title: Comparative effects of flavonoids on oxidant scavenging and ischemia-reperfusion injury in cardiomyocytes.
abstract: Since flavonoids scavenge reactive oxygen species, they may potentially protect against ischemia/reperfusion injury. This study compared the scavenging capacity of specific flavonoids towards different reactive oxygen species. Whether the differential oxidant scavenging capacity correlated with their protective efficacy in ischemia/reperfusion injury of cardiomyocytes was determined. The free radical scavenging capacity of five flavonoids (wogonin, baicalin, baicalein, catechin and procyanidin B2) was analyzed using electron spin resonance spectrometry for 3 radicals: 1,1-diphenyl-2picrylhydrazyl (DPPH), superoxide and hydroxyl radical. A well-established chick cardiomyocyte model of ischemia (1 h)/reperfusion (3 h) was used to evaluate flavonoid-induced protection against ischemia/reperfusion injury in chronic treatment (pretreated 72 h and treated through ischemia/reperfusion) and acute treatment protocols (during ischemia/reperfusion or only at reperfusion). The cell viability was assessed by propidium iodide. The DPPH scavenging was most significant with catechin, followed by procyanidin B2, baicalein, baicalin, and wogonin. The superoxide scavenging was, similarly, most significant with catechin, followed by baicalein, procyanidin B2, and baicalin. For hydroxyl radical, only baicalein showed a significant scavenging capacity (>50% reduction in ESR signal). For the cardiomyocyte studies, all flavonoids but wogonin showed protection against ischemia/reperfusion injury in the chronic treatment protocol. When flavonoids were administered only during ischemia/reperfusion, baicalein, procyanidin B2, and catechin significantly reduced cell death. If flavonoids were administered just at reperfusion, only baicalein and procyanidin B2 had protective effects, and the efficacy was less. Flavonoids possess specific but differential radical scavenging capacity, which, in conjunction with the timing of treatment, affects their protective efficacy in cardiomyocytes exposed to ischemia/reperfusion.
authors.affiliation: Emergency Resuscitation Center, Section of Emergency Medicine, Department of Medicine, University of Chicago, Chicago, IL 60637, USA, and Department of Emergency Medicine, National Taiwan University Hospital, Taipei, Taiwan, ROC.
authors.forename: Wei-Tien
authors.initials: WT
authors.lastname: Chang
authors.forename: Zuo-Hui
authors.initials: ZH
authors.lastname: Shao
authors.forename: Jun-Jie
authors.initials: JJ
authors.lastname: Yin
authors.forename: Sangeeta
authors.initials: S
authors.lastname: Mehendale
authors.forename: Chong-Zhi
authors.initials: CZ
authors.lastname: Wang
authors.forename: Yimin
authors.initials: Y
authors.lastname: Qin
authors.forename: Juan
authors.initials: J
authors.lastname: Li
authors.forename: Wen-Jone
authors.initials: WJ
authors.lastname: Chen
authors.forename: Chiang-Ting
authors.initials: CT
authors.lastname: Chien
authors.forename: Lance B
authors.initials: LB
authors.lastname: Becker
authors.forename: Terry L
authors.initials: TL
authors.lastname: Vanden Hoek
authors.forename: Chun-Su
authors.initials: CS
authors.lastname: Yuan
mesh_terms: D000818:Animals; D001713:Biphenyl Compounds / Q000378:metabolism; D002470:Cell Survival / Q000187:drug effects; D002478:Cells, Cultured; D002642:Chick Embryo; D004578:Electron Spin Resonance Spectroscopy; D005419:Flavonoids / Q000494:pharmacology*; D016166:Free Radical Scavengers / Q000494:pharmacology*; D006834:Hydrazines / Q000378:metabolism; D017665:Hydroxyl Radical / Q000378:metabolism; D032383:Myocytes, Cardiac / Q000187:drug effects* / Q000378:metabolism; D016877:Oxidants / Q000378:metabolism; D010851:Picrates; D015427:Reperfusion Injury / Q000188:drug therapy* / Q000378:metabolism; D013481:Superoxides / Q000378:metabolism
chemical_list: D001713:Biphenyl Compounds; D005419:Flavonoids; D016166:Free Radical Scavengers; D006834:Hydrazines; D016877:Oxidants; D010851:Picrates; D013481:Superoxides; D017665:Hydroxyl Radical; C004931:1,1-diphenyl-2-picrylhydrazyl