Effects of dietary consumption of black tea infusion alone and in combination with known clastogens on mouse bone marrow chromosomes in vivo.
TL;DR: Dietary administration of black tea infusion could significantly protect against clastogenic activity of chromium compounds though it was itself mildlyClastogenic, as compared with those of the control in distilled water.
About: This article is published in Food and Chemical Toxicology.The article was published on 1997-07-01. It has received 18 citations till now. The article focuses on the topics: Potassium dichromate.
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TL;DR: Evidence has been accumulated indicating that a diet rich in antioxidants reduce the risks of the major human diseases, and the importance of dietary antioxidants in the defense strategies of organisms against free radicals is discussed.
Abstract: Durante a reducao do oxigenio molecular, especies reativas de oxigenio sao formadas e existe a necessidade permanente de inativar estes radicais livres. Os danos induzidos pelos radicais livres podem afetar muitas moleculas biologicas, incluindo os lipideos, as proteinas, os carboidratos e as vitaminas presentes nos alimentos. As especies reativas de oxigenio tambem estao implicadas nas varias doencas humanas. Evidencias tem sido acumuladas indicando que uma dieta rica em antioxidantes reduz os riscos das principais doencas humanas. Esta revisao discute a importância dos antioxidantes da dieta sobre as estrategias de defesa dos organismos contra os radicais livres.
219 citations
Cites background from "Effects of dietary consumption of b..."
...Outros flavonóides naturais, (-)-epicatequina e (-)-epigalocatequina, com propriedades antioxidantes e inibidores do processo de carcinogênese, são encontrados no chá verde e em menores concentrações no chá preto (Rice-evans et al., 1995; Mukherjee et al., 1997)....
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TL;DR: This review has attempted to evaluate and update the comparative antimutagenic and anticlastogenic effects of green tea, black tea and their polyphenols in different test systems, based on available literature.
Abstract: Tea is the most popular beverage next to water, consumed by over two-thirds of the world's population. It is processed in different ways in different parts of the world to give green, black or oolong tea. Experimental studies have demonstrated the significant antimutagenic and anticlastogenic effects of both green and black tea and its polyphenols in multiple mutational assays. In the present review, we have attempted to evaluate and update the comparative antimutagenic and anticlastogenic effects of green tea, black tea and their polyphenols in different test systems, based on available literature. Existing reports have suggested that the protective effects of black tea is as good as green tea, however, more studies on black tea and its polyphenols are needed before a final conclusion can be made.
190 citations
TL;DR: The analysis of the results revealed that accumulation of toxic metal Cr in leafy vegetables was found more than fruit bearing vegetables/crops growing on contaminated soil, and it is recommended that the Leafy vegetables are unsuitable to grow in such contaminated sites.
Abstract: The implications of metal contamination of agricultural soils due to long term irrigation with treated industrial wastewater and their subsequent accumulation in the vegetables/crops growing on such soils has been assessed in an area of industrial complex, Jajmau, Kanpur (India). Physico-chemical properties of the soil were also studied. The soil and vegetables/crops were sampled from an area of 2100 acre agricultural land and analyzed for physico-chemical properties and metal accumulation in different parts of the plants. The comparison of the data of physico-chemical properties of control and contaminated soil showed that salinity, electrical conductivity, available phosphorous, sodium and potassium content (both water soluble and exchangeable) were found high in contaminated soil. The analysis of plant available metal content in the soil showed the highest level of Fe, which ranged from 529.02 to 2615 μg g−1 dw and lowest level of Ni (3.12 to 10.51 μg g−1 dw). The analysis of the results revealed that accumulation of toxic metal Cr in leafy vegetables was found more than fruit bearing vegetables/crops. Thus, it is recommended that the leafy vegetables are unsuitable to grow in such contaminated sites. It is important to note that toxic metal, Ni was not detected in all the plants. The edible part of the vegetables (under ground) such as, garlic (19.27 μg g−1 dw), potato (11.81 μg g−1 dw) and turmeric (20.86 μg g−1 dw) has accumulated lowest level of toxic metal, Cr than leafy and fruit bearing vegetables. In some fruit part of vegetables such as, bitter gourd, egg plant, jack tree, maize and okra, the accumulation of Cr was not detected and may be grown in this area.
161 citations
TL;DR: There is a wide scope of further research for the efficient use of black tea active conserves/isolates to reap health benefits, as reported in studies on some organisms.
Abstract: Tea is the most widely used ancient beverage in the world and black tea possesses many biological effects on the organisms. It acts as an effective antioxidant because of its free radical-scavenging and metal-chelating ability. Due to this, it is active against inflammation, clastogenesis, and several types of cancer. Tea reduces DNA damage and mutagenesis due to oxidative stress or the presence of pro-mutagens through antioxidant function, blocking activation pathways of mutagens, suppressing transcription of enzymes involved etc. Inhibition of low-density lipoprotein (LDL) peroxidation, suppression of fatty acid synthase etc., suggest that tea may have a role in preventing cardiovascular diseases. Some epidemiological studies support the protective role of black tea against cardiovascular diseases but some do not. Besides, black tea has beneficial effects on the gastrointestinal tract; it affects motility, absorption, microflora etc., by influencing the hormonal balance and antioxidant function black te...
141 citations
TL;DR: Habitual tea consumption, especially for more than 10 years, has significant beneficial effects on BMD of the total body, lumbar spine, and hip regions in adults.
