heart-health

Author: Larisa Lvova and Andrey Legin and Yuri Vlasov and Geun Sig Cha and Hakhyun Nam

All-solid-state ‘electronic tongue’ microsystem comprised of polymeric sensors of different types such as highly cross-sensitive sensors based both on \{PVC\} and aromatic polyurethane (ArPU) matrices doped with various membrane active components, electrochemically deposited conductive films of polypyrrole (PPy) and polyaniline (PAn) and potentiometric glucose biosensors has been developed and applied for the analysis of beverages: natural coffee, black tea and different sorts of green teas. The system can discriminate different kinds of teas (black and green) and natural coffees. Components that are responsible for giving unique taste such as caffeine, catechines, sugar, amino acid l-arginine have been determined for green tea samples with unknown manufacturer specifications.

Get the whole article here

Author: Jeong-Hwa Choi and In-Koo Rhee and Keun-Yong Park and Kun-Young Park and Jong-Ki Kim and Soon-Jae Rhee

The purpose of this study was to investigate the effects of green tea catechin on bone metabolic disorders and its mechanism in chronic cadmium-poisoned rats. Sprague-Dawley male rats weighing 100 ± 10 g were randomly assigned to one control group and three cadmium-poisoned groups. The cadmium groups included a catechin free diet (Cd-0C) group, a 0.25% catechin diet (Cd-0.25C) group and a 0.5% catechin diet (Cd-0.5C) group according to their respective levels of catechin supplement. After 20 weeks, the deoxypyridinoline and crosslink values measured in urine were significantly increased in the Cd-0C group. Cadmium intoxication seemed to lead to an increase in bone resorption. In the catechin supplemented group (Cd-0.5C group), these urinary bone resorption marks, were decreased. The serum osteocalcin content in the cadmium-poisoned group was significantly increased as compared with the control group. In the catechin supplemented group serum osteocalcin content values were lower than the control group. The cadmium-intoxicated group (Cd-0C group), had lower bone mineral density than the control group (total body, vertebra, pelvis, tibia and femur). The catechin supplement increased bone mineral density to about the same as the control group. Bone mineral content showed a similar trend to total bone mineral density. Therefore, the bone mineral content of the Cd-0C group at the 20th week was significantly lower than the control group. The catechin supplemented group (Cd-0.5C group) was about the same as the control group. The cause of decreasing bone mineral density and bone mineral content by cadmium poisoning was due to the fast bone turnover rate, where bone resorption occurred at a higher rate than bone formation. The green tea catechin aided in normalizing bone metabolic disorders in bone mineral density, bone mineral content and bone calcium content caused by chronic cadmium intoxication.

Get the whole article here

Author: J.J. Choo

The aim of the present study was to investigate body fat-suppressive effects of green tea in rats fed on a high-fat diet and to determine whether the effect is associated with β-adrenoceptor activation of thermogenesis in brown adipose tissue. Feeding a high-fat diet containing water extract of green tea at the concentration of 20g/kg diet prevented the increase in body fat gain caused by high-fat diet without affecting energy intake. Energy expenditure was increased by green tea extract which was associated with an increase in protein content of interscapular brown adipose tissue. The simultaneous administration of the β-adrenoceptor antagonist propranolol(500 mg/kg diet) inhibited the body fat-suppressive effect of green tea extract. Propranolol also prevented the increase in protein content of interscapular brown adipose tissue caused by green tea extract. Digestibility was slightly reduced by green tea extract and this effect was not affected by propranolol. Therefore it appeared that green tea exerts potent body fat-suppressive effects in rats fed on a high-fat diet and the effect was resulted in part from reduction in digestibility and to much greater extent from increase in brown adipose tissue thermogenesis through β-adrenoceptor activation.

