Schisandrene, a Dibenzocyclooctadiene Lignan from Schisandra chinensis: Structure−Antioxidant Activity Relationships of Dibenzocyclooctadiene Lignans

Phytochemical investigation of the fruits of Schisandra chinensis led to the isolation of 13 lignans including schisandrene (13), a new lignan based on a dibenzocyclooctadiene backbone with an exocyclic double bond. Its structure and absolute configuration were established using NMR, MS, and CD data. Antioxidant activity of the lignans was evaluated using a DCFH-DA cellular-based assay. The structure−activity relationships of the dibenzocyclooctadiene lignans showed that the exocyclic methylene functionality was essential for antioxidant activity, with the benzoyloxy group probably enhancing such effects.