Antibacterial activities of tea polyphenols against foodborne pathogenic bacteria (studies on antibacterial effects of tea polyphenols. Part III.

Kouno

2004

421

286

Recently, many biochemical and epidemiologic studies have revealed that polyphenols of various foods and herbs are beneficial to human health, and some extracts of polyphenolrich plants, such as green tea and grape seed, have been applied to functional foods or supplements. The potent biological activities of green tea polyphenols in, for example, cancer and cardiovascular disease prevention, 1) have in particular been attracting scientists in medicinal and pharmaceutical fields. Tea polyphenols were also shown to have antibacterial, 2-5) antiviral, 6) and antifungal activities 7) in addition to their inhibitory effects on exotoxins. 4,8) In these studies, only a few types of cultures such as from the American Type Culture Collection (ATCC) were examined according to different protocols.2,5,9,10) And therefore differences in susceptibility against the same species were indicated. 11)These differences were partly ascribable to the limited number of trial strains used in previous studies. Furthermore, in addition to tea polyphenols, other types of polyphenols, such as hydrolyzable and condensed tannins, are widely distributed in the plant kingdom and have the potential to be functional material. In the present study, we examined the antibacterial activities of 10 different plant polyphenols by comparing their minimum inhibitory concentrations (MICs) against a total of 96 strains of four groups of food-borne pathogenic bacteria including gram-positive and gram-negative species. Taking into consideration the future application of the results in the environmental and sanitation fields, we selected polyphenols that can be obtained in large amounts from plant material. MATERIALS AND METHODSChemicals Epigallocatechin (EGC, 1) and epigallocatechin-3-O-gallate (EGCg, 2) were isolated from commercial green tea, 12) punicalagin (3) was isolated from the peel of Punica granatum, 13) tannic acid (4) was purchased from Kanto Chemical Co. (Tokyo, Japan), castalagin (5) was isolated from wood of Castanea crenata, 14) and prodelphinidin oligomers (6) were isolated from the bark of Elaeocarpus sylvestris var. ellipticus; an aqueous acetone extract of the dried bark was separated by Sephadex LH-20 column chromatography with H 2 O containing increasing proportions of MeOH and finally with H 2 O-acetone (1 : 1, v/v). Prodelphinidin oligomers were then eluted out with 80-100% MeOH and aqueous acetone. Thiol degradation of 6 with mercaptoethanol-HCl 15) showed that this prodelphinidin is composed of EGC and EGCg, and the molecular weight of the peracetate was estimated to be 2000 daltons (peak top molecular weight) by gel permeation chromatography with a TSK-gel G4000H6 column (TOSOH) using polystylene as a standard. Geraniin (7) was isolated from the leaves of E. sylvestris var. ellipticus, 16) and loquat procyanidins (8) were isolated from the seeds of Eriobotrya japonica; fresh seeds were extracted with 80% acetone-H 2 O, and the extract was separated on a Diaion HP-20 column using H 2 O containing increasing amounts of MeOH, which ...

Section: Sensitivity Of Bacterial Species To Polyphenolsmentioning

confidence: 99%

Antimicrobial Activity of 10 Different Plant Polyphenols against Bacteria Causing Food-Borne Disease

Taguri

Kouno

2004

421

286

“…1,2) Although tea polyphenols and their extracts have been examined in detail, [3][4][5][6] other extracts of polyphenol-rich plants have not been properly evaluated, because the activity of their chemical constituents has not been clearly demonstrated. 7,8) Many reports on the antibacterial activity of pure polyphenols have been published, 4,[9][10][11][12] however, each result was not able to be compared directly because different methods of evaluation were applied and various bacterial species were used. In order to overcome this problem, we compared the activity of a wide variety of polyphenols against many bacterial species to clarify their antibacterial spectrum, using the same standard method of the minimum inhibitory concentration (MIC).…”

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confidence: 99%

Antibacterial Spectrum of Plant Polyphenols and Extracts Depending upon Hydroxyphenyl Structure

