How to separate and purify ginkgolid from gingko leaf

摘要

(a) adjusting the pH of an aq. soln. of an extract of Ginko tree leaves to 7-9 by adding alkaline aq. soln.; (b) extracting the aq. soln. obtd. in (a) with lower acetates, lower ketones or benzenes, dehydrating and drying the organic layer to obtain a powder; (c) adjusting the pH of the aq. layer to 1-3 by adding acidic aq. soln., extracting the soln. with lower ethers or CHCl3, dehydrating the extract; (d) dissolving the dry powder obtd. in (b) and the residue obtd. in (c) in a lower alcohol; and (e) adding an aq. soln. of lead acetate to the soln. obtd. in (d), removing the ppts. and concentrating the filtrate.