Antitumor alkaloids for Cephalataxus harringtonia: structure and activity.

0 Cephalotaxine and several of its esters were isolated from Cephalotaxus harringtonia K. Koch var. harringtonia. Although cephalotaxine is inactive, harringtonine, isoharringtonine, homoharringtonine, and deoxyharringtonine have shown significant activity against experimental P388 leukemia and against L-121O leukemia in mice. Keyphrases 0 Cepha/otaxus harringtollia alkaloids-structure. antitumor activity 0 Harringtonine, isoharringtonine, homoharringtonine. deoxyharringtonine-antitumor activity 0 Antitumor alkaloids from Cephalotaxus harringtonia-structure, activity 0 NMR spectroscopy-identification, Cepha/otaxus alkaloids In a search for tumor inhibitors of plant onglO, an alcoholic extract of the seed of Cephalotaxus harringtonia var. drupacea (Sieb. & Zucc.) Koidzumi 1 showed activity against lymphoid leukemia L-121O and P388 leukemia in mice 2• Subsequent fractionation of the seed extract and of an extract obtained from C. harringIonia (Forbes) K. Koch var. harringlonia cv. Fastigiata (entire plants) revealed four alkaloids with significant antitumor activity (l). The active Cephalotaxus alkaloids are esters of cephalotaxine (I); these include 1 Cephaloraxus plant materials were received from Dr. Robert E. Perdue, Jr., U. S. Department of Agriculture (USDA). Beltsville. Md., under a program developed with USDA by Drug Research and Development, National Cancer Institute (formerly the Cancer Chemotherapy National Service Center). , Assays performed under Drug Research and Development auspices. Procedures are described in Cancer Chemorher. Rep., 25, 1(1962). harringtonine (II), isoharringtonine (III), homoharringtonine (IV), and deoxyharringtonine (V).