The Effect of Mushroom Culture Filtrates on the Inhibition of Mycotoxins Produced by Aspergillus flavus and Aspergillus carbonarius

Two of the mycotoxins of greatest agroeconomic significance are aflatoxin B-1 (AFB(1)), and ochratoxin A (OTA). It has been reported that extracts from some wood-decaying mushrooms, such as Lentinula edodes and Trametes versicolor showed the ability to inhibit AFB(1) or OTA biosynthesis. Therefore, in our study, a wide screening of 42 isolates of different ligninolytic mushrooms was assayed for their ability to inhibit the synthesis of OTA in Aspergillus carbonarius and AFB(1) in Aspergillus flavus, in order to find a metabolite that can simultaneously inhibit both mycotoxins. The results showed that four isolates produce metabolites able to inhibit the synthesis of OTA, and 11 isolates produced metabolites that inhibited AFB(1) by >50%. Two strains, the Trametes versicolor strain TV117 and the Schizophyllum commune strain S.C. Ailanto, produced metabolites able to significantly inhibit (>90%) the synthesis of both mycotoxins. Preliminary results suggest that the mechanism of efficacy of the S. commune rough and semipurified polysaccharides could be analogous to that found previously for Tramesan(R), by enhancing the antioxidant response in the target fungal cells. The overall results indicate that S. commune's polysaccharide(s) could be a potential agent(s) in biological control and/or a useful component of the integrated strategies able to control mycotoxin synthesis.