Potential Cancer Chemopreventive Activity of Protocatechuic Acid

A natural phenolic compound, protocatechuic acid (3,4-dihydroxybenzoic acid), is present in many edible and medicinal plants. Recent studies, including our animal experiments, indicate that this simple phenolic acid could be protective against the development of epithelial malignancy in different tissues and cardiovascular diseases as well. The mechanism of the action is mostly associated with antioxidant activity, including inhibition of generation as well as scavenging of free radicals and upregulating antioxidant enzymes. The influence on Phases I and II of the metabolism of certain carcinogens and, perhaps, direct blocking of specific binding sites of ultimate carcinogens with DNA molecule, thus preventing adduct formation that may result in mutations and neoplastic transformation, also account for its cancer protective action. However, other biological aspects of the chemopreventive activity of protocatechuic acid are not fully studied. They include influence on the activity of inducible isoenzyme of cyclooxygenase and nitric oxide synthase, cell cycle–regulating proteins, or inflammatory cytokines, which are involved in oncogenesis. In view of its reported biological properties and relative safety, protocatechuic acid is a potential cancer chemopreventive product.