How Oleuropein Influences Extra Virgin Olive Oil Taste and Health Benefits

Along with oleocanthal and hydroxytyrosol, oleuropein is one of the main polyphenols found in extra virgin olive oil that determines its sensory characteristics and health benefits.
By Simon Roots
Apr. 22, 2024 23:54 UTC

Oleuropein, one of the major phe­no­lic com­pounds found in extra vir­gin olive oil, is key to many olive oil health ben­e­fits and even its fla­vor. 

The olive tree pro­duces the com­pound as a defen­sive mech­a­nism, its bit­ter­ness act­ing as a nat­ural deter­rent to pests. That same bit­ter­ness trans­lates to a marker of qual­ity in oil.

Oleuropein, iden­ti­fied as the first sec­oiri­doid in olive oil by Panizzi et al. in 1958, is a sig­nif­i­cant com­po­nent of olive polyphe­nols. Its pres­ence in olives and oil varies depend­ing on the olive vari­ety, milling tech­niques and tech­nol­ogy and stor­age con­di­tions. 


Secoiridoids, present in all Oleaceae plants, includ­ing olive trees, con­sti­tute the major­ity of bioac­tive polyphe­nols in olive oil and dru­pes. These com­pounds, char­ac­ter­ized by cyclopen­tanopy­ran ring struc­tures, undergo sec­oiri­doid cleav­age to pro­duce bioac­tive deriv­a­tives with diverse phar­ma­co­log­i­cal activ­i­ties. Research indi­cates that sec­oiri­doids, includ­ing those from olives, pos­sess antiox­i­dant and anti-inflam­ma­tory prop­er­ties, poten­tially pro­mot­ing over­all health and dis­ease pre­ven­tion.

Oleuropein serves as a qual­ity marker through­out pro­duc­tion. The bit­ter, pun­gent taste of extra vir­gin olive oil pri­mar­ily arises from its main phe­no­lic com­pounds, includ­ing oleo­can­thal, hydrox­y­ty­rosol and oleu­ropein. 

Extensive research has explored the ben­e­fi­cial effects of oleu­ropein on ail­ments includ­ing can­cer, hyper­ten­sion, heart issues and var­i­ous viral and bac­te­r­ial dis­eases.

How oleu­ropein impacts sen­sory attrib­utes

Research con­ducted by Andrewes and col­leagues in 2003 iso­lated and eval­u­ated indi­vid­ual phe­no­lic com­pounds present in olive oil. 

They found that the com­pound p‑HPEA-EDA, a sec­oiri­doid deriv­a­tive of oleu­ropein, elicited a strong burn­ing pun­gent sen­sa­tion at the back of the throat, con­tribut­ing sig­nif­i­cantly to the oil’s pun­gent attribute. In con­trast, another com­pound, 3,4‑DHPEA-EDA, pro­duced only a slight burn­ing or numb­ing sen­sa­tion, pre­dom­i­nantly per­ceived on the tongue.

Further analy­sis using the cal­cium mobi­liza­tion func­tional assay revealed that sev­eral phe­no­lic com­pounds acti­vate bit­ter taste recep­tors TAS2R1, TAS2R8 and TAS2R14. 

See Also:The Flavors of Extra Virgin Olive Oil

Ligstroside agly­con and oleu­ropein agly­con were iden­ti­fied as the most potent bit­ter tas­tants in olive oil. TAS2R8 and TAS2R1 were found to be the pri­mary bit­ter taste recep­tors respond­ing to phe­no­lic com­pounds, with oleu­ropein acti­vat­ing TAS2R8 exclu­sively, albeit with lower potency com­pared to the algy­cons.

While oleu­ropein has low potency towards the recep­tor TAS2R8, research sug­gests that the intensely bit­ter sen­sa­tion expe­ri­enced when chew­ing raw olives is pri­mar­ily due to the spon­ta­neous con­ver­sion of oleu­ropein into agly­con forms. 

Oleuropein and oleu­ropein glu­cosi­dase are typ­i­cally found in sep­a­rate cel­lu­lar com­part­ments and only come into con­tact when olive fruit cells are dam­aged, such as dur­ing chew­ing or crush­ing for oil pro­duc­tion.

