2.4. DPPH radical scavenging activity
The free radical scavenging activity of the extract was first screened by the free radical 2,2-diphenyl-1-
picrylhydrazyl (DPPH) assay. The reduction of the DPPH was determined on TLC plate spotted with 1 mg/ml of
sample and developed with CHCl3: EtOAc (1:4). After drying, the plate was sprayed with a 0.2% solution of DPPH
(Fluka, BioChemika, Switzerland) in MeOH and left at r.t. for 8 h. Activated products appeared as yellow spots against
a purple background [10].
In order to measure the degree of antioxidant activity, DPPH free radical scavenging assay was carried out according
to the procedure described by Sanchez et al. [11]. Briefly, aliquots of the sample in MeOH solution (1 mg/ml) were
added to 3 ml of a 0.0004% MeOH solution of DPPH and the reaction mixture was shaken vigorously. The reaction
involved a color change from violet to yellow which could be measured by the decrease in an absorbance at 515 nm
after 10 min. The radical scavenging activity was obtained from the following equation:
Inhibition Activityð%Þ ¼ ðOD control−OD sampleÞ
OD control
100
OD control represents the absorbance without extract
OD sample represents the absorbance with extract