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PubMed2004

[Influence of teas with fruit aroma and ice teas on pH and buffer capacity of saliva].

A number of teas with fruit aroma and ice teas has been tested on erosivity. The teas with a fruit taste have at their drinking temperature (45 degrees C) a pH between 6.2 to 7.4. Even teas with a citron or citrus flavour are neutral. The most acidic tea tested has a mango-peach-taste, but contains no buffer system. After mixing 1 ml of total saliva up to 10 ml tea or by rinsing the oral cavity with tea the pH of oral fluid was hardly lowered (minimum 6.3). In contrast, ice teas are rather acidic (pH < 4) and have a strong buffer capacity. Rinsing the oral cavity with 5 ml ice tea resulted in a decrease of the pH of the oral fluid to 4.1-4.9. However, within 2 minutes the pH in the oral fluid was already increased to 5.9-7.1 and after 5 minutes to 6.3-7.1. In other words, the teas with fruit aroma, based on organic taste components do not have an erosive potential. On the other hand, ice teas decrease the pH of the oral fluid drastically to a level that they become erosive. Therefore, from a dental point of view, teas with only a taste of fruit can be advised to replace drinking of soft drinks, but ice teas not.

Beverages↗
PubMed2006

Green tea and its polyphenolic catechins: medicinal uses in cancer and noncancer applications.

Can drinking several cups of green tea a day keep the doctor away? This certainly seems so, given the popularity of this practice in East Asian culture and the increased interest in green tea in the Western world. Several epidemiological studies have shown beneficial effects of green tea in cancer, cardiovascular, and neurological diseases. The health benefits associated with green tea consumption have also been corroborated in animal studies of cancer chemoprevention, hypercholesterolemia, artherosclerosis, Parkinson's disease, Alzheimer's disease, and other aging-related disorders. However, the use of green tea as a cancer chemopreventive or for other health benefits has been confounded by the low oral bioavailability of its active polyphenolic catechins, particularly epigallocatechin-3-gallate (EGCG), the most active catechin. This review summarizes the purported beneficial effects of green tea and EGCG in various animal models of human diseases. Dose-related differences in the effects of EGCG in cancer versus neurodegenerative and cardiovascular diseases, as well as discrepancies between doses used in in vitro studies and achievable plasma understanding of the in vivo effects of green tea catechins in humans, before the use of green tea is widely adopted as health-promoting measure.

Aging↗
PubMed1996

Coffee and alcohol intake, smoking and risk of multiple pregnancy.

We analysed the relationship between coffee and alcohol intake, smoking and risk of multiple pregnancies using data from a case-control study on risk factors for multiple births conducted in Italy. Cases were 133 women who delivered multiple births not related to treatment for infertility (33 monozygotic and 100 dizygotic twins). Controls were 395 women admitted for normal delivery at the same clinic where cases had been identified. The odds ratios (OR) of multiple pregnancy were 1.5[95% confidence interval (CI) 0.8-2.8] and 2.0 (95% CI 1.0-3.7) for women drinking respectively one to two or three or more cups of coffee per day in comparison with non-coffee drinkers. Considering separately dizygotic and monozygotic pregnancies, the estimated OR were respectively for women drinking three or more cups of coffee, 1.7 and 3.1 for dizygotic and monozygotic pregnancies. The risk of multiple pregnancy tended to be higher in women drinking >or= 15 alcohol drinks per week: in comparison with tea-totallers the estimated OR for drink > or = 15 glasses per week were 2.3 and 2.6 respectively for dizygotic and monozygotic pregnancies. Heavy smokers (> or = 10 cigarettes per day) were at increased risk of multiple pregnancy: in comparison with never smokers, the estimated OR for multiple pregnancy was 1.6 (95% CI 0.9-2.7). Considering separately the two groups of multiple pregnancy, the OR of dizygotic and monozygotic pregnancy were 1.4 (95% CI 0.8-2.5) and 2.4 (95% CI 0.9-6.1) for women smoking > or = 10 cigarettes/day, but the trend in risk with number of cigarettes smoked per day and duration of the habit was not significant.

