DNA strand break induction, mutagenicity, and cytotoxicity of the mycotoxins 11-β-hydroxy-7-deoxy-rosenonolactone, rosenonolactone, and trichothecin.

11-β-hydroxy-7-deoxy-rosenonolactone (TSS1), a mycotoxin of the rosenane class, was tested on cytotoxicity, induction of DNA single strand breaks and muta-genicity. Its effects were compared to those of rosenonolactone and trichothecin. TSS1 had stronger antibiotic activity againstEscherichia coli (EC 50: 10μg/mL) than rosenonolactone (EC 50: >200μg/mL) but weaker activity than trichothecin (EC 50: 3μg/mL). The same order of activity was found for the inhibition of yeast fermentation (EC 50 of TSS1: 45μg/mL; EC 50 of rosenonolactone: > 120μg/mL; EC 50 of trichothecin: 3.4μg/mL).In the trypan blue exclusion test using V79 Chinese hamster cells, TSS1 proved to be cytotoxic (EC50: 30μg/mL) at even lower doses than trichothecin (EC50: 200μg/mL). Rosenonolactone had no significant toxicity up to the highest soluble concentration (500μg/mL).DNA single strand breaks caused by TSS1 occurred at the same concentrations at which damage of the cell membrane became apparent. For trichothecin single strand breaks were detected only at concentrations at which the membrane was already highly damaged. No single strand breaks were observed in V79 cells after incubation with rosenonolactone up to the limit of solubility (500μg/mL).In the reversion assay withhis Salmonella typhimurium strains TA 98 and TA 100, no mutagenicity was observed for any of the examined mycotoxins up to 800μg/plate with and without the addition of a rat liver preparation for metabolism of the test compound.