Epigenetic Modifications Induced by Olive Oil and Its Phenolic Compounds: A Systematic Review

Abstract

Many studies demonstrated that olive oil (especially extra virgin olive oil: EVOO) phenolic compounds are bioactive molecules with anti-cancer, anti-inflammatory, anti-aging and neuroprotective activities. These effects have been recently attributed to the ability of these compounds to induce epigenetics modifications such as miRNAs expression, DNA methylation and histone modifications. In this study, we systematically review and discuss, following the PRISMA statements, the epigenetic modifications induced by EVOO and its phenols in different experimental systems. At the end of literature search through "PubMed", "Web of Science" and "Scopus", 43 studies were selected.Among them, 22 studies reported data on miRNAs, 15 on DNA methylation and 13 on histone modification. Most of the "epigenomic" changes observed in response to olive oil phenols' exposure were mechanistically associated with the cancer preventive and anti-inflammatory effects. In many cases, the epigenetics effects regarding the DNA methylation were demonstrated for olive oil but without any indication regarding the presence or not of phenols. Overall, the findings of the present systematic review may have important implications for understanding the epigenetic mechanisms behind the health effects of olive oil. However, generally no direct evidence was provided for the causal relationships between epigenetics modification and EVOO health related effects. Further studies are necessary to demonstrate the real physiological consequences of the epigenetics modification induced by EVOO and its phenolic compounds.

Keywords: DNA methylation; anti-cancer; anti-inflammatory; epigenetics; extra virgin olive oil; histone modification; miRNA; phenolic compounds; secoiridoids.

Figure 1

Flow diagram of study selection process.

Figure 2

Main effects of olive oil and/or its phenolic compounds on miRNAs expression in relation to different biological and healthy properties. “↑” and “↓” indicate increment and decrement of miRNA expression, respectively.

Figure 3

Main effects of olive oil and/or its phenolic compounds on DNA methylation in relation to different biological and healthy properties. “↑” and “↓” indicate increment and decrement of DNA methylation, respectively.

Figure 4

Main effects of olive oil and/or its phenolic compounds on histone modification in relation to different biological and healthy properties. “↑” and “↓” indicate increment and decrement of histone modification, respectively.