Adult↗
PubMed2001

Colonic fermentation after ingestion of fructose-containing sports drink.

BACKGROUND: Many commercially available sports drinks contain 5-6% carbohydrates, some of which is fructose. However, a number of studies of abdominal complaints have indicated fructose malabsorption. In the present study, we examined colonic fermentation of a fructose-containing sports drink. METHODS: Colonic fermentation was determined in normal subjects by measuring breath hydrogen after ingestion of 350 ml sports drink, cow s milk, or green tea with a 200 g rice ball. RESULTS: The incidence of colonic fermentation after ingesting sports drink, milk, and green tea was five (62.5%), six (75%), and none (0%), respectively in eight subjects. Peak increases (ppm) after ingestion of sports drink and milk varied from 0 to 6 (3.1 +/- 0.9) and 0 to 12 (6.5 +/- 1.7), respectively. CONCLUSIONS: Although the increase of breath hydrogen was not associated with abdominal discomfort and its effect on exercise is still unclear, we suggest avoiding a large ingestion of fructose-containing sports drink before and during exercise.

Adult↗
PubMed1985

[Supplementation with fully adapted milk substitute or calorie-free tea in the first days of life. Effect on drinking behavior and some measurements in mature healthy newborns].

180 mature newborn infants (birth-weight 3390 +/- 397 g) were randomly divided into 2 groups of 90 each: all were breast-fed according to the guide-lines recommended by "La Leche League". When breast feeds did not suffice the infants in group A were supplemented with sugar-free tea (o kcal), those in group B with a fully adapted formula (518 kcal/dl). Group A infants generally were more hungry, scored a greater suckling activity, higher feeding frequency and less calorie intake. 19% of them received 1-2 additional milk-feeds because of severe hunger reactions. Group B had a somewhat lower intake of breast milk, a statistically significant higher intake of supplementary feeds and a higher calorie intake. 5.5% in either group were not supplemented at all. The groups did not differ in body temperature, greatest weight loss, serum bilirubin and blood glucose levels and red blood cell count. Supplementation of formula revealed no obvious advantage over supplementation of tea in the first 4 days of life. However, feeding frequency was lower in infants receiving milk supplements.

Birth Weight↗
PubMed2007

Structure-activity relationships of tea compounds against human cancer cells.

The content of the biologically active amino acid theanine in 15 commercial black, green, specialty, and herbal tea leaves was determined as the 2,4-dinitrophenyltheanine derivative (DNP-theanine) by a validated HPLC method. To define relative anticarcinogenic potencies of tea compounds and teas, nine green tea catechins, three black tea theaflavins, and theanine as well as aqueous and 80% ethanol/water extracts of the same tea leaves were evaluated for their ability to induce cell death in human cancer and normal cells using a tetrazolium microculture (MTT) assay. Compared to untreated controls, most catechins, theaflavins, theanine, and all tea extracts reduced the numbers of the following human cancer cell lines: breast (MCF-7), colon (HT-29), hepatoma (liver) (HepG2), and prostate (PC-3) as well as normal human liver cells (Chang). The growth of normal human lung (HEL299) cells was not inhibited. The destruction of cancer cells was also observed visually by reverse phase microscopy. Statistical analysis of the data showed that (a) the anticarcinogenic effects of tea compounds and of tea leaf extracts varied widely and were concentration dependent over the ranges from 50 to 400 microg/mL of tea compound and from 50 to 400 microg/g of tea solids; (b) the different cancer cells varied in their susceptibilities to destruction; (c) 80% ethanol/water extracts with higher levels of flavonoids determined by HPLC were in most cases more active than the corresponding water extracts; and (d) flavonoid levels of the teas did not directly correlate with anticarcinogenic activities. The findings extend related observations on the anticarcinogenic potential of tea ingredients and suggest that consumers may benefit more by drinking both green and black teas.

Anticarcinogenic Agents↗
PubMed1982

Effects of cigarette smoking, alcohol, coffee and tea consumption on preterm delivery.

