The article presents information on a study which described the isolation of isoflavones and their glycosides from kudzu root, Pueraria lobata Ohwi. The bioactivity of the isolated compounds was analyzed. The antioxidative activities of five major compounds, namely, puerarin, daidzin, daidzein, biochanin A and genistein, were evaluated and compared. Findings showed that the five compounds acted as free-radical scavengers and blocked both linoleic acid peroxidation and lipoxygenase activity.