heart-health

According to Harvard Medical School, “lowering your risk of cardiovascular disease may be as easy as drinking green tea. Studies suggest this light, aromatic tea may lower LDL cholesterol and triglycerides, which may be responsible for the tea's association with reduced risk of death from heart disease and stroke.”

Recent Research Papers on
heart-health

Active film from chitosan incorporating green tea extract for shelf life extension of pork sausages

Author: Ubonrat Siripatrawan and Suparat Noipha

Chitosan film incorporating green tea extract (CGT-film) was used as active packaging for shelf life extension of pork sausages. The physical, chemical, microbiological, and sensory qualities of pork sausages wrapped with CGT-film were compared with those wrapped with chitosan-alone film (C-film) and those without chitosan film wrapping (control). Changes in the qualities of pork sausages including color, texture, lipid oxidation with respect to thiobarbituric value (TBA), and microbiological qualities including total plate counts, yeasts and molds, and lactic acid bacteria were determined throughout the storage at 4 °C. The sensory qualities including odor, color, slime formation, and overall acceptability were evaluated using Quantitative Descriptive Analysis. It was found that samples wrapped with CGT-film showed lower changes in color, texture, TBA value, microbial growth, and sensory characteristics than those wrapped with C-film and control, respectively. Successful inhibition of lipid oxidation and microbial growth in the refrigerated pork sausages was possible with chitosan film incorporating green tea extract. The results suggested that incorporation of green tea extract into chitosan film could enhance the antioxidant and antimicrobial properties of the film and thus maintained the qualities and prolonged the shelf life of the sausages.

Get the whole article here

Nanoemulsified green tea extract shows improved hypocholesterolemic effects in C57BL/6 mice

Author: Young Jun Kim and Soung-Jin Houng and Jae Hoon Kim and Young-Rok Kim and Hong Geun Ji and Sung-Joon Lee

Nanoemulsification of nutrients could improve bioavailability by enhancing intestinal uptake. We investigated the antioxidant and hypolipidemic effects of nanoemulsified green tea extract (NGTE). Antioxidant effect was measured by 2,2′-azino-bis(3-ethylbenzthiazoline-6-sulfonic acid) (ABTS) radical scavenging assay and dichlorofluorescein diacetate (DCFH-DA) assay. C57BL/6 mice were fed a control high-fat diet, green tea extract (GTE), or NGTE diet for 4 weeks. In composition analysis, GTE and NGTE contained similar total catechin concentrations. The antioxidative effect of GTE was comparable with that of NGTE. In the ABTS assay, GTE had a marked effect, although NGTE was more effective than GTE in the DCFH-DA assay. In the mouse feeding experiment, total and low-density lipoprotein (LDL) cholesterol concentrations were significantly reduced after NGTE treatment in comparison with GTE treatment in high-fat-fed C57BL/6J mice over the course of 4 weeks. The hypocholesterolemic effects were greater in the NGTE group compared with the GTE group (24% vs. 15.4% LDL cholesterol reduction compared with the control). Expression of 3-hydroxy-3-methylglutaryl coenzyme A reductase was significantly down-regulated. Protein expression of LDL receptor was significantly increased in the livers of both the GTE- and NGTE-treated groups (+234.1%, P<.01 and +274.7%, P<.001), with a greater effect in the NGTE than in the GTE group. Cholesterol 7α-hydroxylase gene expression was similarly increased in both the GTE and NGTE groups. These results suggest that nanoemulsification significantly increased hypocholesterolemic effects of GTE in vivo due to increased bioavailability.

Get the whole article here

Evaluation of the hepatoprotective effect of green tea extract and selenium on CCL4-induced fibrosis

Author: Mona F. Mahmoud and A. Fahmy and Marwa A. Auf

Background & aims This investigation aimed to evaluate the possible hepatoprotective effects of green tea extract and selenium on liver fibrosis in comparison with silymarin and to study the underlying mechanisms. Methods Liver fibrosis was induced in rats by i.p. injection of CCL4 (3 times a week for 6 weeks in a dose of 25 μl/100 gb.w). Green tea extract (200 mg/kg), selenium (0.945 mg/kg) and silymarin (100 mg/kg) were given orally and daily for 8 weeks (2 weeks before CCL4 and 6 weeks along with CCL4). Results CCL4-induced fibrosis as indicated by increased activities of liver enzymes and increased lactate dehydrogenase (LDH) activity is an indicator of cell death. It also elevated serum nitric oxide (NO), inflammatory mediators like tumor necrosis factor alpha (TNF-α) and liver lipid peroxidation and decreased liver reduced glutathione (GSH) content. It also increased liver collagen fiber percent and caused liver cell damage. On the other hand, green tea and selenium reduced these changes and improved the pathological effects caused by CCL4. Both drugs’ effects were similar to silymarin hepatoprotective effects but they cause greater reduction of collagen fiber percent than silymarin. Conclusions Findings of the present study suggest that green tea extract and selenium have protective effects similar in most aspects to silymarin via anti-inflammatory and antioxidant effects. In addition, their antifibrotic effect was stronger than that of silymarin. So both natural products may be used as adjunctive therapy in liver fibrosis.

