[Show abstract][Hide abstract] ABSTRACT: Objective To determine whether ingesting a green tea beverage enriched with catechins with a galloyl moiety during a meal reduces body fat in moderately obese adults. Design Randomized double-blind placebo-controlled study. Subjects A total of 126 obese subjects (25 ≤ body mass index < 30 kg m(-2)) were randomly assigned to a group receiving green tea beverages without catechins (placebo), or a group receiving green tea beverages with a low or high content of catechins with a galloyl moiety. Each subject ingested 500 mL bottled green tea beverages containing 25, 180, or 279.5 mg green tea catechins (0, 149.5, or 246.5 mg catechins with a galloyl moiety, respectively), at mealtimes for 12 weeks; the subjects were instructed to ingest the beverage during the meal that had the highest fat content on that day. Methods Anthropometric measurements and blood chemistry analysis were performed during the run-in period; at weeks 0, 4, 8, and 12 of the intake period; and at the end of the withdrawal period. Abdominal fat area was measured by computed tomography at weeks 0, 8, and 12 of the intake period and at the end of the withdrawal period. Results Both the low- and high-dose groups exhibited significant reductions in visceral and subcutaneous fat areas compared to the control group at 12 weeks post-intervention. Conclusion Ingestion of a green tea beverage enriched with catechins with a galloyl moiety during a high-fat meal reduces body fat in moderately obese adults.
[Show abstract][Hide abstract] ABSTRACT: Green tea is rich in polyphenols, including catechins which have antioxidant activities and are considered to have beneficial effects on cardiovascular health. In the present study, we investigated the effects of green tea catechins on low-density lipoprotein (LDL) oxidation in vitro and in human studies to test the hypothesis that catechins are incorporated into LDL particles and exert antioxidant properties. In a randomized, placebo-controlled, double-blind, crossover trial, 19 healthy men ingested green tea extract (GTE) in the form of capsules at a dose of 1 g total catechin, of which most (>99%) was the gallated type. At 1 hour after ingestion, marked increases of the plasma concentrations of (−)-epigallocatechin gallate and (−)-epicatechin gallate were observed. Accordingly, the plasma total antioxidant capacity was increased, and the LDL oxidizability was significantly reduced by the ingestion of GTE. We found that gallated catechins were incorporated into LDL particles in nonconjugated forms after the incubation of GTE with plasma in vitro. Moreover, the catechin-incorporated LDL was highly resistant to radical-induced oxidation in vitro. An additional human study with 5 healthy women confirmed that GTE intake sufficiently increased the concentration of gallated catechins, mainly in nonconjugated forms in LDL particles, and reduced the oxidizability of LDL. In conclusion, green tea catechins are rapidly incorporated into LDL particles and play a role in reducing LDL oxidation in humans, which suggests that taking green tea catechins is effective in reducing atherosclerosis risk associated with oxidative stress.
No preview · Article · Nov 2015 · Nutrition research
[Show abstract][Hide abstract] ABSTRACT: Objective: We performed this study in order to clarify whether Streptococcus thermophilus strain 9618 yogurt supplementation possess beneficial effects on Influenza infection or Cold Syndrome. Methods: A randomized parallel-group trial was performed in nursing homes, located in Sapporo area. One hundred elderly subjects, who permanently reside in nursing homes, were administrated with Streptococcus thermophilus strain 9618 yogurt or placebo food for 5 months. Subjects were monitored for prevalence of Influenza and Cold Syndrome in between intake periods. As secondly endpoints, QOL and subjective symptoms in daily life were monitored by care persons and by a questionnaire. Results: Prevalence of Cold Syndrome was significantly reduced in the Streptococcus thermophilus strain 9618 yogurt group, compared to placebo group (P=0.0265). Co-primary end-points, prevalence of Influenza appeared not to be significantly influenced. The result of the secondly endpoints' analysis showed that symptoms related to Cold Syndrome tended to be improved by the intakes of Streptococcus thermophilus strain 9618 yogurt. Conclusions: Streptococcus thermophilus strain 9618 yogurt supplementation may be an effective strategy in protection against Cold Syndrome.
