Inhibition of growth of mycotoxigenic Fusarium species by butylated hydroxyanisole and/or carvacrol

The antifungal effect of butylated hydroxyanisole (BHA) and carvacrol alone and in combination on six toxigenic Fusarium species was examined in potato dextrose broth (PDB) cultures. The highest percentage of mycelial inhibition was recorded for F. poae in the presence of 200 mu g/ml of BHA or carvacrol and BHA and carvacrol combined (50 mu g/ml each and 100 mu g/ml each), while F. moniliforme was the least sensitive of the test fungi at the same concentrations. A synergistic activity of BHA and carvacrol combined (50 mu g/ml each) was observed against several of the test fungi. The pH of the filtrates from BHA or carvacrol and BHA plus carvacrol-amended cultures ranged between 5.0 and 5.4. The highest amount of total dissolved solids (TDS) was recorded for F. graminearum in the presence of 200 mu g/ml of BHA. Leakage of amino acids, sugars, and protein was detected at each concentration of BHA or carvacrol alone and in combination. For the majority of the test fungi, the amount of leakage in the culture filtrates increased as the concentration of the test compounds increased. The leakage of sugars, amino acids, and protein may be an indication of mycelial membrane disruption by the BHA and/or carvacrol as an initial step in inhibition of the test fungi in vitro.