Abstract

Previous work indicated that some of the new synthesized analogues of dehydroacetic acid (DHA) were inhibitory to the growth of mycotoxin producing moulds and accumulation of aflatoxin B₁ (AFB₁) and ochratoxin A (OTA). The objective of this study was to determine the specific new synthesized chemical compounds that may be effective against mould growth and vomitoxin (deoxynivalenol) (DON) accumulation by Fusarium graminearum. The effect of the investigated 3-/2-aminophenylamine-(p-toluoyl)-4-hydroxy-6-(p-tolyl)-2H-pyrane-2-one (Schiff base) and 4-hydroxy-3-(p-toluoyl)-6-(p-tolil)-2H-pyrane-2-one (DHT) on growth and DON accumulation were studied using a mould F. graminearumZMPBF 1244 and maize grain hybrid to determine the possible use of these compounds as a mean of controlling DON accumulation. Schiff base was inhibitory at 0.05 and 0.1 µg/g and DHT at 0.5 µg/g of maize grain. The inhibitory effect of these substances was judged to be the inhibition of growth rather than toxin accumulation. When growth occurred after a delay, DON accumulation occurred when the cultures reached secondary metabolism. Given sufficient time, cultures which were inhibited initially, but which subsequently inhibited their growth, produced toxin levels equivalent to the control cultures. Levels of the Schiff base above 0.2 µg/g almost completely inhibited mould growth or permitted only a small amount of growth that never reached secondary metabolism and never produced DON during the time of this study.

Key words: Fusarium graminearum, vomitoxin, Schiff base, chitin, Artemia salina.

Abbreviation

 DHA, Dehydroacetic acid; AFB1, aflatoxin B1; OTA, ochratoxin A; DON, vomitoxin (deoxynivalenol); Schiff base, 3-/2-aminophenylamine-(p-toluoyl)-4-hydroxy-6-(p-tolyl)-2H-pyrane-2-one; DHT, 4-hydroxy-3-(p-toluoyl)-6-(p-tolil)-2H-pyrane-2-one; MIC, minimal inhibitory concentration; ZEA, zearalenone; PDA, potato-dextrose agar; TLC, thin layer chromatography; HPLC, high performance liquid chromatography.