Study On The Quality Of Ginkgo Biloba Extract Non - Quality Components And Ginkgo Biloba Oral Preparations

Ginkgo biloba L., Ginkgoaceae family, is a deciduous tree and one of the surviving species 180 million years ago, known as "living fossil". Ginkgo leaves extract and its preparations are widely used for treating diseases including cardiovascular disease, dementia, memory loss and cerebral ischemia in the world. Three flavonol aglycones and four terpene lactones are used as main constituents to evaluate the quality of Ginkgo biloba leaves and extracts. Although the indirect method for the quantitative analysis of flavonol glycosides by using an acidic hydrolysis avoids the deficiency of reference substances, the approach is insufficient for the accutate information about original flavonol glycosides. The measurement of the flavonol aglycones does not preclude the possibility of adulteration of Ginkgo biloba leaves or extracts. The thesis mainly aimed to study components of Ginkgo leaves extract which were still out of quality control. C18 thin layer chromatography method for identification of Ginkgo biloba preparations was developed. A series of ultra-performance liquid chromatographic fingerprints of Ginkgo biloba oral preparations were also established.The established C18 TLC identification of Ginkgo biloba preparations achieved a rapid and high throughput detection to improve the efficiency of detection and reduce the costs of testing. In addition, Silica gel TLC identification of the flavonol aglycones in Ginkgo biloba was also established.Fingerprints of Ginkgo biloba oral preparations including tablets, capsules, tinctures, drops, dropping pills and soft capsules were developed by using the ultra-performance liquid chromatography method. The main peaks were separated clearly and the similarity of precision, reproducibility and stability appropriated to detection requirements. The proposed fingerprints were successfully applied to analyze Ginkgo biloba oral preparations. The results demonstrated that this fingerprints can be used not only for quality assurance but also well identification of process abnormalities and adulteration phenomenon, even to quickly distinguish counterfeit and inferior drugs.In order to solve the deficiency of reference flavonol glycosides, a reference extract including six flavonoids glycosides was prepared from Ginkgo leaves extract, which can be used as a reference substance for quality evaluation of Ginkgo biloba and its preparations. Based on previous researches, four compounds were identified from the water eluent of macroporous resin of Ginkgo leaves extract including gallic acid,6-hydroxykynurenic acid, kynurenic acid and p-coumaric acid hexoside by using LC/MS-MS.