heart-health
Recent Research Papers on
heart-health
Author: Michele Antonello and Domenico Montemurro and Massimo Bolognesi and Marco Di Pascoli and Anna Piva and Franco Grego and Daniele Sticchi and Luisa Giuliani and Spiridione Garbisa and Gian Paolo Rossi
Author: Seung I. Jang and Moo-Hyung Jun and Hyun S. Lillehoj and Rami A. Dalloul and Il-Keun Kong and Suk Kim and Wongi Min
Anticoccidial effects of green tea (GT)-based diets were evaluated in chickens following oral infection with Eimeria maxima an ubiquitous intestinal parasite of poultry that impairs the growth and feed efficiency of infected birds. Five-week-old chickens were assigned to four groups (GT 0.5%, GT 2.0%, untreated/infected and non-infected control) and each group consisted of 15 chickens. Chickens were fed a standard diet supplemented with ground green tea for 2 weeks prior to infection with E. maxima (10,000 sporulated oocysts per bird). The effects of green tea on E. maxima infection were assessed by two parameters, fecal oocyst shedding and body weight gain. The green tea-fed chickens produced significantly reduced fecal oocysts (P < 0.05) when compared to the E. maxima-infected group fed standard diet. The green tea-based diet, however, did not improve body weight loss caused by E. maxima infection. This study is the first to demonstrate anticoccidial effect of green tea on Eimeriaparasites.
Author: Michelle L. Fraser and Gladys S. Mok and Andy H. Lee
Summary Background Stroke is a leading cause of morbidity and mortality in many countries. Green tea is a simple and inexpensive beverage that is showing promise in the prevention of several diseases, including stroke. However, epidemiological studies examining the preventive effects of tea on stroke have generated inconsistent results. Objective To review the emerging evidence for green tea in stroke prevention. Methods Published articles were located by searching the PubMed, ProQuest, CINAHL and other databases, using the keywords ‘tea’ and ‘stroke’ with no restriction on publication date. Reference lists of identified articles were also searched for relevant publications. Results Two published epidemiological studies on green tea reported positive findings. A large number of studies have also proposed biological mechanisms by which tea or tea components may reduce the stroke risk. Additional studies are required from a variety of populations, assessing duration and different types of tea consumption on subtypes of stroke to provide further evidence. Conclusion Green tea is a safe and cheap beverage. Its consumption should be encouraged because it could potentially serve as a practical method for stroke prevention.
Author: Sancho Bañón and Pedro Díaz and Mariano Rodríguez and María Dolores Garrido and Alejandra Price
Green tea (GTE) and grape seed (GSE) extracts are proposed as preservatives for increasing the shelf life of low sulphite raw beef patties. The antioxidant and antimicrobial activities of both extracts were compared with ascorbate. Five groups were established for the patties: Control (with no additives), S (100 SO2), SA (100 SO2 + 400 sodium ascorbate), ST (100 SO2 + 300 GTE) and SG (100 SO2 + 300 GSE) (mg per kg of meat). Patties were stored at 4 °C in aerobic packaging for 0, 3, 6 or 9 days under retail display conditions. Meat spoilage (total viable and coliform counts, pH, lightness, chroma, hue angle, metmyoglobin and TBARS) was determined. The sensory contribution of the extracts to cooked patties was evaluated (colour, odour, flavour and texture). The results pointed to the possibility of using low SO2-vegetable extract combinations to preserve raw meat products. ST, SG and SA delayed microbial spoilage, redness loss and lipid oxidation, thus increasing the shelf life of the raw sulphite beef patties by 3 days. ST, SG and SA also delayed the onset of rancid flavours in cooked patties. No anomalous sensory traits were caused by either extract. Ascorbate, GTE and GSE improved the preservative effects of SO2 on beef patties, especially against meat oxidation. This suggested that the quantity of SO2 added can be reduced to obtain healthier raw meat products.
Author: Christina A. Bursill and Mavis Abbey and Paul D. Roach
Green tea extracts enriched in catechins decrease plasma cholesterol in hamsters, mice and rats. The aims of this study were to determine whether a catechin-enriched extract of green tea could lower plasma cholesterol in the cholesterol-fed rabbit and to determine the mechanism of action. Four groups of six New Zealand White rabbits were initially made hypercholesterolaemic by feeding a 0.25% (w/w) cholesterol diet for 2 weeks before the diet was supplemented with a catechin extract from green tea at 0, 0.5, 1 or 2% (w/w) for 4 weeks. Administration of the crude catechin extract from green tea significantly (p < 0.05) lowered cholesterol in plasma (−60%), VLDL + IDL (−70%), LDL (−80%), liver (total by −25% and unesterified by −15%) and aorta (−25%) compared to control. There was a significant reduction in the cholesterol synthesis index (−60%) and a significant increase in hepatic LDL receptor activity (+80%) and protein (+70%) but there was no change in the intrinsic capacity to absorb cholesterol from the intestines. These results suggest that green tea catechins lowered plasma, liver and aortic cholesterol in the cholesterol-fed rabbit by lowering cholesterol synthesis and upregulating the hepatic LDL receptor.
