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PubMed2005

Effect of polymeric black tea polyphenols on benzo(a)pyrene [B(a)P]-induced cytochrome P4501A1 and 1A2 in mice.

The chemopreventive activity of green tea polyphenols (GTPs) is, in part, due to modulation of cytochrome P450s (CYPs). To investigate the enzyme modulatory properties of major black tea polyphenols, the effect of decaffeinated black tea extract (DBTE) or polymeric black tea polyphenol (PBP) mix was studied on CYP1A1 and CYP1A2 in mouse tissues. Animals receiving 2.5% DBTE or 1% PBP mix or drinking water (15 days) were challenged with single oral benzo(a)pyrene (B(a)P) (1 mg/mouse) treatment on the 14th day. Liver and lung microsomes isolated after 24 h were analysed for CYP1A1 and CYP1A2, using biochemical substrate(s) and Western blot analysis. Treatment with 2.5% DBTE or 1% PBP mix did not significantly alter the basal activity and level of CYP1A1 and CYP1A2, whereas pretreatment with 2.5% DBTE or 1% PBP mix resulted in a significant decrease in both the activity and the level of B(a)P-induced CYP1A1 and CYP1A2 in liver and lungs. The PBP mix possesses enzyme modulatory properties exhibited by monomeric GTPs.

Administration, Oral↗
PubMed1998

Inhibition of spontaneous formation of lung tumors and rhabdomyosarcomas in A/J mice by black and green tea.

We investigated the effects of black tea (BT) and green tea (GT) infusion on the spontaneous formation of lung tumors and rhabdomyosarcomas in A/J mice. Female A/J mice, 6 weeks of age, were allocated into five groups (50 per group) and were given the following as the sole source of drinking fluid: (i) deionized water (control group), (ii) 0.5% BT, (iii) 1% BT, (iv) 2% BT and (v) 1% GT. After 60 weeks, the mice were killed by decapitation. Lung tumor incidence, multiplicity and volume were significantly lower in the 2% BT group as compared with the controls (27 versus 52%, 0.33 versus 0.72 tumors/mouse and 4.27 versus 38.3 mm3, respectively). The 1% GT group had significantly lower lung tumor multiplicity (0.41/mouse), while the 1% BT group had significantly decreased tumor volume (7.17 mm3). Rhabdomyosarcomas were found in 34% of the mice in the control group, and both the 1 and 2% BT groups had significantly lower incidences at 13 and 14%, respectively. The mice in the 2% BT group weighed 16% less than those in the control group, although they consumed more food than the control group. The other tea-consuming groups also weighed less than the control group (7.8-11%) while consuming more food and fluid. In a separate experiment, similar carcinogenesis inhibition was also observed in female A/J mice that were given 0.6% and then 0.3% instant black tea for 52 weeks. These results demonstrate the inhibitory activity of BT against the spontaneous formation of lung tumors and rhabdomyosarcomas in mice.

Animals↗
PubMed1982

Smoking, personality and reasons for smoking.

The relationships, reasons for smoking and personality were investigated in 98 cigarette smokers. Contrary to the usual findings, smoking did not relate to extraversion (E) but related instead to psychoticism (P). It is suggested that this relation is the true one, and previous findings have been due to a contaminated measure of E. Neuroticism (N) was related to the amount smoked, and particularly to a willingness to give reasons for smoking. There was no relation between the Reasons for Smoking Questionnaire, and attempts or success at giving up smoking. Smokers who rolled their own cigarettes were more introverted than others. No measures showed significant relations with the nicotine content of cigarettes.

Adolescent↗
PubMed1998

Diet and gastric cancer: a casecontrol study in Fujian Province, China.

