• Login
    View Item 
    •   Repository Home
    • Research Publications
    • School of Agriculture and Biotechnology
    • Department of Crop Science
    • View Item
    •   Repository Home
    • Research Publications
    • School of Agriculture and Biotechnology
    • Department of Crop Science
    • View Item
    JavaScript is disabled for your browser. Some features of this site may not work without it.

    Antioxidant, antimicrobial and synergistic activities of tea polyphenols

    Thumbnail
    View/Open
    Full Text (282.7Kb)
    Date
    2015
    Author
    Koech, K.R.
    Wachira, F.N.
    Ngure, R.M.
    Wanyoko, J.K.
    Bii, C.C.
    Karori, S.M.
    Kerio, L.C.
    Metadata
    Show full item record
    Abstract
    Microbial resistance to conventional antibiotics has become an increasing global problem and there is a need to find out novel, potent antimicrobial agents with alternative modes of action as accessories to antibiotic therapy. This study investigated the antioxidant, antimicrobial and synergistic properties of tea polyphenols. The tea germplasm from Kenya, China and Japan that are grown in Kenya were characterised for their biochemical profiles. The total phenolic content, theaflavins and thearubigins content of different tea products used in this study were determined spectrophotometrically according to Folin-Ciocalteus and flavognost methods respectively. The individual catechin contents were characterised by high performance liquid chromatography (HPLC) and identified according to their HPLC retention times, elution order and comparison with authentic standards. The antioxidant activity of tea polyphenols was determined using UV-Vis spectrophotometer on its ability to scavenge 2,2-diphenyl-1-picrylhydrazyl (DPPH) radical. The Agar Disc Diffusion method was used to screen for antimicrobial and synergistic activities of the tea liquors. Black, green, purple coloured leaf and white (silvery tips) tea products characterised for their biochemical profiles differed significantly in the levels of total polyphenols, total catechins, catechins fractions, theaflavins and thearubigins (P ≤ 0.05). Green, purple coloured leaf (aerated) and black tea from terminal buds and white tea products analysed in this study exhibited slightly higher antioxidant activity compared to black tea. The different types of tea products assayed in this study exhibited significant influence on the inhibition zone diameters against bacteria and fungi exposed to the tea extracts. Methicillin and penicillinase resistant S. aureus ATCC 25923, C. albicans ATCC 90028 and a clinical isolate of C. neoformans were more susceptible to all tea extracts than E. coli and S. typhi. There was synergism between most tea extracts and penicillin G against methicillin and penicillinase resistant S. aureus ATTC 25923.
    URI
    http://karuspace.karu.ac.ke/handle/20.500.12092/1834
    Collections
    • Department of Crop Science [37]

    Karatina University copyright © 2017-2019  | Powered by DSpace
    Contact Us | Send Feedback | OAI-PMH Compliant
    Theme by Systems Librarian
      

     

    Browse

    All of RepositoryCommunities & CollectionsBy Issue DateAuthorsTitlesSubjectsThis CollectionBy Issue DateAuthorsTitlesSubjects

    My Account

    LoginRegister

    Statistics

    View Usage Statistics

    Karatina University copyright © 2017-2019  | Powered by DSpace
    Contact Us | Send Feedback | OAI-PMH Compliant
    Theme by Systems Librarian