Mehanizmi antibakterijskog djelovanja inovativnog ekstrakta propolisa

master's thesis

• Title (english): Antibacterial action mechanisms of innovative propolis extract
• Author: Mihaela Vranješ
• Mentor: Ivana Tlak Gajger (mentor)
• Mentor: Josipa Vlainić (mentor)
• Committee member: Andreja Prevendar Crnić (predsjednik povjerenstva)
• Committee member: Josipa Vlainić (član povjerenstva)
• Committee member: Ivana Tlak Gajger (član povjerenstva)
• Committee member: Krešimir Matanović (član povjerenstva)
• Granter: University of Zagreb; Faculty of Veterinary Medicine; Zagreb
• Defense date and country: 2023-07, Croatia
• Scientific / art field, discipline and subdiscipline: BIOMEDICINE AND HEALTHCARE; Veterinary Medicine; Animal Production and Biotechnology

Abstract

Propolis je pčelinji proizvod poznat ljudima više od dvije tisuće godina. Njegova su
antimikrobna svojstva bila predmet brojnih istraživanja u kojima su se najčešće koristili
alkoholni (etanolni) ekstrakti propolisa. Iako učinkoviti i često korišteni, takvi ekstrakti zbog
učinka etanola nisu primjereni za uporabu kod određenih stanja i pacijenata u humanoj i
veterinarskoj medicini. Potaknuti navedenim činjenicama smo u našem istraživanju koristili
bezalkoholni, standardizirani i neškodljivi ekstrakt propolisa. Cilj nam je bio utvrditi njegovu
antimikrobnu učinkovitost prema bakteriji S. aureus i gljivici C. albicans te mehanizme
njegovog antibakterijskog djelovanja. Koncentracije aktivnih tvari u ekstraktu smo odredili
HPLC metodom, a zatim smo nizom mikrobioloških postupaka istražili njegovo djelovanje
prema ispitivanim mikroorganizmima. Bezalkoholni ekstrakt propolisa je uz flavonoide
sadržavao feruličnu kiselinu, para-kumarinsku kiselinu, kavenu kiselinu i CAPE. Minimalna
inhibicijska koncentracija (MIK) propolisa za bakteriju S. aureus iznosila je 0,883 % i 1,324
% propolisa, a za gljivicu C. albicans 0,883 % propolisa. Mjerenjem koncentracije proteina i
dvolančane DNK u izvanstaničnom matriksu nakon primjene propolisa na S. aureus smo
potvrdili da su nastale promjene u bakterijskoj membrani i stijenci zbog kojih je došlo do
istjecanja unutarstaničnog materijala u izvanstanični matriks. Također, provođenjem metode
dinamičke procjene antimikrobne aktivnosti smo zaključili da propolis na S. aureus djeluje
baktericidno, a na C. albicans mikostatski. Zaključno, istraživanjem smo dokazali da
standardizirani i bezalkoholni ekstrakt propolisa narušava cjelovitost bakterijske membrane i
stijenke te da uzrokuje izlazak staničnog materijala (proteina i dvolančane DNK) bakterije S.
aureus. Osim toga, dokazali smo i mikostatsko djelovanje ekstrakta na gljivicu C. albicans
čime je potvrđen puni antimikrobni potencijal inovativnog ekstrakta propolisa. Dobiveni
rezultati mogu poslužiti kao korisna osnova za provođenje daljnjih istraživanja i moguću
komercijalnu primjenu.

Abstract (english)

Propolis is a bee product known to humans for over two thousand years. Its
antimicrobial properties have been the subject of numerous studies, with alcohol-based
(ethanol) propolis extracts being the most commonly used. Although effective and frequently
utilized, such extracts are not suitable for some conditions and patients in human and veterinary
medicine due to the effects of ethanol. Motivated by these facts, our research employed an
alcohol-free, standardized and harmless propolis extract. We aimed to determine its
antimicrobial effectiveness against the bacterium S. aureus and the fungus C. albicans, as well
as to explore the mechanisms of its antibacterial action. We determined the concentrations of
active substances in the extract using the HPLC method and then examined its effects on the
test microorganisms through a series of microbiological procedures. In addition to flavonoids,
the alcohol-free propolis extract contained ferulic acid, p-coumaric acid, caffeic acid, and
CAPE. The minimum inhibitory concentration (MIC) of propolis against S. aureus was 0.883
% and 1.324 % propolis, while against C. albicans, it was 0.883 % propolis. By measuring the
concentration of proteins and double-stranded DNA (dsDNA) in the extracellular matrix after
applying propolis to S. aureus, we confirmed that changes occurred in the bacterial membrane
and cell wall, leading to the leakage of intracellular material into the extracellular matrix.
Furthermore, by employing a time-kill assay, we concluded that propolis has a bactericidal
effect on S. aureus and a fungistatic effect on C. albicans. In conclusion, our research has
demonstrated that the standardized and alcohol-free propolis extract disrupts the integrity of
the bacterial membrane and cell wall, causing the release of cellular material (proteins and
double-stranded DNA) from S. aureus. Additionally, we have proven the fungistatic activity
of the extract against the fungus C. albicans, thus confirming the full antimicrobial potential
of the alcohol-free propolis extract. The obtained results can serve as a valuable basis for further
research and potential commercial applications.

• Keywords: bezalkoholni ekstrakt propolisa; mehanizam djelovanja; Staphylococcus aureus; Candida albicans
• Keywords (english): alcohol-free propolis extract; mechanism of action; Staphylococcus aureus; Candida albican
• Language: croatian
• URN:NBN: urn:nbn:hr:178:475880
• Study programme: Title: Veterinary Medicine; Study programme type: university; Study level: integrated undergraduate and graduate; Academic / professional title: doktor/doktorica veterinarske medicine (doktor/doktorica veterinarske medicine)
• Type of resource: Text
• File origin: Born digital
• Access conditions: Open access
• Created on: 2023-07-18 13:04:37