5 Flashcards
(22 cards)
highly reactive atom or molecule that has one or more unpaired electrons.
Free Radicals
They are not all bad, free radicals actually help
They are not all bad, free radicals actually help
the body to fight viruses, bacteria, wastes &
toxins.
Characteristic of the free radicals are
Unstable, highly reactive, shortly lived
Type of a free radical
Hydroxyl radical
superoxide radical
hydrogen peroxide
Nitric oxide radical
lipid peroxyl radical
Peroxynitrite
O2. Are formed in the?
Attack the ?
electron transport chain of the me to mitochondria
Attack macromolecule in the cell
Some enzyme also liberate ROS
Xanthine oxidase
Tryptophan oxidase
Indole amine dioxygenase
Free radical they attack sites of
Increase electron density
Such as
-Nitrogen atom present in protein and DNA
-Carbon - carbon double bond poly unsaturated fatty acid and phospholipid
Present of free radical in low concentration is a good for
Immune function
Intracellular signalling
 redox state of the cell
Excessive production of free radicals can damage
Lipid and protein and DNA affecting cell function cell death by necrosis and apoptosis
Induce and undesirable oxidation lead to membrane damage protein modification DNA damage cell death due to DNA fragmentation and lipid peroxidation
§ Nitric oxide free radical (NO.) can react with superoxide radical (O2•− )
form highly toxic peroxy-nitrite (ONOO–).
Peroxy-nitrite reacts with human body fluids and tissues generating nitrotyrosines which were detected in human brain and may be increased in NDs.
The brain has high lipid content.
The brain has the highest level of O2 consumption.
So, it generates the highest levels of ROS.
Exogenous antioxidant
Phytonutrients: Flavonoids
Vitamin C , E,
B carotene: in lipid rich tissue
Vitamin C is considered the most important water soluble chain breaking antioxidant …………..
Vitamin E is a major lipid soluble antioxidant and is the most effective chain breaking antioxidant within the …………………
Vitamin C is considered the most important water soluble chain breaking antioxidant extra fluid
Vitamin E is a major lipid soluble antioxidant and is the most effective chain breaking antioxidant within the cell membrane
Endigenous antioxidants
Catalase
glutathione Peroxides
Superoxide dismutase
Require cofactor as copper zinc magnesium and selenium
mitochondrial a responsible for maintenance of
cellular haemostasis by generation and supplying energy through oxidative phosphorylation
Major site of o2 production
Complex one and complex three of the mitochondria electron transport chain
Causes of NDs
Environmental infection, hereditary oxidative damage
Secondary to toxic processes
Defect in energy metabolism
Risk factor for NDs
Increase an age
Genetic
Cellular Dysfunctions in Aging by Oxidative Stress Imbalance:
1) Cell metabolism generates ROS and reactive nitrogen species (RNS),
which in turn causes oxidative/nitrosative damage.
(2) Proteins are the most affected macromolecules by oxidative stress,
→ several modifications that avoid their being correctly degraded
and recycled by proteasome → impaired protein function.
(3) Oxidative stress also directly affects cytoskeletal proteins, causing
structural damage & signaling changes.
4-Affected
Found that PD patient have
Reduce glutathione levels
And free radical damage in the form increase lipid peroxidation and oxidation of DNA
Vulnerability of Dopaminergic Neurons to Oxidative Stress in PD
CNS contains a large number of mitochondria
§ High iron content in cells of CN
brain has ↑ lipid contents
In PD there is a significant increase of
Cholesterol lipid hydroperoxide
AD characterized by a loss of neurons because of:
characterized by a loss of neurons because of:
- accumulation of extracellular amyloid-β (Aβ) peptides &
- intracellular hyper-phosphorylation of tau protein.
