cancer-prevention

Matcha/green tea has for many centuries been regarded as an essential part of good health in Japan and China. Many believe it can help reduce the risk of cancer, and a growing body of evidence backs this up.

Recent Research Papers on
cancer-prevention

Green tea for ovarian cancer prevention and treatment: A systematic review of the in vitro, in vivo and epidemiological studies

Author: Dominique Trudel and David P. Labbé and Isabelle Bairati and Vincent Fradet and Laurent Bazinet and Bernard Têtu

Objective This systematic review was conducted to examine the effects of green tea or green tea components on the prevention and progression of epithelial ovarian cancer. Methods Using Medline, EMBASE and SciVerse (last researched: July 2011), we retrieved 22 articles including 5 epidemiological studies. Results In epithelial ovarian cancer cell lines, green tea and green tea components have been shown to downregulate the expression of proteins involved in inflammation, cell signalization, cell motility and angiogenesis. Green tea and green tea components would induce apoptosis and could potentiate the effects of cisplatin, a chemotherapeutic agent. In human observational studies, significant associations between green tea intake and both decreased ovarian cancer occurrence and better prognosis were reported. Conclusions Available literature suggests potential molecular targets for green tea in ovarian cancer treatment and also provides data supporting the clinical evaluation of the role of green tea or green tea components in ovarian cancer prevention and treatment.

Get the whole article here

Black and green tea — Luminol false-negative bloodstains detection

Author: Martina Bancirova

The antioxidant properties of black and green teas are well known. It is also possible to determine their antioxidant capacity by using a chemiluminscent method. This method is based on the measurement of the delay in the emission of light from the luminol reaction in the presence of the antioxidant. Bloodstains which are invisible to the naked eye can also be detected by luminol. Three common methods (detection using the Grodsky or Weber formulations and by Bluestar® Forensic latent bloodstain reagent) are based on the luminol chemiluminescence reaction. The bloodstains can be masked by drinks and/or foods containing antioxidants. The aim of this work was to compare the ability of black and green teas containing antioxidants to cause false negative results during chemiluminescent bloodstain detection.

Get the whole article here

Comparisons of different regressions tools in measurement of antioxidant activity in green tea using near infrared spectroscopy

Author: Quansheng Chen and Zhiming Guo and Jiewen Zhao and Qin Ouyang

To rapidly and efficiently measure antioxidant activity (AA) in green tea, near infrared (NIR) spectroscopy was employed with the help of a regression tool in this work. Three different linear and nonlinear regressions tools (i.e. partial least squares (PLS), back propagation artificial neural network (BP-ANN), and support vector machine regression (SVMR)), were systemically studied and compared in developing the model. The model was optimized by a leave-one-out cross-validation, and its performance was tested according to root mean square error of prediction (RMSEP) and correlation coefficient (Rp) in the prediction set. Experimental results showed that the performance of SVMR model was superior to the others, and the optimum results of the SVMR model were achieved as follow: RMSEP = 0.02161 and Rp = 0.9691 in the prediction set. The overall results sufficiently demonstrate that the spectroscopy coupled with the SVMR regression tool has the potential to measure AA in green tea.

Get the whole article here

Chemopreventive potential of the tannase-mediated biotransformation of green tea

Author: J.A. Macedo and L.R. Ferreira and L.E. Camara and J.C. Santos and A. Gambero and G.A. Macedo and M.L. Ribeiro

Green tea (Camellia sinensis) is one of the most widely consumed beverages in the world. The cancer chemopreventive qualities of green tea have been well documented. Epigallocatechin gallate (EGCG) is often described as the most potently chemopreventive green tea catechin; however, the low bioavailability of EGCG is a limiting factor for its biological effect. Thus, the aim of this work was to test the chemopreventive potential of green tea extract and EGCG after tannase-mediated hydrolysis. The results showed that the biotransformed compounds retained most of the beneficial properties of the original compounds, and some beneficial properties were improved in the biotransformed compounds. Biotransformation of EGCG decreased its toxicity without affecting its antiproliferative effects. Furthermore, human cells gene expression profiling showed that the biotransformed compounds modulated the expression of several genes related to carcinogenesis. These results demonstrate the benefits of the biotechnological modification of natural food molecules, allowing the improvement of the nutraceutical potential of a beverage as green tea.

