title: Quantitative analysis of bilobalide and ginkgolides from Ginkgo biloba leaves and Ginkgo products using (1)H-NMR.
abstract: 1H-NMR spectrometry was applied to the quantitative analysis of the bilobalide, ginkgolides A, B, and C in Ginkgo biloba leaves and six kinds of commercial Ginkgo products without any chromatographic purification. The experiment was performed by the analysis of each singlet H-12, which were well separated in the range of delta 6.0-7.0 in the (1)H-NMR spectrum. However, the H-12 protons of bilobalide and ginkgolides may have overlapped with H-6 or H-8 protons of the Ginkgo flavonoids. Therefore, the optimum (1)H-NMR solvent for the analysis of the compound was selected through the evaluation of solvent effects on the resolution of these signals from the compounds. Acetone-d(6)-benzene-d(6) (50 : 50) was found to be the best one among the solvents evaluated. The quantity of the compounds was calculated by the relative ratio of the intensity of each compound to the known amount of internal standard (25 microgram), phloroglucinol. This method allows rapid and simple quantitation of underivatized bilobalide and ginkgolides in 5 min without any pre-purification steps.
authors.affiliation: Division of Pharmacognosy, Leiden/Amsterdam Center for Drug Research, Gorlaeus Laboratories, Leiden University, The Netherlands.
authors.forename: Young Hae
authors.initials: YH
authors.lastname: Choi
authors.forename: Hyung-Kyoon
authors.initials: HK
authors.lastname: Choi
authors.forename: Arno
authors.initials: A
authors.lastname: Hazekamp
authors.forename: Paloma
authors.initials: P
authors.lastname: Bermejo
authors.forename: Yvonne
authors.initials: Y
authors.lastname: Schilder
authors.forename: Cornelis
authors.initials: C
authors.lastname: Erkelens
authors.forename: Robert
authors.initials: R
authors.lastname: Verpoorte
mesh_terms: D003517:Cyclopentanes / Q000032:analysis* / Q000737:chemistry / Q000302:isolation & purification; D004224:Diterpenes; D005069:Evaluation Studies as Topic; D005663:Furans / Q000032:analysis* / Q000737:chemistry / Q000302:isolation & purification; D020441:Ginkgo biloba; D046934:Ginkgolides; D007783:Lactones / Q000032:analysis / Q000737:chemistry / Q000302:isolation & purification; D009682:Magnetic Resonance Spectroscopy / Q000379:methods*; D010936:Plant Extracts / Q000032:analysis / Q000737:chemistry / Q000302:isolation & purification; D018515:Plant Leaves; D011522:Protons
chemical_list: D003517:Cyclopentanes; D004224:Diterpenes; D005663:Furans; D046934:Ginkgolides; D007783:Lactones; D010936:Plant Extracts; D011522:Protons; C058295:ginkgolide C; C045856:ginkgolide B; C073710:bilobalide