The tumor-enhancing principles of Croton tiglium L.

(cocarcinogenic) materials labeled A and C from the seeds of Croton tiglium L. were summarized (10, 11). The chemical constitution of a polyhydroxyphenolic ester, m.p. 96°C, obtained by the catalytic hydrogenation of a biologically active fraction and referred to as croton resin, was also described (10). The present report concerns long-term biologic testing of the active materials A and C, the hydrogenated poly phenolic ester (10), and derivatives of the polyhydroxy cyclic ketone, C20H28O6, obtained by the hydrolysis of croton resin. The isolation of the active materials A and C and the preparation of the polyhydroxy cyclic ketone and some of its derivatives are also described. MATERIALS AND METHODS ANIMALS Female Swiss mice (l\'iillerton Research Farms, l'sIiller ton, N. Y.) were vaccinated against ectromelia and put on test at age 8 weeks. Mice were housed on sterile wood chips in stainless steel cages, 10 to a cage, and were fed Purina laboratory chow and water ad libitum. The ani mal rooms were air-conditioned and were maintained at 72°†" 76°F. PROCED1JRE The backs of the mice were clipped free of hair 2 days before the initial treatment and then as needed for the duration of the experiment. DMBA,2 freshly recrystal lized from acetone, m.p. 121°†" 122°C, was applied by micropipet in a single dose (150 or 300 @@g) in an acetone solution (0.1 ml). This primary treatment was followed 14 days later by applications of promoters given 3 times 2 The abbreviations used are: DMBA, 7,12-dimethylbenz[alan thracene; A and C are fractions A and C from croton resin pre pared as described in this work; CR, croton resin; WSE, whole croton seed extract. a week. Promoter solutions were applied onto the clipped dorsal skin with a No. 5 squirrel hairbrush, with 100 mg of solution delivered per application. Mice were individually weighed before painting was started and at regular intervals thereafter. They were observed regu larly, and their tumors were charted on appearance throughout the duration of the experiment. Papillomas were counted only if they persisted for 4 weeks or more. Papillomas that Persisted for 4 weeks or more and then regressed were counted in the cumulative number of tumors. At death, tumors were excised and confirmed microscopically. Shelled croton seed (Croton tigliuin L., Ceylon) was crushed in a Waring Blendor and extracted exhaustively with methyl alcohol at room temperature. The solvent was distilled off in vacuum in a …