Radical DPPH scavenging activity
Following the method described in the literature (Bondet et al.,
1997) with minor modifications, radical scavenging activities were
determined by using DPPH (2,2-diphenyl-1-picrylhydrazyl) as a free
radical. The tested extracts reacted with DPPH and the decreased in
absorbance at 515 nm, indicating the potential scavenging of the
extracts. Control assays were performed with extracts of the black
carrots to subtract its contribution in this absorbance. The reaction
for scavenging DPPH radicals was performed in a micro-plate
reader of 96 well plates (Biotek Powerwave XS with software KC4).
The reaction was carried out on the plate wells with a temperature
of 25 8C. A solution of 60 mM DPPH was prepared in methanol.
270 mL of this solution was added to each well together with 30 mL
of antioxidant. The compounds tested were a final concentration of
10 mM. The decrease in absorbance was measured at 515 nm, at
t = 0 and every 5 min, for 20 min. For the final analysis, the 0–20 min
reaction time range was used. Antiradical activity was expressed
as Trolox equivalents. The antiradical activity was calculated
from the equation determined from the linear regression after
plotting known solutions with different concentrations of Trolox