Reactions of furfural and methylfurfural with DNA.

Furfural and methylfurfural are dietary mutagens and are present in various food products and beverages. The alkaline-induced unwinding of calf thymus DNA permitted the measurement of the number of strand breaks formed by furfural and methylfurfural, as a function of reaction time with these mutagenic agents. At the fixed DNA bp/mutagens molar ratio of 1:4, furfural treatment resulted in the formation of almost three times as many strand breaks at the end of 16 h reaction. In the presence of 0.2 M NaCl, a 60% reduction in strand breaks occurred in the case of furfural but only 25% with methylfurfural. It is also found that only in the case of methylfurfural treatment did depurination lead to the degradation of DNA, possibly through the alkylation of DNA bases and phosphates. These results suggest that furfural and methylfurfural may act on DNA by different reaction mechanisms.