A case-control study of 175 mothers of singleton, preterm infants and 313 mothers of singleton, term infants was undertaken at Yale-New Haven Hospital during 1977 to explore possible risk factors of preterm delivery. Heavy alcohol consumption (an average of two or more drinks per day) during the pregnancy was associated with an approximately 3-fold risk of preterm delivery. Women who smoked 10 or more cigarettes per day were also at an increased risk of a preterm delivery, but the effect of cigarette smoking was less pronounced once confounding variables had been taken into account. No association was observed between coffee drinking and shortened gestations. Tea consumption, especially four or more cups of tea per day, was more frequent among women with a preterm as compared to a term infant, but no significant relation was evident between heavy tea consumption and preterm delivery after controlling for the effects of other risk factors.

Adolescent↗
PubMed1993

Association of delayed conception with caffeine consumption.

This cross-sectional study investigated the relation between intake of caffeine-containing beverages and time to conception in a population of 1,909 married women in New Haven, Connecticut, between May 12, 1980 and March 12, 1982. Women were interviewed shortly after the first prenatal visit regarding the length of time taken to conceive the index pregnancy, consumption of caffeine during pregnancy, and other exposures occurring prior to and during pregnancy. In logistic regression analyses, intake of caffeine from coffee, tea, and caffeinated soft drinks was associated with an increased risk of a delay of conception of 1 year or more. Compared with no caffeine use, consumption of 1-150 mg/day of caffeine resulted in an odds ratio for delayed conception of 1.39 (95% confidence interval (CI) 0.90-2.13), consumption of 151-300 mg/day of caffeine was associated with an odds ratio of 1.88 (95% CI 1.13-3.11), and that of over 300 mg/day (the equivalent of approximately three cups of coffee) resulted in an odds ratio of 2.24 (95% CI 1.06-4.73), after controlling for last method of birth control used, parity, and number of cigarettes per day. When the risk of conception for each cycle was examined using a discrete analogue of the Cox proportional hazards model, women who reported drinking over 300 mg/day of caffeine had a 27% lower chance of conceiving for each cycle, and those who reported drinking less than 300 mg/day had a 10% reduction in per cycle conception rates compared with women who consumed no caffeine. Risks for coffee, tea, and colas were examined simultaneously in logistic models and were found not to improve the fit of a model that contained a variable for total caffeine intake from all sources.

Beverages↗
PubMed2007

Green tea increases anti-inflammatory tristetraprolin and decreases pro-inflammatory tumor necrosis factor mRNA levels in rats.

BACKGROUND: Tristetraprolin (TTP/ZFP36) family proteins have anti-inflammatory activity by binding to and destabilizing pro-inflammatory mRNAs such as Tnf mRNA, and represent a potential therapeutic target for inflammation-related diseases. Tea has anti-inflammatory properties but the molecular mechanisms have not been completely elucidated. We hypothesized that TTP and/or its homologues might contribute to the beneficial effects of tea as an anti-inflammatory product. METHODS: Quantitative real-time PCR was used to investigate the effects of green tea (0, 1, and 2 g solid extract/kg diet) on the expression of Ttp family genes (Ttp/Tis11/Zfp36, Zfp36l1/Tis11b, Zfp36l2/Tis11d, Zfp36l3), pro-inflammatory genes (Tnf, Csf2/Gm-csf, Ptgs2/Cox2), and Elavl1/Hua/Hur and Vegf genes in liver and muscle of rats fed a high-fructose diet known to induce insulin resistance, oxidative stress, inflammation, and TNF-alpha levels. RESULTS: Ttp and Zfp36l1 mRNAs were the major forms in both liver and skeletal muscle. Ttp, Zfp36l1, and Zfp36l2 mRNA levels were more abundant in the liver than those in the muscle. Csf2/Gm-csf and Zfp36l3 mRNAs were undetectable in both tissues. Tea (1 g solid extract/kg diet) increased Ttp mRNA levels by 50-140% but Tnf mRNA levels decreased by 30% in both tissues, and Ptgs2/Cox2 mRNA levels decreased by 40% in the muscle. Tea (2 g solid extract/kg diet) increased Elavl1/Hua/Hur mRNA levels by 40% in the liver but did not affect any of the other mRNA levels in liver or muscle. CONCLUSION: These results show that tea can modulate Ttp mRNA levels in animals and suggest that a post-transcriptional mechanism through TTP could partially account for tea's anti-inflammatory properties. The results also suggest that drinking adequate amounts of green tea may play a role in the prevention of inflammation-related diseases.