[Show abstract][Hide abstract] ABSTRACT: Green tea is known to have various health benefits for humans. However, the effect of green tea consumption on cognitive dysfunction remains to be clinically verified. We conducted a clinical study to investigate the effects of green tea consumption on cognitive dysfunction. Twelve elderly nursing home residents with cognitive dysfunction (Mini-Mental State Examination Japanese version (MMSE-J) score: <28) participated in the study (2 men, 10 women; mean age, 88 years). The participants consumed green tea powder 2 g/day for 3 months. After three months of green tea consumption, the participants' MMSE-J scores were significantly improved (before, 15.3 ± 7.7; after, 17.0 ± 8.2; p = 0.03). This result suggests that green tea consumption may be effective in improving cognitive function or reducing the progression of cognitive dysfunction; however, long-term large-scale controlled studies are needed to further clarify the effect.
[Show abstract][Hide abstract] ABSTRACT: The mechanisms underlying the effect of epigallocatechin gallate (EGCG) on the micellar solubility of cholesterol were examined. EGCG eliminated both cholesterol and phosphatidylcholine (PC) from bile salt micelles in a dose-dependent manner in vitro. When the bile salt micelles contained a phospholipid other than PC, neither cholesterol nor the phospholipid was eliminated following the addition of EGCG. When vesicles comprised of various phospholipids were prepared and, EGCG was added to the vesicles, EGCG effectively and exclusively eliminated only PC. An intermolecular nuclear Overhauser effect (NOE) was observed between PC and EGCG in bile salt micelles with EGCG added, but not between cholesterol and EGCG, by using a NOE-correlated spectroscopy (NOESY) NMR method. The results of binding analyses using surface plasmon resonance (SPR) showed that EGCG did not bind to cholesterol. These observations strongly suggest that EGCG decreases the micellar solubility of cholesterol via specific interaction with PC.
No preview · Article · Mar 2014 · Journal of Agricultural and Food Chemistry
[Show abstract][Hide abstract] ABSTRACT: Objective: We examined the effect of catechins with a galloyl moiety to reduce dietary lipid absorption in humans. Methods: A randomized double-blind placebo-controlled crossover study was conducted. The beverage (340 mL/bottle) contained 190.9 mg of tea catechins with a galloyl moiety. Fifteen healthy adult subjects were randomly divided into two groups. Group A was requested to consume the drinks, containing catechins with a galloyl moiety, everyday for 10 days and then the placebo for 10 days, after an 11 day interval between these intake periods. On the contrary, Group B consumed the placebo first for 10 days and then the catechin drinks for 10 days, after an 11 day interval between the periods. Each subject in the catechin group was given 3 bottles of the test beverage/day and each subject in the placebo group was given 3 bottles of the placebo beverage/day. During the treatment period, subjects were given the same menu (Male : 2244±35.6 kcal, 84±0.6 g lipids, Female : 1944±35.6 kcal, 66±0.6 g lipids) at each meal. On the last 3 days of each treatment period, feces were collected in order to measure the excretion of lipids. Results: Lipid excretion into feces was found to be significantly higher in the test beverage consumption cases than in the placebo beverage ones on third day. Serum total cholesterol and LDL cholesterol were significantly lower in the test beverage consumption cases than in the placebo beverage ones. Conclusions: Our present observations suggest that consumption of catechins with a galloyl moiety could increase lipid excretion into feces.
