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-Ubidecarenone (coenzyme Q10) has been widely used as a complementary therapy in heart failure and as a dietary supplement for over two decades. Ubidecarenone is manufactured by organic synthesis, yeast (non-Saccharomyces cerevisiae) fermentation, or bacteria fermentation. There are many reports on the safety of ubidecarenone. However, genotoxicity of ubidecarenone manufactured by bacteria fermentation has not been reported. We carried out genotoxicity evaluation of ubidecarenone manufactured by bacteria fermentation through the bacterial reverse mutation test (Ames test) and in vitro chromosome aberration test in compliance with the Japanese guidelines on genotoxicity testing of phartesting chemicals. The results indicate neither increase of revertant colonies nor chromosome aberration, suggesting that the ubidecarenone manufactured by bacteria fermentation has no genotoxic activities under the condition of this study.

Background The human genome is constantly exposed to numerous environmental genotoxicants. To prevent the detrimental consequences induced by the expansion of damaged cells, cellular protective systems such as nucleotide excision repair (NER) exist and serve as a primary pathway for repairing the various helix-distorting DNA adducts induced by genotoxic agents. NER is further divided into two sub-pathways, namely, global genomic NER (GG-NER) and transcription-coupled NER (TC-NER). Both NER sub-pathways are reportedly involved in the damage response elicited by exposure to genotoxins. However, how disruption of these sub-pathways impacts the toxicity of different types of environmental mutagens in human cells is not well understood. Results To evaluate the role of NER sub-pathways on the cytotoxic effects of mutagens, we disrupted XPC and CSB to selectively inactivate GG-NER and TC-NER, respectively, in human lymphoblastoid TK6 cells, a standard cell line used in genotoxicity studies. Using these cells, we then comparatively assessed their respective sensitivities to representative genotoxic agents, including ultraviolet C (UVC) light, benzo [a] pyrene (B(a)P), 2-amino-3,8-dimethylimidazo [4,5-f] quinoxaline (MeIQx), 2-amino-1-methyl-6-phenylimidazo [4,5-b] pyridine (PhIP), γ-ray, and 2-acetylaminofluorene (2-AAF). CSB −/− cells exhibited a hyper-sensitivity to UVC, B(a)P, and MeIQx. On the other hand, XPC −/− cells were highly sensitive to UVC, but not to B(a)P and MeIQx, compared with wild-type cells. In contrast with other genotoxins, the sensitivity of XPC −/− cells against PhIP was significantly higher than CSB −/− cells. The toxicity of γ-ray and 2-AAF was not enhanced by disruption of either XPC or CSB in the cells. Conclusions Based on our findings, genetically modified TK6 cells appear to be a useful tool for elucidating the detailed roles of the various repair factors that exist to combat genotoxic agents, and should contribute to the improved risk assessment of environmental chemical contaminants.