Olive Polyphenols: Antioxidant and Anti-Inflammatory Properties

Abstract

Oxidative stress and inflammation triggered by increased oxidative stress are the cause of many chronic diseases. The lack of anti-inflammatory drugs without side-effects has stimulated the search for new active substances. Plant-derived compounds provide new potential anti-inflammatory and antioxidant molecules. Natural products are structurally optimized by evolution to serve particular biological functions, including the regulation of endogenous defense mechanisms and interaction with other organisms. This property explains their relevance for infectious diseases and cancer. Recently, among the various natural substances, polyphenols from extra virgin olive oil (EVOO), an important element of the Mediterranean diet, have aroused growing interest. Extensive studies have shown the potent therapeutic effects of these bioactive molecules against a series of chronic diseases, such as cardiovascular diseases, diabetes, neurodegenerative disorders and cancer. This review begins from the chemical structure, abundance and bioavailability of the main EVOO polyphenols to highlight the effects and the possible molecular mechanism(s) of action of these compounds against inflammation and oxidation, in vitro and in vivo. In addition, the mechanisms of inhibition of molecular signaling pathways activated by oxidative stress by EVOO polyphenols are discussed, together with their possible roles in inflammation-mediated chronic disorders, also taking into account meta-analysis of population studies and clinical trials.

Extra Virgin Oil Polyphenols Improve the Protective Effects of Hydroxytyrosol in an In Vitro Model of Hypoxia-Reoxygenation of Rat Brain

“…It is indisputable that the antioxidant effects play a fundamental role in the effects of the studied compounds, and there are other mechanisms that possibly participate, such as the anti-inflammatory effects [ 26 ]. As can be seen in Table 3 , except for those of DHPG, there is a parallel between the IC 50 values for the inhibition of lipid peroxidation and the formation of peroxynitrite and LDH efflux.…”

Wine, Polyphenols, and Mediterranean Diets. What Else Is There to Say?

“…Olive oil phenolics have been extensively studied for their potential to counteract the onset and progression of a variety of chronic and aging-related diseases, and is attributed to hypoglycemic, anti-obesity, cardioprotective, neuroprotective, antimicrobial, and anti-cancer properties [ 47 , 48 , 49 ]. Several in vitro and in vivo studies have associated the health-promoting effects of olive oil phenolics to their antioxidant and anti-inflammatory potential as related to their ability to modulate a series of molecular pathways.…”

“…Additionally, in vitro and animal studies have reported that oleuropein and hydroxytyrosol may reduce fat tissue accumulation by downregulating the expression of adipogenesis-related genes like PGC-1α, lipoprotein lipase, acetyl CoA carboxylase-1, and carnitine palmitoyltransferase-1 [ 54 ]. Recent reviews can be consulted for further information on olive oil phenolic effects and mechanisms of action [ 44 , 47 , 49 , 55 , 56 ].…”

The Potential Role of Polyphenols in Oxidative Stress and Inflammation Induced by Gut Microbiota in Alzheimer’s Disease

“…They are classified as either flavonoid (anthocyanins, flavones, flavonols, flavanones, flavanols, and isoflavones) or non-flavonoid (stilbenes, lignans, tannins, phenolic acids, and hydroxycinnamic acids) [ 66 ]. Polyphenols exert positive effects and have a broad spectrum of biological activities against many human diseases such as type-2 diabetes mellitus, cancer, cardio-metabolic diseases, and neurodegenerative diseases, as well as having potential to modulate gut dysbiosis ( Figure 3 ) [ 67 ]. However, due to the extensive metabolism by phase-I and II enzymatic reactions and poor absorption, their bioactivity on targeted organs is significantly less.…”