LAUSR

7,8,3’,4’,5’-Pentahydroxyisoflavone (8,3’,5’-trihydroxydaidzein) and 6,7,8,3’,4’,5’-hexahydroxyisoflavone (6,8,3’,5’-tetrahydroxydaidzein) are synthesized via a simple and effective method using commercially available daidzein as a raw material. Their structures are confirmed using spectroscopic analyses (infrared, nuclear magnetic resonance, and mass spectrometry), and their purities are determined by high-performance liquid chromatography. The antioxidant capacities are investigated by utilizing 1,1-diphenyl-2-picryl-hydrazyl radical scavenging, superoxide radical scavenging, nitric oxide radical scavenging, reducing power, and phosphomolybdenum assays. The antihypoxia activity is examined using a hypoxia-induced PC12 cell injury model. The antioxidant and antihypoxia abilities of 8,3’,5’-trihydroxydaidzein and 6,8,3’,5’-tetrahydroxydaidzein are greatly improved in comparison with daidzein. These results indicate that 8,3’,5’-trihydroxydaidzein and 6,8,3’,5’-tetrahydroxydaidzein are excellent antioxidant agents and can be used for alleviating injury induced by hypoxia.