Document Type

Journal Article

Department/Unit

School of Chinese Medicine

Title

Quantitative analysis of the flavonoid glycosides and terpene trilactones in the extract of Ginkgo biloba and evaluation of their inhibitory activity towards fibril formation of β-amyloid peptide

Language

English

Abstract

The standard extract of Ginkgo biloba leaves (EGb761) is used clinically in Europe for the symptomatic treatment of impaired cerebral function in primary degenerative dementia syndromes, and the results of numerous in vivo and in vitro studies have supported such clinical use. The abnormal production and aggregation of amyloid β peptide (Aβ) and the deposition of fibrils in the brain are regarded as key steps in the onset of Alzheimer's Disease (AD), and the inhibition of Aβ aggregation and destabilization of the preformed fibrils represent viable approaches for the prevention and treatment of AD. Flavonoid glycosides and terpene trilactones (TTLs) are the two main components of EGb761 which represent 24 and 6% of the overall content, respectively. In our research, seven abundant flavonoid glycosides 1-7 were isolated from the extract of Ginkgo biloba leaves and characterized by spectroscopic analysis. Furthermore, an ultra-high performance liquid chromatography method was established for the simultaneous quantification of these seven flavonoids. The inhibitory activities of these flavonoids, as well as four TTLs, i.e., ginkgolides A, B, and C and bilobalide (compounds 8-11), were evaluated towards Aβ42 fibril formation using a thioflavin T fluorescence assay. It was found that three flavonoids 1, 3 and 4 exhibited moderate inhibitory activities, whereas the other four flavonoids 2, 5, 6 and 7, as well as the four terpene trilactones, showed poor activity. This is the first report of the inhibition of Aβ fibril formation of two characteristic acylated flavonoid glycosides 6, 7 in Ginkgo leaves, on the basis of which the structure-activity relationship of these flavonoids 1-7 was discussed. © 2014 by the authors; licensee MDPI, Basel, Switzerland.

Keywords

Flavonoid glycoside, Ginkgo biloba, Inhibitory activity, Quantitative analysis, Terpene trilactone, β-amyloid fibril formation

Publication Date

2014

Source Publication Title

Molecules

Volume

19

Issue

4

Start Page

4466

End Page

4478

Publisher

MDPI

DOI

10.3390/molecules19044466

Link to Publisher's Edition

http://dx.doi.org/10.3390/molecules19044466

ISSN (print)

14203049

ISSN (electronic)

14203049

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