PURPOSE: To provide a treating method capable of obtaining an extract of ginkgo leaves, removing bitterness components and slightly water-soluble components, being orally administered to human body readily, having excellent absorption efficiency in human body.
CONSTITUTION: A method of treating a solution containing an extract of ginkgo leaves is characterized by passing a solution (I) containing an extract of ginkgo leaves through a nonpolar porous resin, absorbing a bitterness component and a slightly water-soluble component consisting essentially of a non-glycoside, which is contained in the solution comprising an extract of ginkgo leaves and is extremely difficult to become an α-glycosylated glycoside, in the nonpolar porous resin and removing. A method of treating solution containing an extract of ginkgo leaves is characterized by passing the solution (I) containing an extract of ginkgo leaves through the nonpolar porous resin, absorbing the bitterness component and the slightly water-soluble component, which are contained in the solution comprising an extract of ginkgo leaves, in the nonpolar porous resin, removing these components to provide the solution (II) containing an extract of ginkgo leaves, treating this solution with a glycosyltransferase, preferably an enzyme produced by a bacterium of Bacillus stearothermophilus.
IIDA SUMIHISA
GUNJI YUKINOBU
