Novel semiautomated method for assessing in vitro cellular antioxidant activity using the light-scattering properties of human erythrocytes.

The novel method developed for screening cellular antioxidant activity relies on differences in light-scattering properties (turbidity) between intact and lysed human erythrocytes. AAPH, a peroxyl radical generator, was used to enhance lipid peroxidation. The consequent hemolysis triggered a loss of the light-scattering ability in the lysed erythrocytes. When an antioxidant was added, the area under the absorbance decay curve (AUC) was linearly proportional to the concentration of antioxidant compound. This erythrocyte cellular antioxidant activity (ERYCA) method was found to be relatively fast, sensitive, accurate, and repeatable, even when using erythrocytes from different donors and for different storage times. The method was used to assess the antioxidant capacity of pure phenolic compounds, fruit juices, stimulant beverages, and blood plasma and compared with ORAC values. The values resulting from the two methods did not correlate as the mechanisms involved were different.