Isolation and purification of enniatins A, A1, B, B1, produced by Fusarium tricinctum in solid culture, and cytotoxicity effects on Caco-2 cells

Enniatins (ENs) are antibiotic compounds of hexadepsipeptidic structure produced by several strains of Fusarium spp. The ENs A, A1, B, B1 were purified from extracts of Fusarium tricinctum grown on a solid medium of corn, by a low pressure liquid chromatography (LPLC) on reverse phase of Amberlite XAD-7 followed by semipreparative LC. The purity and the structure of the isolated compounds were confirmed by LC–MS/MS.The technique of the purification of the fungal extract enabled complete separation of the ENs A, A1, B, B1 with a mean purity of 97% for all the compounds.The cytoxicity of the ENs was tested in the cell lines of human origin (epithelial colorectal adenocarcinoma cells, Caco-2) by MTT assays. Only EN A1 and B1 evoked toxicity at the tested concentrations. The inhibitory concentration (IC50) for EN A1 on Caco-2 cells was 12.3 μM, whereas the IC50 produced by the EN B1 was 19.5 μM.This study indicates that ENs, fungal metabolites that are commonly found in corn and in general in product composed by corn, may have a toxic potential for human health.