N‐Fatty Acylation of Hydrolyzed Fumonisin B1, But Not of Intact Fumonisin B1, Strongly Enhances In Vitro Mammalian Toxicity

Abstract

Fumonisin B1 (FB1) is the most abundant of a series of sphingosine‐analog mycotoxins produced by Fusarium verticillioides, the major fungal contaminant of stored corn (maize) world‐wide. Fumonisins were originally isolated as environmental tumor promoters, and they remain a concern because they are frequent contaminants of corn‐derived food products intended for direct human consumption. FB1 inhibits ceramide synthase, which may account for its acute toxic effects, but understanding of its tumor promotion mechanism has been limited by the general lack of understanding in the field. There is no evidence for functional metabolism of fumonisins in mammals, but abiogenic conversions during food processing are a concern because some known conversion products retain biological activity, including hydrolyzed FB1 (HFB1). HFB1, formed by alkaline removal of FB1 side chains, is a frequent contaminant of lime‐treated corn products such as tortillas and tortilla chips. Humpf et al. (J. Biol. Chem., 273, 19060, 1998) ...