`Researchers Investigate Role of Bioactive Compounds in Neurodegenerative Diseases - Olive Oil Times

Researchers Investigate Role of Bioactive Compounds in Neurodegenerative Diseases

By Paolo DeAndreis
May. 23, 2023 23:32 UTC

The Mediterranean diet is one of the best eat­ing pat­terns for low­er­ing the risk of neu­ro­log­i­cal dis­or­ders, a lit­er­a­ture review of the impacts of nutri­tion on the devel­op­ment of neu­rode­gen­er­a­tive dis­eases has con­cluded.

Researchers from the University of Messina, Italy, ana­lyzed more than 200 sci­en­tific stud­ies on the bioac­tive com­pounds of the Mediterranean diet, includ­ing flavonoids, polyphe­nols and antho­cyanins.

They focused on how these bioac­tive com­pounds affect the devel­op­ment of Alzheimer’s dis­ease and Parkinson’s dis­ease, the two most com­mon neu­rode­gen­er­a­tive dis­eases glob­ally.

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According to the World Health Organization, about 60 mil­lion peo­ple glob­ally have either Alzheimer’s dis­ease or Parkinson’s dis­ease, both of which have no cure.

Separate research from The Lancet esti­mates that demen­tia cases, of which Alzheimer’s is the most com­mon form, will triple by 2050 as life expectan­cies grow longer and pop­u­la­tions in North America, East Asia and Western Europe age.

Inflammation, oxida­tive stress and excess reac­tive oxy­gen are known to play a sig­nif­i­cant role in the devel­op­ment and pro­gres­sion of neu­rode­gen­er­a­tive dis­or­ders.

As a result, the bioac­tive com­pounds asso­ci­ated with com­mon foods in the Mediterranean diet, includ­ing extra vir­gin olive oil, were of par­tic­u­lar inter­est to the researchers as many have anti-inflam­ma­tory and antiox­i­dant prop­er­ties that may post­pone the devel­op­ment of neu­rode­gen­er­a­tive dis­eases.

Because of their poten­tial for neu­ro­pro­tec­tion, antiox­i­dant and anti-inflam­ma­tory effects and mito­chon­dr­ial home­osta­sis to resist neu­roin­flam­ma­tory dis­or­ders asso­ci­ated with mito­chon­dr­ial dys­func­tion, bioac­tive com­pounds have attracted the inter­est of sci­en­tists,” the researchers wrote.

The researchers inves­ti­gated stud­ies on flavonoids – found in veg­eta­bles, fruits, nuts, seeds, tea, cof­fee and wine – and found their con­sump­tion can have sev­eral pos­i­tive health effects, includ­ing a decreased risk of devel­op­ing Parkinson’s dis­ease.

Their phys­i­o­log­i­cal actions, which include antiox­ida­tive, anti-inflam­ma­tory, anti-apop­totic and lipid-low­er­ing qual­i­ties, are the rea­son for this,” they wrote.

The researchers added that cer­tain flavonoids also have neu­ro­pro­tec­tive effects due to their abil­ity to reduce presy­nap­tic glu­ta­mate release and reassem­ble post­sy­nap­tic glu­ta­mate recep­tors, which are crit­i­cal for healthy brain func­tion.

The poten­tial ben­e­fi­cial effect of flavonoids in the brain appears to be linked to their abil­ity to inter­act with glial sig­nal­ing and intra­cel­lu­lar neu­ronal path­ways, trig­ger­ing neu­ronal regen­er­a­tion, increas­ing exist­ing neu­ronal func­tions, pro­tect­ing vul­ner­a­ble neu­rons or influ­enc­ing the cere­brovas­cu­lar and periph­eral sys­tem,” they wrote.

Among the most com­mon group of flavonoids are antho­cyanins, to which the researchers paid par­tic­u­lar atten­tion. Anthocyanins are respon­si­ble for the red, vio­let and blue col­or­ings of many fruits and veg­eta­bles.

Anthocyanins ame­lio­rate oxida­tive stress by low­er­ing free rad­i­cal pro­duc­tion and lipid per­ox­i­da­tion,” they wrote. The com­plex mech­a­nisms by which antho­cyanins can directly scav­enge free rad­i­cals, pre­vent the for­ma­tion of reac­tive oxy­gen species… or encour­age the release of antiox­i­dant enzymes are what give them their antiox­i­dant prop­er­ties.”

The researchers said higher antho­cyanin con­sump­tion might help to pre­vent the devel­op­ment of neu­rode­gen­er­a­tive dis­eases in old age due to the links between Alzheimer’s dis­ease and car­dio­vas­cu­lar and meta­bolic health.

Based on the lit­er­a­ture review, the researchers also deter­mined that antho­cyanins lower the con­cen­tra­tion of ions and inhibit pro­teins that reg­u­late neu­ronal apop­to­sis, or cell death.


They also pro­tected against mem­ory loss as assessed by behav­ioral tests and mea­sure­ment of anx­i­ety, mem­ory and motor func­tions,” they wrote.

In a study in mice, the researchers said antho­cyanin con­sump­tion appeared to be asso­ci­ated with dimin­ished brain tis­sue dam­age caused by the build-up of pro­teins asso­ci­ated with Alzheimer’s dis­ease.

