Abstract: In order to explore the biological functions of active ingredients in dried ginger, high performance liquid chromatography (HPLC) and mass spectrometry (MS) with selective reaction monitoring/multi-reaction monitoring (SRM/MRM) were used for qualitative and quantitative analysis of active ingredients in dried ginger. The antioxidant and uric acid-lowering activities of dried ginger extract and its active components were determined. The results showed that the most abundant phenylpropanoid components in dried ginger extract were phenylalanine, ferulic acid and p-coumaric acid. All these compounds had significant antioxidant capacity in terms of 1,1-diphenyl-2-picrylhydrazyl (DPPH) and hydroxyl radical scavenging capacity and ferric ion reducing power, and the decreasing order of the antioxidant capacity was ferulic acid > dried ginger extract > p-coumaric acid. In vitro xanthine oxidase inhibition assay showed that all the three drugs had strong uric acid lowering activity, the effect of p-coumaric acid being more pronounced than that of ferulic acid and dried ginger extract. Molecular docking revealed that ferulic acid and p-coumaric acid inhibited xanthine oxidase by the formation of hydrogen bonds, van der Waals force and π-π stacking with amino acid residues in the enzyme. In this study, ferulic acid, p-coumaric acid and ginger extract have good antioxidant capacity and xanthine oxidase inhibitory activity in vitro, and therefore have the potential to be developed into new uric acid-lowering products.

Key words: dried ginger; ferulic acid; p-coumaric acid; antioxidant activity; xanthine oxidase; molecular docking