Chemoprevention of digestive organs carcinogenesis by natural product protocatechuic acid.

The worldwide increase in cancer mortality demands a practical and effective chemopreventive approach to this problem. Using animal bioassay, the authors demonstrated protocatechuic acid (PCA, 3,4-dihydroxybenzoic acid), a simple and antioxidative phenolic acid present in fruits, vegetables, and nuts, to be an efficacious agent in reducing the carcinogenic action of 4-nitroquinoline 1-oxide in oral cavity, N-methyl-N-nitrosourea in glandular stomach, azoxymethane in colon, and diethylnitrosamine in liver. PCA exerts its chemopreventive action partly through inhibition of cell proliferation induced by carcinogens in the target organs. The prospect of this agent as chemopreventive against human cancer warrants a thorough investigation, such as dose-dependent efficacy and its potential toxicity at an effective dose level in other species of animals. Considering its promising anticarcinogenic potency, proliferation biomarkers, including tissue and blood polyamine levels, might eventually be useful in assessing the possible role of PCA intake in high risk populations for cancers of these organs.