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PubMed2006

Chronic black tea administration protects plasma proteins, plasma, liver and kidney lipids against oxidation.

BACKGROUND: Black tea is known to have protective effects against plasma lipid and lipoprotein oxidation, but its influence on lipid peroxidation in tissue has been less studied. The effect of oral black tea consumption on protein oxidation has also not been demonstrated. The present study investigated the antioxidant effects of oral black tea consumption. MATERIAL/METHODS: Male Sprague-Dawley rats were fed a regular murine chow diet. The controls were supplied with water ad libitum, while the black tea group received aqueous black tea extract as the sole source of liquids. At the end of the ten-week experimental period, intestinal brush border, liver and kidney reduced-glutathione concentrations were evaluated as an index of cellular antioxidant defence. Plasma and tissue malondialdehyde concentrations and plasma protein carbonyl content were measured to evaluate lipid peroxidation and protein oxidation, respectively. RESULTS: The plasma malondialdehyde and protein carbonyl contents of rats consuming the black tea were significantly less than in controls. Similarly, liver and kidney malondialdehyde concentrations were significantly lower in the experimental group, while jejunoileal mucosa were not affected. Ten weeks of black tea administration caused significantly higher reduced-glutathione levels in the kidneys of black tea-administered rats, and a significant negative correlation was observed between kidney malondialdehyde and glutathione concentrations. CONCLUSIONS: These findings provide evidence that long term black tea supplementation is capable of protecting both plasma proteins and plasma lipids from oxidative injury, and demonstrate that chronic black tea administration protects both liver and kidney tissues - but not the jejunoileal mucosa - against oxidation.

Administration, Oral↗
PubMed1991

Inhibitory effect of Chinese tea on N-nitrosation in vitro and in vivo.

The inhibitory effect of 145 samples of Chinese tea on the formation of N-nitrosomorpholine was studied in vitro. The rates of inhibition by green tea, crush, tear, curl (CTC) black tea, brick tea, jasmine tea, Oolong tea, sun-dried tea and black tea were positively correlated with their polyphenol contents. An inhibitory effect of green and black tea on endogenous N-nitrosation was also confirmed in humans. Drinking tea after a meal had a greater effect than drinking it before a meal.

Carcinogens↗
PubMed1979

[The effect of rooibos tea on iron absorption].

A study was carried out to determine if rooibos tea (Aspalathus linearis) has a deleterious effect on iron absorption similar to that of ordinary tea (Camellia sinensis). Three groups of volunteers, each consisting of 10 healthy young men comparable with regard to iron status and body dimensions, were studied. After ingestion of 1 muCi 59Fe and 16 mg of elemental iron, group A drank rooibos tea, group B ordinary tea and group C boiled water. Iron absorption was measured 14 days later with a whole body counter. Mean iron absorption after ingestion of rooibos tea, ordinary tea, and water was 7,25%, 1,70% and 9,34% respectively. In contrast to ordinary tea (P less than 0,0001), rooibos tea did not affect iron absorption significantly. The ascorbic acid content of rooibos tea varies between 121,8 and 154,9 mumol/l, depending on the method of preparation. Rooibos tea contains small amounts of iron, magnesium, phosphorus, sodium, chloride and potassium. These findings have practical nutritional and therapeutic implications.

Adult↗
PubMed1996

Tea and cancer: a review of the epidemiological evidence.

Numerous recent reports of inhibition of carcinogenesis in experimental animals by tea or tea compounds raise the possibility that tea drinking may lower cancer risk in humans. Thus, studies around the world were reviewed to evaluate whether there is a consensus of epidemiologic evidence on the relation of tea drinking to cancer overall or to specific cancers. Ecological data suggest at most a modest benefit, since there is considerable international variation in tea consumption but generally small differences in cancer rates. More relevant case-control and cohort studies show mixed results. Detailed data from these studies on cancer risks according to amount and duration of tea intake are quite limited, and consistent dose-related patterns. have yet to emerge. Nevertheless, several investigations point to the possibility of lowered risks of digestive tract cancers among tea drinkers, especially those consuming green tea. Further research, particularly in population with wide ranges of tea consumption, is needed before definitive conclusions on tea's impact upon cancer risk can be reached.

Case-Control Studies↗
PubMed1997

Chemopreventive effect of green tea (Camellia sinensis) against cigarette smoke-induced mutations (SCE) in humans.

