Modified Fusarium Mycotoxins in Cereals and Their Products—Metabolism, Occurrence, and Toxicity: An Updated Review

Abstract

Mycotoxins are secondary fungal metabolites, toxic to humans, animals and plants. Under the influence of various factors, mycotoxins may undergo modifications of their chemical structure. One of the methods of mycotoxin modification is a transformation occurring in plant cells or under the influence of fungal enzymes. This paper reviews the current knowledge on the natural occurrence of the most important trichothecenes and zearalenone in cereals/cereal products, their metabolism, and the potential toxicity of the metabolites. Only very limited data are available for the majority of the identified mycotoxins. Most studies concern biologically modified trichothecenes, mainly deoxynivalenol-3-glucoside, which is less toxic than its parent compound (deoxynivalenol). It is resistant to the digestion processes within the gastrointestinal tract and is not absorbed by the intestinal epithelium; however, it may be hydrolysed to free deoxynivalenol or deepoxy-deoxynivalenol by the intestinal microflora. Only one zearalenone derivative, zearalenone-14-glucoside, has been extensively studied. It appears to be more reactive than deoxynivalenol-3-glucoside. It may be readily hydrolysed to free zearalenone, and the carbonyl group in its molecule may be easily reduced to α/β-zearalenol and/or other unspecified metabolites. Other derivatives of deoxynivalenol and zearalenone are poorly characterised. Moreover, other derivatives such as glycosides of T-2 and HT-2 toxins have only recently been investigated; thus, the data related to their toxicological profile and occurrence are sporadic. The topics described in this study are crucial to ensure food and feed safety, which will be assisted by the provision of widespread access to such studies and obtained results.

Variation of Fusarium Free, Masked, and Emerging Mycotoxin Metabolites in Maize from Agriculture Regions of South Africa

“…Of the major mycotoxins, HT-2 was not detected at all in the eastern region but was quantified only in 2% of the maize from the western region at 40.2 µg/kg concentration. Detection of HT-2 in the warm western region and not the cold eastern region as would be expected is contrary as it was reported that HT-2 was previously considered a problem in colder European climates [13]. Of the fumonisin Bs, FB1 occurred at the most frequency rate than FB2, FB3, and FB4.…”

Detoxification of Mycotoxins through Biotransformation

“…To our knowledge, no detailed review has focused on detoxification of mycotoxins through biotransformation though a series of reviews on the detoxification of certain mycotoxins have been published over the last 20 years [4,5,7,8,[13][14][15][16][17][18][19]. Furthermore, significant advances in the knowledge on detoxification of mycotoxins by biotransformation have been achieved recently.…”

“…Fusaric acid (FA, 19) was reduced to fusarinol (64), also called 5-butyl-2-pyridinemethanol, by the fungus Aspergillus tubingensis ( Figure S29) [59]. Fusarinol (64) was significantly less phytotoxic than fusaric acid (19). In fusarinol (64), the acid has been reduced to an alcohol group.…”

“…In fusarinol (64), the acid has been reduced to an alcohol group. The reduced phytotoxicity of fusarinol (64) indicates the importance of the carboxylic acid in the toxic function of FA (19). The fungus A. tubingensis provides a novel detoxification mechanism against FA (19), which may be utilized to control Fusarium wilt [59].…”

“…In contrast, biotransformation methods, which have high specificity, produce harmless products, and even lead to complete detoxification under mild and environmentally friendly conditions, have been recognized as the promising solution for decontamination of mycotoxins [6,11]. Living organisms 10-Hydroxy AME (16) Microsomes from rat, human and porcine liver [23] Destruxin B (17) Hydroxydestruxin B (18) Crucifers such as Brassica napus [24] Fusaric acid (19) 8-Hydroxyfusaric acid (20) Mucor rouxii (fungus) [27] Ochratoxin A(OTA, 21)…”