Journal Article↗
PubMed2004

Silent peptic ulcer disease: frequency, factors leading to "silence," and implications regarding the pathogenesis of visceral symptoms.

BACKGROUND: Peptic ulcer disease may occur in the absence of dyspeptic symptoms. The pathogenesis of dyspepsia in peptic ulcer disease is unclear. Whether the presence of Helicobacter pylori infection or use of non-steroidal anti-inflammatory drugs affects dyspeptic symptoms in patients with peptic ulcer disease has not been determined. The aim of the study was to determine the frequency and risk factors for peptic ulcer disease in a cohort of asymptomatic, unselected patients undergoing routine screening EGD. METHODS: This was a prospective study of a cohort of Chinese subjects undergoing screening EGD as part of a routine health maintenance program. Routine EGD screening was performed in 6457 consecutive subjects who underwent a self-paid, health evaluation. Those with endoscopy-confirmed peptic ulcer disease were enrolled to assess the risk factors that distinguish asymptomatic patients with peptic ulcer disease from patients with symptoms because of peptic ulcer disease. RESULTS: A total of 704 (10.9%) patients were found to have peptic ulcer disease, of which two thirds (n=496) were asymptomatic. Both uni- and multivariate analysis showed that the asymptomatic patients tended to have a larger body mass index, to be habitual tea drinkers, and to have an ulcer that was less than 1 cm in diameter and in a healing stage. Gender, blood group, history of hypertension and/or diabetes, ulcer location, Helicobacter pylori status, use of non-steroidal anti-inflammatories or sedative medications, habitual coffee drinking, and habits with respect to smoking of tobacco or ingestion of alcohol, had no association with symptoms. CONCLUSIONS: The results of this study suggest that silent peptic ulcer disease is common in Taiwan. Dyspeptic symptoms because of peptic ulcer disease may be influenced by intrinsic (body mass index and ulcer characters) and extrinsic (habitual tea drinking) factors. Non-steroidal anti-inflammatory drug use and Helicobacter pylori status had no significant effect on the symptomatology of peptic ulcer disease. These findings may contribute to the understanding of the pathogenesis in the visceral symptoms of peptic ulcer disease.

Adult↗
PubMed2006

Green tea (Camellia sinensis) extract ameliorates endotoxin induced sickness behavior and liver damage in rats.

Immune activation, either by cytokines or endotoxin, elicits a constellation of nonspecific symptoms such as weakness, malaise, listlessness, fatigue, adipsia, anorexia, depression and anxiety collectively termed as sickness behavior. Further, endotoxin administration in animals has been implicated in the pathogenesis of many types of liver disease. Green tea, a common household drink, is rich in antioxidant polyphenols demonstrating inhibitory effects on cytokine production. The present study was designed to investigate the effect of chronic treatment of green tea extract (GTE) on lipopolysaccharide (LPS)-induced sickness behavior and liver damage in rats. The hypothesis was tested through the analysis of LPS-induced behavioral changes in rats, in plus maze and open field paradigms. Other parameters such as feeding and water consumption, weight loss and organ weight index were also estimated. Liver function tests were conducted to investigate the effect of GTE supplementation on LPS-induced hepatic dysfunction. The results of the study demonstrated that GTE significantly attenuated LPS-induced sickness behavior as well as hepatic damage either by its antioxidant activity or by inhibiting LPS induced cytokine production in rats.

