Effects of baicalein and alpha-tocopherol on lipid peroxidation, free radical scavenging activity and 12-O-tetradecanoylphorbol acetate-induced ear edema.

The effects of baicalein, a flavonoid, and alpha-tocopherol (vitamin E) on lipid peroxidation in rat forebrain homogenates, on free radical scavenging action against diphenyl-p-picrylhydrazyl (DPPH), and on 12-O-tetradecanoylphorbol acetate (TPA)-induced ear edema in mice were studied. Baicalein inhibited lipid peroxidation in forebrain homogenates, DPPH-induced free radical and TPA-induced ear edema as potently as did quercetin and nordihydroguaiaretic acid (NDGA), a lipoxygenase inhibitor, and more potently than BW755C, a mixed cyclooxygenase and lipoxygenase inhibitor. Lipid peroxidation in forebrain homogenates, DPPH-induced free radical and TPA-induced ear edema were also inhibited by alpha-tocopherol. Flavone showed no reaction. These results suggest that lipid peroxidation may play an important role in the pathogenesis of TPA-induced ear edema in mice.