Novel C₁₉ Homolignans, Taiwanschirin A, B, and Cytotoxic Taiwanschirin C, and a New C₁₈ Lignan, Schizanrin A, from <i>Schizandra </i><i>a</i><i>risanensis</i>

Abstract

Three novel C 19 homolignans with a 3,4-pentano-2,3-dihydrobenzo[ b ]furan skeleton, taiwanschirin A ( 1 ), taiwanschirin B ( 2 ), and taiwanschirin C ( 3 ), and a new C 18 dibenzocyclooctadiene lignan, schizanrin A ( 4 ) were isolated from Schizandra arisanensis . Taiwanschirin C ( 3 ) and schizarin A ( 4 ) exhibited in vitro cytotoxicity against hepatoma (Hepa-3B, ED 50 = 2.2 μg/mL for 3, and ED 50 = 4.2 μg/mL for 4 ). Compound 4 also showed marginal activity against colon carcinoma (COLO-205, ED 50 = 2.9 μg/mL). Their structural elucidation by spectral and single-crystal X-ray analyses, and structure−activity relationships are discussed.