Purification of Flavones from Gingko biloba Leaves by Macroporous Resin

The flavones was extracted with 70% ethanol from degreased powder of Ginkgo biloba leaves(GBLs),and technical conditions of macroporous resins for the purification of flavones from GBLs were studied. The performances of adsorption-desorption of three resins AB-8,D101 and HPD-100 were investigated by using adsorption and desorption rate as indexes. And the AB-8 was considered to be the optimum resin to purify the flavones of GBLs due to its highest adsorption-desorption properties. Combination of static and dynamic experiments of resin adsorption-desorption,the preferable technical conditions of flavones of GBLs by AB-8 resin were obtained. The results were as follows: dilution of extracted solution 1.5 times(concentration of diluted sample 0.094 mg/mL),pH 4.85,loading velocity 1.5 BV/h,sample volume 200 mL,pH 4.95 eluant for desorption and 80% alcohol,desorption velocity 2~2.5 BV/h and eluant volume 50 mL. The flavones content of GBLs gained under these conditions was 26.16%,and 3.2 times more than that of the original sample. The technical condition is scientific and reasonable that can be used to separate and purify flavones of GBLs and improve the content of flavones in GBLs extracts.