Hanson Kerry M, Clegg Robert M
Laboratory for Fluorescence Dynamics, Department of Physics, University of Illinois, Urbana-Champaign, Illinois, USA.
J Cosmet Sci. 2003 Nov-Dec;54(6):589-98.
The ability of sunscreens and antioxidants to deactivate highly destructive reactive oxygen species in human skin has remained inconclusive. Two-photon fluorescence imaging microscopy was used to determine the effect of sunscreen/antioxidant combinations upon UV-induced ROS generation in ex vivo human skin. A sunscreen combination containing octylmethoxycinnamate (Parsol MCX) and avobenzone (Parsol 1789) at SPF 8 and SPF 15 was tested for its ability to prevent UV radiation from generating ROS in the viable epidermal strata of ex vivo human skin. A UV dose equivalent to two hours of North American solar UV was used to irradiate the skin. Each sunscreen reduced the amount of ROS induced in the viable strata by a value consistent with the SPF level. UV photons that were not absorbed/scattered by the sunscreen formulations generated ROS within the viable epidermal layers. The addition of the bioconvertible antioxidants vitamin E acetate and sodium ascorbyl phosphate (STAY-C 50) improves photoprotection by converting to vitamins E and C, respectively, within the skin. The bioconversion forms an antioxidant reservoir that deactivates the ROS generated (within the strata granulosum, spinosum, and basale) by the UV photons that the sunscreens do not block in the stratum corneum.
防晒剂和抗氧化剂使人类皮肤中极具破坏性的活性氧失活的能力尚无定论。采用双光子荧光成像显微镜来确定防晒剂/抗氧化剂组合对体外人皮肤中紫外线诱导的活性氧生成的影响。测试了一种防晒组合，其含有辛基甲氧基肉桂酸酯（帕索 MCX）和二苯甲酰甲烷（帕索 1789），防晒系数分别为 8 和 15，评估其防止紫外线辐射在体外人皮肤的活表皮层中产生活性氧的能力。使用相当于北美两小时太阳紫外线的剂量来照射皮肤。每种防晒剂都将活表皮层中诱导产生的活性氧量减少到与防晒系数水平相符的值。未被防晒配方吸收/散射的紫外线光子在活表皮层内产生活性氧。添加可生物转化的抗氧化剂维生素 E 醋酸酯和抗坏血酸磷酸酯钠（STAY-C 50）可分别在皮肤内转化为维生素 E 和维生素 C，从而增强光保护作用。这种生物转化形成了一个抗氧化剂库，可使防晒剂在角质层中未阻挡的紫外线光子在颗粒层、棘层和基底层中产生活性氧失活。