AIM:To explore the relationship between consumption of fish sauce, other dietary factors, living habits and the rish kf gastric cancer.METHODS:From May 1994 to July 1995, a population-based 1 2 case-control study was in Carried out inhigh-risk areas of gastric cancer, Changle and Fuqing cities, Fujian Province. Totally 272 cases and 544 age, gender-matched controls were included. Risk state analyses were made by ASRS package.RESULTS:Risk state single-factor analysis indicated that gastric cancer risk rose with high intake of fish sauce(OR =2.57), salted vegetables (OR =1.41), salted/fried fish and small shrimps (OR =1.57), low consumption of fresh vegetables (OR =1.95), fresh citrus fruits (OR =1.41), other fresh fruits (OR =1.31), green tea (OR =1.72), exposure to moldy foods (OR =2.32), irregular dinners (OR =5.47) and familial history of malignancy (OR =3.27).No significant relationship was observed between smoking, drinking, salt intake, use of refrigerator and gastric cancer rish. The results of rish state conditional Logistic regression showed that fish sauce, salted/dried fish and small shrimps, irregular dinners, familial history of malignancy were included in the best rish set. The summary ARS for the four factors was 75.49%.CONCLUSION:High intake of fish sauce, salted foods, moldy foods, irregular dinners and familial history of malignancy were possible risk factors for gastric cancer, whereas fresh vegetables and fruits.and green tea might have protective effects for gastric cancer.

Journal Article↗
PubMedDate not supplied

Tea consumption and ovarian cancer risk in a population-based cohort.

BACKGROUND: Substantial evidence from laboratory studies indicates that green and black tea preparations may protect against various cancers. Few epidemiologic studies, however, have examined the relationship specifically between tea consumption and risk of ovarian cancer. METHODS: We prospectively examined the association between tea consumption and risk of ovarian cancer in 61 057 women aged 40 to 76 years who were participants in the population-based Swedish Mammography Cohort. Participants completed a validated 67-item food frequency questionnaire at enrollment between 1987 and 1990 and were followed for cancer incidence through December 2004. RESULTS: During an average follow-up of 15.1 years, 301 incident cases of invasive epithelial ovarian cancer were ascertained. Tea consumption was inversely associated with the risk of ovarian cancer after controlling for potential confounders (P for trend, .03). Compared with women who never or seldom (less than monthly) consumed tea, the multivariate hazard ratios for those who consumed less than 1 cup per day, 1 cup per day, and 2 or more cups per day were 0.82 (95% confidence interval [CI], 0.62-1.08), 0.76 (95% CI, 0.56-1.04), and 0.54 (95% CI, 0.31-0.91), respectively. Each additional cup of tea per day was associated with an 18% lower risk of ovarian cancer (multivariate hazard ratio, 0.82; 95% CI, 0.68-0.99). CONCLUSION: These results suggest that tea consumption is associated with a reduced risk of epithelial ovarian cancer in a dose-response manner.

Adult↗
PubMed1977

Selected beverage consumption patterns among Mormon and non-Mormon populations from the same geographic location.

This study presents data from a mail questionnaire survey designed to determine the daily beverage consumption patterns of Mormon and non-Mormon households in Utah and southern Idaho. Mormons differed significantly from their non-Mormon counterparts in both their low intake of coffee, tea, and beer, and increased daily consumption of milk and water. A high percentage of Mormons adhere to Church doctrin in their beverage intake habits and the results would appear to substantiate previous preliminary studies of the dietary habits in this religious group.

Adult↗
PubMed1992

Tea components: antimutagenic and anticarcinogenic effects.

