Kadsutherins A–C: Three New Dibenzocyclooctane Lignans from the Stems ofKadsura Species

Three new dibenzocyclooctane-type lignans, kadsutherins A–C (1–3), were isolated from the stems of two Kadsura species. Their structures and configurations were elucidated by spectroscopic methods including 2D-NMR and HR-MS techniques. Kadsutherin C (3) is the first dibenzocyclooctane lignan without an oxygen-containing substituent at C(2).