Inhibition of growth and ochratoxin A biosynthesis in Aspergillus carbonarius by flavonoid and nonflavonoid compounds.

The effect of naturally occurring phenolic compounds on Aspergillus carbonarius growth and ochratoxin A (OTA) production was studied. Caffeic acid and the flavonoids, rutin and quercetin, were added to Czapek Yeast Extract agar at concentrations ranging between 50 and 500 mg/l. All phenolic compounds had a significant influence on growth rate and lag phase of A. carbonarius at 250 mg/l. The growth was completely inhibited with 500 mg/l. In comparison with the control, a significant decrease in OTA production was observed with all phenolic compounds. In general, effect on growth was less evident than effect on toxin production. An inhibitory effect on growth and OTA production, as concentration was increased was observed in all cases. The response of A. carbonarius to the flavonoids, rutin and quercetin, was similar. The inhibitory effect of these natural phenolic compounds on fungal growth and OTA production could be an alternative to the use of chemical fungicides.