Assessment of the scavenging action of reduced glutathione, (+)-cyanidanol-3 and ethanol by the chemiluminescent response of the xanthine oxidase reaction.

The free radical scavenging capacity of reduced glutathione (GSH), (+)-cyanidanol-3 and ethanol was assessed by their interference with the maximal chemiluminescent response produced by the xanthine oxidase reaction. GSH and (+)-cyanidanol-3 induce a progressive inhibition of chemiluminescence when increasing amounts are added to the reaction mixture. GSH and (+)-cyanidanol-3 added together at low concentrations (1 and 0.05 mM respectively) exhibit an additive effect. The addition of ethanol presents a biphasic effect. It inhibits chemiluminescence at low concentrations (10-50 mM) while at higher concentrations (75-500 mM) this effect is reversed. Estimation of the concentrations required to produce half of the maximal inhibition of chemiluminescence by these agents revealed that ethanol is less effective than GSH and (+)-cyanidanol-3 as a free radical scavenger in the system used.