Tea Extract (tea + extract)

Distribution by Scientific Domains

Kinds of Tea Extract

  • green tea extract


  • Selected Abstracts


    GREEN TEA EXTRACT IMPEDES DYSLIPIDAEMIA AND DEVELOPMENT OF CARDIAC DYSFUNCTION IN STREPTOZOTOCIN-DIABETIC RATS

    CLINICAL AND EXPERIMENTAL PHARMACOLOGY AND PHYSIOLOGY, Issue 12 2006
    PV Anandh Babu
    SUMMARY 1The efficacy of green tea extract (GTE) on serum and cardiac lipids was investigated in streptozotocin (STZ)-diabetic rats. 2Diabetes was induced in rats by a single intraperitoneal injection of STZ (60 mg/kg bodyweight). Six weeks after the induction of diabetes, GTE was administered orally for 4 weeks (300 mg/kg bodyweight daily). Bodyweight, heart weight, heart weight : bodyweight ratio, blood glucose, serum and cardiac lipids were determined in experimental rats. 3In diabetic rats, there was a significant decrease in bodyweight with an increase in heart weight : bodyweight ratio and blood glucose. Diabetic rats had significantly increased serum levels of cholesterol, triglycerides, free fatty acids and low-density lipoprotein,cholesterol (LDL-C) and decreased levels of high-density lipoprotein,cholesterol (HDL-C). In the hearts of diabetic rats, there was a significant increase in cholesterol, triglycerides and free fatty acids levels, with an increase in lipoprotein lipase activity. 4The administration of GTE to diabetic rats resulted in significant recovery in bodyweight, heart weight : bodyweight ratio and blood glucose levels. The administration of GTE reduced cholesterol, triglyceride, free fatty acid and LDL-C levels, and increased HDL-C levels, in the serum of diabetic rats. In addition, GTE decreased cholesterol, triglyceride, free fatty acids levels and lipoprotein lipase activity in the myocardium of diabetic rats. These beneficial effects of GTE are ascribed to its antihyperglycaemic and hypolipidaemic activity. In conclusion, green tea can reduce the risk of cardiovascular disease in diabetes with a significant improvement in lipid metabolism. [source]


    THERAPEUTIC EFFECT OF GREEN TEA EXTRACT ON ADVANCED GLYCATION AND CROSS-LINKING OF COLLAGEN IN THE AORTA OF STREPTOZOTOCIN DIABETIC RATS

    CLINICAL AND EXPERIMENTAL PHARMACOLOGY AND PHYSIOLOGY, Issue 4 2006
    Pon Velayutham Anandh Babu
    SUMMARY 1The therapeutic effect of green tea extract (GTE) on the aortic collagen content and its characteristics were investigated in streptozotocin diabetic rats. 2Diabetes was induced in rats by a single intra peritoneal injection of streptozotocin (60 mg/kg bodyweight). Six weeks after diabetes induction, GTE was administered orally for four weeks (300 mg/kg bodyweight daily). Systolic blood pressure, blood glucose, anti-oxidant status, collagen content, extent of glycation, collagen linked fluorescence and aortic collagen solubility pattern were determined in experimental rats. 3At the end of the experimental period, there was a significant increase in the systolic blood pressure and blood glucose in diabetic rats. The lipid peroxides increased whereas glutathione and vitamin C levels were decreased in the serum of diabetic rats. The collagen content, extent of glycation, the advanced glycation end products (AGEs) and degree of cross-linking were increased in the aorta of diabetic rats. 4The oral administration of GTE to diabetic rats significantly reduced the systolic blood pressure and blood glucose. The level of lipid peroxides reduced and the content of glutathione and vitamin C increased in the serum of GTE treated diabetic rats. Green tea extract also impede the accumulation of aortic collagen, extent of glycation, formation of AGEs and cross-linking of collagen in diabetic rats. The antihyperglycemic, anti-oxidant and antiglycating effects of GTE ascribed for these beneficial effects. In conclusion, green tea may have therapeutic effect in the treatment of cardiovascular complications characterized by increased AGE accumulation and protein cross-linking associated with diabetes. [source]


