Antimutagenic and/or genotoxic effects of processed humic acids as tested upon S. cerevisiae D7

Humic acids (HAs) are formed during decomposition of organic matter. Their adsorption, dispersion or emulsification properties attract the interest of medical science and pharmacy. The aim of this work was to study antimutagenic effects of processed HA. Yeast strain Saccharomyces cerevisiae D7 was first used for HA antimutagenicity testing. The highest antimutagenic activity was found in potassium and sodium humates. Humates isolated from lignite pre-treated by HNO(3) exhibited slightly lower antimutagenic activity; this effect is caused probably by their higher oxidation degree. Sodium humate processed at 250A degrees C exhibited genotoxic effect, which is probably connected with accelerated formation of reactive oxygen species such as superoxide anion by HA at higher temperature.