Get the whole article here

Author: Tsung O. Cheng

Get the whole article here

Author: Rachel J. Batchelder and Richard J. Calder and Chris P. Thomas and Charles M. Heard

The aim of this study was to investigate the feasibility of the transdermal delivery of catechins and caffeine from green tea extract. Drug-in-adhesive patches containing 1.35, 1.03, 0.68, and 0.32 mg cm−2 green tea extract were formulated and the dissolution of (−)-epigallocatechin gallate (EGCg), (−)-epigallocatechin (EGC) and (−)-epicatechin (EC) from these was determined. Transdermal delivery was determined across full thickness pig ear skin from saturated solutions of green tea extract in pH 5.5 citrate–phosphate buffer, polyethylene glycol 400 and a 50:50 mixture of the citrate phosphate buffer and polyethylene glycol in addition to patches containing 1.35 mg cm−2 green tea extract. Dissolution experiments indicated first order release which was dose dependent in respect of the loading level, although the amounts permeated were not always proportional to the amounts in the formulation. The highest percentage permeation of EGCg was found to be from the patch formulation. EGCg, EGC and EC were all successfully delivered transdermally from saturated solutions and adhesive patches containing green tea extract in this study. There was some evidence for the dermal metabolism of EGCg, but after 24 h 0.1% permeated from the patches containing 1.35 mg cm−2 green tea extract. This was equivalent to the percentage absorbed after intragastric administration of green tea extract in rats. In addition, the concentration of EGCg in the Franz cell receptor chamber after 24 h permeation from the 0.9 cm diameter patch containing 1.35 mg cm−2was within the range of Cmax plasma levels achieved after oral dosing of 2.2–4.2 g m−2 green tea extract. Caffeine was also delivered at concentrations above those previously reported.

Get the whole article here

Author: Deborah J Kuhn and Audrey C Burns and Aslamuzzaman Kazi and Q Ping Dou

Green tea has been shown to lower plasma cholesterol, associated with up-regulation of the low-density lipoprotein receptor (LDLR) although the responsible molecular mechanism is unknown. Previously, we reported that ester bond-containing green tea polyphenols (GTPs), such as (−)-epigallocatechin-3-gallate [(−)-EGCG], potently inhibit the tumor cellular proteasome activity, which may contribute to the cancer-preventative effect of green tea. In the current study, we hypothesize that the proteasome is a heart disease-associated molecular target of GTPs. We have shown that ester bond-containing GTPs, including (−)-EGCG, potently inhibit the proteasomal activity in intact hepatocellular carcinoma HepG2 and cervical carcinoma HeLa cells, as evident by accumulation of ubiquitinated proteins and three natural proteasome targets (p27, IκB-α and Bax). (−)-EGCG selectively inhibits the chymotrypsin-like, but not trypsin-like, activity of the proteasome. Associated with proteasome inhibition by ester bond-containing GTPs, there was a significant, time- and concentration-dependent increase in levels of the cleaved, activated, but not the precursor, form of sterol regulatory element-binding protein 2 (SREBP-2), an essential factor for LDLR transcription. Subsequently, LDL receptor expression was increased dramatically in HepG2 and HeLa cells treated with (−)-EGCG. Our results suggest that ester bond-containing GTPs inhibit ubiquitin/proteasome-mediated degradation of the active SREBP-2, resulting in up-regulation of LDLR. This identified molecular mechanism may be related to the previously reported cholesterol-lowering and heart disease-preventative effects of green tea.

Get the whole article here

Author: S. Coimbra and P. Rocha-Pereira and I. Rebelo and S. Rocha and A. Santos-Silva and E.M.B. Castro

Several studies suggest a protective effect of green tea prepared with leafs of Camellia sinensis for CVD. The interest of the green tea is due to its high content in catechins. Our aim was to evaluate the effect of green tea on some risk factors for CVD. A sample of 34 Portuguese individuals was used. We evaluated the total cholesterol, HDLc, LDLc, triglycerides, lipoprotein (a), apolipoprotein A-I and B, total antioxidant status, lipid peroxidation products, oxidative changes in erythrocyte membrane and the P-selectin levels. The analyses were performed at the beginning, after 3 weeks drinking 1 liter of water daily, and after 4 weeks drinking 1 liter of green tea daily. The tea was prepared everyday in the same conditions. We found no dilution effect on the analyzed parameters. After ingestion of green tea, we found a significant reduction in total cholesterol, LDLc, and apolipoprotein B; an increase in HDLc and apolipoprotein A-I; a decrease in lipid peroxidation and a significant reduction in the oxidative stress within the erythrocyte. We found also an increase in the antioxidant capacity and a decrease in P-selectin levels. Our resuts suggest that green tea has a beneficial effect, protecting for CVD, by improving the lipid profile and the oxidative stress. 