BACKGROUND: Tea from the Camellia sinensis species of the Theaceae family is one of the most ancient and, next to water, the most widely consumed beverage in the world. Since tea contains several polyphenols and since several other naturally occurring dietary polyphenols have shown antimutagenic effects in bacteria and anticarcinogenic effects in animal bioassay systems, we studied whether polyphenols extracted from Chinese green tea (GTP) also possess antimutagenic and anticarcinogenic effects. RESULTS: GTP and its constituent epicatechin derivatives were found to interact with hepatic cytochrome P450 (P450) and inhibited the P450-dependent mixed-function oxidase enzymes in skin and liver. GTP and its epicatechin derivatives exhibited antimutagenic effects in several test systems. GTP showed substantial anti-skin-tumor-initiating and anti-skin-tumor-promoting activities when assessed in murine skin tumorigenesis bioassay systems. In these model systems polyaromatic hydrocarbons, benzo[a]pyrene (BP), 3-methyl-cholanthrene, 7,12-dimethylbenz[a]anthracene, and (+)-7 beta,8 alpha-dihydroxy-9 alpha,10 alpha-epoxy-7,8,9,10- tetrahydrobenzo[a]pyrene (an ultimate carcinogenic metabolite of BP) were used as model skin carcinogens. The feeding of GTP in drinking water to SKH-1 hairless mice also afforded significant protection against ultraviolet-B-radiation-induced skin photocarcinogenesis. CONCLUSIONS: These data suggest that tea components possess antimutagenic and anticarcinogenic effects, and that they could protect humans against the risk of cancer by environmental agents.

Animals↗
PubMed1992

Contribution of acetone and osmotic-diuresis by streptozotocin-induced diabetes in attenuation of cephaloridine nephrotoxicity.

Previous studies have indicated that cephaloridine nephrotoxicity was reduced in streptozotocin (STZ)-induced diabetic rats. Experiments were performed to investigate if a shorter duration of diabetes would reduce cephaloridine nephrotoxicity. Studies were also conducted to examine the contribution of osmotic diuresis and ketone accumulation to the mechanism for reduced toxicity. Male Fischer 344 (F344) rats were injected with 30 mg/kg STZ or vehicle. Seven days after STZ or vehicle administration, the animals were treated (i.p.) with 1500 mg/kg cephaloridine. Increased kidney weight, blood urea nitrogen (BUN) level and decreased renal cortical slice accumulation of p-aminohippurate (PAH) and tetraethyl-ammonium (TEA) were measured in the normoglycemic group. No differences in renal function were detected between diabetic groups treated with cephaloridine or vehicle (PFC). Pretreatment of euglycemic rats with 0 or 10% dextrose in the drinking water and by oral gavage failed to prevent the renal damage produced by 1500 mg/kg cephaloridine despite glucosuria and urine output comparable to diabetic animals. However, dextrose-diuresis afforded a slight reduction in toxicity as indicated by changes in kidney weight and renal cortical slice accumulation of PAH and TEA. Pretreatment (oral) with 0 or 1.5 ml/kg acetone had no effect on cephaloridine toxicity (1000 mg/kg, i.p.). These findings suggested that attenuation of cephaloridine toxicity may be independent of the duration of diabetes. These results also indicated that glucose-mediated osmotic diuresis and acetone accumulation cannot account for reduced cephaloridine toxicity in diabetic rats.

Acetone↗
PubMed2006

Therapeutic effect of green tea extract on advanced glycation and cross-linking of collagen in the aorta of streptozotocin diabetic rats.

1. The therapeutic effect of green tea extract (GTE) on the aortic collagen content and its characteristics were investigated in streptozotocin diabetic rats. 2. Diabetes was induced in rats by a single intra peritoneal injection of streptozotocin (60 mg/kg bodyweight). Six weeks after diabetes induction, GTE was administered orally for four weeks (300 mg/kg bodyweight daily). Systolic blood pressure, blood glucose, anti-oxidant status, collagen content, extent of glycation, collagen linked fluorescence and aortic collagen solubility pattern were determined in experimental rats. 3. At the end of the experimental period, there was a significant increase in the systolic blood pressure and blood glucose in diabetic rats. The lipid peroxides increased whereas glutathione and vitamin C levels were decreased in the serum of diabetic rats. The collagen content, extent of glycation, the advanced glycation end products (AGEs) and degree of cross-linking were increased in the aorta of diabetic rats. 4. The oral administration of GTE to diabetic rats significantly reduced the systolic blood pressure and blood glucose. The level of lipid peroxides reduced and the content of glutathione and vitamin C increased in the serum of GTE treated diabetic rats. Green tea extract also impede the accumulation of aortic collagen, extent of glycation, formation of AGEs and cross-linking of collagen in diabetic rats. The antihyperglycemic, anti-oxidant and antiglycating effects of GTE ascribed for these beneficial effects. In conclusion, green tea may have therapeutic effect in the treatment of cardiovascular complications characterized by increased AGE accumulation and protein cross-linking associated with diabetes.

