Dietary antioxidants and chromatin modifying compounds as potential anti-cancer therapies

Despite the efficacy of novel chemotherapeutic agents and radiation therapy, considerable developments are still necessary to improve the tolerance and reduce the toxicity in healthy cells of cancer patients. Dietary polyphenols have received increasing interest as an alternative approach, particularly in cancer treatment, as they display strong antioxidant properties and reduced toxicity profiles in normal cells. For decades, the Mediterranean diet but particularly olive oil has been linked with increased health benefits and has been associated with decreased risks in cardiovascular diseases and cancers. The minor constituents of olives are its phenolic compounds including oleuropein, tyrosol, hydroxytyrosol and homovanillic alcohol. These main phenolic compounds all possess antioxidant activity, with particular potency exhibited in hydroxytyrosol (HT). An imbalance of reactive oxygen species cause oxidative stress that can damage cells, and consequently lead to the formation of cancer or various diseases. Here, we provide evidence for the dietary antioxidant and polyphenolic compound hydroxytyrosol for its potential application as both a chemopreventive and anti-cancer agent for the treatment of haematological and solid malignancies. Aberrant gene expression caused by histone acetylation has also been associated with cancer and represents a potentially useful therapeutic target for dietary compounds. The use of histone deacetylase inhibitors derived naturally from the diet, such as butyrate, dially disulphide and sulforaphane, in the inhibition of carcinogenesis has been supported by numerous studies. Similarly probiotics have been reported to have positive health effects. We describe the underlying mechanisms and discuss the possible limitations and benefits of using dietary antioxidants and chromatin modifying compounds as potential anti-cancer agents.