Glycyrrhiza uralensis (or licorice) is a widely used Oriental herbal medicine from which the phenylflavonoids
dehydroglyasperin C (DGC),
dehydroglyasperin D (DGD), and
isoangustone A (IsoA) are derived. The purpose of the present study was to evaluate the
antioxidant properties of DGC, DGD, and IsoA. The three compounds showed strong ferric reducing activities and effectively scavenged DPPH,
ABTS(+), and
singlet oxygen radicals. Among the three compounds tested, DGC showed the highest
free radical scavenging capacity in human
hepatoma HepG2 cells as assessed by
oxidant-sensitive
fluorescent dyes dichlorofluorescein diacetate and
dihydroethidium bromide. In addition, all three compounds effectively suppressed lipid peroxidation in rat tissues as well as H(2)O(2)-induced ROS production in
hepatoma cells. This study demonstrates that among the three phenylflavonoids isolated from licorice, DGC possesses the most potent
antioxidant activity, suggesting it has protective effects against
chronic diseases caused by
reactive oxygen species as well as potential as an
antioxidant food additive.