| abstract |
Provided is an extract of Ginkgo biloba leaves as a crude drug, prepared by alcohol extraction of Ginkgo biloba leaves, comprising ≤4.0% of rutin, ≤0.4% of quercetin, 2.6-4.8% of bilobalide, 0.1-0.5% of ginkgolide J, ≤0.5% of residual ethanol, and ≤0.02% of biflavones, the biflavones comprising amentoflavone, bilobetin, and ginkgetin. The extract does not comprise genistin and ginkgolide M. Also provided is a method for preparing the extract of Ginkgo biloba leaves as a crude drug, comprising: extracting minced Ginkgo biloba leaves with an aqueous ethanol solution by heating under reflux, followed by filtration to obtain a filtrate; subjecting the filtrate to concentration followed by precipitation in water to obtain a supernatant, which is then centrifuged to obtain a centrifugate; loading the centrifugate to a macroporous resin column and conducting water washing and solvent elution to obtain a first eluate, then loading a low concentration solvent first eluate to a polyamide column and conducting water washing and ethanol elution to obtain a second eluate; combining the second eluate with a high concentration solvent first eluate and conducting concentration, followed by extraction, drying, milling, sieving, and blending. The resulting extract of Ginkgo biloba leaves as a crude drug can be prepared into various formulations containing the extract. |