Page 63 - Natural Antioxidants, Applications in Foods of Animal Origin

42 Natural Antioxidants: Applications in Foods of Animal Origin
VetBooks.ir body, degenerative disorders, and cancer. Oxidative stress can cause single/

multi-organ disorders/diseases including brain disorders like Alzheimer,
Parkinson, obsessive–compulsive disorder (OCD), attention deficit hyperac-
tivity disorder (ADHD), autism, migraine, stroke, trauma, and cancer; lung
disorders like asthma, chronic obstructive pulmonary disease (COPD), aller-
gies, acute respiratory distress syndrome (ARDS), and cancer; eye disor-
ders like macular or retinal degeneration and cataract; heart disorders like
coronary heart diseases (CHD), cardiac fibrosis, hypertension, ischemia,
and myocardial infarction; kidney disorders like chronic kidney diseases,
renal graft, and nephritis; bone and joint disorders like rheumatism, osteo-
arthritis, and psoriasis; blood vessel disorders like restenosis, atheroscle-
rosis, endothelial dysfunction, and hypertension; skin disorders like skin
aging, sunburn, psoriasis, dermatitis, and melanoma; multi-organ disorders
like diabetes, aging, and chronic fatigue; and immune system disorders like
chronic inflammations, auto-immune disorders, lupus, inflammatory bowel
disease (IBD), multiple sclerosis (MS), and cancer. Oxidative stress in the
body leads to the generation of free radicals like ROS and RNS which cause
the above-mentioned disorders/diseases. Now, the million-dollar question
is how to reduce the oxidative stress in the body? The answer would be by
slowing down the oxidative processes inside the body. How would it be
achieved? The answer is ANTIOXIDANTS.
As we said earlier, antioxidants are compounds which neutralize free radi-
cals or inhibit free radicals. An antioxidant can be defined as: “any substance
that, when present in low concentrations compared to that of an oxidisable
substrate, significantly delays or inhibits the oxidation of that substrate.”
This oxidisable substrate (lipid, protein, and carbohydrate) can generate
free radicals if it involves transfer of unpaired single electrons. Examples
of oxygen-centered free radicals, also known as ROS, are superoxide (O ),
−
2
hydroxyl (HO ), peroxyl (ROO ), alkoxyl (RO ), and nitric oxide (NO ). The
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hydroxyl (half-life of 10 s) and the alkoxyl (half-life of seconds) free radi-
−9
cals are very reactive and rapidly attack the molecules in nearby cells, and
probably the damage caused by them is unavoidable and is dealt with by
repair processes (Gülcin, 2012). The repair process involves scavenging free
radicals by antioxidant compounds. Antioxidants have dual role: shelf-life
prolongation and combating oxidative stress. Antioxidants are often added
to foods to prevent the radical chain reactions of oxidation, and they act
by inhibiting the initiation and propagation step leading to the termination
of the reaction and delay the oxidation process (Shahidi & Wanasundara,
1992; Gülcin, 2006). Antioxidants may be broadly grouped according to
their mechanism of action into primary or chain-breaking antioxidants and