Antimicrobial, antioxidant and anti-inflammatory phenolic activities in extra virgin olive oil

https://doi.org/10.1016/j.copbio.2011.09.006Get rights and content

The Mediterranean diet is associated with a lower incidence of chronic degenerative diseases and higher life expectancy. These health benefits have been partially attributed to the dietary consumption of extra virgin olive oil (EVOO) by Mediterranean populations, and more specifically the phenolic compounds naturally present in EVOO. Studies involving humans and animals (in vivo and in vitro) have demonstrated that olive oil phenolic compounds have potentially beneficial biological effects resulting from their antimicrobial, antioxidant and anti-inflammatory activities. This paper summarizes current knowledge on the biological activities of specific olive oil phenolic compounds together with information on their concentration in EVOO, bioavailability and stability over time.

Highlights

► Phenolic compounds naturally present in olive oil are health benefiting. ► Olive oil phenolic compounds are bioavailable. ► Olive oil phenolic compounds beneficially alter microbial activity, oxidative processes and inflammation.

Introduction

The advantageous health effects of consuming a traditional Mediterranean diet were first reported in the Seven Countries Study [1], and these findings have been subsequently observed in further investigations [2, 3•, 4, 5, 6, 7]. It is widely recognised that those residing in the Mediterranean region experience reduced rates of chronic disease (i.e. cardiovascular disease (CVD), atherosclerosis, some types of cancers, and Alzheimer's disease), and a higher life expectancy in comparison to other worldwide populations [8]. The Mediterranean style of eating encompasses a number of dietary components that are thought to contribute protective health effects, including the consumption of 25–50 ml/day of extra virgin olive oil (EVOO) [2]. EVOO contains a significant, albeit minor phenolic portion, which has been shown to possess antimicrobial, antioxidant and anti-inflammatory properties, in vivo and in vitro [9, 10]. Therefore, the phenolic component of EVOO is of particular interest for its health promoting and protective effects. The following review provides insight into the modes of action in which EVOO phenolic compounds may exert their health protective effects, together with information on the concentrations in which they are found in EVOO, their degree of bioavailability and stability.

Section snippets

Concentration, bioavailability and stability of olive oil phenolic compounds in EVOO

At least 36 phenolic compounds have been identified in EVOO to date, and there is much variation in the composition and concentration of these phenolic compounds (0.02–600 mg/kg) [10]. Variation may be caused by numerous factors including: variety, region in which the olive is grown, agricultural techniques used to cultivate the olive, maturity of the olive fruit at harvest, and processing (for review see [10]). Although the phenolic concentration and composition of EVOO is an important

Antimicrobial properties of olive oil phenolic compounds

Compounds with antimicrobial properties may aid in the inhibition of the growth of microorganisms and act as therapeutic agents in the treatment of some infectious diseases [24]. Phenolic compounds found in EVOO including the dialdehydic form of decarboxymethyl oleuropein aglycon, oleocanthal, hydroxytyrosol and tyrosol have been shown to possess potent activity against several strains of bacteria responsible for intestinal and respiratory infections in vitro (Figure 2). However, they have also

Antioxidant properties of olive oil phenolic compounds

An excess of free radicals can cause oxidative damage to biomolecules (i.e. lipids and DNA), increasing the risk of developing numerous chronic diseases such as atherosclerosis, cancer, CVD, chronic inflammation, stroke and other degenerative diseases [28]. Phenolic compounds in EVOO have been shown to exert beneficial effects on lipid oxidation, DNA oxidative damage and in general oxidative stress, in vitro and in vivo (Figure 2), and these activities have been shown to have a subsequent

Anti-inflammatory properties of olive oil phenolic compounds

It is well established that the pathophysiology of common disease states such as cancer, cardiovascular disease, arthritis and neurodegenerative disease are associated with chronic inflammation [52, 53, 54, 55]. Phenolic compounds derived from EVOO have been reported to have significant anti-inflammatory capacity. In vivo and in vitro research has suggested that the dietary intake of EVOO, containing significant concentrations of phenolics, may attenuate inflammatory responses in the body and

Conclusion

In summary, the bioavailable nature of olive oil phenolic compounds supports evidence that such components exert beneficial effects on physiological processes related to health and disease. Furthermore, phenolic compounds have been demonstrated to remain stable under appropriate storage conditions. Various studies (in vivo and in vitro) have demonstrated that olive oil phenolic compounds beneficially alter microbial activity, oxidative processes and inflammation. The modes of action by which

References and recommended reading

Papers of particular interest, published within the period of review, have been highlighted as:

  • • of special interest

Acknowledgements

The authors wish to thank Professor Andrew Sinclair for the discussion and comments on the manuscript. This study was supported by SRC funding from the Faculty of Health, Deakin University, Australia.

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