Animals↗
PubMed1997

Inhibitory effect of black tea on the growth of established skin tumors in mice: effects on tumor size, apoptosis, mitosis and bromodeoxyuridine incorporation into DNA.

Female CD-1 mice were initiated with a single topical application of 7,12-dimethylbenz[a]anthracene and promoted with 12-O-tetradecanoylphorbol-13-acetate. Mice with established papillomas were then treated with black tea or decaffeinated black tea (approximately 4 mg tea solids/ml) as the sole source of drinking fluid for 11-15 weeks. In four separate experiments, oral administration of black tea inhibited the growth of papillomas (increase in tumor volume/mouse) by an average of 35%, 37%, 41% and 48%, respectively. Studies with decaffeinated black tea gave inconsistent results. In one experiment, administration of decaffeinated black tea inhibited papilloma growth (increase in tumor volume/mouse) by 27%, but in two additional experiments papilloma growth was stimulated by 14% and 193%, respectively. In a separate experiment, skin tumors were generated by treating SKH-1 female mice with ultraviolet B light (UVB; 30 mJ/cm2) twice weekly for 22 weeks, after which UVB administration was stopped. Tumors were allowed to develop during the following 13 weeks, and tumor-bearing mice were then treated with black tea (6 mg/ml tea solids) as the drinking fluid for 11 weeks. In this experiment, tumor growth (increase in tumor volume/mouse) was inhibited by 70%. Histological examination revealed that tea-treated mice had a 58% decrease in the number of nonmalignant tumors (primarily keratoacanthomas)/mouse and a 54% decrease in the number of squamous cell carcinomas/mouse. In addition, administration of black tea decreased the volume per tumor by 60% for nonmalignant tumors and by 84% for carcinomas. Mechanistic studies with tumors from these mice revealed that administration of black tea decreased the bromodeoxyuridine labeling index in squamous cell papillomas, keratoacanthomas and squamous cell carcinomas by 56%, 45% and 35%, respectively, and the apoptosis index was increased by 44%, 100% and 95%, respectively. Administration of black tea decreased the mitotic index in keratoacanthomas and squamous cell carcinomas by 42% and 16%, respectively. The results indicate that oral administration of black tea to tumor-bearing mice inhibited proliferation and enhanced apoptosis in nonmalignant and malignant skin tumors.

9,10-Dimethyl-1,2-benzanthracene↗
PubMed2003

Investigation of biochemical and histopathological effects of Mentha piperita L. and Mentha spicata L. on kidney tissue in rats.

Peppermint plants have been used as a herbal medicine for many conditions, including loss of appetite, common cold, bronchitis, sinusitis, fever, nausea, vomiting and indigestion. This study is aimed at investigating the biochemical and histological effects of Mentha piperita L., growing in the Yenisar Bademli town of Isparta City, and Mentha spicata L., growing on the Anamas high plateau of Isparta City, on rat kidney tissue. Forty-eight male Wistar albino rats weighing 200-250 g were used for this study. Animals were divided into four experimental groups, each with 12 rats, as follows: control group (group I); 20 g/L M. piperita tea (group II); 20 g/L M. spicata tea (group III); 40 g/L M. spicata tea (group IV). The control group rats were given commercial drinking water (Hayat DANONESA water). The tea for the other groups was prepared daily and provided at all times to the rats during 30 days as drinking water. Plasma urea and creatinine levels were determined, and the levels of thiobarbituric acid reactive substance (TBARS) and the activities of glutathione peroxidase (GSH-Px), catalase (CAT) and superoxide dismutase (SOD) were studied in the homogenates of kidney tissue. The levels of plasma urea and creatinine were increased significantly (P < 0.0033) in groups III and IV when compared with group I. The activities of SOD and GSH-Px were decreased significantly (P < 0.0033) in group IV when compared with group I. The activities of CAT were decreased significantly in groups III and IV (P < 0.033, P < 0.0033, respectively) when compared with group I. TBARS levels were increased significantly (P < 0.0033) in groups III and IV when compared with group I. In groups II, III and IV, hydropic degeneration of tubular epithelial cells, the epithelial cells with picnotic nuclei and eosinophilic cytoplasm, tubular dilatation and enlargements in Bowman capsules were observed histologically. However, in group II histopathological changes were more slight than in groups III and IV. In group IV, in addition to these changes, extremely hydropic degeneration of tubular epithelial cells, some atrophic tubules and glomerules, and focal mononuclear cell infiltrations in the kidney tissues of the rats were observed. In conclusion, the results indicate that M. piperita does not show nephrotoxicity but M. spicata presents markedly nephrotoxic changes in rats.

