Research Database

Author: Christian H. Coyle and Brian J. Philips and Shelby N. Morrisroe and Michael B. Chancellor and Naoki Yoshimura

Genitourinary tract inflammation/ailments affect the quality of life and health of a large segment of society. In recent years, studies have demonstrated strong antioxidant effects of green tea and its associated polyphenols in inflammatory states. This in vitro study examined the antioxidant capabilities (and putative mechanisms of action) of green tea extract (GTE), polyphenon-60 (PP-60, 60% pure polyphenols), (−)-epicatechin-3-gallate (ECG) and (−)-epigallocatechin-3-gallate (EGCG) in normal/malignant human bladder cells following catechin treatment ± 1 mM H2O2 (oxidative agent). Cell viability, apoptosis and reactive oxygen species (ROS) formation were evaluated. Our results showed that H2O2exposure significantly reduced normal (UROtsa) and high-grade (TCCSUP, T24) bladder cancer (BlCa) cell viability compared with control-treated cells (p < 0.001). No affect on low-grade RT4 and SW780 BlCa cell viability was observed with exposure to H2O2. Compared to H2O2-treated UROtsa, treatment with PP-60, ECG and EGCG in the presence of H2O2 significantly improved UROtsa viability (p < 0.01), with strongest effects evoked by ECG. Additionally, though not as effective as in UROtsa cells, viability of both high-grade TCCSUP and T24 BlCa cells, in comparison to H2O2-treated cells, was significantly improved (p < 0.01) by treatment with PP-60, ECG, and EGCG in the presence of H2O2. Overall, our findings demonstrate that urothelium cell death via H2O2-induced oxidative stress is mediated, in part, through superoxide (O2−">;), and potentially, direct H2O2 mechanisms, suggesting that green tea polyphenols can protect against oxidative stress/damage and bladder cell death.

 

 

Get the whole article here

Author: Naghma Khan and Hasan Mukhtar

Tea ranks second only to water as a major component of fluid intake worldwide and has been considered a health-promoting beverage since ancient times. For the past two decades, we and others have been investigating the potential cancer preventive and therapeutic effects of green tea and its polyphenolic mixture termed GTP. It has become clear that much of these effects of GTP are mediated by its most abundant catechin, epigallocatechin gallate (EGCG). Large amount of encouraging data from in vitro and animal models has emerged making clear that green tea is a nature’s gift molecule endowed with anticancer effects. Epidemiological and geographical observations suggest that these laboratory data may be applicable to human population. Clinical trials of GTP, especially in prostate cancer patients have yielded encouraging results. This article briefly reviews properties of GTP, especially EGCG with reference to multitargeted therapy of cancer.

 

 

Get the whole article here

Antioxidant synergism of green tea polyphenols with α-tocopherol and l-ascorbic acid in SDS micelles

Author: Fang Dai and Wei-Feng Chen and Bo Zhou

The synergistic antioxidant effect of polyphenols extracted from green tea, i.e. (−)-epicatechin (EC), (−)-epigallocatechin (EGC), (−)-epicatechin gallate (ECG), (−)-epigallocatechin gallate (EGCG) and gallic acid (GA), with α-tocopherol (vitamin E) and l-ascorbic acid (vitamin C) against the peroxidation of linoleic acid has been studied in sodium dodecyl sulfate (SDS) micelles. The peroxidation was initiated thermally by a water-soluble azo initiator 2,2′-azobis(2-amidinopropane) hydrochloride (AAPH), and the reaction kinetics were studied by monitoring the formation of linoleic acid hydroperoxides and consumption of the antioxidants. It was found that the mixture of the green tea polyphenol, vitamin E and vitamin C could act synergistically to protect lipid peroxidation. Kinetic and mechanistic studies on the antioxidation process revealed that this antioxidant synergism was due to the regeneration of vitamin E by the green tea polyphenol and the regeneration of the latter by vitamin C.

 

 

Get the whole article here

Author: Tsung O. Cheng

 

Get the whole article here

Author: Elvira Gonzalez de Mejia and Marco Vinicio Ramirez-Mares and Sirima Puangpraphant

Tea is one of the most widely consumed beverages worldwide. Several studies have suggested that catechins and theaflavins found in tea may reduce the risk of various types of cancers. Major advances have been made to understand the molecular events leading to cancer prevention; however, the evidence is not conclusive. Evidence from pre-clinical and clinical studies also suggests that persistent inflammation can progress to cancer. Several possible mechanisms of action may explain the cancer preventive aspects of tea components specifically anti-inflammatory effects. In regards to brain health, green tea catechins have been recognized as multifunctional compounds for neuroprotection with beneficial effects on vascular function and mental performance. Theanine, a unique amino acid in tea, enhances cognition in humans and has neuroprotective effects. Human interventional studies with well characterized tea products are needed.

 

 

Get the whole article here

Author: A.B. Sharangi

The medicinal effects of tea have a history dating back almost 5000 years. The chemical components of green tea chiefly include polyphenols, caffeine and amino acids. Tea also contains flavonoids, compounds reported to have anti-oxidant properties having many beneficial effects. Tea flavonoids reduce inflammation, have antimicrobial effects and prevent tooth decay. Consumption of tea may have diuretic effects due to the caffeine. A related compound found in tea is theophylline, a licensed medicine for the treatment of respiratory diseases such as asthma. Today’s computer-driven world can generate complicated lifestyle-related disorders and consumption of certain natural product like tea may very well replace the ill-effects of chemical drugs leading to a safer world with happier life. The paper is an overview of revealing all such ethno medicinal research efforts throughout the world over the times.

