Antioxidant activity of extracts and standard compounds ((+)-
-tocopherol, mangiferin and quercetin 3--d-glucoside) was
determinedby 2,2-diphenyl-1-picrylhydrazyl radical(DPPH) assay.
The method employed was designed having in account the methods
described by Brand-Williams and Scherer and Godoy [33,34].
About 0.1 mL aliquots of methanolic solutions of the samples or
standards at different concentrations were each added to 3.9 mL
of a 6 × 10−5 mol/L DPPH methanolic solution. The absorbance of
DPPH was monitored spectrophotometrically at 515 nm at 0 min
and every 2 min until the reaction reached the steady state. The
DPPH concentration (CDPPH)in the reaction medium was calculated
from a calibration curve determined by linear regression with Eq.
(1):