Oleuropein

Oleuropein
Names
IUPAC name
(4S,5E,6S)-4-[2-[2-(3,4-dihydroxyphenyl)ethoxy]-2-oxoethyl]- 5-ethylidene-6-[[(2S,3R,4S,5S,6R)-3,4,5-trihydroxy-6-(hydroxymethyl)- 2-tetrahydropyranyl]oxy]-4H-pyran-3-carboxylic acid, methyl ester
Identifiers
32619-42-4 YesY
ChEMBL ChEMBL1911053 N
ChemSpider 4444876 YesY
Jmol interactive 3D Image
PubChem 5281544
Properties
C25H32O13
Molar mass 540.51 g/mol
Except where otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa).
N verify (what is YesYN ?)
Infobox references


Oleuropein is the main polyphenol present in leaves and fruit of the olive tree; it is found in olive oil, both in a form bound to a glucose molecule (glycoside), and in a non-glycated form.

The oleuropein is the main constituent responsible for the bitter taste of olives and olive leaves. Like the other phytoalexins, it possesses antimicrobial activity, fungicide and insecticide, acting as a defense against infections and infestations.

Beneficial properties against many diseases such as cancer, cardiovascular diseases, diabetes and neurodegenerative diseases have been attributed to oleuropein. These properties are not limited to the well-known antioxidant power of polyphenols; recent studies have, in fact, demonstrated the clinical effectiveness of oleuropein in humans and unveiled the cellular mechanisms by which this substance and its metabolites exert these effects, which are at the base of the health benefits associated with the so-called Mediterranean diet.

Experimental studies, clinical evidence

Available results from clinical trials, together with the epidemiological and experimental data, consistently support the effect of protection associated to the daily intake of oleuropein through the use of nutraceutical preparations, consisting of enriched olive leaf extracts. Data provided by the scientific researchers are especially significant regarding the anti-neurodegenerative and anti-diabetic effects of oleuropein [1].

Hypoglycemic effect

The anti-diabetic action of oleuropein is supported by recent experimental researches and clinical trials. One of these has shown that the daily administration of about 50 mg of polyphenol for 12 weeks to a group of overweight middle-aged subjects and, therefore, at risk for developing type 2 diabetes, reduced glycaemia and improved both insulin secretion and sensitivity [2]. Another study conducted on human subjects with type 2 diabetes treated with 500 mg of oleuropein for 14 weeks, showed a significant improvement of glucose homeostasis, with reduction of glycated hemoglobin and fasting insulin levels. In rats treated with oleuropein, a reduction of digestion and absorption of starch was noted [3]. Other studies have shown that in vitro oleuropein prevents the amylin amyloid aggregation, a peptide secreted with insulin from pancreatic beta cells, where the aggregates are considered co-responsible for cell dishomeostasis that accompanies the onset of type 2 diabetes. In peripheral tissues, the effect on the reduction of insulin resistance activity appears to be based on mechanisms common to those ascribed to metformin [4]. The effectiveness of oleuropein in counteracting both the onset of Type 2 diabetes and some of its consequences, can be framed in a wider effect of protection against metabolic syndrome. In fact, other studies have shown that in mice oleuropein attenuates hepatic steatosis and reduces obesity induced by a high fat diet. The anti-obesity effect and modulation of glucose homeostasis was previously reported for other plant polyphenols.

The use of oleuropein and its metabolites for the treatment of type 2 diabetes has recently been the subject of a patent granted in Europe [5].

Effects on neurodegeneration

The anti-neurodegenerative effects have been focused in studies carried out both on neuronal cultured cells and on model animals, in particular on mice genetically modified in order to mimic a brain condition similar to that of Alzheimer's disease, the major form of dementia associated with human aging. These effects, which show a clear dose-dependency, can partly be attributed to the mobilization of calcium from intracellular stores with the consequent activation of signals that result in the activation of autophagy [6].
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In conclusion, the available scientific data convincingly support the efficacy of an adequate daily dose of oleuropein, through integration with nutraceutical products of the normal dietary content of the substance, in order to prevent and treat metabolic syndrome and related diseases, in particular type 2 diabetes mellitus. This guidance is also maintained by the absence of side effects related to the assumption of adequate amount of this polyphenol [7].

See also

References

  1. ↑ Casamenti F, Grossi C, Rigacci S, Pantano D, Luccarini L, Stefani M. Oleuropein Aglycone: A Possible Drug against Degenerative Conditions. In Vivo Evidence of its Effectiveness against Alzheimer's Disease. J Alzheimers Dis. 2015;45(3):679-88
  2. ↑ De Bock M, Derraik JG, Brennan CM, Biggs JB, Morgan PE, Hodgkinson SC, Hofman PL, Cutfield WS. Olive (Olea europaea L.) leaf polyphenols improve insulin sensitivity in middle-aged overweight men: a randomized, placebo-controlled, crossover trial. PLoS One. 2013;8(3):e57622.
  3. ↑ Wainstein J, Ganz T, Boaz M, Bar Dayan Y, Dolev E, Kerem Z, Madar Z. Olive leaf extract as a hypoglycemic agent in both human diabetic subjects and in rats. J Med Food. 2012 Jul;15(7):605-10
  4. ↑ Rigacci S, Guidotti V, Bucciantini M, Parri M, Nediani C, Cerbai E, Stefani M, Berti A. Oleuropein aglycon prevents cytotoxic amyloid aggregation of human amylin. J Nutr Biochem. 2010 Aug;21(8):726-35
  5. ↑ http://www.google.com/patents/EP2285388B1?cl=en
  6. ↑ Rigacci S, Miceli C, Nediani C, Berti A, Cascella R, Pantano D, Nardiello P, Luccarini I, Casamenti F, Stefani M. Oleuropein aglycone induces autophagy via the AMPK/mTOR signalling pathway: a mechanistic insight. Oncotarget. 2015 Nov 3;6(34):35344-57
  7. ↑ Barbaro B, Toietta G, Maggio R, Arciello M, Tarocchi M, Galli A, Balsano C. Effects of the olive-derived polyphenol oleuropein on human health. Int J Mol Sci. 2014 Oct 14;15(10):18508-24.

Further reading

External links

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