Institute of Pharmaceutical Chemistry/ZAFES, Goethe University, Max-von-Laue-Str. 9, 60438, Frankfurt am Main, Germany.
Clin Pharmacokinet. 2013 Sep;52(9):727-49. doi: 10.1007/s40262-013-0074-5.
Ginkgo biloba is among the most favourite and best explored herbal drugs. Standardized extracts of Ginkgo biloba represent the only herbal alternative to synthetic antidementia drugs in the therapy of cognitive decline and Alzheimer's diseases. The clinical efficiency of such standardized Ginkgo biloba extracts (GBE) is still controversial, but authors of numerous international clinical studies recommended the use of GBE in the described therapies.Extracts of Ginkgo biloba are a mixture of substances with a wide variety of physical and chemical properties and activities. Numerous pharmacological investigations lead to the conclusion that the terpene trilactones (TTL) and the flavonoids of GBE are responsible for the main pharmacological effects of the extract in the therapy of cognitive decline. Therefore, the quality of GBE products must be oriented on a defined quantity of TTL and flavonoids. Furthermore, because of their toxic potential the amount of ginkgolic acid should be less than 5 ppm.However, data on pharmacokinetics and bioavailability, especially related to the central nervous system (CNS), which is the target tissue, are relatively rare. A few investigations characterize the TTL and flavonoids of Ginkgo biloba pharmacokinetically in plasma and in the brain. Recent investigations show that significant levels of TTL and Ginkgo biloba flavonoids cross the blood-brain barrier and enter the CNS of rats after oral application of GBE. Knowledge about the pharmacokinetic behaviour of these substances is necessary to discuss the pharmacological results on a more realistic basis.
银杏是最受欢迎和研究最多的草药之一。银杏叶提取物是治疗认知能力下降和阿尔茨海默病的唯一替代合成抗痴呆药物的草药。这种标准化银杏叶提取物（GBE）的临床疗效仍存在争议，但许多国际临床研究的作者建议在描述的治疗中使用 GBE。
银杏叶提取物是具有广泛物理和化学性质和活性的物质的混合物。许多药理学研究得出的结论是，银杏叶提取物的萜烯三内酯（TTL）和类黄酮是提取物在治疗认知能力下降中的主要药理作用的原因。因此，GBE 产品的质量必须以 TTL 和类黄酮的特定数量为导向。此外，由于其潜在的毒性，银杏酸的含量应低于 5ppm。
然而，关于药代动力学和生物利用度的数据，特别是与中枢神经系统（CNS）相关的数据，相对较少。一些研究在血浆和大脑中对银杏叶的 TTL 和类黄酮进行了药代动力学特征描述。最近的研究表明，口服 GBE 后，银杏叶的 TTL 和银杏叶类黄酮可显著水平地穿过血脑屏障并进入大鼠的中枢神经系统。了解这些物质的药代动力学行为对于在更现实的基础上讨论药理结果是必要的。