Get the whole article here

Author: Dong-Wook Han and Young Hwan Park and Jeong Koo Kim and Kwon-Yong Lee and Suong-Hyu Hyon and Hwal Suh and Jong-Chul Park

The potential role of green tea polyphenol (GtPP) in preserving the human saphenous vein was investigated under physiological conditions. The vein segments were incubated for 1, 3, 5, 7 and 14 days, either after 4 h of treatment with 1.0 mg/ml GtPP or in the presence of GtPP at the same concentration. After incubation, the endothelial cell viability, endothelial nitric oxide synthase (eNOS) expression and the vein histology were evaluated. When the veins were not treated with GtPP, the viability of the endothelial cells was significantly reduced with the progress in the culture time, and none of the cells expressed eNOS after 5 days. Furthermore, severe histological changes and structural damage were observed in the non-treated veins. In contrast, incubating the veins after 4 h of GtPP treatment significantly prevented these phenomena. The cellular viability of the GtPP-treated vein was approximately 64% after 7 days, and eNOS expression was maintained up to 40%, compared to that of the fresh vein. The histological observations showed that the vasculature was quite similar to that of the fresh vein. When incubated with GtPP, the vein could also be preserved for 1 week under physiological conditions retaining both its cellular viability (61%) and eNOS expression level (45%) and maintaining its venous structure without any morphological changes. These results demonstrate that GtPP treatment may be a useful method for preserving the HSV.

Get the whole article here

Author: Periasamy Srinivasan and Kuruvimalai Ekambaram Sabitha and Chennam Srinivasulu Shyamaladevi

In cancer, a high flux of oxidants not only depletes the cellular thiols, but damages the whole cell as well. Epidemiological studies suggest green tea may mitigate cancers in human and animal models for which several mechanisms have been proposed. In the present investigation, the levels of cellular thiols such as reduced glutathione (GSH), oxidised glutathione (GSSG), protein thiols (PSH), total thiols, lipid peroxidation product conjugated dienes and the activity of gamma glutamyl transferase (GGT) were assessed in tongue and oral cavity. In 4-Nitroquinoline 1-oxide- (4-NQO) induced rats, there was a decrease in the levels of GSH, PSH and total thiols and an increase in the levels of GSSG, conjugated dienes and the activity of GGT. On supplementation of green tea polyphenols (GTP) for 30 days (200 mg/kg) for the oral cancer-induced rats, there was a moderate increase in the levels of GSH, PSH and total thiols and a decrease in the levels of GSSG, conjugated dienes and the activity of GGT. Thus, GTP reduces the oxidant production thereby maintains the endogenous low molecular weight cellular thiols in oral cancer-induced rats. From the results, it can be concluded that GTP supplementation enhances the cellular thiol status thereby mitigate oral cancer.

Get the whole article here

Author: Marcel W.L. Koo and Chi H. Cho

Green tea is rich in polyphenolic compounds, with catechins as its major component. Studies have shown that catechins possess diverse pharmacological properties that include anti-oxidative, anti-inflammatory, anti-carcinogenic, anti-arteriosclerotic and anti-bacterial effects. In the gastrointestinal tract, green tea was found to activate intracellular antioxidants, inhibit procarcinogen formation, suppress angiogenesis and cancer cell proliferation. Studies on the preventive effect of green tea in esophageal cancer have produced inconsistent results; however, inverse relationships of tea consumption with cancers of the stomach and colon have been widely reported. Green tea is effective to prevent dental caries and reduce cholesterols and lipids absorption in the gastrointestinal tract, thus benefits subjects with cardiovascular disorders. As tea catechins are well absorbed in the gastrointestinal tract and they interact synergistically in their disease-modifying actions, thus drinking unfractionated green tea is the most simple and beneficial way to prevent gastrointestinal disorders.

Get the whole article here