Biginkgosides A–I, Unexpected Minor Dimeric Flavonol Diglycosidic Truxinate and Truxillate Esters from Ginkgo biloba Leaves and Their Antineuroinflammatory and Neuroprotective Activities

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• 作者：Guang-Lei Ma ; Juan Xiong ; Guo-Xun Yang ; Li-Long Pan ; Chang-Ling Hu ; Wei Wang ; Hui Fan ; Qiu-Hua Zhao ; Hai-Yan Zhang ; Jin-Feng Hu
• 刊名：Journal of Natural Products
• 出版年：2016
• 出版时间：May 27, 2016
• 年：2016
• 卷：79
• 期：5
• 页码：1354-1364
• 全文大小：591K
• 年卷期：0
• ISSN：1520-6025

文摘

Nine unexpected new flavonol glycoside cyclodimers in the truxinate (1–7, biginkgosides A–G, respectively) or truxillate [biginkgosides H (8) and I (9)] forms were isolated as minor components from the extract of Ginkgo biloba leaves. The new dimers possess an unusual cyclobutane ring formed by a [2+2]-cycloaddition between two symmetric (for compounds 1–5 and 7–9) or nonsymmetric (for 6) flavonol coumaroyl glucorhamnosides. A plausible biosynthetic pathway for these new compounds based on the frontier molecular orbital theory of cycloaddition reactions is briefly discussed. An antineuroinflammatory screening revealed that biginkgosides E (5) and H (8) inhibited nitric oxide production in lipopolysaccharide-activated BV-2 microglial cells, with IC₅₀ values of 2.91 and 17.23 μM, respectively. Additionally, biginkgoside F (6) showed a significant neuroprotective effect (34.3% increase in cell viability at 1 μM) against Aβ_25–35-induced cell viability decrease in SH-SY5Y neuroblastoma cells.