Mosley Charity N, Wang Lei, Gilley Stephanie, Wang Shuguang, Yu Hongtao
Department of Chemistry, Jackson State University, Jackson, MS 39217, USA.
Int J Environ Res Public Health. 2007 Jun;4(2):126-31. doi: 10.3390/ijerph2007040006.
2-phenylbenzimidazole (PBI) is an ingredient found in sunscreen agents. PBI can absorb the UV portion of the solar light and undergo a series of light-induced reactions to cause adverse effects in humans. Therefore, chemical and photochemical toxicity of PBI were investigated in the bacteria Salmonella typhimurium TA 102 and human skin keratinocyte cells. There is no appreciable bacteria death due to the exposure to PBI alone, indicating that PBI is not chemically toxic to the bacteria at a dose as high as 625 microM. However, exposure to PBI and a solar simulator light (300-W Xe/Hg lamp, 30 min, 18.6 J/cm2, equivalent to 30 min outdoor sunlight) causes significant bacteria death: 35% at 25 microM and 55% at 625 microM PBI. Exposure of the bacteria to light and PBI at doses 5-25 microM causes the bacteria to revert, an indication of mutation. In the presence of PBI but without light irradiation, the number of revertant bacteria colonies is around 200 due to spontaneous mutation. Combination of light irradiation and PBI causes the number of revertant TA 102 colonies to increase in a dose dependent manner, reaching a maximum of around 1700 revertant colonies at 25 microM PBI. At higher PBI concentrations, the number of revertant colonies remains constant. This result clearly indicates that PBI is photomutagenic in TA 102. Exposure of the human skin HaCaT keratinocytes in aqueous solution in the presence of PBI causes the cell to lose its viability with or without light irradiation. There is no significant difference in cell viability for the light irradiated or non-irradiated groups, indication PBI is not photocytotoxic. However, exposure of the cells to both PBI and light irradiation causes cellular DNA damage, while exposure to PBI alone does not cause DNA damage.
2-苯基苯并咪唑（PBI）是防晒剂中的一种成分。PBI能吸收太阳光中的紫外线部分，并经历一系列光诱导反应，从而对人体产生不良影响。因此，在鼠伤寒沙门氏菌TA 102和人皮肤角质形成细胞中研究了PBI的化学毒性和光化学毒性。单独暴露于PBI不会导致明显的细菌死亡，这表明在高达625微摩尔的剂量下，PBI对细菌没有化学毒性。然而，暴露于PBI并同时接受太阳模拟器光（300瓦氙/汞灯，30分钟，18.6焦耳/平方厘米，相当于30分钟户外阳光照射）会导致显著的细菌死亡：在25微摩尔PBI时为35%，在625微摩尔PBI时为55%。将细菌暴露于5-25微摩尔剂量的光和PBI下会导致细菌回复突变，这是突变的一个迹象。在存在PBI但无光照的情况下，由于自发突变，回复突变细菌菌落的数量约为200。光照和PBI的联合作用导致回复突变TA 102菌落的数量呈剂量依赖性增加，在25微摩尔PBI时达到最大值，约为1700个回复突变菌落。在更高的PBI浓度下，回复突变菌落的数量保持不变。这一结果清楚地表明PBI在TA 102中具有光致突变性。在PBI存在的情况下，将人皮肤HaCaT角质形成细胞暴露于水溶液中，无论有无光照，细胞都会失去活力。光照组和非光照组的细胞活力没有显著差异，表示PBI没有光细胞毒性。然而，将细胞同时暴露于PBI和光照下会导致细胞DNA损伤，而单独暴露于PBI不会导致DNA损伤。