Animals↗
PubMed2003

Suppression of tumorigenesis in the Apc(min) mouse: down-regulation of beta-catenin signaling by a combination of tea plus sulindac.

Epidemiological and animal studies suggest that tea may be protective towards cancers of the GI tract. White tea, the least processed form of tea, contains high levels of polyphenols and, like green tea, is chemopreventive towards heterocyclic amine-initiated colonic aberrant crypt formation in male F344 rats. We examined for the first time the relative effectiveness of white and green tea in suppressing intestinal tumorigenesis in C57BL/6J-Apc(Min/+) (Apc(min)) mice. Each tea was also compared with sulindac, a non-steroidal anti-inflammatory drug known to be highly effective in Apc(min) mice. Male C57BL/6J (+/+) (wild-type) and Apc(min) mice were treated in the drinking water with white tea or green tea (1.5% w/v, 2 min brew-time), 80 p.p.m. sulindac, a combination of 80 p.p.m. sulindac in 1.5% white tea, or pH buffered water. After 12 weeks of treatment, Apc(min) mice given white tea, green tea, or sulindac had significantly fewer tumors than controls (P < 0.05). The protection provided by 1.5% green or white tea was comparable to that provided by 80 p.p.m. sulindac. Mice treated with a combination of white tea plus sulindac had significantly fewer tumors than either treatment alone (P < 0.05). beta-catenin and beta-catenin/Tcf-4 regulated proteins Cyclin D(1) and c-Jun were readily detected in polyps, but markedly reduced in normal-looking intestines of mice treated with both tea and sulindac. This research provides evidence that teas, particularly when administered in combination with sulindac, are highly effective at inhibiting intestinal neoplasia in male Apc(min) mice via direct or indirect effects on the beta-catenin/APC pathway.

Animals↗
PubMed1997

[Exposure of inhabitants of Poznan to fluorides. I. Fluorides in atmospheric air, tap water and selected additional fluids].

The purpose of the study was to obtain information about fluoride pollution of the human environment. Fluoride concentrations were measured in atmospheric air, water and certain drinks. The measurements were done with a ion-selective electrode. In the atmospheric air of Poznań and its environs the concentrations ranged from 0.0006 mg/m3 to 0.0122 mg/m3. Tap water in Poznań contained 0.2 mg F3/dm3, on average. The selected drinks--mineral water and tea contained 0.3 and 1.5 mg F-/dm3 respectively. The acceptable values of fluoride concentrations were not exceeded, but fluoride concentration in atmospheric air was higher than that found usually in other regions of the country. In drinking water fluoride concentration in Murowana Goślina was within the acceptable range, and in Poznań it was twice lower.

Air Pollutants↗
PubMed2001

Changes in Ca, Cu, Fe, Mg, and Zn contents in mouse brain tissues after prolonged oral ingestion of brick tea liquor containing a high level of Al.

