Schizarin B, C, D, and E, four new lignans from Kadsura matsudai and their antihepatitis activities

Bioassay-directed fractionation of ethanolic extract of Kadsura matsudai Hayata has resulted in the isolation of four novel C-18 dibenzocyclooctadiene lignans, schizarin B (1), schizarin C (2), schizarin D (3), and schizarin E (4). Schizarin B (1) showed moderate to strong activity for antihepatitis in both anti-HBsAg and anti-HBeAg assays, and 3 and 4 also were active in the latter assay. Compounds 1-4 were inactive in vitro against HIV replication in H9 lymphocytes. All new structures were elucidated using spectral analysis. Their structural elucidation by spectral and structure-activity relationships is also discussed.