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.

2 new limonoid-type terpenes have been isolated from an aqueous extract of seeds produced by the Eastern Himalayan (India) plant Aphanamixis grandifolia B1. By interpreting principally mass spectral and nuclear magnetic resonance data, the structures of 12-hydroxyamoorastatin (2b) and amoorastatone (3) were elucidated. Unequivocal evidence for the 12-hydroxyamoorastatin structural assignment was obtained by chemical conversion to sendanin (4). Amoorastatin derivative 2b was found to significantly inhibit growth of the murine P388 lymphocytic leukemia cell lines but amoorastatone in the same system was inactive. In a comparative biological study, sendanin (4) and anthothecol (7) were also found significantly to inhibit growth of the P388 cell line, while rohitukin (8) and limonin (9) were found to be inactive.