Preparation of polyhydroxyl adsorbent and its application in the removal of Ginkgolic acids

Abstract

Extracts of Ginkgo biloba (EGb) have many biological activities, but contain a small amount of toxic ginkgolic acids, limiting the use of EGb. Based on the structural characteristics of ortho-hydroxy-carboxyl group on ginkgolic acids, we introduced hydrophilic polyhydroxy structure into hydrophobic polydivinylbenzene (PDVB) frameworks by reinitiation of suspended double bonds. A kind of adsorbent (DVA adsorbent) with hydrophobic - hydrophilic framework, uniform functional group distribution, high specific surface area and high crosslinking structure was synthesized. DVA adsorbent can selectively remove ginkgolic acids based on synergistic effect of multiple weak interactions with ginkgolic acids. DVA-20, which had the highest adsorption capacity and the best adsorption selectivity. After 30 bed volume (BV) adsorption solution was treated with DVA-20, the concentration of ginkgolic acids in the effluent decreased from 1781 ppm to 1.5 ppm, and the recovery of ginkgo flavonoids and lactones was nearly 100%. Moreover, DVA-20 has good repeatability. The EGb production process based on DVA-20 was established. The new process is continuous and can obtain both ginkgolic acids and EGb while meeting international standards, and has a very broad application prospect.