Health

Polyphenols Shown to Have Distinct Anti-Bacterial Properties

Research on the antibacterial activity of olive varieties grown in southern Italy shows promise for natural treatments against E. coli and Pseudomonas aeruginosa.

Feb. 26, 2020
By Ylenia Granitto

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Olive vari­eties with dif­fer­ent polyphe­nol pro­files have dif­fer­ent antibac­te­r­ial prop­er­ties, accord­ing to new research out of Italy.

Researchers at the National Research Coun­cil’s insti­tute of food sci­ences (ISA-CNR) and the Uni­ver­sity of Salerno tested the antibac­te­r­ial activ­ity of three olive vari­eties. Their find­ings now pave the way for the explo­ration of new nat­ural med­ica­tion.

This could be a basis of com­ple­men­tary stud­ies to for­mu­late ideal drugs of nat­ural ori­gin, com­posed of opti­mal mix­tures of polyphe­nols.- Filom­ena Naz­zaro, senior sci­en­tist at the ISA-CNR

We first con­ducted a study con­cern­ing the bio­chem­i­cal pro­file, includ­ing volatile com­pounds, and the rela­tion­ship between the antiox­i­dant activ­ity and polyphe­nols of extra vir­gin olive oils obtained by autochtho­nous vari­eties of Cam­pa­nia, Ruvea Antica, Ravece, and Ogliarola,” Filom­ena Naz­zaro, a sci­en­tist at the ISA-CNR, told Olive Oil Times. Then, in a sec­ond exper­i­ment, we ana­lyzed the antibac­te­r­ial activ­ity cor­re­lated to the polyphe­nol pro­files of the above-men­tioned vari­eties.”

This last research, in par­tic­u­lar, exam­ined the inhibitory effect of the polyphe­no­lic extracts against sev­eral gram-pos­i­tive and gram-neg­a­tive bac­te­r­ial strains,” she added. They gave us remark­able results in terms of their activ­ity against path­o­genic species, namely those that are respon­si­ble for the for­ma­tion of biofilms, which are very inter­est­ing when it comes to human health since they increase the resis­tance of bac­te­ria to syn­thetic antibi­otics.”

See more: Research News

The analy­sis of the polyphe­nol frac­tions of the extra vir­gin olive oils con­firmed well-known antibac­te­r­ial prop­er­ties, show­ing that the qual­i­ta­tive and quan­ti­ta­tive pro­file of polyphe­nols can affect those prop­er­ties in dif­fer­ent ways.

The researchers applied a sta­tis­ti­cal method to pre­dict the syn­er­gis­tic effect of polyphe­nols and the influ­ence of each of them, based also on their amount, on the activ­ity of the whole extract.

The tests were per­formed using 2.5 and 4.9 micro­grams of the three polyphe­nol extracts against dif­fer­ent pathogens. The results showed that the min­i­mum con­cen­tra­tion nec­es­sary to inhibit the growth of the path­o­genic tester strains was low for all the polyphe­no­lic extracts, and this con­firmed their gen­eral capac­ity to inhibit the growth of path­o­genic or unwanted microor­gan­isms.

In par­tic­u­lar, all three extracts were effec­tive in inhibit­ing the growth of Escherichia coli [with 4.9 micro­grams of polyphe­no­lic extracts from Ravece and Ogliarola],” Naz­zaro said. In our opin­ion, this result could find an inter­est­ing prac­ti­cal appli­ca­tion, since this bac­terium is one of the causes of uri­nary tract infec­tions. Research on polyphe­no­lic extracts, as well as essen­tial oils, are actu­ally open­ing new hori­zons in the treat­ment of, for exam­ple, com­mon catheter infec­tions, which are painful and dif­fi­cult to erad­i­cate.”

The three extracts also were found to be capa­ble of inhibit­ing the growth of Pseudomonas Aerug­i­nosa, a well-known pathogen that is respon­si­ble for the for­ma­tion of the afore­men­tioned biofilms.

The extracts of Ogliarola and Ravece were more effec­tive than those of Ruvea Antica in inhibit­ing the growth of the strain; in par­tic­u­lar, 2.5 micro­grams of polyphe­nols extract of Ravece were twice as effec­tive as that of Ruvea Antica against Pseudomonas Aerug­i­nosa; 4.9 micro­grams of Ravece polyphe­nols extract were three times more effec­tive than those of Ruvea Antica.

The researchers stud­ied the antiox­i­dant activ­ity of the extracts fol­low­ing the same method­ol­ogy, with extra vir­gin olive oils from vari­eties grown in the same plot of land at the same time. This lim­ited the vari­ables involved and led to the find­ing that Ruvea Antica con­tained the great­est amount of total polyphe­nols, show­ing the high­est antiox­i­dant activ­ity.

The research team also sug­gested that it would be inter­est­ing to con­duct this research on sev­eral vari­eties, in dif­fer­ent years.

This could be a basis of com­ple­men­tary stud­ies to for­mu­late ideal drugs of nat­ural ori­gin, com­posed of opti­mal mix­tures of polyphe­nols, which are able to exer­cise with the min­i­mum effort, in terms of quan­tity, and the max­i­mum result, namely against the great­est num­ber of pathogens, their antibac­te­r­ial effi­cacy,” Naz­zaro said. Future research should also take into account the use of the extra vir­gin olive oil by-prod­ucts, which are rich in polyphe­nols.”

More­over, this makes us under­stand the impor­tance of assum­ing that every day a fair amount of extra vir­gin olive oil, which is digested and trans­formed into mol­e­cules that are ben­e­fi­cial for our micro­biome, also coun­ter­acts the growth of path­o­genic species,” Naz­zaro con­cluded.





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