Allen J M, Gossett C J, Allen S K
Department of Chemistry, Indiana State University, Terre Haute 47809, USA.
Chem Res Toxicol. 1996 Apr-May;9(3):605-9. doi: 10.1021/tx950197m.
Evidence is presented for the photochemical formation of singlet molecular oxygen (1O2) in air-saturated aqueous solutions of several sunscreen active ingredients using sunlight-range illumination. This is of significance because (1) 1O2 is known to be cytotoxic, and (2) there have been several reports of toxic effects associated with the use of some sunscreens; most notably, with p-aminobenzoic acid (PABA). Illuminated aqueous solutions of PABA, 2-ethylhexyl p-(dimethylamino)benzate (ODPABA), 2-hydroxy-4-methoxybenzophenone (BZ3), 2,2'-dihydroxy-4-methoxybenzophenone (BZ8), 2-ethylhexyl 2-cyano-3,3-diphenylacrylate (OCR), 2-ethylhexyl p-methoxycinnamate (OMC), and 2-ethylhexyl salicylate (OCS) were evaluated individually for 1O2 formation. Furfuryl alcohol (FFA), a well-known chemical trap for 1O2, was added to each of the aqueous sunscreen solutions. The FFA was consumed when solutions of PABA, ODPABA, OMC, and OCR were illuminated, but no loss of FFA other than by direct photolysis occurred in solutions of BZ3, BZ8, or OCS. There was also no significant loss of FFA in any of these solutions kept in the dark. Further evidence for the formation of 1O2 in illuminated aqueous sunscreen solutions is provided by the results of experiments in which individual solutions containing sunscreen active ingredients and FFA that were diluted with D2O exhibited an increased rate of FFA consumption while the addition of azide ion (N3-) reduced the rate of FFA consumption. Continuous sunlight-range illumination of aqueous PABA solutions produced significantly higher steady-state concentrations of 1O2 than in solutions containing any of the other sunscreen active ingredients evaluated. The substituted benzophenone compounds (BZ3 and BZ8) and the salicylate-based compound (OCS) not only appear to produce no 1O2, but they also appear to produce no other reactive oxidant species that are capable of consuming FFA. This indicates that BZ3, BZ8, and OCS may be peferable, from the standpoint of toxic oxidant formation, for use as sunscreen active ingredients when compared to the other compounds evaluated in this study.
有证据表明，在几种防晒活性成分的空气饱和水溶液中，利用阳光范围内的光照可光化学形成单线态分子氧（1O2）。这具有重要意义，因为（1）已知1O2具有细胞毒性，（2）有几份报告称使用某些防晒霜会产生毒性作用；最显著的是对氨基苯甲酸（PABA）。分别评估了对氨基苯甲酸（PABA）、2-乙基己基对（二甲基氨基）苯甲酸酯（ODPABA）、2-羟基-4-甲氧基二苯甲酮（BZ3）、2,2'-二羟基-4-甲氧基二苯甲酮（BZ8）、2-乙基己基 2-氰基-3,3-二苯基丙烯酸酯（OCR）、2-乙基己基对甲氧基肉桂酸酯（OMC）和2-乙基己基水杨酸酯（OCS）的光照水溶液中1O2的形成情况。糠醇（FFA）是一种众所周知的1O2化学捕获剂，被添加到每种防晒水溶液中。当PABA、ODPABA、OMC和OCR的溶液被光照时，FFA被消耗，但在BZ3、BZ8或OCS的溶液中，除了直接光解外，没有FFA的损失。在黑暗中保存的任何这些溶液中，FFA也没有显著损失。含有防晒活性成分和FFA的单个溶液用重水稀释后，FFA消耗速率增加，而叠氮离子（N3-）的添加降低了FFA消耗速率，这些实验结果进一步证明了光照防晒水溶液中形成了1O2。与评估的其他任何防晒活性成分的溶液相比，对氨基苯甲酸水溶液的连续阳光范围内光照产生的1O2稳态浓度显著更高。取代二苯甲酮化合物（BZ3和BZ8）和水杨酸基化合物（OCS）似乎不仅不产生1O2，而且似乎也不产生其他能够消耗FFA的活性氧化物种。这表明，从有毒氧化剂形成的角度来看，与本研究中评估的其他化合物相比，BZ3、BZ8和OCS可能更适合用作防晒活性成分。
