title: Protective effect of Castanea sativa and Quercus robur leaf extracts against oxygen and nitrogen reactive species.
abstract: 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.
authors.affiliation: Departamento de Tecnologia Farmacêutica, Faculdade de Farmácia da, Universidade do Porto, Rua Aníbal Cunha 164, 4099-030 Porto, Portugal.
authors.forename: Isabel F
authors.initials: IF
authors.lastname: Almeida
authors.forename: Eduarda
authors.initials: E
authors.lastname: Fernandes
authors.forename: José L F C
authors.initials: JL
authors.lastname: Lima
authors.forename: P C
authors.initials: PC
authors.lastname: Costa
authors.forename: M F
authors.initials: MF
authors.lastname: Bahia
mesh_terms: D000042:Absorption; D000287:Administration, Topical; D029962:Fagaceae / Q000737:chemistry*; D016166:Free Radical Scavengers / Q000008:administration & dosage / Q000494:pharmacology*; D006801:Humans; D010936:Plant Extracts / Q000008:administration & dosage / Q000494:pharmacology*; D018515:Plant Leaves / Q000737:chemistry*; D029963:Quercus / Q000737:chemistry*; D026361:Reactive Nitrogen Species / Q000378:metabolism*; D017382:Reactive Oxygen Species / Q000378:metabolism*
chemical_list: D016166:Free Radical Scavengers; D010936:Plant Extracts; D026361:Reactive Nitrogen Species; D017382:Reactive Oxygen Species