CONICET | Buscador de Institutos y Recursos Humanos

Introduction: Fungi of the genus Fusarium are widely found in plant debris and crop plants worldwide. Several species from this genus are economically relevant by their ability to cause tissue destruction and produce mycotoxins on important crops such as corn, wheat and other small grains on the field, and in storage. Fusarium verticillioides and F. proliferatum are probably the most important producers of fumonisin B1 (FB1). It has been found to be associated with several animal diseases. With respect to humans, their occurrence in corn has been associated with high incidences of esophageal cancer and liver cancer. In recent years, particular interest has been focused on the potential application of natural products such as monoterpenes and phenolic compounds, to prevent fungal growth and mycotoxins production in grain and cereal. However, little is knowledge about the molecular properties related to the antitoxigenic activity of them. Objetives: 1) To study the effects of phenolic compounds on FB1 by Fusarium verticillioides MRC 4316. 2) To determine the links between the structure and molecular properties and the antitoxigenic activity of the phenolic compounds Methods: The phenolic compounds used were: thymol, carvacrol, eugenol, methyl-eugenol, isoeugenol, vanillin, orto-cresol, meta-cresol, para-cresol, creosol, estragol y guaiacol. The MYRO liquid culture was prepared as described previously (1). It was inoculated with 500 µL of a conidia suspension of F. verticillioides MRC 4316. Cultures were incubated with agitation in darkness at 28 ºC for 21 days. The phenolic compounds were inserted into the flask on the 5th day post inoculation, in a final concentration of 1.0 mM. Quantification of FB1 was done as described Shephard, et al. (2). Multivariate methods of numerical analysis were applied here to determine the links between the structure and molecular properties and the antitoxigenic activity of the phenolic compounds. These are principal components analysis and Canonical correlations analysis. All statistical analyses were calculated by using InfoStat software. Results: All the phenolic compounds evaluated showed some inhibitory effects on FB1 production by F. verticillioides. The most active inhibitors were carvacrol, thymol and isoeugenol, followed by eugenol and methyl-eugenol, respectively. The rest of the phenolic compouds evaluated had little effect on FB1 production. Structural studies have revealed that the 75% of the antifumonisin activity of the phenolic compounds can be explained by the radical scavenger activity (DPPH), the acidity (pka), the Van der Waals surface (vdWSA) and the lipophilicity (Log P) of them. Conclusions: The results obtained in this work reveal the molecular properties of phenolic compounds, necessary to exercise inhibitory effects on FB1 production. Such findings would allow a large contribution to guide the search for new compounds with antitoxigenic activity.