Genotoxic and apoptotic activities of the food flavourings myristicin and eugenol in AA8 and XRCC1 deficient EM9 cells

Some food flavourings, such as safrole and methyleugenol, are known for their genotoxic and hepatocarcinogenic properties whereas for others, such as myristicin, there is less data. Myristicin and eugenol are both alkenylbenzenes, and we compared their direct genotoxicity in repair proficient (AA8) and repair deficient XRCC− (EM9) Chinese hamster ovary cells. Cell viability was assessed by the MTT assay. The comet assay was used to evaluate DNA breaks, and the γ-H2AX assay to evaluate induction of double strand breaks. We assessed apoptosis by measuring caspases activation, and the TUNEL assay. Reduction of cell viability was similar in AA8 and EM9 cells, for both compounds. After 1 h eugenol produced DNA strand breaks in the comet assay and induced double strand breaks in the γ-H2AX assay in AA8 cells, while myristicin was not genotoxic in both the comet and the γ-H2AX assays. Both flavourings were negative in EM9 cells. After 24 h eugenol and myristicin induced DNA fragmentation detected by TUNEL in both cell lines, but only myristicin activated caspases. Myristicin was more apoptotic than eugenol, in both cell lines. The XRCC1 protein does not influence the apoptotic activity of either compound.