Oleuropein

Source: Wikipedia, the free encyclopedia.
Oleuropein
Names
IUPAC name
Methyl (2S,3E,4S)-4-{2-[2-(3,4-Dihydroxyphenyl)ethoxy]-2-oxoethyl}-3-ethylidene-2-(β-D-glucopyranosyloxy)-2H-pyran-5-carboxylate
Systematic IUPAC name
Methyl (2S,3E,4S)-4-{2-[2-(3,4-Dihydroxyphenyl)ethoxy]-2-oxoethyl}-3-ethylidene-2-{[(2S,3R,4S,5S,6R)-3,4,5-trihydroxy-6-(hydroxymethyl)oxan-2-yl]oxy}-2H-pyran-5-carboxylate
Other names
2-(3,4-Dihydroxyphenyl)ethyl [(2S,3E,4S)-3-ethylidene-2-(β-D-glucopyranosyloxy)-5-(methoxycarbonyl)-3,4-dihydro-2H-pyran-4-yl]acetate
Identifiers
3D model (
JSmol
)
ChEMBL
ChemSpider
ECHA InfoCard
 100.046.466 Edit this at Wikidata
UNII
  • InChI=1S/C25H32O13/c1-3-13-14(9-19(29)35-7-6-12-4-5-16(27)17(28)8-12)15(23(33)34-2)11-36-24(13)38-25-22(32)21(31)20(30)18(10-26)37-25/h3-5,8,11,14,18,20-22,24-28,30-32H,6-7,9-10H2,1-2H3/b13-3+/t14-,18+,20+,21-,22+,24-,25-/m0/s1 checkY
    Key: RFWGABANNQMHMZ-ZCHJGGQASA-N checkY
  • InChI=1/C25H32O13/c1-3-13-14(9-19(29)35-7-6-12-4-5-16(27)17(28)8-12)15(23(33)34-2)11-36-24(13)38-25-22(32)21(31)20(30)18(10-26)37-25/h3-5,8,11,14,18,20-22,24-28,30-32H,6-7,9-10H2,1-2H3/b13-3+/t14-,18+,20+,21-,22+,24-,25-/m0/s1
    Key: RFWGABANNQMHMZ-ZCHJGGQABE
  • O=C(OCCc1ccc(O)c(O)c1)C[C@H]2C(=C/C)\[C@@H](O\C=C2\C(=O)OC)O[C@@H]3O[C@@H]([C@@H](O)[C@H](O)[C@H]3O)CO
Properties
C25H32O13
Molar mass 540.518 g·mol−1
Except where otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa).
☒N verify (what is checkY☒N ?)

Oleuropein is a glycosylated seco-iridoid, a type of phenolic bitter compound found in green olive skin, flesh, seeds, and leaves.[1] The term oleuropein is derived from the botanical name of the olive tree, Olea europaea.

Because of its bitter taste, oleuropein must be completely removed or decomposed to make olives edible. During processing of bitter and inedible green olives for consumption as table olives, oleuropein is removed from olives via a number of methods, including by immersion in lye.[2][3]

Chemical treatment

Oleuropein is a derivative of

ester bond and to a molecule of glucose by a glycosidic bond.[4] When olives are immersed in a lye solution, the alkaline conditions lead to hydrolysis of the ester bond. The basic conditions also significantly increases the solubility of these derivatives, facilitating their release into the lye solution.[5][6]

The high pH accelerates the oxidation of the phenolics, leading to blackness, as during their normal ripening, if the solution is oxygenated by air injection (alkaline oxidation of olives is also called the California process).[7][8]

The lye solution is replaced several times until the bitter taste has dissipated. An alternative process uses amberlite macroporous resins to trap the oleuropein directly from the solution, reducing waste water while capturing the extracted molecules.[9][10]

Enzymatic hydrolysis during the maturation of olives is also an important process for the decomposition of oleuropein and elimination of its bitter taste.[6][11]

Green olive blackening

Green olives may be treated industrially with

ferrous ions form a black complex, giving the final color of the treated olives.[9][10][7] Black olives treated with iron(II) gluconate are also depleted in hydroxytyrosol, as iron salts are catalysts for its oxidation.[13]

Research

Oleuropein has been proposed as a proteasome activator.[14][15]

See also

References

  1. ^ Rupp R. (1 July 2016). "The bitter truth about olives". National Geographic. Archived from the original on 10 July 2019. Retrieved 24 June 2019.
  2. ^ "How olives are made". California Olive Committee. 2017. Archived from the original on 5 August 2017. Retrieved 5 August 2017.
  3. ^ Colmagro S.; Collins G.; Sedgley M. "Processing technology of the table olive" (PDF). Archived (PDF) from the original on 9 August 2017. Retrieved 25 June 2019.
  4. ^ Panizzi, L.; Scarpati, M.L.; Oriente, E.G. (1960). "Structure of the bitter glucoside oleuropein. Note II". Gazzetta Chimica Italiana. 90: 1449–1485.
  5. PMID 25679050
    .
  6. ^
    PMID 27041317. Archived
    (PDF) from the original on 2018-07-23. Retrieved 2019-09-27.
  7. ^
    ISSN 0145-8892
    .
  8. ISSN 0308-8146
    .
  9. ^ a b "A 'greener' way to take the bitterness out of olives". phys.org. Archived from the original on 23 June 2019. Retrieved 23 June 2019.
  10. ^
    S2CID 58570570. Archived
    from the original on 2020-06-26. Retrieved 2021-05-18.
  11. PMID 21575132
    .
  12. ISSN 0567-7572
    .
  13. doi:10.1016/S0308-8146(00)00338-1
    .
  14. PMID 17518699. Archived
    from the original on 2020-11-15. Retrieved 2020-10-15.
  15. PMID 32821821
    .
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