3. *Definition: a free radical is any atom (e.g.
oxygen, nitrogen) with at least one unpaired
electron in the outermost shell, and is
capable of independent existence
4.
5. *Unstable molecule
*They seek out to capture
electrons to neutralize
themselves
*Another free radical
formed
*Chain of reaction sets in
*Within seconds thousands
of free radicals formed
6. *A free radical is formed when a
covalent bond between entities
(atoms) is broken and one electron
remains with each newly formed
atom
7. Electron transport chain
drug metabolism by CYPs
phagocytosis.
Transition metals present in
the body ( e.g. Fe, Cu etc.),.
(they have variable oxidation
numbers ,so can accept or
donate electons)
10. * Oxidize the biomolecules leading to
tissue injury and cell death.
*After initiation, the chain can
propagates to form a vicious cycle
inducing further damage.
11. *Destroys PUFA of cell membranes
*Destabilises membrane receptors
*Inactivate enzymes
*Breaks DNA strands
* involved in physiological
processes like ageing and
pathologically in diseases with
multi organ involvement.
12. *Carcinogenesis (due
to DNA damage)
*Rheumatiod arthritis
*Amyloidosis
*CNS – Parkinson’s
disease
*CVS – Myocardial
infarction,
Atherosclerosis.(LDL
oxidatin)endothelial
dysfuction
*GIT – Peptic ulcer,
Cirrhosis, Pancreatitis
*Renal – Nephrotoxicity
due to
glomerulonephritis /
Heavy metals.
*Respiratory – asthma
*Vision –
Cataract,Retinopathy.
13.
14. Substances that neutralize free radicals
or their actions
Limit free radical formation
Destroy free radicals
Stimulate antioxidant enzyme
activity
15.
16. Endogenous enzymatic anti oxidants are constituted
by three major enzyme groups
*Superoxide Dismutase
*Catalase
*Peroxidase
17.
18.
19. *An imbalance in the oxidant to anti oxidant
levels lead to a condition termed oxidative
stress.
*increased generation and impaired
degradation of the free radicals.
*Impaired degradation in conditions like
amyotrophic lateral sclerosis (ALS), where
there are presumed decreases in
superoxide dismutase.
20.
21.
22. *α tocoferol has the highest vit
E activity
Dietary source
*Wheat germ oil, vegetable
seed oil, nuts, egg yolk, peas.
23. Physiological role as anti-oxidant
*Prevents oxidation of coenzyme Q
* protects poly unsaturated fatty acids from
oxidative break down( lipid peroxidation)
*tocopherol phenoxyl radical
*Major chain breaking antioxidant
*Protection against cancer, coronary artery
disease, AD and cataracts.
*400 IU to 800 IU( daily recommentation)
26. *Reacts with H2O2, peroxide and
super oxide to get oxidised to
dehydroascorbate.
*Carcinogenic effect of tobacco
through nitrosamines are inhibited
by Vit C & E
*Deficiency can predispose to
atherosclerosis and
carcinogenicity.
*60 mg ( daily recommentation)
34. *Act as phytoestrogen
*Bind to estrogen receptors
*Actions
Increase bone density
Decrease serum cholesterol
Decrease post cancer prostrate
growth
Decrease hormone dependent
cancer( anti estrogen effect)
35. *Blue green algae
*Good source of SOD ,B carotene and B
complex vitamin
*Most powerfull food on earth
38. a. N acetyl cysteine – glutathione
precursor
b. Ebselen – congener of glutathione
* Both augment endogenous
glutathione peroxidase activity
* Anti oxidant effect of n acetyl
cysteine is used in paracetamol
poisoning
40. d) Selenium
*Enhances the antioxidant
effect of Vit E
*Promotes synthesis of
glutathione peroxidase
*Immunostimulant
e) Mn,Zn, Cu, Cr
*Also augments the synthesis
of anti oxidant enzymes (SOD,
GP, Catalase)
41. f)Xanthine oxidase inhibitors
(Allopurinol, Oxypurinol)
*Xanthine oxidase generates
super oxide free radicals from
reduced flavins
*Important in reperfusion
injury after ischemia