Green tea (Camellia sinensis) is consumed daily between the meals or after meals in Japan and other Asian countries. In recent years, green tea and its major polyphenolics have been demonstrated to prevent chemically induced tumors in a variety of experimental animal models system. The exact mechanism(s) of its anticarcinogenic activity remains to be elucidated, but green tea polyphenolics have demonstrated antimutagenic, anticarcinogenic, antioxidant, and antipromotional effects, including inhibition of Phase I and inducing Phase II enzymes. Enzyme activities of glutathione peroxidase, catalase, and quinone reductase, and glutathione S-transferase are also induced. However, a paucity of green tea effects in humans prompted us to investigate antimutagenic effects of green tea against smoke-induced mutation in humans. Chemopreventive effects of green tea and coffee among cigarette smokers were examined in 52 clinically healthy male subjects between 20-51 years of age. Blood specimens were obtained from non-smokers (Group I), smokers (II), smokers consuming green tea (III), and smoker/coffee drinkers (IV). The mean years of cigarette smoking (> 10 cigarettes/day) of Groups II, III, and IV ranged from 13.4-14.7 years. Daily intake of green tea and coffee was 3 cups/day/6 months (III and IV). The frequencies of sister-chromatid exchange (SCE) in mitogen-stimulated peripheral lymphocytes from each experimental group were determined and statistically analyzed. SCE rates were significantly elevated in smokers (9.46 +/- 0.46) vs. non-smokers (7.03 +/- 0.33); however, the frequency of SCE in smokers who consumed green tea (7.94 +/- 0.31) was comparable to that of non-smokers, implying that green tea can block the cigarette-induced increase in SCE frequency. Coffee, by contrast, did not exhibit a significant inhibitory effect on smoking-induced SCE.

Adult↗
PubMed1998

Inhibition of lung carcinogenesis by black tea in Fischer rats treated with a tobacco-specific carcinogen: caffeine as an important constituent.

Here, we examined the effect of black tea and caffeine on lung tumorigenesis in F344 rats induced by the nicotine-derived carcinogen 4-(methylnitrosamino)-1-(3-pyridyl)-1-butanone (NNK) in a 2-year bioassay. NNK was administered s.c. at a dose of 1.5 mg/kg body weight three times weekly for 20 weeks. Animals were given either black tea as drinking water at concentrations of 2%, 1%, or 0.5%, or caffeine in drinking water at concentrations identical to those in 2% and 0.5% tea infusions for 22 weeks. The treatment period began 1 week before and ended 1 week after the NNK administration. The animals were sacrificed on week 101 for the examination of tumors in target organs, including lung, liver, nasal cavity, and other major organs. The NNK-treated group, given 2% black tea, showed a significant reduction of the total lung tumor (adenomas, adenocarcinomas, and adenosquamous carcinomas) incidence from 47% to 19%, whereas the group given 1% and 0.5% black tea showed no change. The 2% tea also reduced liver tumor incidence induced by NNK from 34% in the group given only deionized water to 12%. The tumor incidence in the nasal cavity, however, was not affected by either black tea or caffeine at any of the concentrations tested. The most unexpected finding was the remarkable reduction of the lung tumor incidence, from 47% to 10%, in the group treated with 680 ppm caffeine, a concentration equivalent to that found in the 2% tea. This incidence is comparable to background levels seen in the control group. This study demonstrated for the first time in a 2-year lifetime bioassay that black tea protects against lung tumorigenesis in F344 rats, and this effect appears to be attributed, to a significant extent, to caffeine as an active ingredient of tea.

Animals↗
PubMed2005

Lead contamination in tea garden soils and factors affecting its bioavailability.