Abstract: Background: Researchers have hypothesized that bone mineral density (BMD) may be influenced by chemical compounds such as caffeine, phytoestrogen, fluoride, and many compounds that are contained in tea extracts. Hence, the relationship between habitual tea consumption and BMD is an interesting issue. Methods: Based on an epidemiological survey, we enrolled 497 men and 540 women, 30 years and older, in our study. All subjects were questioned about their habit of tea consumption and other lifestyle characteristics by means of a structured questionnaire. Dual-energy x-ray absorptiometry was used to measure the BMD of the total body, lumbar spine (L1-L4), hip neck, and Ward triangle regions. Results: Five hundred two subjects (48.4%) were habitual tea drinkers, with a mean duration of tea consumption of approximately 10 years. Compared with nonhabitual tea drinkers, subjects with habitual tea consumption of 6 to 10 years showed higher lumbar spine BMDs, and those with consumption of more than 10 years showed the highest BMDs of all measured regions. Under the multiple stepwise regression models, sex, age, body mass index, total physical activity, and habit of tea consumption were the major significant variables for the different BMD regions. Regarding the behavioral characteristics of tea consumption, the duration of tea consumption was the only independent determinant for the BMDs. Conclusion: Habitual tea consumption, especially for more than 10 years, has significant beneficial effects on BMD of the total body, lumbar spine, and hip regions in adults.
123 citations
References
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TL;DR: The relative antioxidant activities, against radicals generated in the aqueous phase, of a range of plant-derived polyphenolic flavonoids, constituents of fruit, vegetables, tea and wine, have been assessed and compounds such as quercetin and cyanidin have antioxidant potentials four times that of Trolox, the vitamin E analogue.
Abstract: The relative antioxidant activities, against radicals generated in the aqueous phase, of a range of plant-derived polyphenolic flavonoids, constituents of fruit, vegetables, tea and wine, have been assessed. The results show that compounds such as quercetin and cyanidin, with 3′,4′ dihydroxy substituents in the B ring and conjugation between the A and B rings, have antioxidant potentials four times that of Trolox, the vitamin E analogue. Removing the ortho-dihydroxy substitution, as in kaempferol, or the potential for electron deloculisation by reducing the 2.3 double bond in the C ring, as in catechin and epicatechin, decreases the antioxidant activity by more than 50%. but these structures are still more effective than α-tocopherol or ascorbate. The relative significance of the positions and extents of hydroxylation of the A and B rings to the total antioxidant activity of these plant polyphenols is demonstrated.
2,101 citations
Book•
01 Jan 1973
TL;DR: In this article, the authors introduce the concept of biostatistics and introduce the Biostatistic Approach to Biometrics (BAPB) as a method for biometrics.
Abstract: Introduction to Biostatistics , Introduction to Biostatistics , کتابخانه مرکزی دانشگاه علوم پزشکی تهران
1,874 citations
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TL;DR: A critical review of the relationship between tea consumption and human cancer risk is provided, covering basic chemistry and biochemical activity of tea, epidemiologic investigations, and laboratory studies, as well as possible directions for future research.
Abstract: Tea is one of the most popular beverages consumed worldwide. The relationship between tea consumption and human cancer incidence is an important concern. This topic has been studied in different populations by many investigators, but no clear-cut conclusion can be drawn. Whereas some studies have shown a protective effect of tea consumption against certain types of cancers, other studies have indicated an opposite effect. Our purpose is to provide a critical review of this topic, covering basic chemistry and biochemical activity of tea, epidemiologic investigations, and laboratory studies, as well as possible directions for future research. Studies have demonstrated either a lack of association between tea consumption and cancer incidence at specific organ sites or inconsistent results. On the other hand, many laboratory studies have demonstrated inhibitory effects of tea preparations and tea polyphenols against tumor formation and growth. This inhibitory activity is believed to be mainly due to the antioxidative and possible antiproliferative effects of polyphenolic compounds in green and black tea. These polyphenolics may also inhibit carcinogenesis by blocking the endogenous formation of N-nitroso compounds, suppressing the activation of carcinogens, and trapping of genotoxic agents. The effect of tea consumption on cancer is likely to depend on the causative factors of the specific cancer. Therefore, a protective effect observed on a certain cancer with a specific population may not be observable with a cancer of a different etiology. On the basis of this concept, we suggest future laboratory and epidemiologic studies to elucidate the relationship between tea consumption and human cancer risk.
1,040 citations
Book•
01 Oct 1959
TL;DR: In this article, the authors report critical values (to four significant figures) which have been found by inverse interpolation in the new table of the probability integral of the studentized range.
Abstract: Abstract : The purpose of this paper is to report critical values (to four significant figures) which have been found by inverse interpolation in the new table of the probability integral of the studentized range. Included are corrected tables for significance levels alpha = 0.05, 0.1 and new tables for significance levels alpha = 0.10, 0.005, 0.001-all with sample sizes n = 2(1) 20(2)40(10)100 and degrees of freedom nu = 1(1)20, 24, 30, 60, 120, infinity.
614 citations
TL;DR: In this paper, the authors report critical values (to four significant figures) which have been found by inverse interpolation in the new table of the probability integral of the studentized range.
Abstract: : The purpose of this paper is to report critical values (to four significant figures) which have been found by inverse interpolation in the new table of the probability integral of the studentized range. Included are corrected tables for significance levels alpha = 0.05, 0.1 and new tables for significance levels alpha = 0.10, 0.005, 0.001-all with sample sizes n = 2(1) 20(2)40(10)100 and degrees of freedom nu = 1(1)20, 24, 30, 60, 120, infinity.
579 citations