Screening of free radical scavenging compounds in water extracts of Mentha samples using a postcolumn derivatization method.
An on-line high-performance liquid chromatography-1,1-diphenyl-2-picrylhydrazyl (HPLC-DPPH*) method has been improved for the detection of polar and nonpolar radical scavenging compounds in complex plant extracts. Nine water extracts were prepared from different Mentha species, varieties, hybrids, and cultivars. After the components within each extract had been separated by reverse phase chromatography using 10-100% methanol with 2% acetic acid as a mobile phase, analytes within the eluent capable of scavenging a citric acid-sodium citrate-buffered methanol 1,1-diphenyl-2-picrylhydrazyl solution were detected by postcolumn derivatization at 517 nm. The HPLC-DPPH* on-line method was applied to the qualitative and quantitative analysis of Mentha extracts. There was a strong correlation between the scavenging (negative) peak area and the concentration of the radical scavenging reference substances used. The minimum detectable concentration (microg/mL) of the antioxidant compounds was determined. Caffeic acid, eriocitrin (eriodictyol-7-O-rutinoside), luteolin-7-O-glucoside, and rosmarinic acid were identified as the dominant radical scavengers in these extracts by this method.
Division of Pharmacognosy, Faculty of Pharmacy, University of Helsinki, P.O. Box 56 (Viikinkaari 5E), FIN-00014, Finland. mkosar@anadolu.edu.tr
Müberra
M
Koşar
H J Damien
HJ
Dorman
K Hüsnü
KH
Can Başer
Raimo
R
Hiltunen
D000975:Antioxidants / Q000032:analysis; D001713:Biphenyl Compounds; D002851:Chromatography, High Pressure Liquid / Q000379:methods; D016166:Free Radical Scavengers / Q000032:analysis*; D027541:Mentha / Q000737:chemistry*; D010851:Picrates; D010936:Plant Extracts / Q000737:chemistry*; D014867:Water
D000975:Antioxidants; D001713:Biphenyl Compounds; D016166:Free Radical Scavengers; D010851:Picrates; D010936:Plant Extracts; D014867:Water; C004931:1,1-diphenyl-2-picrylhydrazyl