title: 3,5,4'-Trihydroxy-6,7,3'-trimethoxyflavone protects astrocytes against oxidative stress via interference with cell signaling and by reducing the levels of intracellular reactive oxygen species.
abstract: Oxidative stress is tightly involved in various neurodegenerative diseases such as Parkinson's and Alzheimer's diseases, and conditions such as ischemia. Astrocytes, the most abundant glial cells in the brain, protect neurons from reactive oxygen species (ROS) and provide them with trophic support. Therefore, any damage to astrocytes will affect neuronal survival. In a previous study we have demonstrated that an extract prepared from the plant Achillea fragrantissima (Af) prevented the oxidative stress-induced death of astrocytes and attenuated the intracellular accumulation of ROS in astrocytes under oxidative stress. In the present study, using activity guided fractionation, we have purified from this plant the active compound, determined to be a flavonoid named 3,5,4'-trihydroxy-6,7,3'-trimethoxyflavone (TTF). The effects of TTF in any biological system have not been studied previously, and this is the first study to characterize the anti-oxidant and protective effects of this compound in the context of neurodegenerative diseases. Using primary cultures of astrocytes we have found that TTF prevented the hydrogen peroxide (H2O2)-induced death of astrocytes, and attenuated the intracellular accumulation of ROS following treatment of these cells with H2O2 or the peroxyl radicals generating molecule 2,2'-Azobis(amidinopropane) (ABAP). TTF also interfered with cell signaling events and inhibited the phosphorylation of the signaling proteins stress-activated protein kinase/c-Jun N-terminal kinase (SAPK/JNK), extracellular signal regulated kinase (ERK 1/2) and mitogen activated protein kinase kinase (MEK1) and the phosphorylation of the transcription factor cyclic AMP response element-binding protein (CREB). The mechanism of the protective effect of TTF against H2O2-cytotoxicity could not be attributed to a direct H2O2 scavenging but rather to the scavenging of free radicals as was shown in cell free systems. Thus, TTF might be a therapeutic candidate for the prevention/treatment of neurodegenerative diseases where oxidative stress is part of the pathophysiology.
authors.affiliation: Department of Food Quality and Safety, Volcani Center, Agricultural Research Organization, Bet Dagan 50250, Israel. Electronic address: aelmann@volcani.agri.gov.il.
authors.forename: Anat
authors.initials: A
authors.lastname: Elmann
authors.affiliation: Department of Food Quality and Safety, Volcani Center, Agricultural Research Organization, Bet Dagan 50250, Israel.
authors.forename: Alona
authors.initials: A
authors.lastname: Telerman
authors.affiliation: Department of Food Quality and Safety, Volcani Center, Agricultural Research Organization, Bet Dagan 50250, Israel.
authors.forename: Sharon
authors.initials: S
authors.lastname: Mordechay
authors.affiliation: Department of Food Quality and Safety, Volcani Center, Agricultural Research Organization, Bet Dagan 50250, Israel.
authors.forename: Hilla
authors.initials: H
authors.lastname: Erlank
authors.affiliation: Department of Food Quality and Safety, Volcani Center, Agricultural Research Organization, Bet Dagan 50250, Israel.
authors.forename: Miriam
authors.initials: M
authors.lastname: Rindner
authors.affiliation: The Dead Sea & Arava Science Center and Regenerative Medicine & Stem Cell Research Center, Ben-Gurion University of the Negev, Beer-Sheba, 84105, Israel.
authors.forename: Rivka
authors.initials: R
authors.lastname: Ofir
authors.affiliation: School of Chemistry, Tel Aviv University, Ramat Aviv 69978, Israel.
authors.forename: Yoel
authors.initials: Y
authors.lastname: Kashman
mesh_terms: D031162:Achillea; D000818:Animals; D001253:Astrocytes / Q000187:drug effects / Q000378:metabolism*; D002470:Cell Survival / Q000187:drug effects / Q000502:physiology; D002478:Cells, Cultured; D019610:Cytoprotection / Q000187:drug effects / Q000502:physiology; D047309:Flavones / Q000302:isolation & purification / Q000494:pharmacology*; D006861:Hydrogen Peroxide / Q000633:toxicity; D007424:Intracellular Fluid / Q000187:drug effects / Q000378:metabolism*; D018384:Oxidative Stress / Q000187:drug effects / Q000502:physiology*; D010936:Plant Extracts / Q000302:isolation & purification / Q000494:pharmacology*; D051381:Rats; D017208:Rats, Wistar; D017382:Reactive Oxygen Species / Q000037:antagonists & inhibitors / Q000378:metabolism*; D015398:Signal Transduction / Q000187:drug effects / Q000502:physiology
chemical_list: D047309:Flavones; D010936:Plant Extracts; D017382:Reactive Oxygen Species; D006861:Hydrogen Peroxide
keywords: 3,5,4′-trihydroxy-6,7,3′-trimethoxyflavone; Achillea fragrantissima; Astrocytes; Flavonoids; Neurodegenerative diseases; Oxidative stress