In human life Oxygen is really indispensable, without oxygen we can non last. Our evolutionary ascendants developed defence mechanisms that can minimise the toxic effects of O, without this protection causes the terminal of life. Natural defense mechanisms are imperfect, the harm of the cells caused by O can be minimized by utilizing antioxidants. The diseases like malignant neoplastic disease, cardiovascular disease, cataracts, age related diseases and degenerative diseases of nervous system. A batch of research plants are made in this past decennaries. In this survey the metabolites produced by the O species and with research plants they have learned how to forestall the diseases caused by the reactive O species. Now research plants are making for bettering the antioxidant activity.
Free groups are cardinal to any biochemical procedure and stand for an indispensable portion of aerophilic life and our metamorphosis. They are continuously produced by organic structure ‘s normal usage of O such as respiration and some cell mediated immune maps. The O ingestion inherent in cell growing leads to the coevals of reactive O species.
A free group may be defined as any atom, group of atoms or molecule holding one or more odd negatrons in its outermost orbital and are capable of independent being. They are typically unstable and extremely reactive. A free group is formed when a covalent bond between molecules is broken and the corresponding negatron remains with the freshly formed atom.
Free groups are highly reactive due to the presence of odd negatrons as it gives the molecule a considerable grade of responsiveness and one time formed they act as extremely reactive groups capable of concatenation reactions.
Fig. 4 Free extremist formation
Any free extremist holding O can be referred to as a ROS. Oxygen centered free extremist species hold 2 odd negatrons in the outer shell. When free groups capture an negatron from the neighbouring compound or molecule a new free group is formed and this reaction proceeds as a concatenation reaction until the free groups are all neutralized ( Wijk et al. , 2008 ) .
Causes of free groups Formation
Food preservatives and pesticides
MECHANISM OF ACTION OF FREE RADICALS OR ROS FORMATION
Oxygen in the ambiance has two odd negatrons and these odd negatrons have parallel spins and it is considered to be in a land ( inactive ) province. Oxygen is usually non reactive to organic molecules that have paired negatrons with opposite spin, but can be activated to singlet aroused ( active ) province by two mechanisms.
Absorption of equal energy to change by reversal the spin on one of the odd negatrons.
Monovalent decrease ( accept a individual negatron )
Superoxide is formed during the monovalent decrease reaction which farther gets reduced to organize H2O2. H2O2 so in the presence of ferric salts ( Fe2+ ) gets reduced to hydroxyl groups. This reaction was ab initio described by Fenton and subsequently developed by Haber and Weiss ( Daniel et al. , 1998 ) .
Antioxidants are any substance, nowadays at lower concentration compared to that of oxidizable substance that hold or inhibits oxidative harm to a mark molecule. Antioxidants defuse the free groups by donating their negatrons and therefore seting an terminal to the C stealing belongings of the free group. They work as scavengers and therefore prevent cell and tissue harm that can take to cellular hurt and disease. They are agents that protect other critical chemicals and macro molecules of the organic structure from oxidization reactions by responding with free groups and other ROS within the organic structure. One antioxidant molecule can merely respond with individual free group and hence there is a changeless necessity to refill antioxidant militias either endogenously or through dietetic addendum.
The organic structure has developed legion endogenous antioxidant systems to battle the production of reactive O intermediates ( ROI ) . These systems can be loosely divided into:
Non – Enzymatic. Fig 7 shows the antioxidant system.
Fig. 7 Antioxidant system
Superoxide Dismutase ( SOD )
SODs are a household of metalloenzymes that converts superoxide to hydrogen peroxide ( H2O2 ) and are chiefly the primary line of protection against O toxicity. Basically three isoforms of the enzyme have been discovered. The first is chiefly found in the cytol of cells and it incorporating Cu and Zn at its active site ( Cu/Zn SOD-1 ) , the 2nd containing Mn at its active site is located in chondriosome ( Mn SOD-2 ) and the 3rd ( Cu/Zn SOD-3 ) is present in the extracellular fluid like plasma. SOD is a emphasis protein which is synthesized largely in response to oxidative emphasis. It is found that small sum of Cu, Zn and Mn metals are important for keeping the antioxidant activity of SOD ( Ray and Husain, 2002 ) .
