracts against F. proliferatum and F. culmorum. However, more research on other Fusarium species is needed, as well as in vivo applications, before considering lemon balm extracts as a natural alternative to synthetic fungicides.

Structure-toxicity relationships, toxicity mechanisms and health risk assessment of food-borne modified deoxynivalenol and zearalenone: A comprehensive review

Mycotoxin, as one of the most common pollutants in foodstuffs, poses great threat to food security and human health. Specifically, deoxynivalenol (DON) and zearalenone (ZEN)-two mycotoxin contaminants with considerable toxicity widely existing in food products-have aroused broad public concerns. Adding to this picture, modified forms of DON and ZEN, have emerged as another potential environmental and health threat, owing to their higher re-transformation rate into parent mycotoxins inducing accumulation of mycotoxin in humans and animals. Given this, a better understanding of the toxicity of modified mycotoxins is urgently needed. Moreover, the lack of toxicity data means a proper risk assessment of modified mycotoxins remains challenging. To better evaluate the toxicity of modified DON and ZEN, we have reviewed the relationship between their structures and toxicities. The toxicity mechanisms behind modified DON and ZEN have also been discussed; briefly, these involve acute, subacute, chronic, and combined toxicities. In addition, this review also addresses the global occurrence of modified DON and ZEN, and summarizes novel methods-including in silico analysis and implementation of relative potency factors-for risk assessment of modified DON and ZEN. Finally, the health risk assessment of modified DON and ZEN has also been discussed comprehensively.

Citrinin Mycotoxin Contamination in Food and Feed: Impact on Agriculture, Human Health, and Detection and Management Strategies

Citrinin (CIT) is a mycotoxin produced by different species of Aspergillus, Penicillium, and Monascus. CIT can contaminate a wide range of foods and feeds at any time during the pre-harvest, harvest, and post-harvest stages. CIT can be usually found in beans, fruits, fruit and vegetable juices, herbs and spices, and dairy products, as well as red mold rice. CIT exerts nephrotoxic and genotoxic effects in both humans and animals, thereby raising concerns regarding the consumption of CIT-contaminated food and feed. Hence, to minimize the risk of CIT contamination in food and feed, understanding the incidence of CIT occurrence, its sources, and biosynthetic pathways could assist in the effective implementation of detection and mitigation measures. Therefore, this review aims to shed light on sources of CIT, its prevalence in food and feed, biosynthetic pathways, and genes involved, with a major focus on detection and management strategies to ensure the safety and security of food and feed.