Formation of Fumonisin B1-Glucose Reaction Product, in vitro Cytotoxicity, and Lipid Peroxidation on Kidney Cells

Fumonisin B1 (FB1) content in corn products decreases during the heating process in foods containing reducing sugars, mainly because of the formation of N-(carboxymethyl)fumonisin B1. In this study, a rapid method has been developed for the determination of both compounds in corn products using a high-speed blender, Ultra-Turrax, for solvent extraction and liquid chromatographytandem mass spectrometry. The kinetics of FB1 degradation and the formation of the Maillard adduct were studied in a model system constituted by corn bread spiked with FB1 and heated at 160, 180, and 200 C for 3, 6, 10, 15, and 20 min. FB1 decreased from 0.96 to 0.3 mg/kg and N-(carboxymethyl)fumonisin B1 increased to 0.1 mg/kg. Cytotoxicity and lipid peroxidation were studied in monkey kidney cells (Vero cells). After 24 h exposure, FB1 revealed an IC50 (median inhibitory concentration) of 55 ( 7 μM with neutral red uptake, but no IC50 was obtained after N-(carboxymethyl)fumonisin B1 exposure at the studied concentrations. Lipid peroxidation was assessed using the thiobarbituric acid reactive substance (TBARS) method for 90 min and 24 and 48 h. FB1 significantly increased the production of malondialdehyde in Vero cells exposed to 1 μM FB1 after 24 h, while malondialdehyde increased after 5 μM N-(carboxymethyl)fumonisin B1 exposure. These findings showed that the transformation products exhibit lower cytotoxicity than fumonisin B1 and lipid peroxidation may be involved in the cytotoxicity induced by both toxins.