Radical scavenging activity of plant extracts against stable 2,
2 diphenyl 2 picryl hydrazyl hydrate (DPPH) was determined
by the slightly modified method of Brand-Williams et al
1995. [17] DPPH reacts with an antioxidant compound, which
can donate hydrogen, and reduce DPPH. The change in
colour (from deep violet to light yellow) was measured at
517 nm on a UV visible light spectrophotometer. The
solution of DPPH in methanol 6 × 10-5 M was prepared fresh
daily before UV measurements. Three ml of this solution was
mixed with 100 microgram/ml concentration of individual
plant extracts as well as herbal preparation. The samples
were kept in the dark for 15 minutes at room temperature and
the decrease in absorbance was measured. The experiment
was carried out in triplicate. Radical scavenging activity was
calculated by the following formula