Fenolni profil, antioksidacijski i antimikrobni potencijal odabranoga ljekovitoga bilja mediteranskoga podneblja

doctoral thesis

• Title (english): Phenolic profile, antioxidant and antimicrobial potential of selected mediterranean herbs
• Author: Ivana Generalić; MBZ: 298955
• Mentor: Višnja Katalinić (mentor); MBZ: 110963
• Committee member: Mara Banović (predsjednik povjerenstva); MBZ: 83392
• Granter: University of Zagreb; Faculty of Food Technology and Biotechnology; Zagreb
• Defense date and country: 2011-10-12, Croatia
• Scientific / art field, discipline and subdiscipline: BIOTECHNICAL SCIENCES; Food Technology
• Universal decimal classification (UDC): 633/635 - Horticulture. Fruit growing. Viticulture. Gardening

Abstract

U ovom radu je istražena povezanost između kemijskog sastava i bioloških svojstava ekstrakata ljekovitoga bilja mediteranskoga podneblja. Polifenolni profil biljnih ekstrakta određen je primjenom spektrofotometrijskih metoda i HPLC tehnike, a za određivanje antioksidacijske aktivnost korištene su metode FRAP, DPPH, ABTS, superoksid anion, BR, kelatiranje i β-karoten metoda. Antimikrobni učinak ispitan je prema gram-negativnim i gram-pozitivnim bakterijama. Rezultati istraživanja ukazuju na varijacije među biljnim ekstraktima u sadržaju ukupnih fenola, pojedinih fenolnih podgrupa i pojedinačnih fenola određenih HPLC tehnikom. Za Lamiaceae je potvrđen visok udio neflavonoida i dominacija ružmarinske kiseline, kao i njen utjecaj na antioksidacijska svojstva tih ekstrakata. U istraživanim ekstraktima ljekovitog bilja je dokazana prisutnost stilbena, koja prema dostupnim podacima, u mediteranskim biljkama, do sada još nije bila istraživana. Dokazane su razlike u antioksidacijskoj aktivnosti i antimikrobnoj učinkovitosti među istraživanim ekstraktima. Za Lamiaceae su dokazana najbolja antioksidacijska svojstva primjenom svih metoda. Svi ekstrakti su pokazali antibakterijsko djelovanje prema gram-pozitivnim bakterijama, a najniže MIC vrijednosti dobivene su za ekstrakte smilja i kadulje. Svi biljni ekstrakti su djelovali na Campylobacter coli, dok su ostale gram-negativne bakterije bile otpornije. Istraživanjem utjecaja fenofaze, dokazan je značajan utjecaj perioda branja na fenolni sastav i biološka svojstva ekstrakta kadulje. Najveći sadržaj flavonoida, najbolja antioksidacijska i antibakterijska svojstva imao je ekstrakt kadulje iz svibnja.

Abstract (english)

In this work, the connection between chemical composition and biological properties of selected Mediterranean herbs, was investigated. Polyphenolic profile of plant extracts was determined using spectrophotometic methods and HPLC, while the antioxidant capacity was measured by FRAP, DPPH, ABTS, superoxide anion, Briggs-Rauscher oscillating reaction, chelating ability and β-carotene methods. Antimicrobial activity was tested against gram-positive and gram-negative bacteria strains. Obtained results point to differences between among plant extracts, both in total phenol and phenolic subgroups content and in concentrations of individual phenolics detected using HPLC. Lamiaceae plants have high share of nonflavonoids, with dominant rosmarinic acid which has a high influence on their antioxidant properties. The presence of stilbenes in analyzed medicinal plant extracts was confirmed, which according to available literature data is the first time that these compounds were investigated in Mediterranean herbs. Differences in antioxidant and antimicrobial activity among investigated extracts were also established. Lamiaceae plants showed the best antioxidant properties using all methods. All extracts showed antibacterial activity against gram-positive bacteria strains, and the lowest MIC values were obtained for immortelle and sage. All plant extracts were efficient against Campylobacter coli, while other gram-negative bacteria strains were more resistant. Phenophase influence research showed that the sample collection period has a high impact on phenolic composition and on biological properties of sage extracts. May sage extract had the highest share of flavonoids, and the best antioxidant and antibacterial activity.

• Keywords: mediteransko bilje; fenolni spojevi; HPLC; antioksidacijska svojstva; antimikrobna svojstva
• Keywords (english): Mediterranean herbs; phenolic compounds; HPLC; antioxidant properties; antimicrobial properties
• Language: croatian
• URN:NBN: urn:nbn:hr:159:013805
• Promotion: 2012-07-01
• Study programme: Title: Food Technology; Study programme type: university; Study level: postgraduate; Academic / professional title: doktor/doktorica znanosti (doktor/doktorica znanosti)
• Type of resource: Text
• File origin: Born digital
• Access conditions: Access restricted to students and staff of home institution
• Created on: 2018-05-16 09:15:11