Separation and purification of (−)schisandrin B from schisandrin B stereoisomers

Schisandrin B (Sch B), consisting of a mixture of its stereoisomers, namely (−)Sch B and (±)γ-schisandrin, is the most abundant and biologically active dibenzocyclooctadiene lignan present in Fructus Schisandrae (FS). The objective of this study is to develop a process for large-scale separation and purification of a single stereoisomer of Sch B, (−)Sch B, which offers the highest desirable bioactivities. 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 (±)γ-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 (±)γ-schisandrin-enriched product a 26% increase, indicating a potentially more efficacious pharmaceutical preparation.