Hydroxytyrosol Explained

Hydroxytyrosol is an organic compound with the formula . It is a phenylethanoid, i.e. a relative of phenethyl alcohol. Its derivatives are found in a variety of natural sources, notably olive oils and wines. Hydroxytyrosol is a colorless solid,[1] [2] although samples often turn beige during storage. It is a derivative, formally speaking, of catechol.

It or its derivatives occurs in olives and in wines[3] [4]

Occurrence

Olives

thumb|left|Oleuropein, bitter compound, an ester of hydroxytyrosol found in green olive skin

The olives, leaves, and olive pulp contain large amounts of hydroxytyrosol derivative Oleuropein, more so than olive oil. Unprocessed, green (unripe) olives, contain between 4.3 and 116 mg of hydroxytyrosol per 100g of olives, while unprocessed, black (ripe) olives contain up to 413.3 mg per 100g.[5] The ripening of an olive substantially increases the amount of hydroxytyrosol.[6] Processed olives, such as the common canned variety containing iron(II) gluconate, contained little hydroxytyrosol, as iron salts are catalysts for its oxidation.[7]

Food safety

Hydroxytyrosol is considered safe as a novel food for human consumption, with a no-observed-adverse-effect level of 50 mg/kg body weight per day, as evaluated by the European Food Safety Authority (EFSA).[8]

In the United States, hydroxytyrosol is considered to be a safe ingredient (GRAS) in processed foods at levels of 5 mg per serving.[9]

Function and production

In nature, hydroxytyrosol is generated by the hydrolysis of oleuropein that occurs during olive ripening. Oleuropein accumulates in olive leaves and fruit as a defense mechanism against pathogens and herbivores. During olive ripening or when the olive tissue is damaged by pathogens, herbivores, or mechanical damage, the enzyme β-glucosidase catalyzes hydroxytyrosol synthesis via hydrolysis from oleuropein.[10]

Metabolism

Shortly after olive oil consumption, 98% of hydroxytyrosol in plasma and urine appears in conjugated forms (65% glucuronoconjugates), suggesting extensive first-past metabolism and a half-life of 2.43 hours.[11]

Mediterranean diet

Mediterranean diets, characterized by regular intake of olive oil, have been shown to positively affect human health, including reduced rates of cardiovascular diseases.[12] [13] Research on consumption of olive oil and its components includes hydroxytyrosol and oleuropein, which may inhibit oxidation of LDL cholesterol a risk factor for atherosclerosis, heart attack or stroke.[14] The daily intake of hydroxytyrosol within the Mediterranean diet is estimated to be between 0.15 and 30 mg.[15]

Regulation

Europe

The EFSA has issued a scientific opinion on health claims in relation to dietary consumption of hydroxytyrosol and related polyphenol compounds from olive fruit and oil, and protection of blood lipids from potential oxidative damage.[16]

EFSA concluded that a cause-and-effect relationship existed between the consumption of hydroxytyrosol and related compounds from olives and olive oil and protection of blood lipids from oxidative damage,[16] providing a health claim for consumption of olive oil polyphenols containing at least 5 mg of hydroxytyrosol and its derivatives (oleuropein complex and tyrosol) per 20 g of olive oil.[17]

