Antimicrobial, Cytotoxic Lignans and Terpenoids from the Twigs of Pseudolarix kaempferi

Seven new compounds, including four lignans, (+)-(8S, 8'S)-9,9'-dibenzoylsecoisolariciresinol (1), (+)-(8S*, 8'R*)-4,4'-dimethyloxomatairesinol (2), (+)-(7S*, 8R*, 8'R*, 9'S*)-9'-n-butoxytsugacetal (3), and pseudolarkaemin A (4), a pyronane glycoside, pseudolarkaemin B (5), an ent-beyerene glycoside, pseudolarkaemin C (6), and a triterpene, 25-epi-pseudolarolide Q (7), along with 25 known compounds (8-32) were isolated from the twigs of Pseudolarix kaempferi. Their structures were elucidated mainly by the analysis of their NMR and MS data. Pseudolarolide C acid (24) was isolated for the first time as a natural product. All compounds were evaluated for antimicrobial activity against Candida albicans and Staphylococcus aureus, and cytotoxic activity against K562, HT29, B16, BGC-823, BEL-7402, SGC-7901, U251, and A549 cancer cell lines were assayed. Results indicated that the new compounds 3, 7, and some known compounds showed antimicrobial and cytotoxic activities.