Antioxidant activity of flavonoids evaluated with myoglobin method.

Antioxidant activities of four flavonoids (rutin, quercetin, luteolin, and kaempferol) and two non-flavonoids (chlorogenic acid and pyrocatechol) against four reactive oxygen species (ROS) have been measured with a myoglobin method developed by our group. The myoglobin method uses the absorbance changes of myoglobin (a probe molecule) due to the reaction with the ROS as an indicator for the antioxidant activity measurement. Myoglobin protective ratio (MPR) was defined to express the antioxidant activities of the specimens.