Almeida Isabel F, Fernandes Eduarda, Lima José L F C, Costa P C, Bahia M F
Departamento de Tecnologia Farmacêutica, Faculdade de Farmácia da, Universidade do Porto, Rua Aníbal Cunha 164, 4099-030 Porto, Portugal.
J Photochem Photobiol B. 2008 May 29;91(2-3):87-95. doi: 10.1016/j.jphotobiol.2008.02.001. Epub 2008 Feb 8.
Topical natural antioxidants are a useful strategy for the prevention of photoaging and oxidative stress mediated skin diseases. In view of this underlying principle, the screening of natural plant extracts with scavenging activity for pro-oxidant reactive species is a primary requirement for the development of new topical antioxidant formulations. In the present study, an ethanol:water (7:3) extract from Castanea sativa leaves and a ethanol:water (2:3) extract from Quercus robur leaves were evaluated for their putative in vitro scavenging effects on reactive oxygen species (ROS) namely superoxide radical (O(2)(-)), hydroxyl radical (HO()), peroxyl radical (ROO()), hydrogen peroxide (H(2)O(2)) and singlet oxygen ((1)O(2)) as well as on reactive nitrogen species (RNS) namely nitric oxide (()NO) and peroxynitrite (ONOO(-)). The extracts presented a high potency to scavenge the tested reactive species, all the IC(50)s being found at the microg/mL level. IC(50)s (mean+/-SE) for the ROS O(2)(-),HO(),H(2)O(2) and (1)O(2) were 13.6+/-1.8; 216+/-4; 410+/-8; 12.3+/-0.7 microug/mL, respectively, for C. sativa, and 11.0+/-0.5; 285+/-22; 251+/-32; 7.90+/-0.56 microg/mL, respectively, for Q. robur. The ORAC values obtained for ROO() were 1.24+/-0.13 for C. sativa and 1.09+/-0.06 for Q. robur. The IC(50)s (mean+/-SE) for ()NO and ONOO(-) were 3.10+/-0.14 and 1.49+/-0.10 microg/mL, respectively, for C. sativa and 3.13+/-0.11 and 0.95+/-0.02 microg/mL, respectively, for Q. robur. The content of total phenolics for C. sativa and Q. robur were 284+/-9 and 346+/-4 mg of gallic acid equivalents (GAE)/g of lyophilized extract respectively. The observed effects might be of relevance considering the putative interest of these extracts as topical antioxidants.
局部应用天然抗氧化剂是预防光老化和氧化应激介导的皮肤病的一种有效策略。基于这一基本原理，筛选具有清除促氧化反应性物种活性的天然植物提取物是开发新型局部抗氧化剂配方的首要要求。在本研究中，评估了欧洲栗叶乙醇:水（7:3）提取物和夏栎叶乙醇:水（2:3）提取物对活性氧（ROS）即超氧阴离子自由基（O(2)(-)）、羟基自由基（HO(·)）、过氧自由基（ROO(·)）、过氧化氢（H(2)O(2)）和单线态氧（(1)O(2)）以及对活性氮物种（RNS）即一氧化氮（(·)NO）和过氧亚硝酸根（ONOO(-)）的体外清除作用。提取物对所测试的反应性物种具有高效清除能力，所有半数抑制浓度（IC(50)）均在微克/毫升水平。对于欧洲栗，ROS的O(2)(-)、HO(·)、H(2)O(2)和(1)O(2)的IC(50)（平均值±标准误）分别为13.6±1.8、216±4、410±8、12.3±0.7微克/毫升，对于夏栎，分别为11.0±0.5、285±22、251±32、7.90±0.56微克/毫升。欧洲栗对ROO(·)的氧自由基吸收能力（ORAC）值为1.24±0.13，夏栎为1.09±0.06。对于(·)NO和ONOO(-)，欧洲栗的IC(50)（平均值±标准误）分别为3.10±0.14和1.49±0.10微克/毫升，夏栎分别为3.13±0.11和0.95±0.02微克/毫升。欧洲栗和夏栎的总酚含量分别为284±9和346±4毫克没食子酸当量（GAE）/克冻干提取物。考虑到这些提取物作为局部抗氧化剂的潜在价值，所观察到的效果可能具有重要意义。