Oleuropein’s role in olive oil health ben­e­fits

Oleuropein and its deriv­a­tive, hydrox­y­ty­rosol, pos­sess potent antiox­i­dant prop­er­ties, con­tribut­ing to olive oil’s rep­u­ta­tion for com­bat­ing inflam­ma­tion and asso­ci­ated dis­eases. 

Notably, oleu­ropein has demon­strated a capac­ity to sig­nif­i­cantly reduce blood pres­sure, both sys­tolic and dias­tolic, in ani­mal mod­els, align­ing with olive leaf’s tra­di­tional use in treat­ing hyper­ten­sion. 

See Also:Health News

Recent stud­ies reveal that oleu­ropein’s mech­a­nism in reduc­ing blood pres­sure involves pro­tect­ing the hypo­thal­a­mus from oxida­tive stress through Nrf2-medi­ated sig­nal­ing, offer­ing poten­tial as a pre­ven­tive and ther­a­peu­tic approach for hyper­ten­sion.

Beyond blood pres­sure reg­u­la­tion, oleu­ropein exhibits var­i­ous health-pro­mot­ing func­tions, includ­ing car­dio­pro­tec­tion, anti-inflam­ma­tory, antiox­i­dant, anti-can­cer, anti-angio­genic and neu­ro­pro­tec­tive effects. 

Oleuropein and Alzheimer’s dis­ease

Numerous in vitro inves­ti­ga­tions have explored the antiox­i­dant and neu­ro­pro­tec­tive attrib­utes of extracts from extra vir­gin olive oil, uncov­er­ing their ther­a­peu­tic poten­tial in com­bat­ing Alzheimer’s dis­ease

When admin­is­tered before expo­sure, these extracts have been shown to upreg­u­late key antiox­i­dant enzymes in neu­rob­las­toma cells, mit­i­gat­ing oxida­tive dam­age induced by free rad­i­cals.

Phenolic com­pounds found in extra vir­gin olive oil, such as hydrox­y­ty­rosol and oleu­ropein, have demon­strated the abil­ity to impede the translo­ca­tion of nuclear fac­tor kappa B (NFkB) into the nucleus, lead­ing to dimin­ished pro­duc­tion of pro-inflam­ma­tory agents and thus curb­ing neu­roin­flam­ma­tion dri­ven by microglia. 

See Also:Olive Oil Basics

Moreover, these com­pounds have been observed to enhance the secre­tion of anti-inflam­ma­tory cytokines while sup­press­ing the pro­duc­tion of pro-inflam­ma­tory cytokines, pre­sent­ing a mul­ti­fac­eted approach to com­bat­ing neu­roin­flam­ma­tion.

In exper­i­ments using neu­rob­las­toma cells, a com­bi­na­tion treat­ment involv­ing oleu­ropein agly­cone and hydrox­y­ty­rosol has exhib­ited the acti­va­tion of autophagic flux, reduc­tion in free rad­i­cal pro­duc­tion, pre­ven­tion of mito­chon­dr­ial dys­reg­u­la­tion and inhi­bi­tion of cel­lu­lar dam­age inflicted by amy­loid-beta plaques. 

Furthermore, inter­ven­tions involv­ing oleu­ropein sup­ple­men­ta­tion have shown promise in enhanc­ing cog­ni­tive func­tions, mem­ory and behav­ioral dis­or­ders in patients with mild Alzheimer’s dis­ease. 

Oleuropein and osteo­poro­sis

Age-related bone den­sity loss is asso­ci­ated with osteoblast insuf­fi­ciency dur­ing the body’s con­tin­u­ous bone remod­el­ing. 

Studies sug­gest that the for­ma­tion of osteoblasts in bone mar­row is closely asso­ci­ated with adi­po­ge­n­e­sis, the for­ma­tion of adipocytes (fat cells) from stem cells and that age-related changes in this rela­tion­ship could be respon­si­ble for the increas­ing adi­pos­ity of bone mar­row asso­ci­ated with osteo­poro­sis.

Puel et al. exam­ined oleu­ropein’s effects on ovariec­tomized rats with and with­out inflam­ma­tion, find­ing pos­i­tive impacts on bone loss only in inflamed rats. 

See Also:Consuming Oleuropein May Mitigate the Effects of Aging on Muscular Atrophy

Oleuropein enhances osteoblast for­ma­tion while reduc­ing adipocyte gen­er­a­tion, sug­gest­ing pre­ven­tive effects against osteo­poro­sis and age-related bone loss. 

