Qualitative and quantitative analysis of biologically active principles ...

The extracts were filtered, concentrated and evaporated to dryness.
The dried extracts were dissolved in phosphate buffer saline (PBS)
and used for further biological studies.
In vitro antioxidant activities
The antioxidant properties of the plants were analysed by
determining the scavenging effects of free radicals such as
superoxide, hydroxyl radical and lipid peroxidation generated with
in vitro assay systems.
Superoxide radical scavenging activity
The scavenging activity of extracts on superoxide anion radicals was
determined by light induced superoxide generation with riboflavin
and subsequent reduction of nitro blue tetrazolium (NBT) (McCord
and Fridovich, 1969). Different concentrations of extracts ranging
from 10 to 1000 mg were added to the reaction mixture containing 3
mg NaCN in 0.1 M EDTA; 0.12 mM riboflavin and 0.6 M phosphate
buffer (pH 7.8) in a final volume of 3 ml. The tubes containing the
reaction mixture were continuously illuminated with incandescent
lamp for 15 minutes. The optical density measurements were taken
at 530 nm before and after illumination. The effect of test material
to inhibit superoxide generation was evaluated by comparing the
Optical Density (OD) of control and treated samples.
% of inhibition = (OD of Control – OD of treated/ OD of Control)
x 100
Hydroxyl radical scavenging activity
The scavenging activity of extracts on the hydroxyl radical (OH ­ ) was
measured by the thiobarbituric acid reacting substances (TBARS)
method. The scavenging activity was measured by studying the
competition between scavenging and test compounds for hydroxyle
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