Purification of Danshensu from Salvia miltiorrhiza Extract Using Graphene Oxide-Based Composite Adsorbent

Danshensu has generated significant interest due to its therapeutic properties as a cardiovascular, antitumor, and neurology drug. Column chromatography techniques that are currently used for the separation of danshensu from Salvia miltiorrhiza extract have some drawbacks such as high pressure drop, slow separation, and the need for organic solvents. We discuss the use of a novel composite adsorbent consisting of graphene oxide (GO) modified cotton fiber for danshensu purification at high flow rate and low back pressure. This adsorbent was prepared by directly grafting GO onto the surface of cotton fiber. Danshensu was purified from aqueous Salvia miltiorrhiza extract based on hydrophobic interaction in a flow-through mode. The adsorbent could then be regenerated by elution of bound impurities using 0.04 M NaOH solution. HPLC analysis showed that the purity of danshensu increased from 24.8% in the feed solution (crude aqueous extract) to about 70-75% in the purified danshensu sample, the recovery being greater than 96.0%. Adsorbent fouling was minimal as indicated by the low back pressure at the end of the process.