STUDIES ON EXTRACTION AND ISOLATION OF FLAVONOIDS FROM GINKGO LEAVES

摘要

The leaf of Ginkgo (Ginkgo biloba L.) contains various substances that are considered to have health-promoting properties. Most of these biologically active substances fall into two groups: flavonoids and terpenoids. This paper describes a method to extract and isolate flavonoids from Ginkgo leaves. The method consists of extraction with an ethanol solution and isolation with affinity column chromatography. Results show that 50% ethanol gave a better extraction yield than 70% ethanol while 20% or 40% ethanol concentration was the choice as a wash solvent. The highest yield resulted from the use of 50% ethanol as extractant and 40% ethanol as wash solvent. This combination produced a final extract with a flavone glycoside concentration as high as 24.31%, constituting about 3.7% of the dry matter in the original leaves. The procedure is rather simple and readily adaptable for commercialization.