Epigenetic mechanisms of plant-derived anticancer drugs.

Epigenetic mechanisms are essential for normal development and maintenance of adult life. Disruption of epigenetic processes results in deregulated gene expression and leads to life-threatening diseases, in particular, cancer. Global epigenetic alterations are a hallmark of cancer. Cancer epigenetics revealed the deregulation of all components of the epigenetic machinery including DNA methylation, histone modifications, chromatin structure, and non-coding RNAs. Drugs targeting epigenetic processes, or "epi-drugs", are at the forefront of drug discovery, and plant-derived compounds have shown promise. Most of the plant-derived anticancer drugs that work through epigenetic mechanisms are polyphenols; the others are alkaloids, organosulfur compounds, and terpenoids. This review focuses on the epigenetic machinery and its basis for cancer therapy, highlights plant-derived anticancer drugs with epigenetic mechanisms of action, and discusses their potential use in epigenetic therapy.