title: The effect of copper(II), iron(II) sulphate, and vitamin C combinations on the weak antimicrobial activity of (+)-catechin against Staphylococcus aureus and other microbes.
abstract: Few attempts have been made to improve the activity of plant compounds with low antimicrobial efficacy. (+)-Catechin, a weak antimicrobial tea flavanol, was combined with putative adjuncts and tested against different species of bacteria. Copper(II) sulphate enhanced (+)-catechin activity against Pseudomonas aeruginosa but not Staphylococcus aureus, Proteus mirabilis or Escherichia coli. Attempts to raise the activity of (+)-catechin against two unresponsive species, S. aureus and E. coli, with iron(II) sulphate, iron(III) chloride, and vitamin C, showed that iron(II) enhanced (+)-catechin against S. aureus, but not E. coli; neither iron(III) nor combined iron(II) and copper(II), enhanced (+)-catechin activity against either species. Vitamin C enhanced copper(II) containing combinations against both species in the absence of iron(II). Catalase or EDTA added to active samples removed viability effects suggesting that active mixtures had produced H(2)O(2)via the action of added metal(II) ions. H(2)O(2) generation by (+)-catechin plus copper(II) mixtures and copper(II) alone could account for the principal effect of bacterial growth inhibition following 30 minute exposures as well as the antimicrobial effect of (+)-catechin-iron(II) against S. aureus. These novel findings about a weak antimicrobial flavanol contrast with previous knowledge of more active flavanols with transition metal combinations. Weak antimicrobial compounds like (+)-catechin within enhancement mixtures may therefore be used as efficacious agents. (+)-Catechin may provide a means of lowering copper(II) or iron(II) contents in certain crop protection and other products.
authors.affiliation: School of Life Sciences, Faculty of Science Engineering and Computing, Kingston University, London KT1 2EE, UK.
authors.forename: Andrew C
authors.initials: AC
authors.lastname: Holloway
authors.forename: Irene
authors.initials: I
authors.lastname: Mueller-Harvey
authors.forename: Simon W J
authors.initials: SW
authors.lastname: Gould
authors.forename: Mark D
authors.initials: MD
authors.lastname: Fielder
authors.forename: Declan P
authors.initials: DP
authors.lastname: Naughton
authors.forename: Alison F
authors.initials: AF
authors.lastname: Kelly
mesh_terms: D000900:Anti-Bacterial Agents / Q000008:administration & dosage; D000975:Antioxidants / Q000008:administration & dosage; D001205:Ascorbic Acid / Q000008:administration & dosage*; D028241:Camellia sinensis / Q000737:chemistry; D002392:Catechin / Q000008:administration & dosage* / Q000302:isolation & purification; D019327:Copper Sulfate / Q000008:administration & dosage*; D004357:Drug Synergism; D004926:Escherichia coli / Q000187:drug effects; D005296:Ferrous Compounds / Q000008:administration & dosage*; D011513:Proteus mirabilis / Q000187:drug effects; D011550:Pseudomonas aeruginosa / Q000187:drug effects; D013211:Staphylococcus aureus / Q000187:drug effects* / Q000254:growth & development / Q000378:metabolism
chemical_list: D000900:Anti-Bacterial Agents; D000975:Antioxidants; D005296:Ferrous Compounds; C020748:ferrous sulfate; D002392:Catechin; D019327:Copper Sulfate; D001205:Ascorbic Acid; C029451:ferrous chloride