Cytotoxic Quassinoids from Simaba cedron

During a survey of new antitumor substances from higher plants, we have found that the crude extract of Simaba cedron Planchon (Simaroubaceae) showed cytotoxic activity (IC$\sub$50/ 0.7 $\mu\textrm{g}$/mL) against P388 leukemia cells. Activity-guided chromatographic purification using P388 cells led to the isolation of five novel quassinoids, cedronolactones A-E (1-5) and nine known quassinoids, simalikalactone D (6), chaparrinon (7), chaparrin (8), glaucarubolone (9), glaucarubol (10), samaderine Z (11), guanepolide (12), ailanquassin A (13), and polyandrol (14). In this seminar, the structural elucidation of 1-5 and the cytotoxic activity of the isolated compounds are discussed.