Dibenzocyclooctane lignans from the stems of Kadsura induta and their antiviral effect on hepatitis B virus.

Two new dibenzocyclooctane lignans, kadsurindutins A (1) and B (2), were isolated from the stems of Kadsura induta, together with the known, structurally related lignans schisantherin L (3), schisantherin P (4), kadsulignan L (5), and neokadsuranin (6). Their structures and configurations were elucidated by spectroscopic methods (UV, ORD, CD, IR, 1D- and 2D-NMR) in combination with mass-spectrometric (HR-MS) techniques. Compounds 1, 5, and 6 showed in vitro antiviral effects on hepatitis B virus.