Schisandrin B (Sch B), consisting of a mixture of its stereoisomers, namely (−)Sch B and (±)g-schisandrin, is the most abundant and biologically active dibenzocyclooctadiene lignan present in Fructus Schisandrae (FS). Among the stereoisomers of Sch B in FS, (−)Sch B was found to produce more potent enhancing effect on cellular glutathione and protection against oxidative injury in both cultured cardiomyocytes and hepatocytes. Therefore, it is desirable to recover (−)Sch B in a purified form to achieve the highest bioactivities.

The objective of this study is to develop a process for large-scale separation and purification of (−)Sch B from the Sch B stereoisomeric mixture. To this end, a crystallization-based separation and purification process has been conceptualized. Bench-scale crystallization experiments guided by experimental solid-liquid equilibrium phase diagrams were performed to verify process feasibility. A (−)Sch B product with a purity of 98.5 wt% and a (±)g-schisandrin-enriched product with a purity of 65.0 wt% were obtained. The (−)Sch B product caused a 32% increase in cellular glutathione level and the (±)g-schisandrin-enriched product a 26% increase, indicating a potentially more efficacious pharmaceutical preparation.