Get the whole article here

Potential protection of green tea polyphenols against intracellular amyloid beta-induced toxicity on primary cultured prefrontal cortical neurons of rats

Author: Xiao-Yan Qin and Yong Cheng and Long-Chuan Yu

The present study was performed to explore the effect of green tea polyphenols on the intracellular Aβ (iAβ)-induced toxicity to cultured rat primary prefrontal cortical neurons. Administration of 100 nM, 1 μM or 10 μM of green tea polyphenols significantly inhibited the iAβ-induced toxicity to cultured rat primary prefrontal cortical neurons tested by MTT and LDH release assays. We further studied the involvement of neuroprotective pathway protein AKT in green tea polyphenols protection against iAβ-induced cytotoxicity on cultured rat primary prefrontal cortical neurons. The results demonstrated that the content of p-AKT decreased significantly after iAβ treatment, while administration of green tea polyphenols significantly inhibited the iAβ-induced decrease in the content of p-AKT. Moreover, blockade of AKT signalling inhibited the protective effects of green tea polyphenols against iAβ-induced neurotoxicity. The results suggest that green tea polyphenols may play a protective effect on cultured rat primary prefrontal cortical neurons against iAβ-induced cytotoxicity and AKT is involved in the green tea polyphenols-induced protective effects.

Get the whole article here

Green tea: An effective synergist with anticancer drugs for tertiary cancer prevention

Author: Hirota Fujiki and Masami Suganuma

Green tea is now an acknowledged cancer preventive in Japan. Based on evidence that colorectal adenomas and prostate cancer in humans have been prevented, we review here the concept that the combination of anticancer drugs with green tea catechin synergistically induces apoptosis of human cancer cells, inhibits tumor formation in mice, and enhances inhibition of tumor growth in xenograft mouse models. As a molecular mechanism by the combination, the induction of growth arrest and DNA damage-inducible 153 (GADD153, CHOP) gene expression is discussed in relation to death receptor 5 and TRAIL-apoptotic pathway. The combination of anticancer drugs with green tea could be a new cancer therapeutic strategy in humans.

Get the whole article here

Green tea drinking and risk of pancreatic cancer: A large-scale, population-based case–control study in urban Shanghai

Author: Jing Wang and Wei Zhang and Lu Sun and Herbert Yu and Quan-Xing Ni and Harvey A. Risch and Yu-Tang Gao

Background: Little is known about the etiology of pancreatic cancer. Epidemiological studies on tea consumption and pancreatic cancer risk have been inconclusive. The purpose of the present study was to investigate the association between green tea drinking and the risk of pancreatic cancer in urban Shanghai, China. Methods: In this population-based case–control study conducted in urban Shanghai, 908 cases of pancreatic cancer and 1067 healthy controls were recruited. Information on tea drinking, including type of tea, amount of tea consumption, temperature of tea, and the duration of regular tea drinking, were collected via interview questionnaire. Results: We examined the association of multiple tea drinking habits with the risk of pancreatic cancer. In women, regular green tea drinking was associated with 32% reduction of pancreatic cancer risk (OR 0.68, 95% CI 0.48–0.96), compared to those who did not drink tea regularly. Increased consumption and longer duration of tea drinking were both associated with reduced pancreatic cancer risk in women. Among regular tea drinkers, lower temperature of tea was associated with reduced risk of pancreatic cancer in both men and women, independent of amount or duration of tea drinking. Conclusions: Habits of green tea drinking, including regular drinking, amount of consumption, persistence of the habit, and tea temperature, may lower pancreatic cancer risk.

