Friedman Mendel, Henika Philip R, Levin Carol E, Mandrell Robert E, Kozukue Nobuyuki
Western Regional Research Center, Agricultural Research Service, US Department of Agriculture, Albany, California 94710, USA.
J Food Prot. 2006 Feb;69(2):354-61. doi: 10.4315/0362-028x-69.2.354.
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 21 degrees C for 3, 15, 30, and 60 min. The results obtained demonstrate that (i) (-)-gallocatechin-3-gallate, (-)-epigallocatechin-3-gallate, (-)-catechin-3-gallate, (-)-epicatechin-3-gallate, theaflavin-3, 3'-digallate, theaflavin-3'-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.
我们评估了七种绿茶儿茶素和四种红茶茶黄素（通常称为类黄酮）以及36种市售红茶、绿茶、乌龙茶、白茶和花草茶的水提取物（浸液）对蜡样芽孢杆菌（菌株RM3190）在21摄氏度下孵育3、15、30和60分钟的抗菌活性。所得结果表明：（i）（-）-没食子儿茶素-3-没食子酸酯、（-）-表没食子儿茶素-3-没食子酸酯、（-）-儿茶素-3-没食子酸酯、（-）-表儿茶素-3-没食子酸酯、茶黄素-3,3'-二没食子酸酯、茶黄素-3'-没食子酸酯和茶黄素-3-没食子酸酯在纳摩尔水平显示出抗菌活性；（ii）在可比浓度下，大多数化合物比四环素或万古霉素等药用抗生素更具活性；（iii）茶的杀菌活性可以通过高压液相色谱法测定的儿茶素和茶黄素水平来解释；（iv）新鲜制备的茶浸液比放置一天的茶更具活性；（v）没有没食子酸酯侧链的茶儿茶素、茶叶中也存在的没食子酸以及生物碱咖啡因和可可碱，以及不含类黄酮的花草茶（洋甘菊和薄荷）均无活性。这些研究扩展了我们对食品成分抗菌作用的认识。