    Physical Properties of Gelidium corneum,Gelatin Blend Films Containing Grapefruit Seed Extract or Green Tea Extract and Its Application in the Packaging of Pork Loins

    JOURNAL OF FOOD SCIENCE, Issue 1 2009
    Y.-H. Hong
    ABSTRACT:, Edible Gelidium corneum,gelatin (GCG) blend films containing grapefruit seed extract (GFSE) or green tea extract (GTE) were manufactured, and the quality of pork loins packed with the film during storage was determined. Tensile strength (TS) and water vapor permeability (WVP) of the films containing GFSE or GTE were better than those of the control. The film's antimicrobial activity against Escherichia coli O157:H7 and Listeria monocytogenes increased with increasing antimicrobial concentration, resulting in a decrease in the populations of bacteria by 0.77 to 2.08 and 0.91 to 3.30 log CFU/g, respectively. Pork loin samples were inoculated with E. coli O157:H7 and L. monocytogenes. The samples packed with the GCG film containing GFSE (0.08%) or GTE (2.80%) had a decrease in the populations of E. coli O157:H7 and L. monocytogenes of 0.69 to 1.11 and 1.05 to 1.14 log CFU/g, respectively, compared to the control after 4 d of storage. The results showed that the quality of pork loins during storage could be improved by packaging them with the GCG film containing GFSE or GTE. [source]


    Antilisterial Activity and Consumer Acceptance of Irradiated Chicken Breast Meat Vacuum-Infused with Grape Seed and Green Tea Extracts and Tartaric Acid

    JOURNAL OF FOOD SCIENCE, Issue 7 2010
    K.F. Over
    Abstract:, Contamination of poultry with pathogenic bacteria contributes to human foodborne disease, causes damage to industry brand names, and has a significant economic impact on the food industry in the form of both damage to industry brand names and losses associated with recalls. Irradiation is a safe and effective means of decontaminating poultry products, but the maximum dose strengths allowed negatively impact poultry sensory quality characteristics. The 1st objective of this study was to investigate the potential interactive inhibitory effects of natural antimicrobials as components of a vacuum-marination in addition to various dose levels of irradiation. Tartaric acid (TA) at 2 levels and grape seed (GS) and green tea (GT) extracts were combined, vacuum-infused into chicken breast fillets, and irradiated at 1, 2, and 3 kGy by electron beam irradiation. The 2nd objective was to use a consumer test group to evaluate TA and plant extract infusion into chicken breast fillets with and without irradiation at 2 kGy on overall impression, flavor, texture, appearance, and tenderness. The results showed that samples vacuum-infused with TA at 37.5 and 75.0 mM and irradiated at 1 kGy significantly reduced Listeria monocytogenes (L.m.) levels by 2 and 3 log CFU/g compared to the control after 12 d of refrigerated storage. Vacuum-infusion of TA at 37.5 and 75.0 mM at 2 and 3 kGy irradiation, reduced L.m. to near nondetectable levels. The addition of TA and GS and GT to chicken breast fillets with and without irradiation did not significantly impact consumer preference, tenderness, appearance, or flavor. The addition of tartaric acid and natural plant extracts to chicken marinades could contribute to the prevention of L.m. contamination. [source]


    Green tea extract reduces induction of p53 and apoptosis in UVB-irradiated human skin independent of transcriptional controls

