Inhibitory Effect of Persimmon Extract on Skin Tumor Promotion.

Persimmon (Diospyros) contains polyphenol compounds (proanthocyanidin polymers). The content of polyphenol compounds in persimmon extract was estimated to be 27% by the acidified vanillin method. The effect of persimmon extract on a two-stage model of carcinogenesis which consisted of initiation by 7,12-dimethylbenz [a]-anthracene (DMBA) and promotion by 12-O-tetradecanoyl-phorbol-13-acetate (TPA) was investigated. Formation of mouse skin papillomas was remarkably inhibited by persimmon extract. In in vitro experiments, it was found that the [3H]TPA binding to mouse skin particulates and the activity of ornithine decarboxylase (ODC), a marker enzyme of tumor promotion, were inhibited dose-dependently by the persimmon extract, and that DPPH radicals and active oxygens (OH, O2-) were scavenged by persimmon extract. These findings suggest that the suppression of the skin carcinogenesis results from the inhibition of [3H]TPA binding to mouse skin particulate and ODC activity and the scavenging of active oxygens by the persimmon extract.