The consumption of heavy metals is detrimental to human health and most countries restrict the concentration of metals such as lead (Pb) in food and beverages. Recent tests have detected high Pb concentrations in certain commercial brands of tea leaves and this finding has raised concerns for both producers and consumers. To investigate what factors may be contributing to the increase in Pb accumulation in the tea leaves we collected tea leaves and soils from tea producing areas and analyzed them for Pb concentration, pH and organic matter content. The result showed the Pb concentration of 47% investigated tea leaves samples was beyond 2 mg kg(-1), the permissible levels given by China. The total Pb concentration in the surface and subsurface soil layers averaged 36.4 and 32.2 mg kg(-1), respectively which fall below of the 60 mg kg(-1) limit provided for organic tea gardens in China. The pH of the tea garden soils was severely acidic with the lowest pH of 3.37. Soils under older tea gardens tended to have a lower pH and a higher Pb bioavailability which was defined as the amount of lead extracted by CaCl2 solution than those under younger tea gardens. We found that the concentration of bioavailable Pb and the percentage of bioavailable Pb (bioavailable Pb relative to total Pb concentration) were positively correlated with soil H+ activity and soil organic matter content, and the organic matter accumulation contribute more effects on Pb bioavailability in these two factors. We conclude that soil acidification and organic matter accumulation could contribute to increasing Pb bioavailability in soil and that these could increase Pb uptake and accumulation in the tea leaves.

Biological Availability↗
PubMed2005

Lead contamination in tea leaves and non-edaphic factors affecting it.

Recent tests have detected high lead (Pb) concentrations in some commercial brands of tea leaves and this finding has raised concerns due to the possible health-related problems associated with Pb poisoning. In present research, we investigated the Pb contamination in tea leaves produced in Zhejiang province in China. Pb concentrations in all tea leaves sampled were below 5 mg/kg, the permissible levels given by Chinese Ministry of Agriculture, indicating that Pb contamination in this province is not excessive. We then investigated the non-edaphic factors that may potentially contribute to Pb accumulation in tea leaves. Pb concentration in tea leaves was found to be positively correlated with the industrialization level of a district (R = 0.83, the significant level at P < 0.05), and greater amounts of Pb were washed from the leaves of plants in districts with more industrial activity. This suggests that Pb accumulation in tea leaves could, in part, be attributed to industrial activity through the precipitation of atmospheric Pb. Furthermore greater amounts of Pb were washed from the leaves of plants growing near road than those growing farther away from road. This trend indicates that automobile activity was another likely contributor to Pb accumulation in tea. Pb content of green tea was also affected by the processing of the leaves in the factory. In particular the twisting and water-removal stages caused increases in Pb content in the tea product. This study suggests that non-edaphic factors also contribute to the Pb accumulation in tea.

Air Pollutants↗
PubMed2005

Diuretic factors and second messengers stimulate secretion of the organic cation TEA by the Malpighian tubules of Drosophila melanogaster.

This study showed that four factors which stimulate transepithelial fluid secretion and inorganic ion transport across the main segment of the Malpighian tubules of Drosophila melanogaster also stimulate transepithelial secretion of the prototypical organic cation tetraethylammonium (TEA). TEA fluxes across the Malpighian tubules and gut were measured using a TEA-selective self-referencing (TEA-SeR) microelectrode. TEA flux across isolated Malpighian tubules was also measured using a TEA-selective microelectrode positioned in droplets of fluid secreted by tubules set up in a modified Ramsay assay. TEA flux was stimulated by the intracellular second messengers cAMP and cGMP, which increase the lumen-positive transepithelial potential (TEP), and also by tyramine and leucokinin-I (LK-I), which decrease TEP. The largest increase was measured in response to 1 micromol l-1 LK-I which increased transepithelial TEA flux by 72%. TEA flux in the lower tubule was stimulated slightly (13%) by 1 micromol l-1 tyramine but not by any of the other factors. TEA flux across the midgut was unaffected by cAMP, cGMP or tyramine. This is the first study to demonstrate the effects of insect diuretic factors and second messengers on excretion of organic cations.

Animals↗
PubMed2006

A comparative study on the antimutagenic properties of aqueous extracts of Aspalathus linearis (rooibos), different Cyclopia spp. (honeybush) and Camellia sinensis teas.

Antimutagenic activity of aqueous extracts of the South African herbal teas, Aspalathus linearis (rooibos) and Cyclopia spp. (honeybush) was compared with that of Camellia sinensis (black, oolong and green) teas in the Salmonella mutagenicity assay using aflatoxin B(1) (AFB(1)) and 2-acetylaminofluorene (2-AAF) as mutagens. The present study presents the first investigation on antimutagenic properties of C. subternata, C. genistoides and C. sessiliflora. The herbal teas demonstrated protection against both mutagens in the presence of metabolic activation, with the exception of "unfermented" (green/unoxidised) C. genistoides against 2-AAF, which either protected or enhanced mutagenesis depending on the concentration. Antimutagenic activity of "fermented" (oxidised) rooibos was significantly (P<0.05) less than that of Camellia sinensis teas against AFB(1), while for 2-AAF it was less (P<0.05) than that of black tea and similar (P>0.05) to that of oolong and green teas. Antimutagenic activity of unfermented C. intermedia and C. subternata exhibited a similar protection as fermented rooibos against AFB(1). Against 2-AAF, fermented rooibos exhibited similar protective properties than unfermented C. intermedia and C. sessiliflora. Unfermented rooibos was less effective than the C. sinensis teas and fermented rooibos, but had similar (P>0.05) antimutagenicity to that of fermented C. sessiliflora against AFB(1) and fermented C. subternata against 2-AAF. Fermented C. intermedia and C. genistoides exhibited the lowest protective effect against 2-AAF, while fermented C. intermedia exhibited the lowest protection when utilising AFB(1) as mutagen. Aspalathin and mangiferin, major polyphenols in rooibos and Cyclopia spp., respectively, exhibited weak to moderate protective effects when compared to the major green tea catechin, (-)epigallocatechin gallate (EGCG). Antimutagenic activity of selected herbal tea phenolic compounds indicated that they contribute towards (i) observed antimutagenic activity of the aqueous extracts against both mutagens and (ii) enhancement of the mutagenicity of 2-AAF by unfermented C. genistoides. Antimutagenic activity of the South African herbal teas was mutagen-specific, affected by fermentation and plant material, presumably due to changes and variation in phenolic composition.

2-Acetylaminofluorene↗
PubMed2004

Metabolite profiling using (1)H NMR spectroscopy for quality assessment of green tea, Camellia sinensis (L.).

A set of 191 green teas from different countries was collected and analyzed by (1)H NMR. It was proposed to establish if the teas could be discriminated according to the country of origin or with respect to quality. Both principal component analysis (PCA) and cluster analysis were applied to the data. Some separation of Chinese and non-Chinese teas was observed. The present results did not allow allocation of samples to individual countries, but cluster analysis suggested that it might be possible with an augmented sample set. The PCA did show a separation between the Longjing type (highest quality Chinese tea) and most other Chinese teas and indicated some metabolites that could be responsible for the difference. Longjing teas showed higher levels of theanine, gallic acid, caffeine, epigallocatechin gallate, and epicatechin gallate and lower levels of epigallocatechin when compared with other teas. These compounds have been mentioned previously in connection with quality, but it was also shown that higher levels of theogallin (5-galloyl quinic acid), theobromine, 2-O-(beta-l-arabinopyranosyl)-myo-inositol and some minor sugar-containing compounds were found in Longjing teas while higher levels of fatty acids and sucrose were found in the other teas. These new markers could prove to be useful for the authentication of bulk tea.

Camellia sinensis↗
PubMed1999

Tea drinking and cancer risk: epidemiologic evidence

Tea and tea compounds have been shown to inhibit carcinogenic processes in experimental animals, raising the possibility that tea drinking may lower cancer risk in humans. However, epidemiologic studies have produced inconsistent evidence on the relation between tea drinking and cancer risk. Ecological data show considerable international variation in tea consumption but relatively small differences in cancer rates. Results from case-control and cohort studies also are inconclusive. Nevertheless, high consumption of tea has been linked to a reduced risk of digestive tract cancers in a number of epidemiologic studies. A lack of detailed information on duration and amount of tea drinking, a narrow range of tea intake in some study populations, inadequate control for confounding, and potential biases in recall and reporting of tea drinking patterns in case-control studies may have contributed to the diverse findings. Further research is needed before definitive conclusions on tea's impact upon cancer risk in humans can be reached.

Journal Article↗
PubMed1996

Antifungal activity of the essential oil of Melaleuca alternifolia (tea tree oil) against pathogenic fungi in vitro.

