cytellin and Skin-Neoplasms

A single topical application of 1 microgram of 12-O-tetradecanoylphorbol- 13-acetate (TPA) to the ears of mice was shown to induce edema, and this TPA-induced inflammation was inhibited by 4-methylsterol and triterpene derivatives. The ED50 of these compounds against TPA-induced inflammation was 0.1-3 mumol. Phytosterols had only slight inhibitory effects. Furthermore, application of 5 micrograms TPA to mouse skin rapidly caused accumulation of ornithine decarboxylase (ODC). Similarly, sitosterol and lupane-type triterpene derivatives markedly inhibited this TPA-induced ODC accumulation. In addition, 5 mumol betulinic acid markedly inhibited the promoting effect of 2.5 micrograms TPA applied twice weekly on skin tumor formation in mice initiated with 50 micrograms of 7,12-dimethylbenz[a]anthracene, and 5 mumol of sitosterol caused slight suppression. Thus, the inhibitory effects of sterol and triterpene derivatives on TPA-induced inflammation roughly parallelled their inhibitory activities against tumor promotion.

Topics: 9,10-Dimethyl-1,2-benzanthracene; Animals; Antineoplastic Agents, Phytogenic; Betulinic Acid; Female; Mice; Mice, Inbred ICR; Ornithine Decarboxylase; Pentacyclic Triterpenes; Phytosterols; Sitosterols; Skin Neoplasms; Tetradecanoylphorbol Acetate; Triterpenes