Određivanje biodostupnosti odabranih polifenolnih sastavnica propolisa u uvjetima in vitro simulirane probave

doctoral thesis

• Title (english): Bioaccessibility research of selected propolis polyphenols by in vitro simulated gastrointestinal digestion
• Author: Eleonora Perak Junaković
• Mentor: Svjetlana Terzić (mentor)
• Committee member: Iva Juranović Cindrić (predsjednik povjerenstva)
• Committee member: Predrag Novak (član povjerenstva)
• Committee member: Irena Brčić Karačonji (član povjerenstva)
• Granter: University of Zagreb; Faculty of Science; (Department of Chemistry); Zagreb
• Defense date and country: 2023-02-16, Croatia
• Scientific / art field, discipline and subdiscipline: NATURAL SCIENCES; Chemistry
• Universal decimal classification (UDC): 54 - Chemistry. Crystallography. Mineralogy

Abstract

U ovome radu istražena je stabilnost, biodostupnost i dijalizibilnost polifenola pinocembrina,
galangina, krizina, kavene kiseline i feniletil estera kavene kiseline u uvjetima simulirane
probave in vitro (oralna i želučana faza te faza probave u tankom crijevu s dva modela:
centrifugiranjem i dijalizom kroz polupropusnu membranu) na dva uzorka kontinentalnog
propolisa i smjesi standarda odabranih polifenola. Različitim ekstrakcijskim postupcima i
korištenjem određenih nosača istraženi su ekstrakti prikladni za oralnu primjenu te analizirani
validiranom metodom tekućinske kromatografije visoke djelotvornosti uz primjenu UVdetektora s nizom fotodioda (eng. High Performance Liquid Chromatography - Photodiode
Array Detection, HPLC-PDA). Primjenom 2-hidroksipropil-β-ciklodekstrina (HP-β-CD) i
postupkom liofilizacije dobiven je u vodi topljivi kompleks propolis-HP-β-CD s najvećim
udjelom polifenola. Rezultati analiza RP-HPLC-PDA oba uzorka kontinentalnog propolisa
pokazali su stabilnost odabranih polifenola tijekom svih faza simulirane probave.
Biodostupnost svih polifenola u uvjetima in vitro nakon dijalize kroz polupropusnu
membranu bila je vrlo niska u odnosu na model s centrifugiranjem. Nadalje, rezultati ukazuju
da u modelu s centrifugiranjem nema razlike u biodostupnosti polifenola između dva uzorka
kontinetalnog tipa propolisa. Vodena suspenzija liofilizata kompleksa propolis-HP-β-CD
pokazala se kao potencijalna djelatna tvar u farmaceutskim proizvodima za oralnu primjenu.

Abstract (english)

In this work, the stability, bioaccessibility and dialysability of polyphenols pinocembrin,
galangin, chrysin, caffeic acid and phenylethyl ester of caffeic acid were investigated after in
vitro simulated digestion (oral and gastric phase and small intestine phase with two models:
centrifugation and dialysis through a semi-permeable membrane) on two samples of
continental propolis and standard mixture of selected polyphenols. Extracts suitable for oral
administration prepared by various extraction procedures and the use of certain carriers have
been investigated and analyzed by validated RP-HPLC-PDA method. Using
2-hydroxypropyl-β-cyclodextrin (HP-β-CD) carbohydrate and by lyophilisation procedure, a
propolis water-soluble complex with the highest polyphenol content was prepared. The results
of RP-HPLC-PDA analysis of both propolis samples showed the stability of selected
polyphenols during all phases of simulated digestion. The bioaccessibility of all polyphenols
in in vitro conditions after dialysis through a semi-permeable membrane was very low
compared to the centrifugation model. Furthermore, the results indicate that in the model with
centrifugation there is no difference in the bioaccessibility of polyphenols between the two
samples of the continental type of propolis. The aqueous suspension of the lyophilisate of the
propolis-HP-β-CD complex proved to be a potential active substance in pharmaceutical
products for oral administration.

• Keywords: biodostupnost; HP-β-CD; HPLC; polifenoli; propolis; simulacija probave
• Keywords (english): bioaccessibility; digestion simulation; HP-β-CD; HPLC; polyphenols; propolis
• Language: croatian
• URN:NBN: urn:nbn:hr:217:728078
• Promotion: 2023
• Study programme: Title: Doctoral study in chemistry; Study programme type: university; Study level: postgraduate; Academic / professional title: doktor/doktorica znanosti, područje prirodnih znanosti, polje kemija (doktor/doktorica znanosti, područje prirodnih znanosti, polje kemija)
• Type of resource: Text
• Extent: XXVII, 143 str. ; 30 cm
• File origin: Born digital
• Access conditions: Open access
• Created on: 2023-03-27 11:03:11