Antineoplastic agents. 52. Baileya multiradiata

The desert-marigold Baileya multiradiata Harv. and Gray (Compositae) has been found to produce a series of sesquiterpenes that markedly inhibit growth of the murine lymphocytic leukemia P388 and the corresponding in vitro cell line. Separation guided by bioassay led to the isolation of baileyin (1), fastigilins B and C (3a and 2a), radiatin (3b), pleniradin (4a), and the new pseudoguaianolide multiradiatin (2b). The most significant antitumor activity was displayed by fastigilin C (2a) and radiation (3b).