[Show abstract][Hide abstract] ABSTRACT: Background: The incidence of seasonal allergic rhinoconjunctivitis triggered by cedar pollen (herewith referred to as cedar pollinosis) continues to increase in Japan, affecting 26.5% of the Japanese population. We evaluated a soft drink containing Enterococcus faecalis EC-12 with respect to its antiallergic effect on patients with cedar pollinosis. This study was performed using an environmental exposure unit (EEU), which assists in the development of effective therapeutic and preventive measures. Methods: We recruited 20 patients with cedar pollinosis over a period of 2 years. We administered 200 mL of a drink containing EC-12 daily, for 8 weeks during the offseason for cedar pollen dispersion. The patients were exposed to pollen before and after the intake of the EC-12 drink to examine the subjective symptoms in the pollen exposure room and those during 5 days after the exposure. Results: In the EEU, (a) nasal discharge and (b) itchy eyes decreased significantly after the intake of the EC-12 drink (a ; p=0.041 at 90 min, b ; p=0.034 at 120 min, p=0.038 at 150 min). Nasal obstruction and scratchy throat seemed to improve, and the amount of tears produced seemed to decrease. During 5 days after the exposure, the patients showed a significant difference in the following parameters : (c) disturbance in daily living activities, (d) itchiness of the eyes, (e) the amount of tears produced, and (f) drowsiness (c ; p=0.037 on the night of the exposure, d ; p=0.031 at Day 1, e ; p =0.039 on the night of the exposure, f ; p=0.048 on the night of the exposure, p = 0.044 at Day 4). Sneezing fits and nasal obstruction seemed to improve. The mucous membrane swelling of the inferior concha on pollen exposure significantly improved after the intake of the drink (p=0.0007). Conclusions: These results imply that continuing the intake of the EC-12 drink may alleviate symptoms and improve the quality of life in patients with cedar pollinosis.
[Show abstract][Hide abstract] ABSTRACT: Objective : To evaluate the effects of short-term consumption of a large amount of tea catechins on chromosomal damage, oxidative stress markers, serum lipid, folic acid, and total homocysteine levels in middle-aged healthy volunteers. Methods : Forty volunteers (40-63 years) participated in a randomized, double-blind study. After a 1-week washout, the catechin group consumed approximately 1069 mg/day of total catechins for 1 week. The micronucleated binucleate cells (MNi) frequency in the cytokinesis-block micronucleus cytome assay, urinary 8-hydroxydeoxyguanosine (8-OHdG), isoprostane, lymphocyte and plasma vitamin C, serum lipid, folic acid, and total homocysteine levels were measured at the beginning and end of the intervention. Results : No significant differences were observed between the catechin and placebo groups in terms of MNi frequency, urinary 8-OHdG, isoprostane, or lymphocyte and plasma vitamin C levels. The serum LDL-cholesterol level in the catechin group significantly decreased compared with pre-intervention period, and there was a decreased tendency in the catechin group compared with the placebo group, but the difference was not significant (P = 0.105). The serum folic acid level decreased (P = 0.073) and the total homocysteine level significantly increased in the catechin group (P = 0.029). No serious adverse events were observed during the study. Conclusions : A large amount of tea catechins, which corresponds to approximately 10 cups of green tea per day for 1 week, seemed to be well tolerated, and did not influence chromosomal damage and the oxidative stress markers. Further long-term and large-scale studies are required to clarify the long-term effect of the consumption of a large amount of tea catechins on these markers as well as on improving dyslipidemia. Trial Registration : ClinicalTrials. gov ID. NCT00448513.
No preview · Article · Jan 2012 · Rinsho yakuri/Japanese Journal of Clinical Pharmacology and Therapeutics
[Show abstract][Hide abstract] ABSTRACT: Experimental studies have revealed that green tea catechins and theanine prevent influenza infection, while the clinical evidence has been inconclusive. This study was conducted to determine whether taking green tea catechins and theanine can clinically prevent influenza infection.
A randomized, double-blind, placebo-controlled trial of 200 healthcare workers conducted for 5 months from November 9, 2009 to April 8, 2010 in three healthcare facilities for the elderly in Higashimurayama, Japan.
The catechin/theanine group received capsules including green tea catechins (378 mg/day) and theanine (210 mg/day). The control group received placebo.
The primary outcome was the incidence of clinically defined influenza infection. Secondary outcomes were (1) laboratory-confirmed influenza with viral antigen measured by immunochromatographic assay and (2) the time for which the patient was free from clinically defined influenza infection, i.e., the period between the start of intervention and the first diagnosis of influenza infection, based on clinically defined influenza infection.
