ARS | Publication request: Inhibition of ochratoxin A production and growth of Aspergillus species by phenolic antioxidant compounds

Submitted to: Mycopathologia
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: August 29, 2007
Publication Date: September 12, 2007
Citation: Palumbo, J.D., O Keeffe, T.L., Mahoney, N.E. 2007. Inhibition of ochratoxin A production and growth of Aspergillus species by phenolic antioxidant compounds. Mycopathologia.164(5):241-248.

Interpretive Summary: Ochratoxin A is a toxin produced by several strains of Aspergillus and Penicillium. A number of phenolic compounds with antioxidant activities were tested for inhibition of growth and ochratoxin A production in 12 different Aspergillus strains. Two antioxidants, vanillic acid and 4-hydroxybenzoic acid, were the most effective of the tested compounds, both on ochratoxin A production and on fungal growth. The effects of each compound on each fungal strain were variable, suggesting differences in the response of each fungus to each compound. Also, using compounds that prevent ochratoxin A production but not fungal growth will be useful in future work to find genes that are turned on or off in response to the antioxidants, and begin to define the genetics of ochratoxin A biosynthesis and the environmental factors that control it.

Technical Abstract: The phenolic antioxidants, gallic acid, vanillic acid, protocatechuic acid, 4-hydroxybenzoic acid, catechin, caffeic acid, and chlorogenic acid were studied for their effects on ochratoxin A (OTA) production and fungal growth of ochratoxigenic Aspergilli. Of the 12 strains tested, which included A. alliaceus, A. lanosus, A. ochraceus, A. albertensis, A. melleus, A. sulphureus, A. carbonarius, A. elegans, and A. sclerotiorum, the greatest inhibition of OTA production was seen in A. sulphureus, A. elegans and A. lanosus. Vanillic acid and 4-hydroxybenzoic acid were the most inhibitory to both OTA production and growth of most of the strains tested. However, A. ochraceus was not inhibited by either compound, and A. carbonarius was not inhibited by vanillic acid. The effect of each compound on OTA production and growth was strain-dependent and generally quite variable, suggesting that species-specific, ecological and developmental factors contribute differently to OTA production and response to phenolic compounds. In addition, inhibition of OTA production by antioxidant compounds may be useful in determining biosynthetic and regulatory genes involved in both OTA production and stress response in ochratoxigenic Aspergilli.