Evaluation of Fumonisin B1 and its metabolites absorption and toxicity on intestinal cells line caco-2

The aim of the present paper is to investigate intestinal absorption and toxicity of Fumonisin B1 (FB1) and its partially (PHFB1 and PHFB2) and totally hydrolyzed (HFB1) metabolites, using the human intestinal cell line Caco-2, a very well known in vitro model of intestinal epithelium for absorption and metabolism studies. Caco-2 cells were treated for 48h with several toxin concentrations (in the range of 1-138μM). At the end of exposure period, no significant variation on cell viability has been observed with all chemicals tested, either in undifferentiated cells or in differentiated ones, suggesting a poor toxicity of these mycotoxins for intestinal cells. In any case, FB1 appears the most active in this respect. For which concerns the cellular absorption, FB1, PHFB1 and PHFB2 are never detected into Caco-2 cells. On the contrary, a dose-dependent absorption of HFB1 has been observed in differentiated cells, which express enzymatic and metabolic characteristics of mature enterocytes. Thus HFB1, losing the tricarballylic acid chain, is more bioavailable than FB1 on intestinal cell, supporting the hypothesis that in risk evaluation of fumonisins exposure its metabolites are also relevant.