Cytotoxicity of fumonisin B₁: Implication of lipid peroxidation and inhibition of protein and DNA syntheses

The effects of fumonisin B₁ (FB₁) from Fusarium moniliforme on lipid peroxidation and protein and DNA syntheses were studied in monkey kidney cells (Vero cells). FB₁ was found to be a potent inducer of malondialdehyde (MDA), one of the secondary products formed during lipid peroxidation. At 0.14 μM (0.1 μg/ml), FB₁ induced 0.496 ± 0.1 nmoles of MDA/ mg protein, compared to the control level 0.134 ± 0.01 nmoles of MDA/mg protein (P < 0.005). No inhibition of protein or DNA synthesis was observed at this concentration of FB₁. Inhibition of protein and DNA syntheses was observed at FB₁ concentrations > 14 μM C10 μg/ml) with an IC₅₀ of 33 μM for both protein synthesis and DNA synthesis. These results indicate that lipid peroxidation is a very sensitive cellular response to the mycotoxin fumonisin B₁ observed at concentrations lower than that required to inhibit cellular synthesis of macromolecules, protein and DNA. This oxidative damage induced by FB₁ concentrations encountered in naturally contaminated foodstuffs and feed might lead to mutagenicity and genotoxicity.