Biochemical Characteristics of Trichothecenes

Abstract

In this report, the author summarized the biochemical characteristics of trichothecenes which are a chemically related group of fungal metabolites produced by various species of Fusarium, Myrothecium, Trichoderma, Cephalosporium, Verticimonosparium and Stachybotrys. They are cytotoxic to several kinds of animals and fungal cells and can induce skin inflammation, nausea, vomiting, diarrhea, leukopenia, destruction of bone marrow and haemorrhage in various organs of both human and animals. Biochemical studies on the mechanism of action revealed that trichothecenes are potent inhibitors of protein and DNA synthesis especially in the eukaryotic cells. Binding to the eukaryotic polysomes and ribosomes and the subsequent inactivation of ribosomal cycle may be responsible for their inhibitory effects to initiation and termination reactions. However, different types of trichothecenes were found to have different degree of toxicity between the in vivo and in vitro systems. Thus, lipophilicity of these toxins may have some influences on their cytotoxic properties, and this membrane involvement may be related to their selectivity toward target organs in the whole animal. In addition, trichothecenes have been reported to react with the reactive SH-group of some enzymes through their epoxide ring at C₁₂-C₁₃ , thereby suggesting that this reactivity of the epoxide ring of trichothecenes with SH-group of proteins may also be important in determining their biochemical effects.