The isolation and structure of 13,18-dehydroglaucarubinone, a new antineoplastic quassinoid from Simarouba amara

An investigation of the Guyana plant Simarouba amara Aubl. (Simaroubaceae) for antineoplastic quassinoids led to isolation and structural determination of the new quassinoids 2'-acetylglaucarubine (1a) and 13,18-dehydroglaucarubinone (2). The previously known 2'-acetylglaucarubinone (3a) and glaucarubinone (3b) were also obtained. The new quassinoid 2 was found significantly to inhibit growth of the murine lymphocytic leukemia P388.