title: Rapid and novel discrimination and quantification of oleanolic and ursolic acids in complex plant extracts using two-dimensional nuclear magnetic resonance spectroscopy-Comparison with HPLC methods.
abstract: A novel strategy for NMR analysis of mixtures of oleanolic and ursolic acids that occur in natural products is described. These important phytochemicals have similar structure and their discrimination and quantification is rather difficult. We report herein the combined use of proton-carbon heteronuclear single-quantum coherence ((1)H-(13)C HSQC) and proton-carbon heteronuclear multiple-bond correlation ((1)H-(13)C HMBC) NMR spectroscopy, in the identification and quantitation of oleanolic acid (OA) and ursolic acid (UA)in plant extracts of the Lamiaceae and Oleaceae family. The combination of (1)H-(13)C HSQC and (1)H-(13)C HMBC techniques allows the connection of the proton and carbon-13 spins across the molecular backbone resulting in the identification and, thus, discrimination of oleanolic and ursolic acid without resorting to physicochemical separation of the components. The quantitative results provided by 2D (1)H-(13)C HSQC NMR data were obtained within a short period of time ( approximately 14min) and are in excellent agreement with those obtained by HPLC, which support the efficiency of the suggested methodology.
authors.affiliation: Section of Organic Chemistry & Biochemistry, Department of Chemistry, University of Ioannina, Ioannina GR-45110, Greece.
authors.forename: Vassiliki G
authors.initials: VG
authors.lastname: Kontogianni
authors.forename: Vassiliki
authors.initials: V
authors.lastname: Exarchou
authors.forename: Anastassios
authors.initials: A
authors.lastname: Troganis
authors.forename: Ioannis P
authors.initials: IP
authors.lastname: Gerothanassis
mesh_terms: D002247:Carbon Isotopes / Q000737:chemistry; D002851:Chromatography, High Pressure Liquid / Q000379:methods*; D019686:Lamiaceae / Q000737:chemistry; D009682:Magnetic Resonance Spectroscopy / Q000379:methods*; D029592:Oleaceae / Q000737:chemistry; D009828:Oleanolic Acid / Q000032:analysis*; D010936:Plant Extracts / Q000737:chemistry*; D014315:Triterpenes / Q000032:analysis*; D000097245:Ursolic Acid
chemical_list: D002247:Carbon Isotopes; D009828:Oleanolic Acid; D010936:Plant Extracts; D014315:Triterpenes; D000097245:Ursolic Acid