摘要：We investigated the mutagenicity of rubber additives used in tire and tire extracts. Thiuram and dithiocarbamate type rubber vulcanization accelerators showed mutagenic activity in Salmonella typhimurium TA100 and some tires contain these additives, whereas no significant mutagenic activity was found in the tire extracts. These results suggested that the mutagenic activity of accelerators might be inhibited by other tire components such as the activators or the antioxidants. This paper describes the effects of activators and antioxidants on the mutagenic activity of accelerators. N-Isopropyl-N'-phenyl-p-phenylenediamine (IPPD), widely used as an antioxidant, inhibited the mutagenic activity of thiuram and dithiocarbamate type accelerators when added together. On the other hand, addition of UV irradiated IPPD to these accelerators resulted in no inhibitory effect on the mutagenic activity of these accelerators. Activators had no effect on the mutagenic activity of these accelerators. In order to confirm interaction between accelerators and antioxidants, tire extracts were separated into fractions corresponding to these additives by silica gel column chromatography and each fraction was subjected to the Ames test. The accelerator (Zn-DMDTC) fraction had mutagenic activity while the antioxidant (IPPD) fraction was non-mutagenic. These observations demonstrated that IPPD inhibits or reduces the mutagenic activity of thiuram and dithiocarbamate type accelerators when they are combined such as in tire processing.
