好吧~我承認這標題真是夠爛 什麼讀書心得嘛... 不過 我還是想貼給各位看看..了解這個棕櫚酸維他命A的"瑣事" 對了 也別鞭我保養品成分不該如此看 我當然知道要以"配方"來論定 但是 基於這是可以討論問題 我想還是要提出來給大夥知道 誰叫我是棕櫚酸維他命A愛用者??(笑) 對了 一些日系保養品與歐系保養品(特別是強調抗老的) 也都有這成分喔^^ 先聊聊為什麼會讀這文獻的動機好了 這樣也讓大家知道要怎麼避免 我那錯誤的示範~~ 先來個大家耳熟能詳的成分內容吧... 以下是擷取 http://store.mecare.com/Ingredient.asp?gid=379 內容為:皮膚後轉化成A酸作用刺激性比A酸小，可加速細胞再生使細胞年輕化、 平滑細化角質層、刺激膠原蛋白增生使用一段時間真皮層會變厚表皮細化因此 而改善細紋細皺、緊實皮膚、是抗老化產品之后。同時有減少油脂分泌、 通暢毛孔之效益所以可以改善痘痘，也有減少黑色素美白效益。 而這些內容已經在含有Retinyl Palmitate的產品文案 相信已經耳熟能詳了.. 其中一些有sense的美容實用書 也大力推薦這成分... 當然 我也觀望了好久 查了英文相關網頁 才決定要買有關這成分的產品~ 但是令人科科的來了．．．．． 　　我愛死了這成分 它讓我的臉部更加緊實~ 每天努力的使用之外 還不忘看有關的書籍.. 於是我開燈了!!! 就在開燈看書的隔一天 我的美容師告訴我 你的臉部怎麼黃成這樣????????????????????????????????? 我驚覺得回想我到底怎麼了? 生病了? 還是....? 於是我請美容師看我的脖子 有沒有變黃色? 美容師再三確定 沒有!!!! 突然想到"會不會是這個成分?" (天知道 我只記得A酸別照光 壓根忘了 Retinyl Palmitate是否也要避光? 倘若是日光燈呢? 甚至陽光呢?) 於是 開始查了相關"光與Retinyl Palmitate"的文獻~~ 以下是兩篇期刊 有興趣的板友 在學校倒是可以去抓來瞧瞧... 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 其中第二篇摘要為: 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多項保養品是含有retinyl palmitate 剛剛無聊查有關抗老成分的保養品(沒有特定指定一定要夜間使用的) 就有好幾筆~ 這些有此成分保養品若直接暴露在陽光下 是對皮膚有害的 (如產生ROS) 當然這作者他使用的光源是比較狠的 (直接拿UV光作實驗) 不過 這讓我倒是有更深的了解... 使用retinyl palmitate 的產品要避陽光!!!!要注意防曬!!! 否則會讓皮膚更糟糕!!! 而第一篇文獻則是在標題就指明了----> 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:有直接的證據顯示 以UVA光照射retinyl palmitate 會產生singlet oxygen 和 superoxide radical anion (可俗稱自由基) 而這跟我想要得到的答案 好像得到了 也好像又離得太遠^^! 不過 看了這兩篇文獻 我的總心得是: 假如含有此成分的產品 最好是夜間使用 白天記得加強防曬就對了! 假如產品有標明"白天可以使用" 那還是要加強防曬!! 那使用此成分產品後開日光燈看書呢?? http://210.60.224.4/ct/content/1982/00100154/0013.htm http://www.ge-taiwan.com/GE_Lighting/GEL_Business.files/GEL_Sun.htm 那可能要依照燈管塗佈材料而定 材料decay而定 (這要請燈管達人解釋^^) 我是做最保守的做法 使用retinyl palmitate產品後 一律只開小燈 最後還是要跟大家說明一下: 當然成分不能這樣看啦~ 我想應該很多保養品配方達人看了會搖搖頭 這個羅莉亂來!! 指著產品 我們可是有很周到的配方 也許加入防曬劑? 也許完整配方根本不會照成反黑.. 或者會指著期刊說光源就是UVA 不能與實際情況比較.. 但是我只是提醒大家 別以為retinyl palmitate不像A酸一樣要避陽光 我們讀者不該只是純粹得到retinyl palmitate正面的消息... 多一份小心還是為妙!! 以上又是一篇又臭又長的心得... > < 感謝大家看到結尾~~ ORZ -- ※ 編輯: LOLIVA 來自: 140.123.79.32 (11/19 16:11)