 

 

Get the whole article here

Author: Derya Kara

Sixteen trace metallic analytes (Ba, Ca, Ce, Co, Cr, Cu, Fe, K, La, Mg, Mn, Na, Ni, P, Sr and Zn) in acid digests of herbal teas were determined and the data subjected to chemometric evaluation in an attempt to classify the herbal tea samples. Nettle, Senna, Camomile, Peppermint, Lemon Balm, Sage, Hollyhock, Linden, Lavender, Blackberry, Ginger, Galangal, Cinnamon, Green tea, Black tea, Rosehip, Thyme and Rose were used as plant materials in this study. Trace metals in these plants were determined by using inductively coupled plasma-atomic emission spectrometry and inductively coupled plasma-mass spectrometry. Principal component analysis (PCA), linear discriminant analysis (LDA) and cluster analysis (CA) were used as classification techniques. About 18 plants were classified into 5 groups by PCA and all group members determined by PCA are in the predicted group that 100.0% of original grouped cases correctly classified by LDA. Very similar grouping was obtained using CA.

 

 

Get the whole article here

Author: Yuanfeng Wang and Xinlin Wei and Zhengyu Jin

A neutral polysaccharide, coded as NTPS-1, was obtained from the crude tea polysaccharide (NTPS) of green tea (Camellia sinesis) by a DEAE-Sepharose fast flow column. The polysaccharide appeared to be homogenous with the weight of 21,247 Da by the high performance gel permeation chromatography (HPGPC) analysis. The NTPS-1 was found to consist of galactose. The structure of NTPS-1 was characterized by infrared (IR) spectrum, gas chromatography (GC), periodate oxidation, Smith degradation, 1D NMR and 2D NMR spectroscopy. It was found that NTPS-1 was a galactan consisting of β-(1→4)-linked galactopyranosyl units.

 

 

Get the whole article here

Author: Tae Il Kim and Yong Kyung Lee and Sang Gi Park and Im Seop Choi and Jung Ok Ban and Hyoung Kook Park and Sang-Yoon Nam and Young Won Yun and Sang Bae Han and Ki Wan Oh and Jin Tae Hong

Amyloid β (Aβ)-induced neurotoxicity is a major pathological mechanism of Alzheimer disease (AD). In this study, we investigated the inhibitory effect of l-theanine, a component of green tea (Camellia sinensis), on Aβ1-42-induced neuronal cell death and memory impairment. Oral treatment of l-theanine (2 and 4 mg/kg) for 5 weeks in the drinking water of mice, followed by injection of Aβ1-42 (2 μg/mouse, icv), significantly attenuated Aβ1-42-induced memory impairment. Furthermore, l-theanine reduced Aβ1-42 levels and the accompanying Aβ1-42-induced neuronal cell death in the cortex and hippocampus of the brain. Moreover, l-theanine inhibited Aβ1-42-induced extracellular signal-regulated kinase (ERK) and p38 mitogen-activated protein kinase as well as the activity of nuclear factor κB (NF-κB). l-Theanine also significantly reduced oxidative protein and lipid damage and the elevation of glutathione levels in the brain. These data suggest that the positive effects of l-theanine on memory may be mediated by suppression of ERK/p38 and NF-κB as well as the reduction of macromolecular oxidative damage. Thus, l-theanine may be useful in the prevention and treatment of AD.

 

 

Get the whole article here

Author: Dongsun Park and Jeong Hee Jeon and Sunhee Shin and Seong Soo Joo and Dae-Hyuck Kang and Seol-Hee Moon and Min-Jung Jang and Yeoung Mi Cho and Jae Wook Kim and Hyeong-Jin Ji and Byeongwoo Ahn and Ki-Wan Oh and Yun-Bae Kim

The effects of green tea extract (GTE) on the fetal development and external, visceral and skeletal abnormalities induced by cyclophosphamide were investigated in rats. Pregnant rats were daily administered GTE (100 mg/kg) by gavage for 7 d, from the 6th to 12th day of gestation, and intraperitoneally administered with cyclophosphamide (11 mg/kg) 1 h after the final treatment. On the 20th day of gestation, maternal and fetal abnormalities were determined by Cesarian section. Cyclophosphamide was found to reduce fetal and placental weights without increasing resorption or death. In addition, it induced malformations in live fetuses; 94.6%, 41.5% and 100% of the external (skull and limb defects), visceral (cleft palate and ureteric dilatation) and skeletal (acrania, vertebral/costal malformations and delayed ossification) abnormalities. When pre-treated with GTE, cyclophosphamide-induced body weight loss and abnormalities of fetuses were remarkably aggravated. Moreover, repeated treatment with GTE greatly increased mRNA expression and activity of hepatic cytochrome P-450 (CYP) 2B, which metabolizes cyclophosphamide into teratogenic acrolein and cytotoxic phosphoramide mustard, while reducing CYP3A expression (a detoxifying enzyme). The results suggest that repeated intake of GTE may aggravate cyclophosphamide-induced body weight loss and malformations of fetuses by modulating CYP2B and CYP3A.

 

 

Get the whole article here