GENERATION OF FREE RADICALS, OXIDATIVE STRESS AND THEIR DAMAGING PROPERTIES. ศ. เกียรติคุณ ดร. ไมตรี สุทธจิตต์. E-mail: [email protected]. หัวข้อบรรยาย. 1. อนุมูลอิสระคืออะไร? 2. อนุมูลอิสระเกิดได้อย่างไร?. 3. สมบัติของ อนุมูลอิสระต่อสุขภาพและชีวิต 4. Oxidative stress and health. - PowerPoint PPT Presentation
Welcome message from author
This document is posted to help you gain knowledge. Please leave a comment to let me know what you think about it! Share it to your friends and learn new things together.
Transcript
GENERATION OF FREE GENERATION OF FREE RADICALS, OXIDATIVE STRESS RADICALS, OXIDATIVE STRESS
AND THEIR DAMAGING AND THEIR DAMAGING PROPERTIESPROPERTIES
Free radicals are the most active species in the reaction process, and are characterized by unpaired electrons.
Free radicals are electrically neutral, which distinguish them from the ions that are electrically charged (electrons/protons unbalance)!
PROPERTIES OF PROPERTIES OF FREE FREERADiCALSRADiCALS
- - CChemical processes hemical processes oror combustioncombustion-Consist of a chain of reactions in two -Consist of a chain of reactions in two ways:ways:1. based on 1. based on products and reactantsproducts and reactants..2. based on radicals (initiating, 2. based on radicals (initiating, branching, propagating, terminating).branching, propagating, terminating).
A key role in both normal biological function and in the pathogenesis
M icrobiocidal mechanismI nflammatory responseT oxicity of many drugsAging C arcinogenesis.C ertain diseases: ocular,
neurological, psychiatric
Formation of Free Radicals:Redox Formation of Free Radicals:Redox reactions (Reduction-oxidation)reactions (Reduction-oxidation)
Reactions with exchange of electrons Reactions with exchange of electrons between reactantsbetween reactantsReduction is the gain of electronsReduction is the gain of electrons
R + e- R-R + e- R- Oxidation is the loss of electronsOxidation is the loss of electrons
R- R + e- R- R + e- FeFe2+ Fe Fe 3+ + e- + e- e.g. electric energy, electrochemical e.g. electric energy, electrochemical cells, batteries, cells, batteries,
Peroxidation of Free RadicalsOn Polyunsaturated Lipid (LH)
L. = Lipid alkyl radical
LOO . = Lipid peroxyl radical LL = Polymerized lipids
OH. + LH ---> H2O + L.
L . + O2 ---> LOO .
LOO . + H2O ---> LOOH + L.
L . + L. ---> LL
อนุ�ม�ลอสุระภายในุเซลล� -Mitochondria
Mitochondria: source and target of free radical species.
Homeostasis and Gene ControlGene regulation mechanisms have evolved allowing cells to fine-tune the level of "endogenous" oxidative stress and to cope with increased free radicals from external sources.
The soxRS regulon mobilizes diverse functions to scavenge free radicals and repair oxidative damage in macromolecules, and other mechanisms that exclude many environmental agents, e.g. nitric oxide, activating expression of heme oxygenase 1 through stabilization of its mRNA.
Aging: Cells and Metabolism Cellular theory • Genetics: anti-aging gene • Cell biochemical metabolism • Free radicals/antioxidant balance
Aging and Biological SystemsEndocrinology: Insulin-like hormone Immunity : lymphocyte response
Aging and Factors Outside the BodyNutrition-calorie consumptionEnvironment: toxins and detoxification