Chemistry Reference
In-Depth Information
5.7. Total antioxidant activity
The total antioxidant potential of
E. agallocha
was investigated and compared against
ascorbic acid, the results are explained in Figure 2B. The methanolic extract of
E. agallocha
is
observed to be
more effective - the IC
50
value is calculated as 3.36 g
.
The
phosphomolybdenum method usually detects antioxidants such as ascorbic acid, some
phenolics, -tocopherol and carotenoids [25]. Ascorbic acid, glutathione, cysteine, tocopherols,
polyphenols and aromatic amines have the ability to donate hydrogen and electrons, and can
thus be detected by this assay. Oxidative stress is the condition in which an imbalance between
oxidant stimuli and physiological antioxidants exist leading to the damage of a cell. The body's
physiological response to oxidative stress is through several antioxidant systems which
include enzymes like superoxide dismutase, catalase, glutathione peroxidase and a variety of
large molecules such as albumin and ferrtin, and small molecules such as ascorbic acid,
tocopherol, etc. These antioxidants can be found as water-soluble or lipid-soluble molecules
and localized transiently throughout tissues, cells and cell types.
5.8. DNA nicking induced by hydroxyl radical
Hydroxyl radical is the most reactive among reactive oxygen species, it has the shortest half
life compared with others and is considered to be responsible for much of the biological
damage in free-radical pathology. The radical has the capacity to cause strand breakage in
DNA, which contributes to carcinogenesis, mutagenesis and cytotoxicity [11]. The DNA
protective effect of hexane water and methanol extract of
E. agallocha
Linn leaf was checked
against Fenton's induced DNA damage of pCAMBIA 1301 DNA. The protection offered
against DNA damage by
E. agallocha
(10- 200 g/l) (results not shown) was concentration
dependent. At concentration 100 g/l protection was more effective and slightly close to
that of 5U of Catalase and 50 M of quercetin tried (Figure 3). Native DNA has shown
three forms, form I open circular form, form II single supercoiled band and below it form
III, whereas DNA + Fenton's reagent and hexane fraction has exhibited complete
degradation of DNA. Water fraction of
E. agallocha
Linn has shown very good protective
activity and has retained all three forms. These results indicate that the water extract of
E.
agallocha
Linn effectively mitigates the oxidative stresses on susceptible biomolecules,
such as DNA.
Figure 3.
DNA protective effect of hexane, water and methanol extract of leaf of
E. agallocha
Linn, was
checked against Fenton's induced DNA damage of pCAMBIA 1301 DNA. Effect of fraction of
E.
agallocha
Linn. on oxidative DNA nicking caused by hydroxyl radicals. Lane A: native pCAMBIA 1301
DNA; Lane B: DNA + Fenton's reagent; Lane C: DNA + Fenton's reagent +
E. agallocha.
Linn water
extract (50 g/ml), Lane D: DNA + Fenton's reagent +
E. agallocha.
Linn methanol extract (100 g/ml),