    EXPERIMENTAL DERMATOLOGY, Issue 1 2009
    Christian D. Mnich
    Abstract:, Ultraviolet (UV) irradiation plays a pivotal role in human skin carcinongenesis. Preclinically, systemically and topically applied green tea extract (GTE) has shown reduction of UV-induced (i) erythema, (ii) DNA damage, (iii) formation of radical oxygen species and (iv) downregulation of numerous factors related to apoptosis, inflammation, differentiation and carcinogenesis. In humans, topical GTE has so far only been tested in limited studies, with usually very high GTE concentrations and over short periods of time. Both chemical stability of GTE and staining properties of highly concentrated green tea polyphenols limit the usability of highly concentrated green tea extracts in cosmetic products. The present study tested the utility of stabilized low-dose GTE as photochemopreventive agents under everyday conditions. We irradiated with up to 100 mJ/cm2 of UVB light skin patches which were pretreated with either OM24 -containing lotion or a placebo lotion. Biopsies were taken from both irradiated and un-irradiated skin for both immunohistochemistry and DNA microarray analysis. We found that while OM24 treatment did not significantly affect UV-induced erythema and thymidine dimer formation, OM24 treatment significantly reduced UV-induced p53 expression in keratinocytes. We also found that OM24 treatment significantly reduced the number of apoptotic keratinocytes (sunburn cells and TUNEL-positive cells). Carefully controlled DNA microarray analyses showed that OM24 treatment does not induce off-target changes in gene expression, reducing the likelihood of unwanted side-effects. Topical GTE (OM24) reduces UVB-mediated epithelial damage already at low, cosmetically usable concentrations, without tachyphylaxis over 5 weeks, suggesting GTE as suitable everyday photochemopreventive agents. [source]


    Thymol and modified atmosphere packaging to control microbiological spoilage in packed fresh cod hamburgers

    INTERNATIONAL JOURNAL OF FOOD SCIENCE & TECHNOLOGY, Issue 8 2009
    Maria Rosaria Corbo
    Summary A study on the use of mild technologies to produce packaged fish hamburgers was presented. In particular, the antimicrobial effect of some natural compounds (carvacrol, eugenol, thymol, green tea extract, rosemary extract, grapefruit seed extract and lemon extract), at various concentrations (500,10 000 ppm), was screened in vitro against the main fish spoilage micro-organisms (Shewanella putrefaciens and Photobacterium phosphoreum). Lemon extract and thymol, in combination with modified atmosphere packaging, showed the greatest inhibition activity, therefore, thymol was subsequently used as an ingredient for producing fish hamburgers. Results pointed out that this combination is effective in controlling the growth of microbial species mainly involved in fresh fish spoilage; in particular, it significantly (P < 0.05) reduced the growth rate of bacterial population, performing about 4.8 log CFU g,1 and 6.5 log CFU g,1 reduction of the hydrogen sulphide producing bacteria and psychrotrophic aerobic specific spoilage organisms cell load, respectively, if compared with the control. [source]


    Comparative study on composition and antioxidant properties of mint and black tea extract

    INTERNATIONAL JOURNAL OF FOOD SCIENCE & TECHNOLOGY, Issue 10 2008
    Ekambaram Padmini
    Summary The antioxidant properties of plants could be correlated with oxidative stress defence in different human diseases. The present study was undertaken to evaluate and compare the antioxidant potential and the phytochemical composition in the aqueous extracts of mint leaves, black tea and black tea enriched with mint extract. All the three preparations exhibited free radical-scavenging potential for nitric oxide (NO) radical, superoxide anion radical and hydroxyl radical, and the values were lesser than those of the antioxidants which acted as standards. In comparison, the mint extract exhibited higher free radical and NO scavenging effect. Hydroxyl radical and superoxide scavenging effects were more pronounced in tea with the mint extract, while the reducing power was exhibited more significantly by the black tea extract. The phytochemical compounds were identified and the total phenols and flavonoids were quantified and compared between these extracts. [source]


    Improving the Stability of Probiotic Bacteria in Model Fruit Juices Using Vitamins and Antioxidants

    JOURNAL OF FOOD SCIENCE, Issue 5 2010
    N.P. Shah
    Abstract:, This study examined the survival of probiotic bacteria in a model fruit juice system. Three different strains of probiotic bacteria were used in this study: HOWARU,Lactobacillus rhamnosus,HN001, HOWARU,Bifidobacterium lactis,HN001, and,Lactobacillus paracasei,LPC 37. The probiotic bacteria were inoculated into model juice with various vitamins and antioxidants, namely white grape seed extract, green tea extract, vitamin B2, vitamin B3, vitamin B6, vitamin C, and vitamin E. The model juice without any additives was used as a control. Their viability was assessed on a weekly basis using plate count method. The model juice was made with sucrose, sodium citrate, citric acid powder, and distilled water and was pasteurized before use. Our findings showed that probiotic bacteria did not survive well in the harsh environment of the model fruit juice. However, the model juice containing vitamin C, grape extract, and green tea extract showed better survival of probiotic bacteria. The model juice containing grape seed extract, green tea extract, and vitamin C had the same initial population of 8.32 log CFU/mL, and at the end of the 6-wk storage period it had an average viability of 4.29 log CFU/mL, 7.41 log CFU/mL, and 6.44 log CFU/mL, respectively. Juices containing all other ingredients tested had viable counts of <10 CFU/mL at the end of the 6-wk storage period. [source]


