Toxic potential assessment of hair dye developer 2,4,5,6-tetraaminopyrimidine sulfate exposed under ambient UVB radiation.

Synthetic cosmetics, particularly hair dyes, are becoming increasingly popular among people of all ages and genders. 2,4,5,6-tetraaminopyrimidine sulfate (TAPS) is a key component of oxidative hair dyes and is used as a developer in several hair dyes. TAPS has previously been shown to absorb UVB strongly and degrade in a time-dependent manner, causing phototoxicity in human skin cells. However, the toxic effects of UVB-degraded TAPS are not explored in comparison to parent TAPS. Therefore, this research work aims to assess the toxicity of UVB-degraded TAPS than TAPS on two different test systems, that is, HaCaT (mammalian cell) and Staphylococcus aureus (a bacterial cell). Our result on HaCaT has illustrated that UVB-degraded TAPS is less toxic than parent TAPS. Additionally, UVB-exposed TAPS and parent TAPS were given to S. aureus, and the bacterial growth and their metabolic activity were assessed via CFU and phenotype microarray. The findings demonstrated that parent TAPS reduced bacterial growth via decreased metabolic activity; however, bacteria easily utilized the degraded TAPS. Thus, this study suggests that the products generated after UVB irradiation of TAPS is considered to be safer than their parent TAPS.

Benzo(ghi)perylene (BgP) a black tattoo ingredient induced skin toxicity via direct and indirect mode of DNA damage under UVA irradiation.

Tattooing is a very common fashion trend across all the ages and gender of the society worldwide. Although skin inflammatory diseases are very frequent among tattoo users because of the active chemical ingredients used in tattoo ink, yet no ingredient-specific toxicity study has been performed. Benzo(ghi)perylene (BgP) is one of the PAHs and an important ingredient of black tattoo ink that shows strong absorption in UVA and UVB radiation of sunlight. Therefore, understanding the hazardous potential of BgP especially under UVA exposure is important for the safety of skin of tattoo users by considering the fact that penetration of UVA is in the dermis region where tattoo ingredients reside. To evaluate the hazardous potential of BgP on human skin under UVA exposure, different experimental tools i.e., in-chemico, in-silico and in-vitro were utilized. Our results illustrated that BgP photosensitized under UVA (1.5 mW/cm2) irradiation shows a degradation pattern till 4 h exposure. Photosensitized BgP reduced significant cell viability (%) at 1 µg/ml concentration. However, the pretreatment of singlet and hydroxyl radical quenchers, restoration of cell viability observed, confirmed the role of type-I and type-II photodynamic reactions in phototoxicity of BgP. Further, intracellular uptake of BgP in HaCaT cells was estimated and confirmed by UHPLC analysis. Molecular docking of BgP with DNA and formation of γ-H2AX foci demonstrated the DNA intercalation and double-stranded DNA damaging potential of BgP. Furthermore, acridine orange and ethidium bromide (AO/EB) dual staining showed apoptotic cell death via photosensitized BgP under UVA irradiation. The above findings suggest that BgP reached the human skin cell and induced dermal toxicity via direct and indirect mode of DNA damage under UVA exposure finally promoting the skin cell death. Thus, BgP-containing tattoo ink may be hazardous and may induce skin damage and diseases, especially in presence of UVA radiation of sunlight. To minimize the risk of skin diseases from synthetic ingredients in tattoo ink, the study highlights the importance of developing eco-friendly and skin-friendly tattoo ingredients by companies.