The anti-HBsAg (human type B hepatitis, surface antigen) and anti-HBeAg (human type B hepatitis, e antigen) C-18 dibenzocyclooctadiene lignans from Kadsura matsudai and Schizandra arisanensis

The C-18 dibenzocyclooctadiene lignans including three novel schizanrin F (1), G (2), H (3), along with the known kadsurarin (4), were isolated from Kadsura matsudai. A new C-19 homolignan named schiarisanrin E (5), together with the known C,, lignans, gomisin B (6), G (7) and (+)-gomisin K-3 (8) were obtained from Schizandra arisanensis. Gomisin B, G and (+)-gomisin K-3 showed moderate to strong activity for antihepatitis in anti-HBsAg (human type B hepatitis, surface antigen) and/or anti-HBeAg (human type B hepatitis, e antigen) tests. The structural elucidations of new compounds 1-3 and 5 were based on two-dimensional (2D) NMR techniques including COSY, HMQC, HMBC, NOESY and CD spectra. Preliminary structure-activity relationship studies for these isolated lignans are also discussed.