Taguri

Kouno

2006

281

181

Recently, many biochemical and epidemiological studies have revealed that polyphenols of various foods and herbs have benefits to human health, and some extracts of polyphenol-rich plants, such as green tea and grape seed, have been added to foods or supplements. The antibacterial activity of various plant polyphenols and plant extracts have also been evaluated in several pharmaceutical studies. 1,2) Although tea polyphenols and their extracts have been examined in detail, [3][4][5][6] other extracts of polyphenol-rich plants have not been properly evaluated, because the activity of their chemical constituents has not been clearly demonstrated. 7,8) Many reports on the antibacterial activity of pure polyphenols have been published, 4,[9][10][11][12] however, each result was not able to be compared directly because different methods of evaluation were applied and various bacterial species were used. In order to overcome this problem, we compared the activity of a wide variety of polyphenols against many bacterial species to clarify their antibacterial spectrum, using the same standard method of the minimum inhibitory concentration (MIC). As a result, we found a relatively simple structure-activity relationship, and it was applied to the plant extracts containing various types of polyphenols. MATERIALS AND METHODSChemicals Twenty-two pure or partially pure polyphenols and 26 plant extracts were used in this study (Fig. 1). Polyphenols 1-10 were the same as in our previous study. 12)Epigallocatechin (EGC, 1) and epigallocatechin-3-O-gallate (EGCg, 2) were isolated from commercial green tea; punicalagin (3) was isolated from the peel of Punica granatum; tannic acid (4) was purchased from Kanto Chemical Co., Japan; castalagin (5) was isolated from the wood of Castanea crenata; and prodelphinidins (6) were isolated from the bark of Elaeocarpus sylvestris var. ellipticus; geraniin (7) was isolated from the leaves of E. sylvestris var. ellipticus; loquat procyanidins (8) were isolated from the seeds of Eriobotrya japonica; theaflavins (9) was obtained from black tea; and loquat-treated green tea polyphenols (10) were prepared by treatment of commercial green tea with unripe loquat fruit. Gallic acid monohydrate (11) was purchased from Wako Pure Chemical Industries, Japan. Thearubigin (12) was prepared from black tea as follows: aqueous acetone extract was successively partitioned with AcOEt and n-BuOH. The nBuOH layer was concentrated and subjected to Sephadex LH-20 column chromatography. Elution of 50% acetone yielded 12. (ϩ)-Catechin (13) and (Ϫ)-epicatechin gallate (ECg, 14) were isolated from gambir and green tea, respectively. Myricitrin (15) and rutin (16) were obtained from bark of Myrica rubra and flower bud of Sophora japonica, respectively. Theaflavin mixture (17) was separated from AcOEt soluble fractions of aqueous acetone extracts of black tea. Pyrocatechol (18), pyrogallol (19), protocatechuic acid (20), and caffeic acid (21) were purchased from Sigma Aldrich Japan. Resveratrol (22) was isolated from dried...

“…In general, GBE is well known to prevent ischemia-induced oxidation, 2-4) improve cerebral blood flow 5) and antagonize the action of platelet-activating factor. 6) Catechins have been shown to produce an antioxidative action, 7) antibacterial [8][9][10] and hypotensive effect.11) It was reported that isoflavones produce a prevention of osteoporosis, reduction of menopausal disorders 12) and antioxidative action. 13) Sodium iron chlorophyllin and sodium copper chlorophyllin appear to produce a prevention of halitosis and antiulcerative action.…”

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confidence: 99%

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confidence: 99%

Safety of Dietary Supplements: Chronotropic and Inotropic Effects on Isolated Rat Atria.

Kubota

Umegaki

et al. 2002

Dietary supplements are being used by an increasing number of people and patients in Japan. Ginkgo biloba extract (GBE) has been also used as a dietary supplement in Japan, although it is among the prescribed drugs for peripheral vascular diseases in European countries.1) Recently, catechins, extracts of green tea, isoflavones, extracts of soybean, iron chlorophyllin and copper chlorophyllin have also begun to be sold and used as dietary supplements. In general, GBE is well known to prevent ischemia-induced oxidation, 2-4) improve cerebral blood flow 5) and antagonize the action of platelet-activating factor. 6) Catechins have been shown to produce an antioxidative action, 7) antibacterial [8][9][10] and hypotensive effect.11) It was reported that isoflavones produce a prevention of osteoporosis, reduction of menopausal disorders 12) and antioxidative action. 13) Sodium iron chlorophyllin and sodium copper chlorophyllin appear to produce a prevention of halitosis and antiulcerative action.14,15) These supplements are used for health purposes, but accurate information about the safety and efficacy of the supplement is lacking. Presently, more people suffer cardiovascular diseases, and also tend to take dietary supplement. Little is known about the influence of dietary supplements on heart function. Accordingly, it is important to examine the effect of the dietary supplements described above on cardiac function. As an initial approach to a better clarification of whether the dietary supplements affect cardiac function, we carried out a screening test of the supplements, using atria isolated from rats. Furthermore, particular attention was focused on the active ingredients of GBE and catechins, because these two compounds showed positive chronotropic and inotropic actions. MATERIALS AND METHODSExperiments Male Wistar rats (SLC, Hamamatsu, Japan; ranging from 8 to 11 weeks old) were anesthetized with pentobarbital sodium (60 mg/kg, i.p.) and exsanguinated. The isolated heart was rapidly removed and immediately placed in a Krebs-Henseleit solution of the following composition (mM): NaCl 118.4, KCl 4.7, MgSO 4 1.2, CaCl 2 2.5, NaHCO 3 25.0, KH 2 PO 4 1.2 and glucose 10.0. After excess blood vessels and the ventricle were removed from the heart, the atria preparation which consists of auricular nodes and left-right atrium were mounted in a 5 ml organ bath filled with Krebs-Henseleit solution. The chronotropic and inotropic changes were measured with a force-displacement transducer (Model T-7, NEC San-ei Instruments, Ltd., Tokyo, Japan) coupled to a PowerLab/800 (ADInstruments Pty Ltd., NSW, Australia) under a resting tension of 1.0 g. The bath solution was maintained 32°C and bubbled with a 95% O 2 -5% CO 2 gas mixture. Each preparation was allowed to equilibrate for at least 60 min prior to initiation of experimental procedures, and during this period the incubation medium was changed every 20 min. After the equilibration period, catechins, isoflavones, sodium iron chlorophyllin, sodium copper chlorophyllin, ginkgolid...