Isolation and purification of salvianolic acid A and salvianolic acid B from Salvia miltiorrhiza by high-speed counter-current chromatography and comparison of their antioxidant activity

Abstract: Water-soluble salvianolic acid A (Sal A) and salvianolic acid B (Sal B) were successfully isolated and purified from the crude extract of Salvia miltiorrhiza by high-speed counter-current chromatography (HSCCC). The solvent system was n-hexane–ethyl acetate–methanol–water (3:6:6:10, v/v/v/v). 4.27mg of Sal A and 32.09mg of Sal B were obtained from 260mg of the crude sample. The purities of Sal A and Sal B were 96.67% and 97.43%, respectively. Their structures were identified by 1H NMR and 13C NMR. Antioxidant activities of Sal A and Sal B were also evaluated and compared by the methods of 1,1-diphenyl-2-picrylhydrazyl (DPPH) radical scavenging assay and 2,2-azino-bis-(3-ethylbenzothiazoline-6-sulfonic acid (ABTS +) radical cation decolourisation assay. Both Sal A and Sal B showed high radical scavenging activities with their EC50 values being 1.43±0.09 and 1.81±0.01μg/ml in DPPH radical method. The ABTS results showed that Sal A and Sal B exhibited high total antioxidant activities, their EC50 values were 1.35±0.00 and 1.43±0.01μg/ml, respectively. [Copyright &y& Elsevier]