Get the whole article here

Green tea extract as food antioxidant. Synergism and antagonism with α-tocopherol in vegetable oils and their colloidal systems

Author: Jie Yin and Eleonora Miquel Becker and Mogens L. Andersen and Leif H. Skibsted

The antioxidant effects of α-tocopherol (TOH) in combination with green tea extract (GTE), the green tea polyphenol (−)-epicatechin (EC) or the isomeric (+)-catechin (C), were investigated using different lipid systems based on high linoleic sunflower oil: bulk oil, o/w-emulsion and a phosphatidylcholine-based liposome system. Both polyphenols as well as TOH were efficient antioxidants in all systems when used alone, as detected by the formation of free radicals and conjugated dienes and by oxygen consumption. Strong synergistic effect was found for the combination of TOH and GTE in a methyl linoleate o/w-emulsion and in the pure bulk oil, while only an additive effect was observed in a liposome system. The synergism was already evident for the tendency for radical formation in the bulk oil as detected by electron spin resonance (ESR) spectroscopy. On the contrary, combinations of TOH with either EC or C showed clear synergistic effects in both heterogeneous systems, but antagonistic or additive effects in bulk oil. GTE may accordingly be used to protect both vegetable oils and their emulsions against oxidation through enhancement of the activity of their endogenous antioxidants, while GTE is less efficient in the protection of phospholipids as in liposomes.

Get the whole article here

Analysis of the tumoral cytotoxicity of green tea-infusions enriched with broccoli

Author: Raúl Domínguez-Perles and Diego A. Moreno and Cristina García-Viguera

Broccoli has risen as rich in bioactive phytochemicals (glucosinolates and phenolic compounds) closely linked with the reduction of cancer risk. Green tea infusion is a beverage that also contains anticarcinogenic compounds, mainly represented by flavanols. The compounds present in new broccoli-enriched green tea drinks and their potential antitumoral activity in vitro were evaluated. The distinct compounds present in the prepared beverages were identified by HPLC–PAD–ESI-MSn and quantified by HPLC–PAD. Caco-2 and CCD-18Co cell lines were exposed to growing percentages (0.2–5%) of infusions of distinct combinations of plant material. The time-dependent cytotoxicity on the malignant cells was also achieved. Cell death was evaluated by trypan blue dye exclusion and a more efficient specific cytotoxic effect on Caco-2 cells was observed on the cells incubated with the mixture of broccoli and green tea than on cells exposed to control infusions. Broccoli added to green tea resulted in a combination of phytochemicals with antitumoral activity with potential for further developments in mechanistic models and the design of novel foods.

Get the whole article here

Green tea extract reduces blood pressure, inflammatory biomarkers, and oxidative stress and improves parameters associated with insulin resistance in obese, hypertensive patients

Author: Pawel Bogdanski and Joanna Suliburska and Monika Szulinska and Marta Stepien and Danuta Pupek-Musialik and Anna Jablecka

Green tea (GT) consumption is known to be associated with enhanced cardiovascular and metabolic health. The purpose of this study is to examine the hypothesis that supplementation with GT alters insulin resistance and associated cardiovascular risk factors in obese, hypertensive patients. In a double-blind, placebo-controlled trial, 56 obese, hypertensive subjects were randomized to receive a daily supplement of 1 capsule that contained either 379 mg of GT extract (GTE) or a matching placebo, for 3 months. At baseline and after 3 months of treatment, the anthropometric parameters, blood pressure, plasma lipid levels, glucose levels, creatinine levels, tumor necrosis factor α levels, C-reactive protein levels, total antioxidant status, and insulin levels were assessed. Insulin resistance was evaluated according to the homeostasis model assessment–insulin resistance protocol. After 3 months of supplementation, both systolic and diastolic blood pressures had significantly decreased in the GTE group as compared with the placebo group (P < .01). Considerable (P < .01) reductions in fasting serum glucose and insulin levels and insulin resistance were observed in the GTE group when compared with the placebo group. Serum tumor necrosis factor α and C-reactive protein were significantly lower, whereas total antioxidant status increased in the GTE group compared with the placebo (P< .05). Supplementation also contributed to significant (P < .05) decreases in the total and low-density lipoprotein cholesterol and triglycerides, but an increase in high-density lipoprotein cholesterol. In conclusion, daily supplementation with 379 mg of GTE favorably influences blood pressure, insulin resistance, inflammation and oxidative stress, and lipid profile in patients with obesity-related hypertension.