2.4.2. DPPH radical scavenging activity
The 1,1-diphenyl-2-picryl-hydrazil (DPPH) radical scavenging
activity of astaxanthin/HPCD inclusion complex was measured
using the method of Gülc¸ in, Küfrevio˘glu, Oktay, and Büyükokuro˘glu
(2004) with some modifications. 0.1 mM solution of DPPH in
ethanol was prepared. Then, 2 mL of this solution was added to 2 mL
of sample solutions at different concentrations. The mixture was
shaken and allowed to stand at 25 ◦C for 30 min. The absorbance
was measured at 517 nm in 2100 UV–VIS spectroscopy. Lower
absorbance of the reaction mixture indicated higher free radical
scavenging activity. The DPPH scavenging effect (KD) was calculated
using the following equation: