Fragrant 4-Hydroxy-3(2H)-furanones Swiftly Scavenge Nitrous Acid Causing Concomitant Formation of the Components with Relatively Weak Mutagenicity

Abstract

Reaction of fragrant 4-hydroxy-3(2H)-furanones including 2, 5-dimethyl-4 hydroxy-3(2H)-furanone (DMHF) and 4-hydroxy-2-(or 5)-ethyl-5-(or 2)-methyl 3(2H)-furanone (HEMF) present in many processed foods with nitrous acid was studied. It was found that DMHF or HEMF swiftly reacted with nitrous acid at a molar ratio of 2 : 1 at pH 3 and 37°C. The products from the reaction of DMHF or HEMF with 4 equivalents of nitrous acid in chloroform were analyzed. Elemental analysis of the unpurified products showed that nitrogen atoms were introduced into the products which were found to be composed of multiple unstable furanone ring-opened compounds. The DNA-breaking and reducing activity of parent DMHF and HEMF were lowered by the nitrous acid treatment. The unpurified products were weakly mutagenic to a Salmonella typhimurium TA100 strain without metabolic activation. It was found that DMHF and HEMF effectively scavenged nitrous acid accompanied by concomitant loss of DNA-breaking activity and formation of compounds with relatively weak mutagenicity.