Inhibitory effect of alkane-6,8-diols, the components of safflower, on tumor promotion by 12-O-tetradecanoylphorbol-13-acetate in two-stage carcinogenesis in mouse skin.

Erythro-alkane-6,8-diols were isolated from the flowers of Carthamus tinctorius. 12-0-Tetradecanoylphorbol-13-acetate (TPA, 1 microgram/ear), a tumor-promoting agent, was applied to the ears of mice to induce inflammation. Of 8 alkane-6,8-diols assayed, the C27, C31, C32, C33 and C35 alkane diols inhibited the inflammation. The 50% inhibitory dose of these compounds for TPA-induced inflammation was 0.5-0.7 mg/ear. However, C21, C23 and C25 alkane-6,8-diols were found to have no effect. Furthermore, the mixture of erythro-alkane-6,8-diols from the flowers of C. tinctorius markedly suppressed the promoting effect of TPA on skin tumor formation in mice following initiation with 7,12-dimethylbenz[a]anthracene.