Regarding bone resorp­tion, oleu­ropein at vary­ing con­cen­tra­tions decreased the for­ma­tion of osteo­clast-like cells in spleen cell cul­tures. 

In vitro stud­ies by García Martínez et al. also demon­strated that phe­no­lic extracts from Sicilian vir­gin olive oil increased osteoblast cell num­bers, poten­tially aid­ing bone growth.

Phenolic com­pounds have also been shown to mod­u­late gene expres­sion related to bone growth and dif­fer­en­ti­a­tion in MG-63 osteosar­coma cells. These phe­no­lic com­po­nents ben­e­fit bone phys­i­ol­ogy, poten­tially pro­tect­ing against bone dis­eases by influ­enc­ing osteoblast func­tion.

Oleuropein and can­cer

Over the years, the con­sump­tion of oleu­ropein has been asso­ci­ated with aid­ing in can­cer treat­ment. 

This was ini­tially attrib­uted to its antiox­i­dant prop­er­ties, but it is now rec­og­nized that oleu­ropein’s impact on can­cer extends beyond its antiox­i­dant role. It func­tions as both an anti-pro­lif­er­a­tive and apop­totic pro­moter in var­i­ous can­cer cells, demon­strat­ing many anti­cancer prop­er­ties cur­rently under inves­ti­ga­tion.

Oleuropein shows mul­ti­fac­eted effects in can­cer. It induces apop­to­sis (cell death) in cer­vi­cal can­cer cells via JNK acti­va­tion and acti­vates ERK1/2 through GPER in breast can­cer, inhibit­ing cell growth.

Moreover, it mod­u­lates apop­to­sis reg­u­la­tors like BAX, Bcl2 and p53, enhanc­ing apop­totic path­ways and reduc­ing can­cer cell sur­vival.

See Also:Research Shows the Role of Polyphenols in Inhibiting Cancer Metastasis

A wealth of exper­i­men­tal data sup­ports HER2-induced sig­nal­ing as a key player in can­cer pro­gres­sion. HER2 over­ex­pres­sion, par­tic­u­larly in breast can­cer, acti­vates path­ways like PI3K/Akt and MAPK, dri­ving tumor growth. 

While drugs like trastuzumab tar­get HER2, resis­tance often devel­ops. Oleuropein agly­cone syn­er­gizes with trastuzumab in breast can­cer cells, inhibit­ing HER2 pro­te­olytic pro­cess­ing and down­reg­u­lat­ing its expres­sion, offer­ing a promis­ing ther­a­peu­tic approach.

Combining oleu­ropein with AKT inhibitors enhances apop­to­sis, par­tic­u­larly in cells over­ex­press­ing AKT. Oleuropein also impacts ROS lev­els, reduc­ing them in thy­roid can­cer cells while increas­ing them in prostate can­cer cells, sug­gest­ing cell-spe­cific effects. Additionally, it down­reg­u­lates NF-κB and cyclin D1, inhibit­ing onco­genic path­ways in breast can­cer.

Researchers believe that future stud­ies should explore oleu­ropein’s in vivo effects on redox sta­tus across var­i­ous can­cer stages and microen­vi­ron­ments. Understanding these dynam­ics could lead to the devel­op­ment of tar­geted anti­cancer ther­a­pies.

Know the Basics

Things to know about olive oil, from the Olive Oil Times Education Lab.

  • Extra vir­gin olive oil (EVOO) is sim­ply juice extracted from olives with­out any indus­trial pro­cess­ing or addi­tives. It must be bit­ter, fruity and pun­gent — and free of defects.

  • There are hun­dreds of olive vari­eties used to make oils with unique sen­sory pro­files, just as many vari­eties of grapes are used in wines. An EVOO can be made with just one vari­ety (mono­va­ri­etal) or sev­eral (blend).

  • Extra vir­gin olive oil con­tains healthy phe­no­lic com­pounds. Substituting a mere two table­spoons of EVOO per day instead of less healthy fats has been shown to improve health.

  • Producing high-qual­ity extra vir­gin olive oil is an excep­tion­ally dif­fi­cult and costly task. Harvesting olives ear­lier retains more nutri­ents and extends shelf life, but the yield is far less than that of fully ripe olives that have lost much of their healthy com­pounds.


Related Articles