These chemical compounds are the result of secondary metabolism initiated in response to specific developmental or environmental signals.
Mushroom poisons are fungal metabolites that can cause disease and death in humans and other animals; they are rather arbitrarily excluded from discussions of mycotoxicology.
Mycotoxins have diverse chemical structures, biosynthetic origins, myriad biological effects, and produce numerous different fungal species.
Organic chemists have attempted to classify them by their chemical structures (e.g., lactones, coumarins); biochemists according to their biosynthetic origins (polyketides, amino acid-derived, etc.
Zearalenone is a Fusarium metabolite with potent estrogenic activity; hence, in addition to being called (probably erroneously) a mycotoxin, it also has been labeled a phytoestrogen, a mycoestrogen, and a growth promotant.
[7][8] The four major aflatoxins are called B1, B2, G1, and G2 based on their fluorescence under UV light (blue or green) and relative chromatographic mobility during thin-layer chromatography.
[15][16] The major species of economic importance is Fusarium verticillioides, which grows as a corn endophyte in both vegetative and reproductive tissues, often without causing disease symptoms in the plant.
[24][25][26] Because Aspergillus niger is used widely in the production of enzymes and citric acid for human consumption, it is important to ensure that industrial strains are nonproducers.
For example, it was tested as both a nose and throat spray for treating the common cold and as an ointment for treating fungal skin infections[32] However, during the 1950s and 1960s, it became apparent that, in addition to its antibacterial, antiviral, and antiprotozoal activity, patulin was toxic to both plants and animals, precluding its clinical use as an antibiotic.
The trichothecenes constitute a family of more than sixty sesquiterpenoid metabolites produced by a number of fungal genera, including Fusarium, Myrothecium, Phomopsis, Stachybotrys, Trichoderma, Trichothecium, and others.
They are commonly found as food and feed contaminants, and consumption of these mycotoxins can result in alimentary hemorrhage and vomiting; direct contact causes dermatitis.
Perhaps because the original work on these fungal macrolides coincided with the discovery of aflatoxins, chapters on zearalenone have become a regular fixture in monographs on mycotoxins (see, for example, Mirocha and Christensen [42] and Betina [43]).
Nevertheless, the word toxin is almost certainly a misnomer because zearalenone, while biologically potent, is hardly toxic; rather, it sufficiently resembles 17β-estradiol, the principal hormone produced by the human ovary, to allow it to bind to estrogen receptors in mammalian target cells [44] Zearalenone is better classified as a nonsteroidal estrogen or mycoestrogen.