title: Functionalized graphene quantum dots loaded with free radicals combined with liquid chromatography and tandem mass spectrometry to screen radical scavenging natural antioxidants from Licorice and Scutellariae.
abstract: A novel screening method was developed for the detection and identification of radical scavenging natural antioxidants based on a free radical reaction combined with liquid chromatography with tandem mass spectrometry. Functionalized graphene quantum dots were prepared for loading free radicals in the complex screening system. The detection was performed with and without a preliminary exposure of the samples to specific free radicals on the functionalized graphene quantum dots, which can facilitate charge transfer between free radicals and antioxidants. The difference in chromatographic peak areas was used to identify potential antioxidants. This is a novel approach to simultaneously evaluate the antioxidant power of a component versus a free radical, and to identify it in a vegetal matrix. The structures of the antioxidants in the samples were identified using tandem mass spectrometry and comparison with standards. Fourteen compounds were found to possess potential antioxidant activity, and their free radical scavenging capacities were investigated. The order of scavenging capacity of 14 compounds was compared according to their free radical scavenging rate. 4',5,6,7-Tetrahydroxyflavone (radical scavenging rate: 0.05253 mL mg(-1) s(-1) ) showed the strongest capability for scavenging free radicals.
authors.affiliation: School of Petrochemical Engineering, Lanzhou University of Technology, Lanzhou, China.
authors.forename: Guoying
authors.initials: G
authors.lastname: Wang
authors.forename: XiuLi
authors.initials: X
authors.lastname: Niu
authors.forename: Gaofeng
authors.initials: G
authors.lastname: Shi
authors.forename: Xuefu
authors.initials: X
authors.lastname: Chen
authors.forename: Ruixing
authors.initials: R
authors.lastname: Yao
authors.forename: Fuwen
authors.initials: F
authors.lastname: Chen
mesh_terms: D000975:Antioxidants / Q000032:analysis*; D001688:Biological Products / Q000032:analysis; D002853:Chromatography, Liquid; D016166:Free Radical Scavengers / Q000032:analysis*; D005609:Free Radicals / Q000737:chemistry*; D006035:Glycyrrhiza / Q000737:chemistry*; D006108:Graphite / Q000737:chemistry*; D015394:Molecular Structure; D045663:Quantum Dots; D031363:Scutellaria / Q000737:chemistry*; D053719:Tandem Mass Spectrometry
chemical_list: D000975:Antioxidants; D001688:Biological Products; D016166:Free Radical Scavengers; D005609:Free Radicals; D006108:Graphite
keywords: Antioxidants; Free radicals; Graphene; Quantum dots; Radical scavengers