Animals↗
PubMed2003

Molecular targets for green tea in prostate cancer prevention.

Prostate cancer (PCa) is the most frequently diagnosed malignancy and the second leading cause of cancer-related deaths in American males. For these reasons, it is necessary to intensify our efforts for better understanding and development of novel treatment and chemopreventive approaches for this disease. In recent years, green tea has gained considerable attention as an agent that could reduce the risk of several cancer types. The cancer-chemopreventive effects of green tea appear to be mediated by the polyphenolic constituents present therein. Based on geographical observations that suggest that the incidence of PCa is lower in Japanese and Chinese populations that consume green tea on a regular basis, we hypothesized that green tea and/or its constituents could be effective for chemoprevention of PCa. To investigate this hypothesis, we initiated a program for the chemoprevention of PCa by green tea. In cell-culture systems that employ human PCa cells DU145 (androgen insensitive) and LNCaP (androgen sensitive), we found that the major polyphenolic constituent (-)-epigallocatechin-3-gallate (EGCG) of green tea induces 1) apoptosis, 2) cell-growth inhibition, and 3) cyclin kinase inhibitor WAF-1/p21-mediated cell-cycle dysregulation. More recently, using a cDNA microarray, we found that EGCG treatment of LNCaP cells results in 1) induction of genes that functionally exhibit growth-inhibitory effects, and 2) repression of genes that belong to the G-protein signaling network. In animal studies that employ a transgenic adenocarcinoma of the mouse prostate (TRAMP), which is a model that mimics progressive forms of human prostatic disease, we observed that oral infusion of a polyphenolic fraction isolated from green tea (GTP) at a human achievable dose (equivalent to 6 cups of green tea/d) significantly inhibits PCa development and metastasis. We extended these studies and more recently observed increased expression of genes related to angiogenesis such as vascular endothelial growth factor (VEGF) and those related to metastasis such as matrix metalloproteinases (MMP)-2 and MMP-9 in prostate cancer of TRAMP mice. Oral feeding of GTP as the sole source of drinking fluid to TRAMP mice results in significant inhibition of VEGF, MMP-2 and MMP-9. These data suggest that there are multiple targets for PCa chemoprevention by green tea and highlight the need for further studies to identify novel pathways that may be modulated by green tea or its polyphenolic constituents that could be further exploited for prevention and/or treatment of PCa.

Animals↗
PubMed2003

A pooled analysis of case-control studies of thyroid cancer: cigarette smoking and consumption of alcohol, coffee, and tea.

OBJECTIVE: To analyze the role of smoking, alcohol, coffee and tea in relation to thyroid cancer, we conducted a pooled analysis of 14 case-control studies conducted in the United States, Europe, and Asia. METHODS: The sample consisted of 2725 thyroid cancer cases (2247 females, 478 males) and 4776 controls (3699 females, 1077 males). Conditional logistic regression with stratification on study, age at diagnosis, and gender was used to compute odds ratios and 95% confidence intervals. RESULTS: Thyroid cancer risk was reduced in persons who had ever smoked. The relationship was more pronounced in current smokers (OR = 0.6, 95% CI = 0.6-0.7) than former smokers (OR = 0.9, 95% CI = 0.8-1.1). There were significant trends of reduced risk with greater duration and frequency of smoking. For consumption of wine and beer, there was a significant trend of decreasing thyroid cancer risk (p = 0.02) that was not maintained after adjustment for current smoking (p = 0.12). Thyroid cancer risk was not associated with consumption of coffee or tea. These findings were consistent in both gender-specific and histology-specific (papillary and follicular) analyses. CONCLUSIONS: Pooled analyses of these geographically diverse case-control data indicate a reduced thyroid cancer risk associated with current smoking. A reduced risk associated with alcohol was eliminated after adjustment for smoking, and caffeinated beverages did not alter thyroid cancer risk.

