Screening and Identification of Antioxidant Components in the Extract of Puerariae radix Using HPLC Coupled with MS

Abstract

Puerariae radix is a Chinese traditional medicine for the treatment of coronary heart disease, myocardial infarction, and hypertension. Among the complex constituents in the crude extract of P. radix, puerarin, daidzin, and daidzein were screened and identified to possess the strong antioxidant activity by using high-performance liquid chromatography–mass spectrometry technique for the first time. Antioxidant capacities of the identified compounds were further evaluated by three different assays: 2, 2-diphenyl-1-picrylhydrazyl radical (DPPH·) radical scavenging assay and Fe2+-metal chelating assay and HO· radical scavenging assay. The results showed that daidzein possessed a strong free radical scavenging activity and metal chelating activity. Puerarin exhibited a good DPPH· free radical scavenging activity, while its metal chelating capacity was relatively weak. By contrast, the antioxidant capacity of daidzin was relatively much weaker. The conclusion in this study might give a clue on the understanding of the pharmacological function of P. radix.