Boronic acid functionalized silica microparticles for isolation of flavonoids from Hypericum perforatum

We have selectively separated cis- and/or vicinal-diol-containing flavonoids from Hypericum perfaratum (HP) by adsorption/desorption using aminophenylboronic acid (APBA) functionalized uniform (1.6 μm) silica microparticles (BASPs) synthesized via the Stober method. Silica particles were alkylated by its terminal –OH with 3-aminopropyl trimethoxysilane (APTS), glutaraldehyde (GA) and APBA. The results from model adsorption studies indicated that these microparticles selectively adsorbed quercetin and rutin but partially apigenin. The antioxidant and antiradical activities of the desorption solution were slightly higher than that of the post-adsorption solution. These results indicated that the BASP selectively adsorbed the cis- and/or vicinal antioxidant and antiradical flavonoids.