Alcohol Drinking↗
PubMed1993

[Studies on the rare earth content in food and its daily intake in man].

The rare earth content of major food in China, they are distributed over 17 provinces and cities were examined by three-wavelength spectrophotometry. The rare earth contents were as follows: 0.41 +/- 0.35 mg/kg in grain, 0.23 +/- 0.18 mg/kg in vegetables, 0.19 +/- 0.11 mg/kg in fruits, 0.83 +/- 0.73 mg/kg in beans, 0.66 +/- 0.50 mg/kg in potato, 1.76 +/- 0.23 mg/kg in tea, 0.07 +/- 0.05 mg/kg in meat, birds, domestic fowls and eggs, 0.52 +/- 0.12 mg/kg in aquatic animals, 5.11 +/- 8.68 micrograms/L in drinking water. The possible daily intake of rare earth for a person from common foodstuffs was about 2.10-2. 50 mg/person.day, which was about one tenth to one sixth of ADI allowable daily intake of rare earths for a person.

Edible Grain↗
PubMed2004

Food and drinking patterns as predictors of 6-year BMI-adjusted changes in waist circumference.

Few studies have investigated the prospective associations between diet or drinking patterns and abdominal obesity; we therefore investigated whether food and beverage groups or patterns predicted 6-year changes in waist circumference (WC) and whether these associations were independent of concurrent changes in BMI as a measure of general obesity. The subjects were 2300 middle-aged men and women with repeated measurements of dietary intake, BMI and WC from 1982 to 1993. Intakes from ten food groups and from coffee, tea, wine, beer and spirits were assessed; gender-specific food factors were identified by factor analyses. Multiple linear regression analyses were done before and after adjustment for concurrent changes in BMI. A high intake of potatoes seemed to prevent gain in WC for men, while a high intake of refined bread was associated with gain in WC for women. The association persisted for refined bread, but not for potatoes, after adjustment for concurrent BMI changes. Among women, but not men, high intakes of beer and spirits were associated with gain in WC in both models. A high intake of coffee for women and moderate to high intake of tea for men were associated with gain in WC, but the associations were weakened, especially for women, after adjustment for BMI changes. None of the food factors was associated with WC changes. Based on the present study, we conclude that very few food items and no food patterns seem to predict changes in WC, whereas high intakes of beer and spirits among women, and moderate to high tea intake among men, may promote gain in WC.

Adult↗
PubMed2000

Chinese green tea lowers cholesterol level through an increase in fecal lipid excretion.

Lung Chen Tea, a Chinese green tea, has been found to lower serum and liver cholesterol. In this study, its dose response and mechanisms of action on cholesterol lowering in diet-induced hypercholesterolemic Sprague-Dawley rats were investigated. The activities of three major lipid metabolizing enzymes, 3-hydroxy-3-methylglutaryl-coenzyme A (HMG-Co A) reductase, cholesterol 7alpha-hydroxylase and fatty acid synthase (FAS), as well as fecal excretion of bile acids and cholesterol were examined. Lung Chen Tea administration for eight weeks significantly lowered the serum cholesterol in the 2% and 4% groups. The activities of the three enzymes were not affected by Lung Chen Tea, but the fecal bile acids and cholesterol excretions were significantly increased. These results demonstrated that Lung Chen Tea lowered plasma cholesterol by increasing fecal bile acids and cholesterol excretion. Further investigation is required to evaluate the exact mechanisms of action of Lung Chen Tea.

Animals↗