magistrsko delo
Špela Jelen (Author), Andreja Urbanek Krajnc (Mentor), Maša Primec (Co-mentor), Tadeja Vajdič (Co-mentor)

Abstract

V sklopu magistrskega dela smo analizirali vsebnost skupnih in posameznih fenolov v listih genotipov različnih vrst murv (Morus alba, M. alba × rubra, M. nigra, M. australis). Na podlagi fenolnega profila smo odbrali genotipe z največjimi vsebnostmi in proučili protibakterijski učinek murvovih ekstraktov na rast dveh bakterij, grampozitivne Staphylococcus aureus in gramnegativne Escherichia coli. Skupne fenole vseh genotipov smo analizirali s Folin-Ciocalteujevo metodo, posamezne fenole smo analizirali s tekočinsko kromatografijo z UV/VIS-detekcijo. Protibakterijski učinek etanolnih ekstraktov smo določali s Kirby-Bauerjevo disk difuzijsko metodo in z difuzijskim antibiogramom z vdolbinicami. Vpliv protibakterijskega učinka vodnih murvovih ekstraktov na kinetiko rasti obeh bakterij smo preučevali s pomočjo spektrofotometra na mikrotitrski ploščici. Najvišje vrednosti skupnih fenolov (21,51 ± 2 mg GAE/g SS), klorogenske kisline (14,9 ± 0,86 mg/g SS), 4-kafeoilkininske kisline (4,36 ± 0,22 mg/g SS), 5-p-kumaroilkininske kisline (2,2 ± 1,21 mg/g SS), kvercetin glikozida (0,74 ± 0,01 mg/g SS) in kemferol-acetil-heksozida (4,42 ±0,01 mg/g SS) so dosegali sadni genotipi (M. alba × rubra, M. nigra, M. australis), medtem ko so genotipi bele murve (M. alba) vsebovali največ rutina (2,67 ± 0,7 mg/g SS) in kvercetin-malonil-heksozida (1,59 ± 0,39 mg/g SS). Pri difuzijskem antibiogramu z diski inhibicijskih con pri E. coli ni bilo, medtem ko je bil pri difuzijskem antibiogramu z vdolbinicami učinek bakteriostatičen. Pri poskusu s S. aureus se je inhibicijska cona izrazila pri vseh koncentracijah murvovih ekstraktov, a je bila bakteriostatična. Na podlagi spektrofotometričnih rezultatov lahko sklepamo, da murvov ekstrakt nekaj ur zavira rast bakterij S. aureus in E. coli, nato pa jo vzpodbudi, kar lahko pripišemo proteinom in ogljikovim hidratom v ekstraktu. Za nadaljnje raziskave bi bilo smiselno uporabiti čisti fenolni ekstrakt brez beljakovin in ogljikovih hidratov, saj slednji dve snovi predstavljata hranilo za bakterije

Keywords

Murve (Morus sp.);fenolni profil listov;protibakterijski učinek;S. aureus;E. coli;

Data

Language: Slovenian
Year of publishing:
Typology: 2.09 - Master's Thesis
Organization: UM FKBV - Faculty of Agriculture
Publisher: [Š. Jelen]
UDC: 638.232:547.56:615.281.9(043)=163.6
COBISS: 132753155 Link will open in a new window
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Other data

Secondary language: English
Secondary title: Analysis of phenolics in mulberry (Morus sp.) leaves and their antibacterial effect
Secondary abstract: Content of total and individual phenols in the leaves of genotypes of different mulberry species (Morus alba, M. alba × rubra, M. nigra, M. australis) was analysed for the purposes of the presented master's thesis. Based on the phenolic profile, the genotypes with the highest contents were selected and the antibacterial effect of mulberry extracts on the growth of two bacteria, Gram-positive Staphylococcus aureus and Gram-negative Escherichia coli was investigated. The total phenols of all genotypes were analysed via the Folin-Ciocalteu method. The individual phenols were analysed via liquid chromatography with UV/VIS detection. The antibacterial effect of the ethanol extracts was determined using the Kirby-Bauer disc diffusion method and the diffusion antibiogram with wells. The temporal influence of the aqueous mulberry extract antibacterial effect on the growth kinetics of the two bacteria, was investigated spectrophotometrically on a microtitre plate. The highest concentrations of total phenols (21.51 ± 2 mg GAE /g DW), chlorogenic acid (14.9 ± 0.86 mg/g DW), 4-caffeoylquinic acid (4.36 ± 0.22 mg/g DW), 5-p-coumaroylquinic acid (2.2 ± 1.21 mg/g DW), quercetin glycoside (0.74 ± 0.01 mg/g DW) and kaempferol acetyl hexoside (4.42 ± 0.01 mg/g DW) were obtained with the fruit genotypes (M. alba × rubra, M. nigra, M. australis). In contrast, the genotypes of white mulberry (M. alba) contained the most rutin (2.67 ± 0.7 mg/g DW) and quercetin malonyl hexoside (1.59 ± 0.39 mg/g DW). In the disc diffusion antibiogram, there were no inhibition zones for E. coli, while in the well diffusion antibiogram the effect was bacteriostatic. In the experiment with S. aureus, the zone of inhibition was expressed at all concentrations in the mulberry extracts, but the effect was bacteriostatic. Based on the spectrophotometric results of bacterial growth kinetics, the results indicate that the mulberry extracts inhibit the growth of S. aureus and E. coli bacteria in the first few hours. The later stimulating effect on the bacterial growth rate can be attributed to the proteins and carbohydrates in the extract. For further research, it would be reasonable to use a pure phenolic extract without protein and carbon hydrates, since the latter two substances serve as nutrients for the bacteria
Secondary keywords: Mulberry (Morus sp.);phenolic leaf profile;antibacterial effect;S. aureus;E. coli;Univerzitetna in visokošolska dela;
Type (COBISS): Master's thesis/paper
Thesis comment: Univ. v Mariboru, Fak. za kmetijstvo in biosistemske vede
Pages: 1 spletni vir (1 datoteka PDF (XII, 94, [1] str.))
ID: 17153813