Author: Pon Velayutham Anandh Babu and Kuruvimalai Ekambaram Sabitha and Periasamy Srinivasan and Chennam Srinivasulu Shyamaladevi
The enhanced myocardial collagen content, collagen glycation and the resulting advanced glycation end products (AGE) which exhibit the characteristics of increased cross-linking are proposed for the stiffness of myocardium in diabetes. To explore the cardioprotective effect of green tea in diabetes, we study the effect of green tea extract on myocardial collagen characteristics in streptozotocin diabetic rats. The effect of green tea on marker enzymes in serum and cardiac tissues were also assayed to understand the extent of protection. Six weeks after the diabetes induction, diabetic rats were treated with green tea extract [300 mg (kg body weight)−1 day−1] for 4 weeks. AGE were determined by fluorescence assay and cross-linking of collagen by solubility measurement while collagen content was measured by biochemical assay. The activities of aspartate transaminase (AST), lactate dehydrogenase (LDH) and creatine kinase (CPK) were measured by biochemical assay. The increase in blood glucose, glycated hemoglobin and systolic blood pressure in diabetic rats were reduced upon green tea treatment. The activities of AST, LDH and CPK were significantly increased in serum whereas decreased in cardiac tissues in diabetic rats representing the cardiac damage. Administration of green tea to diabetic rats significantly ameliorates these enzyme activities. There was no significant difference in the myocardial collagen content among the experimental rats. A significant (P < 0.05) increase in collagen linked Maillard-type fluorescence and decrease in collagen solubility in the myocardium of diabetic rats as compared to control rats (0.955 ± 0.02 versus 0.683 ± 0.04 and 30 ± 1.41 versus 45.17 ± 1.17, respectively) indicates the increase in advanced glycation end products formation and degree of collagen cross-linking. Green tea administration to diabetic rats significantly (P < 0.05) decreased the fluorescence (0.73 ± 0.02) whereas increased the solubility of collagen (41.5 ± 1.04) indicating the reduction in advanced glycation end products and collagen cross-linking. The present study reveals that green tea by ameliorating myocardial collagen characteristics may provide a therapeutic option in the treatment of cardiovascular complications of diabetes.
Author: Asuka Hino and Hisashi Adachi and Mika Enomoto and Kumiko Furuki and Yoshiyuki Shigetoh and Maki Ohtsuka and Shun-Ichi Kumagae and Yuji Hirai and Ali Jalaldin and Akira Satoh and Tsutomu Imaizumi
In Japan, metabolic syndrome used to be rare, and the level of coffee consumption was low. However, the Japanese life style has been changing rapidly, and these changes have been associated with a steady increase in the frequency of metabolic syndrome and with greater consumption of coffee. We examined the relationship between metabolic syndrome and the consumption of coffee or green tea. A total of 1902 Japanese aged over 40 years (785 men and 1117 women) received population-based health check-up in 1999. We measured components of metabolic syndrome (blood pressure, waist circumference, fasting plasma glucose, and lipid profiles). Eating and drinking patterns were evaluated by a food frequency questionnaire. Multivariate analyses were performed to clarify the association between coffee or green tea consumption and the components of metabolic syndrome. All components of metabolic syndrome except for HDL-cholesterol were significantly (p < 0.01) and inversely related to coffee but not green tea consumption by multivariate analysis after adjusting for confounding factors. The larger was the number of components of metabolic syndrome, the lower was the level of coffee consumption (p < 0.0001). In addition, there was a high frequency of metabolic syndrome in small coffee drinkers. Thus, coffee but not green tea consumption was inversely associated with metabolic syndrome.
