The superoxide radical-scavenging activity of samples was measured by a
method previously described with following modifications (Aydin et al., 2001a).
Briefly, 50 lL of properly diluted extract were mixed with 1700 lL of substrate
solution containing 0.05 mmol/L xanthine sodium and 0.025 mmol/L 2-(4-iodophenyl)-3-(4-nitrophenol)-5-phenyltetrazolium chloride (INT) in a buffer solution
containing 50 mmol/L CAPS and 0.94 mmol/L EDTA (pH 10.2).