A study was conducted to analyze the regional distribution of Ca, Cu, Fe, Mg, and Zn contents in brain tissues after animals were given liquor of brick tea that contained a high Al content. In 25 normal adult male mice given either water or 0.9% NaCl for 1 mo or 2 mo, the metal concentrations in the serum, liver, frontal cortex, hippocampus, cerebellum, and brain stem were comparable (p > 0.05). When the drinking water was replaced by a 1% brick tea liquor, which contained a high Al content, serum Al concentration was increased significantly 1 mo after the onset of the experiment and remained high at the end of the second month. The level of Al was also elevated in both the cortex and hippocampus at 1 mo after replacing tea for drinking water. In addition to Al, there were a significant increase in hippocampal Zn and a decrease in Cu contents. There was no change in tissue Mg or Fe contents, but there was a significant increase in Ca content in every brain region studied. It was suggested that the increase in Ca might be the result of the effect of other components in tea. Unlike the brain, there was no change in the concentration of any of the metals, including Al, in the liver, which further demonstrated that the changes observed in the brain was specific. The results of the present study confirmed that Al, when given orally in the form of tea, could be absorbed into the bloodstream. The absorbed Al could accumulate in selected brain regions. The presence of Al might also change the tissue content of endogenous trace metals.

Aluminum↗
PubMed2005

Effect of administration of caffeine or green tea on the mutation profile in the p53 gene in early mutant p53-positive patches of epidermal cells induced by chronic UVB-irradiation of hairless SKH-1 mice.

Irradiation of SKH-1 mice with UVB light for 20 weeks resulted in a large number of patches of epidermal cells, which was visualized with an antibody that recognizes mutated p53 protein. Oral treatment of mice with caffeine (0.4 mg/ml) or green tea (6 mg tea solids/ml) as the drinking fluid during UVB irradiation decreased the number of patches by approximately 40%. Sequencing analysis of the p53 gene (exons 3 to 9) detected 88, 82 or 39 point mutations in 67, 70 or 29 patches from water, caffeine or tea treated mice, respectively. A major hotspot at codon 270 (Arg-->Cys) accounted for 47.7% (water), 70.7% (caffeine) or 46.2% (tea) of all mutations. Patches from caffeine treated mice had fewer types of mutations than patches from mice treated with water or tea. Administration of caffeine or tea during 20 weeks of UVB irradiation eliminated mutations at codons 149 (Pro-->Ser) and 210 (Arg-->Cys) but increased the frequency of mutations at codon 238 (Ser-->Phe). Topical applications of caffeine (1.2 mg in 100 microl acetone) once a day, five times a week for 6 weeks after stopping UVB decreased the number of patches by 63% when compared with mice treated with acetone. DNA sequencing analysis detected 63 and 68 mutations in 48 and 57 patches from acetone or caffeine treated mice, respectively. Although no differences in the frequency, position or types of mutations were observed, the caffeine group harbored less homozygous mutations (12.3% of the total) than the acetone group (31.3% of the total, P = 0.029). In summary, oral treatment of mice with caffeine or green tea during chronic UVB irradiation changed the mutation profile of the p53 gene in early mutant p53 positive epidermal patches, and topical applications of caffeine after discontinuation of chronic UVB irradiation specifically eliminated patches harboring homozygous p53 mutations.

Administration, Oral↗
PubMed2004

Chemoprotection against N-nitrosomethylbenzylamine-induced mutation in the rat esophagus.

Prevention of esophageal cancer may be possible through dietary modification or supplementation. In this study we have investigated the mutation preventive properties of ellagic acid, green tea, and diallyl sulfide (DAS) against the mutagenicity of the nitrosamine N-nitrosomethylbenzylamine (NMBA) in the esophagus of the rat. In addition, the effect of the consumption of ethanol on the mutagenicity of NMBA was examined. NMBA is specific in inducing tumors in the rat esophagus and has been used in many studies investigating the mechanism and the prevention of this cancer. We found that the type of mutations induced by two 2-mg/kg subcutaneous injections of NMBA in the lacI gene of "Big Blue" rats is consistent with that found previously for nitrosamines in other systems and consists of G:C-->A:T transitions. We report that the addition of ellagic acid to the feed, replacing drinking water with green tea, and gavage with DAS significantly reduced the mutagenicity of NMBA. In contrast, the addition of 5% ethanol to the drinking water increased the mutagenicity of NMBA. This is consistent with findings that these compounds modulate NMBA-induced carcinogenesis in the rat.

Allyl Compounds↗