Author: Sara Anees Khan and Shubha Priyamvada and Natarajan A. Arivarasu and Sheeba Khan and Ahad Noor Khan Yusufi
Objective Green tea, consumed worldwide since ancient times, is considered beneficial to human health. We hypothesized that green tea would enhance antioxidant defenses and specific metabolic activities of rat intestine, liver, and kidney to improve their functions. Methods The effect of green tea given to rats in the diet or drinking water for 25 d was determined on blood chemistry and on activities of enzymes of carbohydrate metabolism, brush border membrane, and antioxidant defense. Results Serum glucose, cholesterol, phosphate, and body weight decreased, whereas the activities of lactate and malate dehydrogenases and glucose-6- and fructose 1,6-bis-phosphatases increased in the intestine and kidney but slightly changed in the liver. Activity of glucose-6-phosphate dehydrogenase profoundly increased in the renal cortex but decreased in other tissues. Lipid peroxidation increased in the intestine and renal medulla and decreased in the renal cortex and liver; catalase increased in all tissues but the medulla. Superoxide dismutase activity decreased in the intestine but increased in renal tissues. Activities of brush border membrane enzymes in general increased in the intestine and kidney. Conclusion Green tea consumption resulted in enhanced enzyme activities of carbohydrate metabolism and antioxidant defenses, which may lead to improved health.
Author: Rajesh Manian and Nagarajan Anusuya and Perumal Siddhuraju and Sellamuthu Manian
The stem bark and fruits of Ficus bengalensis L. and Ficus racemosa L. are used in India for the treatment of diabetes and a number of other diseases. Since these effects may be correlated with the presence of antioxidant compounds, methanol and 70% acetone (acetone:water, 70:30) extracts of F. bengalensis(aerial root) and F. racemosa (stem bark) were evaluated for their antioxidant activity and radical scavenging capacity in comparison with Camellia sinensis (L.) O. Kuntz (green tea). Methanol extracts of green tea and F. bengalensis and 70% acetone extract of F. racemosa contained relatively higher levels of total phenolics than the other extracts. The antioxidant potential of the extracts were assessed by employing different in vitro assays such as reducing power assay, DPPH, ABTS+ and OH radical scavenging capacities, peroxidation inhibiting activity through linoleic acid emulsion system, antihemolytic assay by hydrogen peroxide induced method and metal ion chelating ability. Though all the extracts exhibited dose dependent reducing power activity, methanol extracts of all the samples were found to have more hydrogen donating ability. Similar line of dose dependent activity has been maintained in all the samples in DPPH and OH scavenging systems. All the extracts exhibited antioxidant activity against the linoleic acid emulsion system (34–38%). The potential of multiple antioxidant activity was evident as it possessed antihemolytic activity and metal ion chelating potency.
Author: Giangiacomo Beretta and Sandra Furlanetto and Luca Regazzoni and Marina Zarrella and Roberto Maffei Facino
The aim of this work was to investigate in vitro the quenching activity of green tea polyphenols against α,β-unsaturated aldehyde, using 4-hydroxy-nonenal (HNE) as prototype and HPLC–ESI–MS/MS techniques. HNE is the most abundant and genotoxic product of oxidation of dietary polyunsaturated fatty acids, and is believed to be involved in the early stage of colorectal carcinogenesis on account of its genotoxic potential. Both epigallocatechin gallate (EGCG, 1.0–3.5 mM), the main constituent of green tea polyphenols, and a green tea aqueous extract are able to quench HNE (50 μM) in colorectal physiomimetic conditions (10 mM phosphate buffer, pH 8.0, 37 °C), giving rise to the formation of six diastereomeric covalent adducts at the ring A of EGCG, as indicated by their ESI–MS/MS fragmentation pathways. The specificity of the adduction positions was explained by 1H NMR experiments. HNE quenching is pH-dependent and maximum at pH 8.0. ESI–MS analysis showed no formation of 4-hydroxy-2,3-epoxy-nonanal, or adduction of the epoxide to EGCG. This implies that too little hydrogen peroxide (1 mM, 24 h incubation, FOX-2 method) develops from auto-oxidation of EGCG in our aerobic experimental conditions to oxidize HNE to its corresponding epoxide, so this mechanism is not responsible for the compound's disappearance. EGCG and green tea extract also quenched acrolein, another genotoxic α,β-unsaturated aldehyde, giving one predominant adduct and minor isobaric species, probably due the adduction of acrolein at different positions of the EGCG ring A. These results suggest that EGCG and green tea extract, beside the proposed mechanisms of chemoprevention that target multiple cell-signaling pathways that control cell proliferation and apoptosis in cancer cells, can also prevent protein carbonylation in the tumor tissue environment, depending on the pH of the medium surrounding the tissue, the type of tumor, the stage of dysregulation of lipid peroxidation and, finally, the stage of carcinoma development.