By caus­ing dam­age to neu­rons and other bio­log­i­cal com­po­nents, oxida­tive stress and neu­roin­flam­ma­tion cause neu­rode­gen­er­a­tion,” they said. Anthocyanins influ­ence these meta­bolic path­ways, enhanc­ing antiox­i­dant and anti-inflam­ma­tory defenses as well as main­tain­ing nor­mal hip­pocam­pus func­tion.”

See Also:Med Diet Adherence Associated with Lower Dementia Risk

The researchers also focused on the role of polyphe­nols, the most preva­lent dietary antiox­i­dant, in Alzheimer’s dis­ease and Parkinson’s dis­ease devel­op­ment.

Due to its high meta­bolic activ­ity, the researchers said the brain is par­tic­u­larly sus­cep­ti­ble to oxida­tive dam­age since it is the loca­tion of increased oxy­gen absorp­tion but low lev­els of antiox­i­dant enzymes.

Oxidative stress and dam­age to brain macro­mol­e­cules are inher­ent processes in neu­rode­gen­er­a­tive dis­eases,” the researchers wrote.

The antiox­i­dant prop­er­ties of many polyphe­nols are pur­ported to pro­vide neu­ro­pro­tec­tion,” they added. The impacts of polyphe­nols on cog­ni­tion and neu­rode­gen­er­a­tive processes appear to be medi­ated via inter­ac­tions with neu­ronal and glial sig­nal­ing path­ways that influ­ence gene expres­sion and inter­fere with cell death mech­a­nisms.”

Polyphenols man­i­fest their antiox­i­dant prop­er­ties by directly scav­eng­ing free rad­i­cals or indi­rectly enhanc­ing the capac­ity of the body’s nat­ural defense sys­tem.

In the case of Parkinson’s dis­ease, the researchers found that polyphe­nol con­sump­tion inhib­ited the aggre­ga­tion of a pro­tein asso­ci­ated with the devel­op­ment of the dis­ease.

The researchers also high­lighted sep­a­rate stud­ies that found that dietary polyphe­nols may acti­vate path­ways asso­ci­ated with adap­tive cel­lu­lar stress responses, upreg­u­late genes that reg­u­late cel­lu­lar oxi­da­tion-reduc­tion lev­els and improve the cell’s nat­ural defenses against oxi­da­tion.

Additionally, one of the most impor­tant polyphe­nols in this field is resver­a­trol,” they wrote. Resveratrol is a polyphe­nol that occurs nat­u­rally in red grapes, peanuts and many other plant species. Administration of resver­a­trol to trans­genic mouse mod­els of Alzheimer’s dis­ease reduces behav­ioral impair­ments and aging-related cen­tral ner­vous sys­tem Aβ [a neu­ro­toxin] depo­si­tion.”

The researchers also inves­ti­gated the role of insol­u­ble phe­no­lic acids in pre­vent­ing the onset of Parkinson’s dis­ease and Alzheimer’s dis­ease.

Extra vir­gin olive oil has 36 phe­no­lic com­pounds, includ­ing tyrosol, hydrox­y­ty­rosols, oleo­can­thal, oleu­ropein and carotenes.

These phe­no­lic chem­i­cals pen­e­trate the brain and exert neu­ro­pro­tec­tive effects via antiox­i­dant, anti-apop­totic, and anti-inflam­ma­tory mech­a­nisms,” they wrote. According to exten­sive research, hydrox­y­ty­rosol func­tions as a scav­enger of reac­tive free rad­i­cals, result­ing in neu­ro­pro­tec­tive effects on brain cells dur­ing oxida­tive stress.”

Regarding the effects of phe­no­lic com­pounds on Alzheimer’s dis­ease, the researchers also inves­ti­gated a study that looked at the role of olive leaves.

“[One study] explored the effect of the admin­is­tra­tion of bioac­tive mol­e­cules of the polyphe­nol class from olive leaves on male mouse neu­rotrophic pro­teins,” they wrote. In par­tic­u­lar, the study sug­gests that nerve growth fac­tor and brain-derived neu­rotrophic fac­tor and glial cell line-derived neu­rotrophic fac­tor are involved in Alzheimer’s dis­ease pathol­ogy. The admin­is­tra­tion of these polyphe­nols exhib­ited a key role in synap­tic growth and pro­tected neu­rons from dam­age.”

While the researchers said plenty of sci­en­tific stud­ies point to the great poten­tial of bioac­tive com­pounds – both in diet and phar­ma­ceu­ti­cals – in the pre­ven­tion and treat­ment of Alzheimer’s dis­ease and Parkinson’s dis­ease symp­toms, they added that more work still needs to be done.

Current research sug­gests that more long-term, dou­ble-blind, ran­dom­ized con­trolled tri­als on a large human pop­u­la­tion are required to pro­mote the Mediterranean diet,” they con­cluded. This might help deter­mine whether bet­ter adher­ence to this diet can help avoid or post­pone the devel­op­ment of neu­rode­gen­er­a­tive dis­eases.”


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