Heat treatment enhances the antimicrobial activity of (+)-Catechin when combined with copper sulphate

Holloway, A. C., Mueller-Harvey, I., Gould, S. W. J., Fielder, M. D., Naughton, D. P. and Kelly, A. F. (2015) Heat treatment enhances the antimicrobial activity of (+)-Catechin when combined with copper sulphate. Letters in Applied Microbiology, 61 (4). pp. 381-389. ISSN 0266-8254 doi: 10.1111/lam.12472

Abstract/Summary

The aim of the study was to compare the antimicrobial activities of freshly-made, heat-treated (HT), and 14 d stored (+)-Catechin solutions with (+)-catechin flavanol isomers in the presence of copper sulphate. (+)-Catechin activity was investigated when combined with different ratios of Cu2+; 100°C heat treatment; autoclaving; and 14 d storage against Staphylococcus aureus. Cu2+-(+)-Catechin complexation, isomer structure-activity relationships, and H2O2 generation were also investigated. Freshly-made, HT, and 14d stored flavanols showed no activity. Whilst combined Cu2+-autoclaved (+)-Catechin and -HT(+)-Catechin activities were similar, HT(+)-Catechin was more active than either freshly-made (+)-catechin (generating more H2O2) or (-)-Epicatechin (though it generated less H2O2) or 14d-(+)-Catechin (which had similar activity to Cu2+ controls - though it generated more H2O2). When combined with Cu2+, in terms of rates of activity, HT(+)-Catechin was lower than (-)-Epigallocatechin gallate and greater than freshly-made (+)-Catechin. Freshly-made and HT(+)-Catechin formed acidic complexes with Cu2+ as indicated by pH and UV-vis measurements although pH changes did not account for antimicrobial activity. Freshly-made and HT(+)-Catechin both formed Cu2+ complexes. The HT(+)-Catechin complex generated more H2O2 which could explain its higher antimicrobial activity.

Item Type	Article
URI	https://reading-clone.eprints-hosting.org/id/eprint/40963
Identification Number/DOI	10.1111/lam.12472
Refereed	Yes
Divisions	Life Sciences > School of Agriculture, Policy and Development > Department of Animal Sciences > Animal, Dairy and Food Chain Sciences (ADFCS)- DO NOT USE
Publisher	Wiley
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