    Physical Properties of Gelidium corneum,Gelatin Blend Films Containing Grapefruit Seed Extract or Green Tea Extract and Its Application in the Packaging of Pork Loins

    JOURNAL OF FOOD SCIENCE, Issue 1 2009
    Y.-H. Hong
    ABSTRACT:, Edible Gelidium corneum,gelatin (GCG) blend films containing grapefruit seed extract (GFSE) or green tea extract (GTE) were manufactured, and the quality of pork loins packed with the film during storage was determined. Tensile strength (TS) and water vapor permeability (WVP) of the films containing GFSE or GTE were better than those of the control. The film's antimicrobial activity against Escherichia coli O157:H7 and Listeria monocytogenes increased with increasing antimicrobial concentration, resulting in a decrease in the populations of bacteria by 0.77 to 2.08 and 0.91 to 3.30 log CFU/g, respectively. Pork loin samples were inoculated with E. coli O157:H7 and L. monocytogenes. The samples packed with the GCG film containing GFSE (0.08%) or GTE (2.80%) had a decrease in the populations of E. coli O157:H7 and L. monocytogenes of 0.69 to 1.11 and 1.05 to 1.14 log CFU/g, respectively, compared to the control after 4 d of storage. The results showed that the quality of pork loins during storage could be improved by packaging them with the GCG film containing GFSE or GTE. [source]


    Inhibitory Effect of Morinda Citrifolia L. on Lipoprotein Lipase Activity

    JOURNAL OF FOOD SCIENCE, Issue 8 2008
    M.S. Pak-Dek
    ABSTRACT:, Efficacy of Morinda citrifolia L. leaf (MLE) and fruit extracts (MFE) in inhibiting lipoprotein lipase (LPL) was determined in vitro. The result of the study showed that the highest inhibition on the LPL activity was exhibited by MLE (66% 2.1%), which is significantly higher than that demonstrated by MFE (54.5% 2.5%), green tea extract (GTE) (54.5% 2.6%), and catechin (43.6% 6.1%). Percent of LPL inhibition increase with concentration of the extracts. Quantitative analysis of the extracts revealed the presence of high levels of (+),catechin at 63.5 17 and 53.7 5.7 mg/g in MLE and MFE, respectively, although not as high as that found in GTE (530.6 42 mg/g). Appreciable amount of epicatechin was found in all extracts tested, while rutin was only found in MLE and MFE. The study suggested that both leaf and fruit of M. citrifolia may be used as antiobesity agents in body weight management. [source]


    Effect of herbal teas on hepatic drug metabolizing enzymes in rats

    JOURNAL OF PHARMACY AND PHARMACOLOGY: AN INTERNATI ONAL JOURNAL OF PHARMACEUTICAL SCIENCE, Issue 10 2001
    Pius P. Maliakal
    We have investigated the effect of herbal teas (peppermint, chamomile and dandelion) on the activity of hepatic phase I and phase II metabolizing enzymes using rat liver microsomes. Female Wistar rats were divided into six groups (n = 5 each). Three groups had free access to a tea solution (2 %) while the control group had water. Two groups received either green tea extract (0.1 %) or aqueous caffeine solution (0.0625 %). After four weeks of pretreatment, different cytochrome P450 (CYP) isoforms and phase II enzyme activities were determined by incubation of liver microsomes or cytosol with appropriate substrates. Activity of CYP1A2 in the liver microsomes of rats receiving dandelion, peppermint or chamomile tea was significantly decreased (P < 0.05) to 15 %, 24 % and 39 % of the control value, respectively. CYP1A2 activity was significantly increased by pretreatment with caffeine solution. No alterations were observed in the activities of CYP2D and CYP3A in any group of the pretreated rats. Activity of CYP2E in rats receiving dandelion or peppermint tea was significantly lower than in the control group, 48 % and 60 % of the control, respectively. There was a dramatic increase (244 % of control) in the activity of phase II detoxifying enzyme UDP-glucuronosyl transferase in the dandelion tea-pretreated group. There was no change in the activity of glutathione-S-transferase. The results suggested that, like green and black teas, certain herbal teas can cause modulation of phase I and phase II drug metabolizing enzymes. [source]