Eligible healthcare workers (n = 197) were enrolled and randomly assigned to an intervention; 98 were allocated to receive catechin/theanine capsules and 99 to placebo. The incidence of clinically defined influenza infection was significantly lower in the catechin/theanine group (4 participants; 4.1%) compared with the placebo group (13 participants; 13.1%) (adjusted OR, 0.25; 95% CI, 0.07 to 0.76, P = 0.022). The incidence of laboratory-confirmed influenza infection was also lower in the catechin/theanine group (1 participant; 1.0%) than in the placebo group (5 participants; 5.1%), but this difference was not significant (adjusted OR, 0.17; 95% CI, 0.01 to 1.10; P = 0.112). The time for which the patient was free from clinically defined influenza infection was significantly different between the two groups (adjusted HR, 0.27; 95% CI, 0.09 to 0.84; P = 0.023).
Among healthcare workers for the elderly, taking green tea catechins and theanine may be effective prophylaxis for influenza infection.
ClinicalTrials (NCT): NCT01008020.
Preview · Article · Feb 2011 · BMC Complementary and Alternative Medicine
[Show abstract][Hide abstract] ABSTRACT: Strictinin, which is a member of the ellagitanin family of hydrolyzable tannins, prevented replication of human, duck and swine influenza A viruses (IAVs) in vitro at non-toxic concentrations. The addition of strictinin at the same time as IAV inoculation to MDCK cells inhibited viral replication in a dose-dependent manner. Strictinin showed 50% inhibitory concentrations for IAVs from 0.09±0.021 to 0.28±0.037μM (mean±S.E.M.) by the focus-forming assay. Treatment of MDCK cells with strictinin before and after viral inoculation resulted in no significant antiviral activity. Further studies showed that strictinin inhibited IAV-induced hemifusion. However, strictinin exhibited no inhibitory effect against receptor binding, sialidase activity. Strictinin also showed an antiviral effect on influenza B virus and human parainfluenza virus type-1 in vitro. The results indicate that strictinin is a useful antiviral agent.
Full-text · Article · Oct 2010 · Antiviral research
[Show abstract][Hide abstract] ABSTRACT: Epidemiologic and preclinical data support the oral cancer prevention potential of green tea extract (GTE). We randomly assigned patients with high-risk oral premalignant lesions (OPL) to receive GTE at 500, 750, or 1,000 mg/m(2) or placebo thrice daily for 12 weeks, evaluating biomarkers in baseline and 12-week biopsies. The OPL clinical response rate was higher in all GTE arms (n = 28; 50%) versus placebo (n = 11; 18.2%; P = 0.09) but did not reach statistical significance. However, the two higher-dose GTE arms [58.8% (750 and 1,000 mg/m(2)), 36.4% (500 mg/m(2)), and 18.2% (placebo); P = 0.03] had higher responses, suggesting a dose-response effect. GTE treatment also improved histology (21.4% versus 9.1%; P = 0.65), although not statistically significant. GTE was well tolerated, although higher doses increased insomnia/nervousness but produced no grade 4 toxicity. Higher mean baseline stromal vascular endothelial growth factor (VEGF) correlated with a clinical (P = 0.04) but not histologic response. Baseline scores of other biomarkers (epithelial VEGF, p53, Ki-67, cyclin D1, and p16 promoter methylation) were not associated with a response or survival. Baseline p16 promoter methylation (n = 5) was associated with a shorter cancer-free survival. Stromal VEGF and cyclin D1 expression were downregulated in clinically responsive GTE patients and upregulated in nonresponsive patients at 12 weeks (versus at baseline). An extended (median, 27.5 months) follow-up showed a median time to oral cancer of 46.4 months. GTE may suppress OPLs, in part through reducing angiogenic stimulus (stromal VEGF). Higher doses of GTE may improve short-term (12-week) OPL outcome. The present results support longer-term clinical testing of GTE for oral cancer prevention.
