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Submitted to: Analytical and Bioanalytical Chemistry
Publication Type: Peer Reviewed Journal Publication Acceptance Date: 4/12/2007 Publication Date: 6/17/2007 Citation: Chen, P., Ozcan, M., Harnly, J.M. 2007. Chromatographic Fingerprints Analysis for Evaluation of Ginkgo Biloba Products. Analytical and Bioanalytical Chemistry. Available on-line doi: 10.1007/s00216-007-1386-9. Interpretive Summary: The leaf extract of Ginkgo biloba has purported value for improving mental capacities in Alzheimer’s patients. The flavonoids and the ginkgolides are considered to be the two main active components that influence human health. This paper compared a chromatographic finger-print method using UV detection for determination of the composition of flavonoids with the traditional HPLC method for total flavonoids quantitation in ginkgo products. A gradient reversed-phase HPLC method was developed that was suitable for separation of flavonol aglycones (Quercetin, Kaempferol, and Isorhamnetin) and flavonol glycosides. Methanol-water (1:1) extracts of ginkgolides and flavonoids from sixteen commercially available Ginkgo biloba products, three standard reference materials (SRM 3246 Ginkgo biloba leaves, SRM 3247 Ginkgo biloba extract, and SRM 3248 Ginkgo biloba tablet) from the National Institute of Standards and Technology (NIST), and hand-picked Ginkgo leaves were analyzed qualitatively, semi-quantitatively, and quantitatively (by UV detection at 370 nm). The results from the fingerprints obtained by chromatography and from the total flavonoids determination were compared for the assessment of the contents of the Ginkgo biloba samples. Technical Abstract: The leaf extract of Ginkgo biloba has purported value for improving mental capacities in Alzheimer’s patients. The flavonoids and the terpene lactones are considered to be the two main active components that influence human health. This paper compared an LC/UV chromatographic fingerprint method with the traditional LC/UV quantitation method for assessment of flavonoids in Ginkgo biloba products. A gradient reversed-phase HPLC method was used for separation of flavonol aglycones (Quercetin, Kaempferol, and Isorhamnetin) and flavonol glycosides. Methanol-water (1:1) extracts of eighteen commercially available Ginkgo biloba products, including three standard reference materials (SRM) from the National Institute of Standards and Technology, an American Herbal Pharmacopoeia verified Ginkgo leaf sample, and fourteen Ginkgo dietary supplements were analyzed qualitatively and quantitatively. The results from the fingerprints obtained by chromatography and from the total flavonoids determination were compared for the assessment of the flavonoids contents of the Ginkgo biloba samples. Significant variations were observed among the fingerprints of the Ginkgo biloba products by peak analysis and chemometric analysis. The traditional quantitation method, however, showed that the amount of total flavonols in most commercial products met the standards. |