The in vitro antifungal activity of tea oil, the essential oil of Melaleuca alternifolia, has been evaluated against 26 strains of various dermatophyte species, 54 yeasts, among them 32 strains of Candida albicans and other Candida sp. as well as 22 different Malassezia furfur strains. Minimum inhibitory concentrations (MIC) of tea tree oil were measured by agar dilution technique. Tea tree oil was found to be able to inhibit growth of all clinical fungal isolates. For the investigated dermatophytes MIC values from 1,112.5 to 4,450.0 micrograms/ml with a geometric mean of 1,431.5 micrograms/ml were demonstrated. Both C. albicans strains and the other strains belonging to the genus Candida and Trichosporon appeared to be slightly less susceptible to tea tree oil in vitro. However, their MIC values, which varied from 2,225.0 to 4,450.0 micrograms/ml (geometric mean 4,080 micrograms/ml), indicated moderate susceptibility to the essential oil of M. alternifolia. The lipophilic yeast M. furfur seemed to be most susceptible to tea tree oil. MIC values between 556.2 and 4,450.0 micrograms/ml (geometric mean 1,261.5 micrograms/ml) were found against the tested M. furfur strains. However, when calculated as percentage tea tree oil of the agar, the above-mentioned concentrations correspond to 0.5-0.44% tea tree oil content. These values are far below the usual relatively high therapeutic concentrations of the agent; approximately 5-10% solution or even the concentrated essential oil are used for external treatment. In comparison with tea tree oil, in vitro susceptibility against miconazole, an established topical antifungal, was tested. As expected, very low MIC values for miconazole were found for dermatophytes (geometric mean 0.2 microgram/ml), yeasts (geometric mean 1.0 microgram/ml), and M. furfur (geometric mean 2.34 micrograms/ml). It is suggested that the in vivo effect of tea tree oil ointment in the therapy of fungal infections of the skin and mucous membranes as well as in the treatment of dandruff, a mild form of seborrheic dermatitis, may be at least partly due to an antifungal activity of tea tree oil.

Antifungal Agents↗
PubMed2000

Green tea and skin.

OBJECTIVE: To discuss the current knowledge of polyphenolic compounds present in green tea as anti-inflammatory, antioxidant, and anticarcinogenic in skin. DATA SOURCES: References identified from bibliographies of pertinent articles, including our work in related fields. STUDY SELECTION AND DATA EXTRACTION: Articles were selected based on the use of green tea or its polyphenolic constituents for prevention against inflammation and cancer in the skin. Also discussed is the possible use of green tea to treat various inflammatory dermatoses. DATA SYNTHESIS: The polyphenolic compounds from green tea were tested against chemical carcinogenesis and photocarcinogenesis in murine skin. These green tea polyphenols were found to afford protection against chemical carcinogenesis as well as photocarcinogenesis in mouse skin. A few experimental studies were conducted in human skin in our laboratory. Analysis of published studies demonstrates that green tea polyphenols have anti-inflammatory and anticarcinogenic properties. These effects appear to correlate with antioxidant properties of green tea polyphenols. CONCLUSIONS: The outcome of the several experimental studies suggests that green tea possess anti-inflammatory and anticarcinogenic potential, which can be exploited against a variety of skin disorders. Although more clinical studies are needed, supplementation of skin care products with green tea may have a profound impact on various skin disorders in the years to come. Arch Dermatol. 2000;136:989-994

Administration, Oral↗
PubMed2004

The protective effect of habitual tea consumption on hypertension.

BACKGROUND: Tea has long been believed to possess hypotensive effects in popular Chinese medicine. However, conflicting results have been shown among human trials and animal studies on the relation between tea consumption and blood pressure. Epidemiological evidence about the long-term effect of tea on hypertensive risk is also inconsistent. METHODS: We examined the effect of tea drinking, measured in detail for the past decades, on the risk of newly diagnosed hypertension in 1507 subjects (711 men and 796 women), 20 years or older, who did not have a hypertensive history during 1996 in Taiwan. RESULTS: Six hundred subjects (39.8%) were habitual tea drinkers, defined by tea consumption of 120 mL/d or more for at least 1 year. Compared with nonhabitual tea drinkers, the risk of developing hypertension decreased by 46% for those who drank 120 to 599 mL/d and was further reduced by 65% for those who drank 600 mL/d or more after carefully adjusting for age, sex, socioeconomic status, family history of hypertension, body mass index, waist-hip ratio, lifestyle factors (total physical activity, high sodium intake, cigarette smoking, alcohol consumption, and coffee drinking), and dietary factors (vegetable, fruit, unrefined grain, fish, milk, visible-fat food, and deep fried food intake). However, tea consumption for more than 1 year was not associated with a further reduction of hypertension risk. CONCLUSION: Habitual moderate strength green or oolong tea consumption, 120 mL/d or more for 1 year, significantly reduces the risk of developing hypertension in the Chinese population.