Get the whole article here

Risk factor for clear cell renal cell carcinoma in Chinese population: A case–control study

Author: Guoping Wang and Jianguo Hou and Liye Ma and Jiaxin Xie and Jianhua Yin and Danfeng Xu and Wenjun Chang and Xiaojie Tan and Tong Su and Hongwei Zhang and Guangwen Cao

Background: Risk factors for clear cell renal cell carcinoma (ccRCC) differ among populations and remain controversial. We carried out a hospital-based case–control study to examine the effects of health status, lifestyle, and some genetic polymorphisms on ccRCC risk in Chinese subjects. Methods: Between 2007 and 2009, 250 newly diagnosed, histologically confirmed ccRCC cases and 299 sex-, age-matched healthy controls provided complete information including consumption of tea and alcohol, smoking, occupational exposure, body mass index (BMI), hypertension, diabetes, and urolithiasis by face-to-face interview in Shanghai. Genetic polymorphisms of cytochrome P450 mono-oxygenase (CYP1A1: 6235T>C, 4889A>G, and 4887C>A), glutathione S-transferase (GSTP1: 342A>G), and N-acetyltransferase (NAT2: 481C>T, 590G>A, and 857G>A) were identified by PCR-RFLP and DNA sequencing. Adjusted odds ratio (AOR) and 95% confidence interval (CI) were derived through multivariate logistic regression. Results: Green tea intake (≥500 ml/d) was inversely associated with ccRCC risk, with an AOR of 0.34 (95% CI 0.21–0.55). BMI (≥25 kg/m2), hypertension, and urolithiasis were independently associated with an increased risk of ccRCC, with AOR (95% CI) of 2.10 (1.32–3.34), 2.49 (1.57–3.93), and 3.33 (1.12–9.89), respectively. No association was observed between smoking, alcohol consumption, or occupational exposure with ccRCC risk. The polymorphisms and their interactions with the environmental exposures were mostly not associated with ccRCC risk. Conclusion: BMI (≥25 kg/m2), hypertension, and urolithiasis are independently associated with an increased risk, whereas green tea intake (≥500 ml/d) is independently associated with a decreased risk of ccRCC. The polymorphisms of the xenobiotic-metabolizing enzymes are weakly associated with ccRCC risk in Chinese subjects.

Get the whole article here

Lipid lowering with dietary supplements: Focus on diabetes

Author: Iwona Rudkowska

Cardiovascular disease (CVD) is the predominant cause of mortality in type 2 diabetic (T2DM) patients. Dyslipidemia is a modifiable risk factor that should be treated early for CVD prevention. Further, dietary supplement intake is increasing in popularity worldwide. This review examines the recent meta-analyses and clinical studies on dietary supplements, specifically psyllium, garlic and green tea, on plasma lipids levels and glycemic control, as well as other potential CVD risk factors in T2DM patients. Generally, results demonstrate that psyllium supplements improve lipid profiles as well as glycemic control beyond a traditional diet in patients with T2DM. On the other hand, the results on the usefulness of garlic and green tea supplementation for dyslipidemia and hyperglycemia are uncertain. Overall, the addition of dietary supplements may be a therapeutic alternative to lower CVD risk factors in T2DM; however, more well-designed intervention studies are needed to assess the benefit of these dietary supplements.

Get the whole article here

3.352 EFFECTS OF GREEN TEA EXTRACT (GTE) ON HALOPERIDOL (HAL) INDUCED NEUROLEPTIC ANXIETY SYNDROME (NAS) AND PARKINSONISM IN RATS

