Könczöl Árpád, Rendes Kata, Dékány Miklós, Müller Judit, Riethmüller Eszter, Balogh György Tibor
Compound Profiling Laboratory, Gedeon Richter Plc., Gyömrői u. 19-21., H-1475 Budapest, Hungary.
Faculty of Chemical Technology and Biotechnology, Budapest University of Technology and Economics, Műegyetem rkp. 3., H-1111 Budapest, Hungary.
J Pharm Biomed Anal. 2016 Nov 30;131:167-174. doi: 10.1016/j.jpba.2016.08.032. Epub 2016 Aug 29.
The linkage between the central nervous system availability and neuropharmacological activity of the constituents of Ginkgo biloba L. extracts (GBE) is still incomplete. In this study, the in vitro blood-brain barrier (BBB) permeability profile of the standardised GBE was investigated by the parallel artificial membrane permeability assay (PAMPA). Biomarkers, such as terpene trilactones, flavonoid aglycones and ginkgotoxin exerted moderate or good BBB-permeability potential (BBB+), while glycosides and biflavones were predicted as unable to pass the BBB. N-methyltyramine (NMT) and N,N-dimethyltyramine or hordenine (Hor) were identified among BBB+ compounds, while subsequent direct HRMS analysis revealed tyramine (Tyr) and N,N,N-trimethyltyramine or candicine (Can) in GBE as trace constituents. Distribution of Tyr, NMT, Hor and Can was determined by a validated ion-exchange mechanism-based liquid chromatography-electrospray ionisation-mass spectrometry (LC-ESI-MS) method in G. biloba samples, such as herbal drugs and dietary supplements. The total content of the four tyramine derivatives in various GBEs ranged from 7.3 up to 6357μg/g dry extract with NMT and Hor as most abundant ones. Considering the pharmacological activities and the revealed fluctuation in the concentration of the analysed adrenergic protoalkaloids, the presented rapid LC-ESI-MS method is proposed for monitoring of the levels of Tyr, NMT, Hor and Can in G. biloba products.
银杏叶提取物（GBE）成分的中枢神经系统可用性与神经药理活性之间的联系仍不完整。在本研究中，采用平行人工膜通透性测定法（PAMPA）研究了标准化GBE的体外血脑屏障（BBB）通透性特征。萜类三内酯、黄酮苷元、银杏毒素等生物标志物具有中等或良好的BBB通透性潜力（BBB+），而糖苷和双黄酮预计无法通过BBB。在BBB+化合物中鉴定出N-甲基酪胺（NMT）、N，N-二甲基酪胺或大麦芽碱（Hor），随后的直接高分辨质谱分析显示GBE中的酪胺（Tyr）和N，N，N-三甲基酪胺或坎地辛（Can）为痕量成分。采用经过验证的基于离子交换机制的液相色谱-电喷雾电离-质谱（LC-ESI-MS）方法测定了银杏叶样品（如草药和膳食补充剂）中Tyr、NMT、Hor和Can的分布。各种GBE中四种酪胺衍生物的总含量范围为7.3至6357μg/g干提取物，其中NMT和Hor含量最高。考虑到药理活性以及所揭示的分析肾上腺素原生物碱浓度的波动，建议采用本文提出的快速LC-ESI-MS方法监测银杏叶产品中Tyr、NMT、Hor和Can的含量。