Glutathione Peroxidase ( GPx )
GPx is one of the of import enzymes responsible for the debasement of H2O2 and organic peroxides in the encephalon. GPx catalyse the oxidization of glutathione into its oxidised signifier ( GSSG ) at the disbursal of H2O2. Two isoforms have been identified ; selenium-dependent GPx which is extremely active towards H2O2 and organic hydroperoxides and Se independent GPx. GPx activity is found to be less in Se lack.
Catalase ( CAT )
It is a heme-containing protein nowadays in some cells. Catalase is 104 times faster than GPx and it consists of four protein fractional monetary units, each incorporating a haem iron ( III ) -protoporphyrin group bound to its active site ( Ray and Husain, 2002 ) .
Carotenoids: It is a lipid soluble antioxidants, normally seen in membrane tissue. The chief map is the remotion of reactive O species.
Bilirubin: It is produced by haem metamorphosis found in blood. The chief map is act as extracellular antioxidants.
Glutathione: It is a non-protein thiol and found in cells. It has the belongings of cellular oxidant defence.
Alpha-lipoic acid: It is endogenous thiol. Its belongings is by functioning replacement for glutathione, recycling vitamin C.
Vitamin C: It is found in aqueous stage of cell. Its belongings is act as free extremist scavenger and besides act in the recycle of vitamin E.
Vitamin Tocopherol: It is found in cells. Function is concatenation interrupting antioxidant.
Uric acid: It is a merchandise of purine metamorphosis. Its belongings is scavenging of hydroxyl ( OH ) group.
MECHANISM OF ACTION OF ANTIOXIDANTS
They chiefly act as
i?? Physical barriers forestalling ROS coevals or ROS entree to of import biological sites.
E.g. UV filters, cell membranes
i?? Chemical traps / sinks ‘absorb ‘ energy and negatrons slaking ROS.
E.g. Carotenoids, anthocyanidins
i?? Catalytic systems neutralize or divert ROS.
E.g. SOD, catalase and glutathione peroxidase
i?? Binding / inactivation of metal ion prevents coevals of ROS by Haber-Weiss reaction.
E.g. Ferritin, catechins
i?? Sacrificial and concatenation extension inhibitor antioxidants scavenge and destroy ROS.
E.g. Ascorbic acid ( Vit.C ) , vitamin Es ( Vit E ) , uric acid,
IN VITRO ANTI-OXIDANT STUDIES OF EXTRACTS OF ROOTS OF CLERODENDRUM SERRATUM RHIZOME.
Nitric oxide extremist scavenging check
Assorted concentrations of the infusion and Na nitroprusside ( 5mM ) in phosphate buffer saline ( 0.025 M, pH 7.4 ) in a entire volume of 3 milliliter was incubated at room temperature for a period of 150 min. After which, 0.5 milliliter of the incubated solution and 0.5 milliliter Griess ‘ reagent ( 1 % sulphanilamide, 2 % O-Phosphoric acid and 0.1 % naphthyethylene diamine dihydrochloride ) were added togather and allowed to respond for 30 min. Control samples without the trial compounds but with equal volume of buffer was prepared in a similar mode as done for the trial. The optical density of the chromophore formed during diazotisation of nitrite with sulphanilamide and consecutive yoke with naphthyethylene diamine dihydrochloride was measured at 546 nanometer. The per centum suppression of the infusions and criterion was calculated. The experiment was carried out in triplicate utilizing curcumin ( 40-200 ?g/ml ) as positive control ( Rao et al. , 2008 ) .
% Scavenging Activity = [ ( Ac- As ) / Ac ] – 100
Where, Ac is the optical density of the control reaction and as is the optical density in the presence of the sample of the infusions. The antioxidant activity of the infusion was expressed as IC50. The IC50 value was defined as the concentration ( in µg/ml ) of infusions that inhibits the formation of free groups by 50 % .
Table 27: NITRIC OXIDE SCAVENGING ACTIVITY
Control optical density [ Ac ] : 1.0022
Concentration ( µg/ml )
Optical density at 546 nm [ As ]
% Anti-oxidant Activity ( % )
( µg/ml )
Petroleum Ether Extract
Ethyl Acetate Extract
Standard [ ASCORBIC ACID ]
Table 28: % of maximal antioxidant activity of infusions
% maximal Anti-oxidant activity [ % ]
Standard [ Ascorbic acid ]