好吧~我承认这标题真是够烂 什麽读书心得嘛... 不过 我还是想贴给各位看看..了解这个棕榈酸维他命A的"琐事" 对了 也别鞭我保养品成分不该如此看 我当然知道要以"配方"来论定 但是 基於这是可以讨论问题 我想还是要提出来给大夥知道 谁叫我是棕榈酸维他命A爱用者??(笑) 对了 一些日系保养品与欧系保养品(特别是强调抗老的) 也都有这成分喔^^ 先聊聊为什麽会读这文献的动机好了 这样也让大家知道要怎麽避免 我那错误的示范~~ 先来个大家耳熟能详的成分内容吧... 以下是撷取 http://store.mecare.com/Ingredient.asp?gid=379 内容为:皮肤後转化成A酸作用刺激性比A酸小，可加速细胞再生使细胞年轻化、 平滑细化角质层、刺激胶原蛋白增生使用一段时间真皮层会变厚表皮细化因此 而改善细纹细皱、紧实皮肤、是抗老化产品之后。同时有减少油脂分泌、 通畅毛孔之效益所以可以改善痘痘，也有减少黑色素美白效益。 而这些内容已经在含有Retinyl Palmitate的产品文案 相信已经耳熟能详了.. 其中一些有sense的美容实用书 也大力推荐这成分... 当然 我也观望了好久 查了英文相关网页 才决定要买有关这成分的产品~ 但是令人科科的来了．．．．． 　　我爱死了这成分 它让我的脸部更加紧实~ 每天努力的使用之外 还不忘看有关的书籍.. 於是我开灯了!!! 就在开灯看书的隔一天 我的美容师告诉我 你的脸部怎麽黄成这样????????????????????????????????? 我惊觉得回想我到底怎麽了? 生病了? 还是....? 於是我请美容师看我的脖子 有没有变黄色? 美容师再三确定 没有!!!! 突然想到"会不会是这个成分?" (天知道 我只记得A酸别照光 压根忘了 Retinyl Palmitate是否也要避光? 倘若是日光灯呢? 甚至阳光呢?) 於是 开始查了相关"光与Retinyl Palmitate"的文献~~ 以下是两篇期刊 有兴趣的板友 在学校倒是可以去抓来瞧瞧... 1.UVA photoirradiation of retinyl palmitate—Formation of singlet oxygen and superoxide, and their role in induction of lipid peroxidation Toxicology Letters Volume 163, Issue 1, 5 May 2006, Pages 30-43 　2.Photoirradiation of Retinyl Palmitate in Ethanol with Ultraviolet Light -Formation of Photodecomposition Products, Reactive Oxygen Species,and Lipid Peroxides Int. J. Environ. Res. Public Health 2006, 3(2), 185-190 其中第二篇摘要为: Abstract: We have previously reported that photoirradiation of retinyl palmitate (RP), a storage and ester form of vitamin A (retinol), with UVA light resulted in the formation of photodecomposition products, generation of reactive oxygen species, and induction of lipid peroxidation. In this paper, we report our results following the photoirradiation of RP in ethanol by an UV lamp with approximately equal UVA and UVB light. The photodecomposition products were separated by reversed-phase HPLC and characterized spectroscopically by comparison with authentic standards. The identified products include: 4-keto-RP, 11-ethoxy-12-hydroxy-RP, 13-ethoxy-14-hydroxy-RP, anhydroretinol (AR), and trans- and cis-15-ethoxy-AR. Photoirradiation of RP in the presence of a lipid, methyl linoleate, resulted in induction of lipid peroxidation. Lipid peroxidation was inhibited when sodium azide was present during photoirradiation which suggests free radicals were formed. Our results demonstrate that, similar to irradiation with UVA light, RP can act as a photosensitizer leading to free radical formation and induction of lipid peroxidation following irradiation with UVB light. 在此作者指出在2004年至少有700多项保养品是含有retinyl palmitate 刚刚无聊查有关抗老成分的保养品(没有特定指定一定要夜间使用的) 就有好几笔~ 这些有此成分保养品若直接暴露在阳光下 是对皮肤有害的 (如产生ROS) 当然这作者他使用的光源是比较狠的 (直接拿UV光作实验) 不过 这让我倒是有更深的了解... 使用retinyl palmitate 的产品要避阳光!!!!要注意防晒!!! 否则会让皮肤更糟糕!!! 而第一篇文献则是在标题就指明了----> UVA photoirradiation of retinyl palmitate—Formation of singlet oxygen and superoxide!! 摘要如下: We have previously reported that photoirradiation of retinyl palmitate (RP) in ethanol with UVA light results in the formation of photodecomposition products, including 5,6-epoxy-RP and anhydroretinol (AR). Photoirradiation in the presence of a lipid, methyl linoleate, induced lipid peroxidation, suggesting that reactive oxygen species (ROS) are formed. In the present study, we employ an electron spin resonance (ESR) spin trap technique to provide direct evidence as to whether or not photoirradiation of RP by UVA light produces ROS. Photoirradiation of RP by UVA in the presence of 2,2,6,6-tetramethylpiperidine (TEMP), a specific probe for singlet oxygen, resulted in the formation of TEMPO, indicating that singlet oxygen was generated. Both 5,5-dimethyl N-oxide pyrroline (DMPO) and 5-tert-butoxycar bonyl 5-methyl-1-pyrroline N-oxide (BMPO) are specific probes for superoxide. When photoirradiation of RP was conducted in the presence of the DMPO or BMPO, ESR signals for DMPO-OOH or BMPO-OOH were obtained. These results unambiguously confirmed the formation of superoxide radical anion. Consistent with a free radical mechanism, there was a near complete and time-dependent photodecomposition of RP and its photodecomposition products. ESR studies on the photoirradiation of 5,6-epoxy-RP and AR indicate that these compounds exhibit similar photosensitizing activities as RP under UVA light. 而在文章作者也指出:有直接的证据显示 以UVA光照射retinyl palmitate 会产生singlet oxygen 和 superoxide radical anion (可俗称自由基) 而这跟我想要得到的答案 好像得到了 也好像又离得太远^^! 不过 看了这两篇文献 我的总心得是: 假如含有此成分的产品 最好是夜间使用 白天记得加强防晒就对了! 假如产品有标明"白天可以使用" 那还是要加强防晒!! 那使用此成分产品後开日光灯看书呢?? http://210.60.224.4/ct/content/1982/00100154/0013.htm http://www.ge-taiwan.com/GE_Lighting/GEL_Business.files/GEL_Sun.htm 那可能要依照灯管涂布材料而定 材料decay而定 (这要请灯管达人解释^^) 我是做最保守的做法 使用retinyl palmitate产品後 一律只开小灯 最後还是要跟大家说明一下: 当然成分不能这样看啦~ 我想应该很多保养品配方达人看了会摇摇头 这个罗莉乱来!! 指着产品 我们可是有很周到的配方 也许加入防晒剂? 也许完整配方根本不会照成反黑.. 或者会指着期刊说光源就是UVA 不能与实际情况比较.. 但是我只是提醒大家 别以为retinyl palmitate不像A酸一样要避阳光 我们读者不该只是纯粹得到retinyl palmitate正面的消息... 多一份小心还是为妙!! 以上又是一篇又臭又长的心得... > < 感谢大家看到结尾~~ ORZ -- ※ 编辑: LOLIVA 来自: 140.123.79.32 (11/19 16:11)