See also

Notes and References

  1. Charoenprasert S, Mitchell A . Factors influencing phenolic compounds in table olives (Olea europaea) . . 60 . 29 . 7081–7095 . July 2012 . 22720792 . 10.1021/jf3017699 .
  2. Karković Marković A, Torić J, Barbarić M, Jakobušić Brala C . Hydroxytyrosol, Tyrosol and Derivatives and Their Potential Effects on Human Health . . 24 . 10 . 2001 . May 2019 . 31137753 . 6571782 . 10.3390/molecules24102001 . free .
  3. 2012-02-15 . Bioactive compounds in wine: Resveratrol, hydroxytyrosol and melatonin: A review . . 130 . 4 . 797–813 . 10.1016/j.foodchem.2011.08.023 . 0308-8146 . Fernández-Mar MI, Mateos R, Garcia-Parrilla MC, Puertas B, Cantos-Villar E .
  4. Hu T, He XW, Jiang JG, Xu XL . Hydroxytyrosol and its potential therapeutic effects . . 62 . 7 . 1449–1455 . February 2014 . 24479643 . 10.1021/jf405820v .
  5. Web site: Showing all foods in which the polyphenol Hydroxytyrosol is found - Phenol-Explorer. 2021-07-02. phenol-explorer.eu.
  6. Rocha J, Borges N, Pinho O . Table olives and health: a review . . 9 . e57 . 2020 . 33354328 . 7737178 . 10.1017/jns.2020.50 .
  7. 10.1016/S0308-8146(00)00338-1 . Phenolic compounds change during California-style ripe olive processing . Marsilio V, Campestre C, Lanza B . Food Chemistry . 74 . 1 . July 2001 . 55–60.
  8. Turck D, Bresson JL, Burlingame B, Dean T, Fairweather-Tait S, Heinonen M, Hirsch-Ernst KI, Mangelsdorf I, McArdle HJ, Naska A, Neuhäuser-Berthold M, Nowicka G, Pentieva K, Sanz Y, Siani A, Sjödin A, Stern M, Tomé D, Vinceti M, Willatts P, Engel KH, Marchelli R, Pöting A, Poulsen M, Schlatter J, Turla E, van Loveren H . 6 . Safety of hydroxytyrosol as a novel food pursuant to Regulation (EC) No 258/97 . EFSA Journal . 15 . 3 . e04728 . March 2017 . 32625437 . 7010075 . 10.2903/j.efsa.2017.4728 .
  9. Web site: 2 July 2021. GRAS notice for hydroxytyrosol. 13 May 2016. US Food and Drug Administration.
  10. Charoenprasert S, Mitchell A . Factors influencing phenolic compounds in table olives (Olea europaea) . Journal of Agricultural and Food Chemistry . 60 . 29 . 7081–7095 . July 2012 . 22720792 . 10.1021/jf3017699 .
  11. Miro-Casas E, Covas MI, Farre M, Fito M, Ortuño J, Weinbrenner T, Roset P, de la Torre R . 6 . Hydroxytyrosol disposition in humans . Clinical Chemistry . 49 . 6 Pt 1 . 945–952 . June 2003 . 12765992 . 10.1373/49.6.945 . free .
  12. Hu T, He XW, Jiang JG, Xu XL . Hydroxytyrosol and its potential therapeutic effects . Journal of Agricultural and Food Chemistry . 62 . 7 . 1449–1455 . February 2014 . 24479643 . 10.1021/jf405820v .
  13. Martínez-González MA, Gea A, Ruiz-Canela M . The Mediterranean Diet and Cardiovascular Health . Circulation Research . 124 . 5 . 779–798 . March 2019 . 30817261 . 10.1161/CIRCRESAHA.118.313348 . free .
  14. Marcelino G, Hiane PA, Freitas KC, Santana LF, Pott A, Donadon JR, Guimarães RC . Effects of Olive Oil and Its Minor Components on Cardiovascular Diseases, Inflammation, and Gut Microbiota . Nutrients . 11 . 8 . 1826 . August 2019 . 31394805 . 6722810 . 10.3390/nu11081826 . free .
  15. de Pablos RM, Espinosa-Oliva AM, Hornedo-Ortega R, Cano M, Arguelles S . Hydroxytyrosol protects from aging process via AMPK and autophagy; a review of its effects on cancer, metabolic syndrome, osteoporosis, immune-mediated and neurodegenerative diseases . Pharmacological Research . 143 . 58–72 . May 2019 . 30853597 . 10.1016/j.phrs.2019.03.005 . 73726654 .
  16. Web site: Scientific Opinion on the substantiation of health claims related to polyphenols in olive and protection of LDL particles . From oxidative damage (ID 1333, 1638, 1639, 1696, 2865), maintenance of normal blood HDL cholesterol concentrations (ID 1639), maintenance of normal blood pressure (ID 3781), “anti-inflammatory properties” (ID 1882), “contributes to the upper respiratory tract health” (ID 3468), “can help to maintain a normal function of gastrointestinal tract” (3779), and “contributes to body defences against external agents” (ID 3467) pursuant to Article 13(1) of Regulation (EC) No 1924/2006. 2021-04-13. European Food Safety Authority. 8 April 2011. en.
  17. Web site: EU Register of nutrition and health claims made on foods (v.3.6). 2021-04-13. ec.europa.eu.

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