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Polyphenols. The miraculous substances of Olive Oil.

Polyphenols. The miraculous substances of Olive Oil.

After permission the website OF SEDIK republishes an article from the newspaper TO VIMA, on polyphenols, due to the interest they present last. Particularly important are the clarifications given by Pharmacology researchers at the University of Athens, regarding  the polyphenols of olive oil. This article reads as follows:

Over the last decade, olive oil is under the microscope of the international scientific community and its interest in exploring the beneficial effects it can have on human health is no longer limited to its “natural space”, the Mediterranean basin. The cause scientists from all over the world have begun to examine thoroughly is the famous phenols it contains. These substances with the “exotic” names such as hydroxytyrosol, oleuropein, oleasin, elaiokanthali,  have not yet passed into our everyday vocabulary, but have begun to appear on product labels on supermarket shelves and pharmacies, while promises about the benefits that can be offered to us are many. How many of what we hear and read about these are still in the ‘promise’ stage and how many have proven their value and security? And, in addition to a very good food that shields health, can olive oil in the future develop into a very good source of medicine?

A conference on olive oil

An answer to these questions was intended to give the international scientific conference entitled “The Bioactive Ingredients of Olive Oil, Applications and Prospects” which was held in Orléans, France, last July by Professor Leandros Skaltsounis, Director of the Department of Pharmacognosy and Chemistry of Natural Products of the School of Pharmacy of the National Kapodistrian University of Athens in collaboration with the University of Orleans. We attended the conference and, now that the olive oil season has begun and olive oil has its honor, we will also try to get back to you with the help of some of the scientists who participated in it.

The “noise” around the phenols or, as is often mentioned, polyphenols or biophenols in olive oil, began to a great extent in 2005, from a publication in the inception “Nature”  as explained by Maria Hallabakaki, who belongs to the teaching and research staff of the School of Pharmacy of the University of Athens. “The publication and research was conducted in America from the University of Pennsylvania. We even met one of the main researchers of this study, Gary Bossan, who told us how he inspired the basic idea in a visit to our workshop, ” says. ” “During a trip to the Mediterranean he was sick and used the known anti-inflammatory ibuprofen, which is quite bitter and creates a “burning” on the neck. At the same time he consumed enough olive oil and felt the same feeling. By combining these two events, returning to America, and excited, as he constantly emphasized, from the special flavor and aromas of olive oil, he thought of exploring the possibility that olive oil would have an ingredient that would have a similar effect. ”

Healing burning on the throat!

So, with this bitterness, the researcher identified elaiokanthali, one of the main components of olive oil, which causes a characteristic “burning” in the throat. In experiments he did, the particular olive oil compound appeared to have significant anti-inflammatory activity, and indeed comparable to that of ibuprofen, which is the active ingredient of many painkillers and antipyretics. And, as was to be expected, the publication of his findings shattered the waters in the olive oil field and not only.

Although it is only a purely primary study in enzyme level, all scientists involved in olive oil wanted to explore the issue more. Thus more systematic studies began, which, in the years that followed, began to look at the action of this as well as other phenols of olive oil, not only in terms of inflammation but also in relation to hypertension, diabetes, cardiovascular diseases, cancer, osteoporosis, Alzheimer’s disease and much more.

However, despite the fact that the studies have multiplied and are constantly increasing, the landscape remains relatively cloudy. It is no coincidence that a few years ago, when the European Food Safety Authority (EFSA) undertook to examine whether olive oil as a foodstuff thanks to the phenols it contains could have a proven health benefit, approved as a “health claim” only one of the seven overall proposals submitted for evaluation: which relates to the antioxidant action of phenols, and in particular their contribution to the protection of blood lipids from oxidative stress.

The valuable polyphenols

But beyond the “total” beneficial effect of olive oil when consuming it as a foodstuff in the context of a balanced Mediterranean diet, how much do we know about the action each of the phenols can contain? “Olive oil is an extremely complex mixture of ingredients. If we take one by one its ingredients, beyond fatty acids and triglycerides, and examine the available scientific data for their biological or pharmacological action, things get complicated ” tells us Mrs. Halabalaki. “There have been several studies in olive oil, but there are several difficulties to make clear and safe conclusions. One of these is the really high variability of phenols from one olive oil to another, a determining factor which makes it necessary to quantify the levels of at least the major phenols in each study. Most researchers usually report using olive oil rich in one or the other ingredient without determining whether or how this component has been measured. This is a basic weakness. ”

As the researcher adds, because most of these substances are not commercially available and their isolation is a demanding and costly process, studies using phenols in “pure” form are much less than those using olive oil. Also, more importantly, in their vast majority the studies that exist so far have been done either in vitro – ie in cells – or, at best, in vivo – that is, in experimental animals. Few have proceeded to reliable clinical trials in humans, which are the necessary “test” to judge the efficacy and safety of an ingredient.

The beneficial polyphenols of olive oil

The best studied phenol of olive oil, and indeed by difference, is hydroxytyrosol. “Most of the literature is of concern to her,” says Mrs. Halabalaki. “Studies have been done in both cells and experimental animals, and clinical trials have begun. Its strong antioxidant action is now taken for granted. ‘ In addition to the documented virtues, Hydroxytyrosol is currently in the early stages of clinical trials as a dietary supplement for patients with multiple sclerosis and as a measure to prevent breast cancer in women who are genetically predisposed. Whether it really works and in these cases we will learn it in the future.

