The recognized active ingredients in ginkgo biloba are ginkgo flavonoids and ginkgolides, which are also unique active ingredients in ginkgo biloba, which have the effects of dilating blood vessels, regulating blood lipids, anti-inflammatory, etc., and have protective effects on the central nervous system, cardiovascular and cerebrovascular systems, and liver.
The content of these active ingredients has a lot to do with the age of the tree, the older the tree is, the lower the content, and the species with high levels of active ingredients have been selected and bred to achieve better results than naturally grown varieties.
Generally, the ginkgo biloba used for medicine is dried leaves, and the harvest season is when the leaves are still green in autumn, and they are dried in time.
Ginkgo biloba contains ginkgolic acid, which may cause allergic reactions, inflammatory reactions and liver damage, so the 2020 edition of the Chinese Pharmacopoeia requires that the total ginkgolic acid in ginkgo biloba extract should not exceed 5 mg kg.
Because ginkgolic acid is easily soluble in water, the extraction method is generally used in the production of ginkgo biloba extract.
At present, the methods for extracting ginkgolic acid from ginkgo biloba extract mainly include cooking and drying treatment, microwave-assisted extraction, organic solvent extraction, resin extraction, ultrasonic-assisted extraction and supercritical carbon dioxide extraction.
In the 2020 Chinese Pharmacopoeia, there are detailed requirements for the preparation of ginkgo biloba extract: take ginkgo biloba, crush it, heat it with dilute ethanol and reflux extract, combine the extract, ** alcohol and concentrate it to the volume, add it to the macroporous adsorption resin sample that has been externalized, sequentially add water and different concentrations of acid to detach, collect the corresponding eluent, **ethanol, spray drying;or **ethanol, concentrated into a thick paste, vacuum dried, crushed, that is.
The higher the cooking temperature, the longer the time, the higher the removal rate of ginkgolic acid, if the hot air treatment is used, the temperature is 80, the treatment time is 9 hours, the new acid can be completely removed, and the content of heptadecanylene ginkgolic acid and ginkgolic acid (these three are all ginkgolic acid components) can be reduced.
There are other methods to remove ginkgolic acid in related studies, such as the use of anion exchange resin elution, adding Pushu extract to reduce toxicity, etc., all of which have achieved good results.
The above methods are for research use only, and should be subject to the Chinese Pharmacopoeia.