    Effect of plant phenolics, tocopherol and ascorbic acid on oxidative stability of pork patties

    JOURNAL OF THE SCIENCE OF FOOD AND AGRICULTURE, Issue 8 2009
    Lindsey Haak
    Abstract BACKGROUND: There is great interest in the use of naturally occurring antioxidants to delay oxidation in meat products. The effect of rosemary extract (RE), green tea extract (TE), tocopherol, trolox, ascorbic acid (AA) and ascorbyl palmitate (AP), at levels of 50,200 ppm of antioxidant components, on colour (CIE L*a*b*), lipid (TBARS) and protein oxidation (thiol groups) in fresh, frozen and cooked pork patties during illuminated chill storage was investigated. Individual components of RE and TE were also tested. RESULTS: RE, TE, AP, tocopherol and trolox equally inhibited lipid oxidation in fresh and frozen patties, whereas for cooked patties RE was most effective. AA stimulated lipid oxidation. No dose effect in the range of 50,200 ppm was found for fresh and frozen patties, whereas for cooked patties higher doses of RE and TE more efficiently prevented lipid oxidation. Protein oxidation was hardly influenced by antioxidant treatment. Colour stability decreased as follows: tocopherol, AA and AP > RE and TE > trolox. Antioxidant properties of the extracts and their major antioxidant components were comparable. CONCLUSION: The relative effect of the antioxidants depends on the oxidation parameter assessed, the applied dose and the hydrophilic/lipophilic character. Copyright 2009 Society of Chemical Industry [source]


    Effects of green tea extract on the quality of bread made from unfrozen and frozen dough processes

    JOURNAL OF THE SCIENCE OF FOOD AND AGRICULTURE, Issue 6 2006
    Rong Wang
    Abstract Two different green tea extracts (GTE-A and -B) as a rich source of tea catechins were incorporated into a no-time bread-making process, where bread made from the unfrozen and frozen dough processes was compared by specific volume and texture profile. GTE-A and -B both exhibited significant effects on bread volume and firmness, but to a different extent. GTE-A with higher content of tea catechins (73%) at a level of 1.5 g kg,1 flour was found to lead to a significant reduction in bread volume in unfrozen dough process and an increment in firmness during storage for 4 days at ambient temperature (22 C). GTE-B, with a lower content of catechins (60%), had relatively mild effects on the bread quality. Significantly negative effects were evident starting at a higher level of 5.0 g kg,1 flour in unfrozen dough process. Frozen storage showed more predominant deteriorating effects than the GTEs over a period of 9 weeks frozen storage at ,20 C. Copyright 2006 Society of Chemical Industry [source]


    Acute liver failure induced by green tea extracts: Case report and review of the literature

    LIVER TRANSPLANTATION, Issue 12 2006
    Michele Molinari
    In industrialized countries, over-the-counter dietary supplements have become popular in preventing and treating an expanding list of medical conditions. Although most commercially available supplements have not been rigorously tested for safety and efficacy, they have found an enlarging market because they are considered natural. Oral supplements containing green tea extract have been marketed as effective for weight loss and to prevent and cure some solid tumors. Although there is little scientific evidence of the effectiveness of green tea extracts to improve the quality of health of regular consumers, there is an increasing body of medical literature supporting the hypothesis that they can cause serious side effects. Our experience adds to previous reports of acute liver toxicity observed in individuals consuming supplements containing green tea extract. We highlight the importance of obtaining a detailed history of dietary supplement consumption when evaluating a patient presenting with acute liver dysfunction. Liver Transpl 12:1892,1895, 2006. 2006 AASLD. [source]