Full-text · Article · Nov 2009 · Cancer Prevention Research
[Show abstract][Hide abstract] ABSTRACT: Administration of black-tea polyphenols (BTP) at 100 and 200 mg/kg of body weight in rats suppressed postprandial hypertriacylglycerolemia in a dose-dependent manner. Administration of BTP also suppressed lymphatic recovery of (14)C-trioleoylglycerol in rats that were cannulated in the thoracic duct. BTP dose-dependently inhibited the activity of pancreatic lipase in vitro with an IC50 of 0.254 mg/mL. When purified theaflavins, which are components of BTP, were used, theaflavins with galloyl moieties, but not those without galloyl moiety, inhibited the activity of pancreatic lipase. Theaflavin-3,3'-digallate (TFDG) was more effective in inhibiting the activity of pancreatic lipase than epigallocatechin gallate (EGCG), epicatechin gallate (ECG), and a mixture of EGCG and ECG. BTP and TFDG had a similar effect in inhibiting the activity of pancreatic lipase when the total polyphenol amount was adjusted to the same. BTP had no effect on micellar solubility of hydrolysis products of triacylglycerol. These results suggest that BTP suppressed postprandial hypertriacylglycerolemia by reducing triacylglycerol absorption via the inhibition of pancreatic lipase activity.
No preview · Article · Sep 2009 · Journal of Agricultural and Food Chemistry
[Show abstract][Hide abstract] ABSTRACT: The overproduction of pigmentary melanin in the skin causes an undesirable cosmetic appearance. The present study was undertaken to evaluate the inhibitory effect of α-Iipoic acid (LA) on melanogenesis using a three-dimensional human skin model with ultraviolet (UV) irradiation. It is evident that melanin biosynthesis in human skin cells was decreased by the treatment with LA under the concentration range from 0.01 to 0.1% (w/v) in a concentration-dependent fashion, reflecting no effect on cell viability.
Full-text · Article · Sep 2009 · Food Science and Technology Research
[Show abstract][Hide abstract] ABSTRACT: Fatigue can be classified as physical and mental depending on the cause. However, in our daily lives, combined fatigue, which is the combination of physical and mental fatigue, is most often experienced. In this study, the effects of (-)-epigallocatechin gallate (EGCg) on combined fatigue were assessed.
To produce an animal model of combined fatigue, rats were kept in a cage filled with water to a height of 1.5 cm for 5 d. To evaluate the extent of fatigue, the rats swam with a load of steel rings that weighed approximately 8% of their body weight and were attached to their tails.
Fatigued rats treated with EGCg (50 or 100 mg/kg intraperitoneally [not for 25 mg/kg]) for 5 d could swim longer than fatigued animals given saline. Although levels of thiobarbituric acid-reactive substances in the plasma, brain, and skeletal muscle were not different between control and fatigued rats, thiobarbituric acid-reactive substance levels were higher in livers of fatigued animals than in livers of control animals. Oral intake of EGCg (50 or 100 mg/kg) for 5 d significantly decreased thiobarbituric acid-reactive substance levels in livers of fatigued animals.
These results suggest that EGCg (50 or 100 mg/kg) is effective for attenuating fatigue. EGCg given orally appears to have an antioxidant effect on the oxidatively damaged liver of fatigued animals.
[Show abstract][Hide abstract] ABSTRACT: The aim of this study was to point out the potential of tartary buckwheat on vascular functions. A nonabsorbed fraction of hot-water extract of tartary buckwheat on a SP70 column (TBSP-T), which was free from rutin, was used for this aim. In a contractile experiment using Sprague-Dawley rat thoracic aorta rings contracted by 1.0 microM phenylephrine (PE) or 50 mM KCl, TBSP-T evoked a significant vasorelaxation [EC50 (mg/ml): PE; 2.2; KCl, 1.9]. By a further fractionation of TBSP-T by liquid-liquid partitioning into basic, neutral and acidic fractions, a marked enhancement of vasorelaxation effect was observed only for acidic fraction (EC50, 0.25 mg/ml). The action of acidic fraction was significantly attenuated in endothelium-denuded aortic rings and in the presence of nitric oxide synthase inhibitor, NG-monomethyl-L-arginine (100 microM). The fraction also enhanced the cyclic guanosine monophosphate (cGMP) production in aortic rings contracted with PE [cGMP (pmol/mg protein): PE, 7.2+/-2.3; PE+Acidic fraction, 35+/-8]. These results indicate that acidic fraction could mediate NO/cGMP pathways, thereby exerting endothelium-dependent vasorelaxation action. In conclusion, tartary buckwheat was proven to regulate vascular tones and have latent acidic candidates except for rutin.
No preview · Article · Apr 2008 · The Journal of Nutritional Biochemistry