Antitumorigenic and antipromoting activities of ellagic acid, ellagitannins and oligomeric anthocyanin and procyanidin

We previously showed that ellagic acid (EA) was inhibiting lung tumorigenesis induced by the tobacco-specific carcinogen 4-(methylnitrosamino)-1-(3-pyridyl)- 1-butanone (NNK) in A/J mice. In the present study, we observed that the inhibition of lung tumorigenesis was independent of the solvent used to purified EA. Pomegranate peels extract containing punicalagin (α and β anomers) (10 g/kg diet) and oligomeric anthocyanins (6 g/kg diet) did not inhibit lung tumorigenesis. Raspberry extract (2 x 15 mg) containing sanguiin H6 and lambertianin D as well as oligomeric procyanidins (2 x 15 mg) inhibit 12-O-tetradecanoylphorbol-13-acetate (TPA)-induced ornithine decarboxylase (ODC) activity by about 30%. The same treatments inhibit TPA-stimulated hydroperoxide (HPx) production by about 30 and 70%. Raspberry ellagitannins and oligomeric procyanidins respectively inhibit TPA stimulated DNA synthesis by 42 and 26%. Our results suggest that hydrolyzable and condensed tannins from various sources, which can inhibit the ODC, HPx, and DNA responses to TPA, might also inhibit the tumor-promoting activity of this agent. The results of this study show that EA and ellagitannins have different antitumorigenic and antipromoting activities.