title: Chemical and cellular antioxidant activity of two novel peptides designed based on glutathione structure.
abstract: Two novel peptides, ECH (Glu-Cys-His) and YECG (Tyr-Glu-Cys-Gly), were designed based on glutathione (Glu-Cys-Gly, GSH) and their antioxidant activities were studied. Various chemical methods based on single-electron-transfer (SET) and hydrogen-atom-transfer (HAT) were applied to evaluate the antioxidant activities of the peptides. For SET-based assay, tripeptide ECH displayed the highest DPPH radical scavenging activity (80.16%) and the strongest reducing power (A(700)=0.378). Besides, ECH also exhibited the best inhibition activity toward linoleic acid peroxidation with inhibition rate 98.25% at 7th day, which is a HAT-based assay. However, for another two HAT-based assays, it was tetrapeptide YECG that showed extraordinary oxygen radical absorption capacity (ORAC value=2.42 μM Trolox/μM) and ABTS free radical scavenging ability (8.88 mM Trolox/mM). In vitro cultured PC12 cell model also suggested that YECG gave the best protection for PC12 cells to resist H(2)O(2)-treated necrosis. It was found that the discrepancy of antioxidant capacity between ECH and YECG was caused by the presence of antioxidant amino acids (His/Tyr) and their position in peptide chain. With His located at C-terminal position, ECH demonstrated good electrons donating capacity, while with Tyr at N-terminal position, YECG exhibited strong oxygen radical absorbance capacity.
authors.affiliation: College of Light Industry and Food Sciences, South China University of Technology, Guangzhou 510640, Guangdong, China.
authors.forename: Longjian
authors.initials: L
authors.lastname: Gu
authors.forename: Mouming
authors.initials: M
authors.lastname: Zhao
authors.forename: Wenzhi
authors.initials: W
authors.lastname: Li
authors.forename: Lijun
authors.initials: L
authors.lastname: You
authors.forename: Jufang
authors.initials: J
authors.lastname: Wang
authors.forename: Haiyan
authors.initials: H
authors.lastname: Wang
authors.forename: Jiaoyan
authors.initials: J
authors.lastname: Ren
mesh_terms: D000818:Animals; D000975:Antioxidants / Q000737:chemistry* / Q000494:pharmacology*; D001713:Biphenyl Compounds / Q000737:chemistry; D016166:Free Radical Scavengers / Q000737:chemistry / Q000494:pharmacology; D005978:Glutathione / Q000737:chemistry*; D006859:Hydrogen / Q000737:chemistry; D006861:Hydrogen Peroxide / Q000633:toxicity; D019787:Linoleic Acid / Q000378:metabolism; D010084:Oxidation-Reduction; D016716:PC12 Cells / Q000187:drug effects / Q000473:pathology; D010455:Peptides / Q000737:chemistry* / Q000494:pharmacology*; D010851:Picrates / Q000737:chemistry; D051381:Rats; D013329:Structure-Activity Relationship
chemical_list: D000975:Antioxidants; D001713:Biphenyl Compounds; D016166:Free Radical Scavengers; D010455:Peptides; D010851:Picrates; D006859:Hydrogen; D019787:Linoleic Acid; D006861:Hydrogen Peroxide; C004931:1,1-diphenyl-2-picrylhydrazyl; D005978:Glutathione