Preparation method of ginkgo biloba extract

The present invention discloses a preparation method of Ginkgo biloba extract, which comprises the following steps in order:

(1) Take dried ginkgo biloba leaves, pulverize, extract with water-containing ethanol, add an antioxidant protectant to the extract after extraction, mix well, and recover the ethanol under reduced pressure to obtain a concentrated solution;

(2) Take the concentrated solution and add 1 to 3 Double the volume of water, stand still, centrifuge or filter, to get the supernatant or filtrate;

(3) Take the supernatant or filtrate, and then use the ultrafiltration membranes of large molecular weight and small molecular weight to perform secondary ultrafiltration to obtain the ultrafiltrate.

(4) Take the ultrafiltrate, add an antioxidant protective agent, concentrate under reduced pressure, and dry the concentrate to obtain a crude extract of Ginkgo biloba;

n the step (1), the aqueous ethanol is 50% to 95% ethanol; In the step (1), the extraction method is leaching at 50°C~80°C for 2 to 4 times, or ultrasonic extraction for 2 to 4 times; in the step (3), the molecular weight of the high molecular weight ultrafiltration membrane 5%〜2% ； For 80,000~120,000, the molecular weight of the small molecular weight ultrafiltration membrane is 8,000~15,000; In step (1) and in, the antioxidant protective agent is vitamin C, and the amount added is 0.5%~2%; The ginkgo leaf extract prepared by the above method has a total ginkgo flavonoid content of 30-45%, and a ginkgo terpene lactone content of 6-12%.

The preparation method of the ginkgo biloba extract of the present invention has reasonable process method, high extraction rate, meets and exceeds international standards, good product quality, and can realize industrialized production.

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