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United States Department of Agriculture

Agricultural Research Service

Research Project: MOLECULAR BIOLOGY AND GENOMICS OF FOODBORNE PATHOGENS

Location: Produce Safety and Microbiology Research

Title: Antimicrobial activities of tea catechins and theaflavins and tea extracts against Bacillus cereus

Authors
item Friedman, Mendel
item Henika, Philip
item Levin, Carol
item Mandrell, Robert
item Kozukue, Nobuyuki - UIDUCK UNIV. KOREA

Submitted to: Journal of Food Protection
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: September 8, 2005
Publication Date: February 9, 2006
Citation: Friedman, M., Henika, P.R., Levin, C.E., Mandrell, R.E., Kozukue, N. 2006. Antimicrobial activities of tea catechins and theaflavins and tea extracts against Bacillus cereus. Journal of Food Protection. 69(2):354-361

Interpretive Summary: We evaluated the antimicrobial activities of seven green tea catechins and four black tea theaflavins, generally referred to as flavonoids, as well as the aqueous extracts (infusions) of 36 commercial black, green, oolong, white, and herbal teas against Bacillus cereus (strain RM3190) incubated at 218C for 3, 15, 30, and 60 min. The results obtained demonstrate that (i) (2)-gallocatechin-3-gallate, (2)-epigallocatechin-3-gallate, (2)-catechin-3-gallate, (2)-epicatechin-3-gallate, theaflavin-3, 39-digallate, theaflavin-39-gallate, and theaflavin-3-gallate showed antimicrobial activities at nanomolar levels; (ii) most compounds were more active than were medicinal antibiotics, such as tetracycline or vancomycin, at comparable concentrations; (iii) the bactericidal activities of the teas could be accounted for by the levels of catechins and theaflavins as determined by high-pressure liquid chromatography; (iv) freshly prepared tea infusions were more active than day-old teas; and (v) tea catechins without gallate side chains, gallic acid and the alkaloids caffeine and theobromine also present in teas, and herbal (chamomile and peppermint) teas that contain no flavonoids are all inactive. These studies extend our knowledge about the antimicrobial effects of food ingredients.

Technical Abstract: We evaluated the antimicrobial activities of seven green tea catechins and four black tea theaflavins, generally referred to as flavonoids, as well as the aqueous extracts (infusions) of 36 commercial black, green, oolong, white, and herbal teas against Bacillus cereus (strain RM3190) incubated at 218C for 3, 15, 30, and 60 min. The results obtained demonstrate that (i) (2)-gallocatechin-3-gallate, (2)-epigallocatechin-3-gallate, (2)-catechin-3-gallate, (2)-epicatechin-3-gallate, theaflavin-3, 39-digallate, theaflavin-39-gallate, and theaflavin-3-gallate showed antimicrobial activities at nanomolar levels; (ii) most compounds were more active than were medicinal antibiotics, such as tetracycline or vancomycin, at comparable concentrations; (iii) the bactericidal activities of the teas could be accounted for by the levels of catechins and theaflavins as determined by high-pressure liquid chromatography; (iv) freshly prepared tea infusions were more active than day-old teas; and (v) tea catechins without gallate side chains, gallic acid and the alkaloids caffeine and theobromine also present in teas, and herbal (chamomile and peppermint) teas that contain no flavonoids are all inactive. These studies extend our knowledge about the antimicrobial effects of food ingredients.

Last Modified: 4/19/2014
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