Triligustilides A and B: Two Pairs of Phthalide Trimers from Angelica sinensis with a Complex Polycyclic Skeleton and Their Activities

Two pairs of enantiomeric phthalide trimers [(-)/(+) triligustilides A (1a/1b) and (-)/(+) triligustilides B (2a/2b)] with complex polycyclic skeletons simultaneously possessing bridged, fused, and spiro ring systems were isolated from Angelica sinensis, together with two pairs of new phthalide dimers. The biogenetic pathways of new phthalides were proposed, and their bioactivities were also evaluated. This is the first time optically pure polymeric phthalides have been obtained from racemates, and their absolute configurations are reported.