Patent ID: 8642099
Filing Date: 2014-02-04
Classification: A23L,A61K,A61P

Abstract:
1. A method for producing an extract of ginkgo biloba having a reduced content of 4′-O-methyl pyridoxine and biflavones, comprising the steps of: a) extracting leaves of ginkgo biloba with an organic solvent, wherein said organic solvent is selected from aqueous acetone, aqueous alcohol having 1 to 3 carbon atoms and anhydrous methanol, to obtain an extract mixture, b) separating the organic solvent from the extract mixture to produce a crude extract, c) diluting the crude extract with water to produce an aqueous solution with a solids content of 5 to 25% by weight, cooling to a temperature below 25° C. and allowing to stand until a precipitate is formed and removing the precipitate from the aqueous solution, d) adding about 30% by weight ammonium sulfate to the aqueous solution and extracting with a mixture of methyl ethyl ketone and acetone to produce an extract solution, e) concentrating the extract solution and diluting with an ethanol-water mixture to obtain a solution containing 50% by weight water and 50% by weight ethanol at a solids content of 10% by weight to produce a reaction mixture, f) adding an aqueous solution of lead hydroxide acetate and filtering the reaction mixture to obtain a filtered solution, g) extracting the filtered solution with an aliphatic or cycloaliphatic solvent having a boiling point of 60 to 100° C. to obtain an aqueous-alcoholic solution, h) concentrating the aqueous-alcoholic solution under reduced pressure to an alcohol content of about 5% and adding about 30% by weight ammonium sulfate to the aqueous solution and extracting with a mixture of methyl ethyl ketone and ethanol to obtain an organic phase, i) concentrating the organic phase to a solids content of 50 to 70% by weight to obtain a concentrate, j) diluting the concentrate obtained in step i) with aqueous alcohol having 1 to 3 carbon atoms to obtain an aqueous alcohol mixture with a solids content of about 15% and optionally filtering the aqueous alcohol mixture to remove undissolved substances, k) filtering the aqueous alcohol mixture obtained in step j) over an adsorber resin and a strongly acidic ion exchanger, wherein said adsorber resin is based on one or more optionally substituted styrene and/or divinylbenzene and wherein the substances to be removed are retained on the resin to obtain a purified solution, and l) drying the purified solution at reduced pressure to obtain a dry ginkgo biloba extract with a water content less than 5%, wherein the extract contains less than 20 ppm 4′-O-methyl pyridoxine and/or less than 20 ppm biflavones.