Protection against chemically induced skin tumorigenesis in sencar mice by tannic acid

Abstract

Tannic acid, a naturally occurring dietary polyphenol, was evaluated as a possible anticarcinogen in an initiation‐and‐promotion skin tumorigenesis protocol. In the 2‐stage tumor protocol in SENCAR mice, using DMBA, BP and MNU as the initiating agents followed by twice‐weekly applications of TPA as tumor promotor, tannic acid was found to be an effective inhibitor of tumor formation whether the tumor data are considered as cumulative number of tumors, percentage of mice with tumors or tumors/mouse. After 9 weeks of TPA application, the number of tumors/mouse in the groups receiving DMBA, BP and MNU were 32.10 ± 3.18, 3.70 ± 0.55 and 2.00 ± 0.53, respectively, whereas the corresponding numbers in the DMBA, BP and MNU groups receiving prior applications of tannic acid were 11.50 ± 2.38, 0.35 ± 0.15 and 0.35 ± 0.13, respectively. These results suggest that tannic acid may prove useful in reducing the risk of chemically‐induced skin tumorigenesis.