title: Protective effects of purified safflower extract on myocardial ischemia in vivo and in vitro.
abstract: Carthamus tinctorius L. (safflower) is one of the most commonly used Chinese herbal medicines to prevent and treat cardiac disease in clinical practice. However, the mechanisms responsible for such protective effects remain largely unknown. In this study, we investigated the anti-myocardial ischemia effects of a purified extract of C. tinctorius (ECT) both in vivo and in vitro. An animal model of myocardial ischemia injury was induced by left anterior descending coronary artery occlusion in adult rats. Pretreatment with ECT (100, 200, 400, 600 mg/kg body wt.) could protect the heart from ischemia injury by limiting infarct size and improving cardiac function. In the in vitro experiment, neonatal rat ventricular myocytes were incubated to test the direct cytoprotective effect of ECT against H(2)O(2) exposure. Pretreatment with 100-400 microg/ml ECT prior to H(2)O(2) exposure significantly increased cell viability as revealed by 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyl tetrazolium bromide (MTT) assay. ECT also markedly attenuated H(2)O(2)-induced cardiomyocyte apoptosis, as detected by Annexin V and PI double labeling with flow cytometry. The intracellular level of reactive oxygen species (ROS) was shown by 2',7'-dichlorofluorescin diacetate (DCFH-DA), and ECT pretreatment significantly inhibited H(2)O(2)-induced ROS increase. We made a preliminary examination of the signaling cascade involved in ECT mediated anti-apoptotic effects. Phosphatidylinositol 3 kinase (PI3K) inhibitor (LY294002) blocked the cytoprotective effect conferred by ECT. Taken together, our findings provide the first evidence that the cardioprotective effects of ECT in myocardial ischemia operate partially through reducing oxidative stress induced damage and apoptosis. The protection is achieved by scavenging of ROS and mediating the PI3K signaling pathway.
authors.affiliation: State Key Laboratory of Natural and Biomimetic Drugs, School of Pharmaceutical Sciences, Peking University Health Science Center, Beijing, PR China.
authors.forename: Shu-Yan
authors.initials: SY
authors.lastname: Han
authors.forename: Hai-Xia
authors.initials: HX
authors.lastname: Li
authors.forename: Xu
authors.initials: X
authors.lastname: Ma
authors.forename: Ke
authors.initials: K
authors.lastname: Zhang
authors.forename: Zhi-Zhong
authors.initials: ZZ
authors.lastname: Ma
authors.forename: Peng-Fei
authors.initials: PF
authors.lastname: Tu
mesh_terms: D000818:Animals; D017209:Apoptosis / Q000187:drug effects; D031187:Carthamus tinctorius; D002470:Cell Survival / Q000187:drug effects; D019610:Cytoprotection / Q000187:drug effects; D004195:Disease Models, Animal; D004365:Drugs, Chinese Herbal / Q000494:pharmacology / Q000627:therapeutic use; D035264:Flowers; D016166:Free Radical Scavengers / Q000494:pharmacology / Q000627:therapeutic use*; D006861:Hydrogen Peroxide / Q000378:metabolism; D008297:Male; D017202:Myocardial Ischemia / Q000188:drug therapy*; D015428:Myocardial Reperfusion Injury / Q000517:prevention & control*; D032383:Myocytes, Cardiac / Q000187:drug effects; D019869:Phosphatidylinositol 3-Kinases / Q000378:metabolism; D008517:Phytotherapy; D010936:Plant Extracts / Q000494:pharmacology / Q000627:therapeutic use*; D010946:Plants, Medicinal; D047428:Protein Kinase Inhibitors / Q000494:pharmacology; D051381:Rats; D017207:Rats, Sprague-Dawley; D015398:Signal Transduction
chemical_list: D004365:Drugs, Chinese Herbal; D016166:Free Radical Scavengers; D010936:Plant Extracts; D047428:Protein Kinase Inhibitors; D006861:Hydrogen Peroxide; D019869:Phosphatidylinositol 3-Kinases