The radical scavenging activity of Spilanthes acmella root extracts was determined as described by Gayatri et al. 4.3mg of DPPH (2, 2-Diphenyl -1- picrylhydrazyl) was dissolved in methanol(6.6ml) to prepare 0.3mM DPPH solution and it was protected from light by covering the test tubes with aluminium foil. DPPH (150µl) was added to 3ml of methanol and absorbance was noticed immediately at
516nm for control reading. Different
cncentrations of test samples i.e 25 µl, 50
µl, 100 µl, 150 µl, 200 µl and 250 µl were
taken and each of the samples was diluted
with methanol up to 3ml, to it 150 µl DPPH
was added. The samples were kept in dark
for 15 min after which the optical density
was observed at 516nm using methanol as
blank. The synthetic antioxidant, Rutin
hydrate was used as positive control.