Author: T. Malik and D.J. Haleem

Introduction: HAL elicits NAS along Parkinsonism. HAL induces c-Fos responsiveness in a distributed anxiety-related neural scheme, selected neuronal population of nucleus accumbens. Mood deficits by HAL metabolically effect via diet restriction that reduced body weight. GTE is known to control appetite and body weight while exerting anxiolytic effects. Aim: The current study testifies the hypothesis that GTE may control HAL elicited NAS with reducing Parkinsonism. Methods: Rats (n=6) were treated with one of the four treatments; oral fluid [water/GTE (1 gm/liter)] plus saline; or oral fluid plus i.p HAL (1 mg/kg/day) administration. Behavioral assessments and neurochemical analysis were performed following six weeks of treatments. Results: suggest that HAL induced decreases in fluid, food intake and growth rate were greater in GTE treated animals. GTE was shown to induce anxiogenic behavior examined in light dark box transitional test but not in fear like exploratory behavior on elevated plus maze and motor deficits on rota rod performance. HAL induced locomotor activity was suppressed, innate aversive and fear like exploratory behaviors were greater in GTE than water drinking animals. HAL induced serotonergic metabolism was increased in the caudate and nucleus accumbens and decreased in the serotonin availability in the rest of the brain regions of GTE treated animals. HAL induced decreased dopamine was increase din the nucleus accumbens of GTE drinking than water drinking animals. Conclusion: Potential mechanism involved in the greater anorexiogenic effects of GTE and greater HAL induced NAS plus Parkinsonism in GTE treated animals is proposed for demonstration in this meeting.

Get the whole article here

Polyphenols in brewed green tea inhibit prostate tumor xenograft growth by localizing to the tumor and decreasing oxidative stress and angiogenesis

Author: Susanne M. Henning and Piwen Wang and Jonathan Said and Clara Magyar and Brandon Castor and Ngan Doan and Carmen Tosity and Aune Moro and Kun Gao and Luyi Li and David Heber

It has been demonstrated in various animal models that the oral administration of green tea (GT) extracts in drinking water can inhibit tumor growth, but the effects of brewed GT on factors promoting tumor growth, including oxidant damage of DNA and protein, angiogenesis and DNA methylation, have not been tested in an animal model. To explore these potential mechanisms, brewed GT was administered instead of drinking water to male severe combined immunodeficiency (SCID) mice with androgen-dependent human LAPC4 prostate cancer cell subcutaneous xenografts. Tumor volume was decreased significantly in mice consuming GT, and tumor size was significantly correlated with GT polyphenol (GTP) content in tumor tissue. There was a significant reduction in hypoxia-inducible factor 1-alpha and vascular endothelial growth factor protein expression. GT consumption significantly reduced oxidative DNA and protein damage in tumor tissue as determined by 8-hydroxydeoxyguanosine/deoxyguanosine ratio and protein carbonyl assay, respectively. Methylation is known to inhibit antioxidative enzymes such as glutathione S-transferase pi to permit reactive oxygen species promotion of tumor growth. GT inhibited tumor 5-cytosine DNA methyltransferase 1 mRNA and protein expression significantly, which may contribute to the inhibition of tumor growth by reactivation of antioxidative enzymes. This study advances our understanding of tumor growth inhibition by brewed GT in an animal model by demonstrating tissue localization of GTPs in correlation with inhibition of tumor growth. Our results suggest that the inhibition of tumor growth is due to GTP-mediated inhibition of oxidative stress and angiogenesis in the LAPC4 xenograft prostate tumor in SCID mice.

Get the whole article here

Green tea extract markedly lowers the lymphatic absorption and increases the biliary secretion of 14C-benzo[a]pyrene in rats

Author: Juyeon Kim and Sung I. Koo and Sang K. Noh

Previously, we have shown that green tea extract (GTE) lowers the intestinal absorption of lipids and lipophilic compounds in rats. This study was conducted to investigate whether GTE inhibits the intestinal absorption and biliary secretion of benzo[a]pyrene (BaP), an extremely lipophilic potent carcinogen, present in foods as a contaminant. Male rats with lymph or bile duct cannula were infused at 3.0 ml/h for 8 h via a duodenal catheter with lipid emulsion containing 14C-BaP with or without GTE in PBS buffer. Lymph and bile were collected hourly for 8 h. The 14C-radioactivities in lymph, bile and intestine were determined and expressed as % dose infused. Results showed that GTE drastically lowered the lymphatic absorption of 14C-BaP (7.6±3.2% in GTE-infused vs. 14.4±2.7% dose/8 h in control rats), with a significantly higher amount of 14C-radioactivity present in the small intestinal lumen and cecum in rats infused with GTE. GTE also markedly increased the hourly rate (3.9±0.1% dose/h in GTE-infused vs. 3.0±0.1% dose/h in control rats) and the total biliary secretion of 14C-BaP (31.5±0.8% dose/8 h in GTE-infused vs. 24.3±0.4% dose/8 h in control rats). The findings provide first direct evidence that GTE has a profound inhibitory effect on the intestinal absorption of BaP and promotes the excretion of absorbed BaP via the biliary route. Further studies are warranted to investigate whether green tea could be recommended as a dietary means of ameliorating the toxicity and carcinogenic effect of BaP.

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

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.