Adult↗
PubMed2006

Tea drinking and the risk of biliary tract cancers and biliary stones: a population-based case-control study in Shanghai, China.

Biliary tract cancers, encompassing tumors of the gallbladder, extrahepatic bile ducts and ampulla of Vater, are rare but highly fatal malignancies. Apart from gallstones, etiologic factors for biliary tract cancer are not clearly defined. Several epidemiologic studies have suggested that consumption of tea, especially green tea, is protective against a variety of cancers, including gastrointestinal malignancies. As part of a large population-based case-control study of biliary tract disease in Shanghai, China, we evaluated the effects of tea consumption on the risk of biliary tract cancers and biliary stones. The study included 627 incident cases with biliary tract cancer, 1,037 cases with biliary stones and 959 randomly selected controls. Study subjects were interviewed to ascertain data on demographic, medical and dietary factors, including tea consumption. Forty-one percent of the controls were ever tea drinkers, defined as those who consumed at least 1 cup of tea per day for at least 6 months. After adjustment for age, education and body mass index, among women, ever tea drinkers had significantly reduced risks of biliary stones (OR = 0.73, 95% CI = 0.54-0.98) and gallbladder cancer (OR = 0.56, 95% CI = 0.38-0.83). The inverse relationship between tea consumption and gallbladder cancer risk was independent of gallstone disease. Among men, tea drinkers were more likely to be cigarette smokers, and the risk estimates were generally below 1.0, but were not statistically significant. Further studies are needed to confirm these results in other populations and clarify the hormonal and other mechanisms that may be involved.

Adult↗
PubMed2006

Beneficial effects of tea and its polyphenols against prostate cancer.

Tea, next to water, is the most widely consumed beverage in the world. Depending upon the level of fermentation, tea can be categorized into three types: green (unfermented), oolong (partially fermented), and black (highly to fully fermented). In general, green tea has been found to be superior to black and oolong tea in terms of antioxidant and health promoting benefits owing to the higher content of (-)-epigallocatechin-3-gallate. Tea polyphenols comprise about one-third of the weight of the dried leaf, and they exhibit biochemical and pharmacological activities including antioxidant activities, inhibition of cell proliferation, induction of apoptosis, cell cycle arrest and modulation of carcinogen metabolism. Several studies demonstrate that most tea polyphenols exert their effects by scavenging reactive oxygen species (ROS) since excessive production of ROS has been implicated in the development of a variety of ailments including cancer of the prostate gland (CaP). Using cell culture and animal model systems, molecular targets for these remarkable beneficial effects of green tea drinking on CaP prevention and therapy have been defined. Geographical and case-control studies are showing that green tea drinking could afford CaP chemopreventive effects in human population. In this review we attempt to summarize the experimental as well as the epidemiological basis for the possible role of tea and its polyphenols for chemoprevention and chemotherapy of CaP.

Androgens↗
PubMed2002

Tea pigments inhibit the production of type 1 (T(H1)) and type 2 (T(H2)) helper T cell cytokines in CD4(+) T cells.

Tea pigments are oxidized products of polyphenols derived from tea leaves (Camellia sinensis). Theaflavins are constituents of tea pigments with antioxidant, antineoplastic and antiinflammatory properties similar to their parent compounds. The biological properties of polyphenols and theaflavins have been linked to their capacity to inhibit the activation of nuclear factor-kappaB (NF-kappaB), a transcription factor, which is critically involved in the molecular regulation of a number of proinflammatory cytokines. The current study examines the requirement for NF-kappaB in the immunosuppressive effects mediated by tea antioxidants. Specifically, we tested the hypothesis that cytokines produced by type 1 (T(H1)) CD4(+) T cells which require NF-kappaB for gene expression, such as interleukin-2 (IL-2) and interferon gamma (IFN gamma), are selectively inhibited by tea pigments. We found that tea pigments potently suppress IL-2 secretion, IL-2 gene expression and the activation of NF-kappaB in murine spleens enriched for CD4(+) T cells, as expected. Consistent with our hypothesis, tea pigments also inhibited the induction of IFNgamma mRNA. However, the expression of the T(H2) cytokines IL-4 and IL-5, which lack functional NF-kappaB sites within their promoters was unexpectedly suppressed by tea pigments, as well. The results indicate that NF-kappaB may be only one of multiple transcription factors inhibited by tea pigments.

Animals↗