Baicalein and Baicalin from the Radix of Scutellaria baicalensis Georgi Inhibits Oxidative DNA Damage and Apoptosis via its Antioxidant Activity

In this study, we evaluated and compared the protective effects of two major constituents, baicalein and baicalin, against oxidative DNA and cell damages caused by hydroxyl radical. Antioxidant properties were evaluated using DPPH and hydroxyl radicals scavenging assays and $Fe^{2+}$ chelating assay. ${\varphi}X$ 174 RFI plasmid DNA and intracellular DNA migration assay were used to evaluate the protective effect against oxidative DNA damage. Also, MTT and lipid peroxidation assays were used to evaluate their protective effects against oxidative cell damage. Both baicalein and baicalin prevented intracellular DNA and cells from oxidative damage caused by hydroxyl radical via antioxidant activities. Baicalein demonstrated a stronger antioxidant activity in scavenging DPPH radicals and chelating $Fe^{2+}$ while baicalin scavenged hydroxyl radicals more efficiently. The differences in the level of baicalein and baicalin pose a different pathological pathway for each. The antioxidant activity of baicalin was due to its ability to scavenge hydroxyl radical whilst baicalein was a stronger $Fe^{2+}$ chelator. Further investigation to compare the molecular mechanisms of antitumor activities of baicalein and baicalin is vital to anticancer research.