Well studied is also the oleuropein, which is mainly found in the olive leaves and in very small concentrations in the olive oil (for the important studies done in Greece on its action on heart protection see the box). The elaiokanthali, on the other hand, although it sounds very last research is far behind – the same as oleasin, which is chemically related to it. These two substances are present at higher concentrations in unripe oil and in “new” oils, because it is unstable with time (after about twelve months in a sealed bottle and much earlier, about four months, if the bottle is opened and the oil comes into contact with oxygen) it breaks down and turns into tyrosol and hydroxytyrosol, respectively. Although elaiokanthali  was the spark for researchers to work closely with olive oil phenols, studies investigating the action of this substance are still limited. “Most have become in cells, few have been done in animals” says Mrs. Halabalaki. “The fact that these are highly unstable molecules, difficult in isolation and in their composition, has sufficiently delayed the research process to assess their safety and biological properties. ”

Nevertheless, the elaiokanthali  is considered promising as in some cell studies has been shown that it could help control metastatic cancers, as well – because it appears to reduce the polymerization of the protein T and the concentration of b -amyloid in the brain- in the fight against Alzheimer’s disease. All experts, however, underline that despite the fact that these results are interesting, we are far from knowing whether they really are valid and if they can be put into practice, as the mechanism of action of elaiokanthali is not yet known and how it is metabolized within the human body. For example, while for hydroxytyrosol and oleuropein we know they are not toxic, we cannot say something equivalent about the elaiokanthali and oleasin – on the contrary, in a study presented at the Orleans conference by Agathi Charistos and Katerina Termentzis by the Laboratory of Toxicological Control of Agricultural Medicines of the Benaki  Phytopathological Institute it was shown that extracts with high concentrations of elaiokanthali may be toxic. “Both for elaiokanthali and oleasin, which are both of the main ingredients of olive oil, we have not yet reached the point of knowing what action they have in humans, “says Mrs. Halabakaki.

Oil is not a medicine

With all these unknown parameters no one can yet talk about drug development from the ingredients of olive oil. At present, there are several food supplements available on the market based on olive and its products, others highlighting permissible health claims and others not, since the legislation in this category is quite loose and control by the competent authorities is only made following a complaint and at a rate of … turtle. At the same time, there are olive oils in the market that state that they offer benefits that “escape” from the EFSA regulation. That’s why it’s good to be very careful and … keep a small basket against the big promises: if they are not based on published studies and large-scale clinical trials, do not believe them.

This does not, of course, mean that the approved health claims for olive oil phenols cannot be spent in the next few years. The ground is considered extremely convenient by the scientific community, which continues its exploration. The team of Mr Skaltsounis has recently undertaken the implementation of a major European program in which a network of universities and research centers from Greece, Spain, Austria, Italy, Germany and France will study in depth the pharmacology and toxicology of these substances to see if they are suitable for the development of medicines and therapies. In one of the predicted studies, Greek researchers, in collaboration with a large hospital in Spain, will proceed to an extensive clinical trial of the bioactive components of olive oil as a treatment for arthritis. The “miracle of olive oil” does not stop here in any case. “Olive oil is an excellent food, which can offer health benefits. It is not a medicine. Whether it can be a source of drug development will be seen in the next period, “says the professor.

Oleuropein, shield for the heart attack?

Thanks to its polyphenols, olive oil protects the heart

Oleuropein is a polyphenol that is mainly found in olive leaves and is studied for several years by scientists. By itself as a substance has been approved for a health claim as a light diuretic while the olive leaf extract, which is rich in oleuropein, has been approved by the European Medicines Agency for use against hypertension. But its action is also being examined  in other diseases, and our country has to show significant activity in this field. Ioanna Andreadou, Associate Professor of Pharmacology at the Faculty of Pharmacy, in collaboration with Efstathios Heliodromitis, Professor of Cardiology, and Dimitris Kremastinos, Peer Professor of Cardiology at the Medical School of the University of Athens, has been studying the substance for years, and the results of their research suggest that it could potentially provide significant heart protection. In one of the studies she presented at the Orleans conference, she and her colleagues administered oleo-europein to rabbits with atheromatous myocardium. and in healthy animals in doses that one can get daily from the Mediterranean, and especially the Cretan, diet and they saw that after six weeks it significantly reduced the extent of myocardial infarction in both atheromatous and normal animals. “This is an important finding, because the end point we are examining is the most” nodal ” says the professor at “Vima”. “It basically means that if you follow a daily diet rich in these ingredients and at some point undergo a myocardial infarction for some reason, a significant part of his myocardium may be saved and not killed. ”

Continuing the same study to investigate the mechanism with which oleuropein is acting the Greek scientists also found that this polyphenol reduces total cholesterol and triglycerides while having significant antioxidant effects in both blood and myocardium. Specifically, in their latest study, published in 2015, tested a sample from the rabbit myocardium and they saw that the oleuropein  had reduced some signs of inflammation and enhanced some signaling pathways that protected the myocardium and inhibited the negative effects of ischemic episodes on metabolism. Finally, in a recent study also presented at the conference but not yet published, the researchers imitated what happened when someone has an acute myocardial infarction and delivered rabbits eluropein at high doses, as a medication complementary to angioplasty. They saw that the extent of myocardial necrosis was significantly reduced, which means a better long-term outcome for the patient, as myocardial necrosis leads to heart failure. At the same time, in other studies done in mice, Ms. Andreadou and her colleagues have seen that oleuropein inhibits myocardial damage to anticancer chemotherapies.

The above findings, which have been judged and published as a cause of international interest, are extremely encouraging. However, Mrs  Andreadou is quick to point out that we should not rush to celebrate. “The problem is that despite the fact that we have all these positive results, clinical trials have not yet been performed in patients so that we can see how oleuropein works in the human body ” she stresses. “What we see in animals does not mean that it can be transferred automatically to humans. If so, we would have solved many problems and many diseases would have been cured. “