    Cyclooxygenase-2 Expression in Murine and Human Nonmelanoma Skin Cancers: Implications for Therapeutic Approaches,

    PHOTOCHEMISTRY & PHOTOBIOLOGY, Issue 1 2002
    Kathy P. An
    ABSTRACT Inflammatory stimuli result in the production of cutaneous eicosanoids, which are known to contribute to the process of tumor promotion. Cyclooxygenase (COX), the rate-limiting enzyme for the production of prostaglandins (PG) from arachidonic acid, exists in at least two isoforms, COX-1 and COX-2. COX-1 is constitutively expressed in most tissues and plays various physiological roles, whereas increased COX-2 expression is known to occur in several types of epithelial neoplasms. Enhanced PG synthesis is a potential contributing factor in UVB-induced nonmelanoma skin cancers (NMSC). Increased COX-2 staining occurs in murine skin neoplasms after chronic exposure to carcinogenic doses of UVB. In this study, immunohistochemical and Western blot analyses were employed to assess longitudinally COX-2 expression in a standard mouse UVB complete carcinogenesis protocol and in human basal cell carcinomas (BCC) and squamous cell carcinomas (SCC). During UVB irradiation of mice, COX-2 expression consistently increased in the hyperplastic skin, the benign papillomas and the SCC. COX-2 expression was also increased in human actinic keratoses, SCC and BCC as well as in murine SCC and BCC. The pattern of COX-2 expression was quite variable, occurring in a patchy distribution in some lesions with staining confined mainly to suprabasal cell layers. In general, COX-2 expression progressively became more extensive in benign papillomas and well-differentiated murine SCC. The staining was predominantly cytoplasmic and perinuclear in some focal areas in tissue stroma around both murine and human tumors. Western blot analysis confirmed negative COX-2 expression in normal skin, whereas acute UVB exposure resulted in increased enzyme expression, which continued to increase in developing papillomas and SCC. Because of the evidence indicating a pathogenic role for eicosanoids in murine and human skin neoplasms, we performed studies to assess the anti-inflammatory and anticarcinogenic effects of green tea extracts, which are potent antioxidants. Acute exposure of the human skin to UVB (minimum erythema dose 4) caused a transient enhancement of the COX-2 expression, which reverted to baseline within hours; however, in murine skin the expression persisted for several days. Pretreatment with the topically applied green tea extract (1 mg/cm2) largely abrogated the acute COX-2 response to UVB in mice or humans. In summary, enhanced COX-2 expression serves as a marker of epidermal UVB exposure for murine and human NMSC. These results suggest that COX-2 inhibitors could have potent anticarcinogenic effects in UVB-induced skin cancer. [source]


    Green tea extract weakens the antibacterial effect of amoxicillin in methicillin-resistant Staphylococcus aureus infected mice

    PHYTOTHERAPY RESEARCH, Issue 1 2010
    Qing Peng
    Abstract Tea (Camellia sinensis) has been known for its modulation of resistance of methicillin-resistant Staphylococcus aureus (MRSA) to ,-lactam antibiotics in vitro. This study aimed to confirm the in vitro effect of green tea extracts with ,-lactams and to determine whether green tea extracts can reduce the minimum inhibitory concentrations (MICs) of amoxicillin in MRSA-infected mice. The catechins in the test tea that account for the reduced resistance to ,-lactams were quantitatively determined by high-performance liquid chromatography. The MICs of the ampicillin, cefazolin, amoxicillin, oxacillin, tea extract alone and tea extract in combination with ,-lactams were determined. Proportions of tea extracts and amoxicillin-tea extract combinations were administered to groups of mice enterally. The in vitro experiment showed that the MICs of four ,-lactams were greatly decreased in the presence of 0.25% tea extract. However, in an in vivo experiment, amoxicillin in combination with 5% tea extract conferred a higher ED50 than that of antibiotic alone. Green tea extract, alone or in combination with amoxicillin, does not have protective benefits in MRSA-infected mice. This study concluded that tea extract weakened the antibacterial effect of amoxicillin in MRSA infected mice. Tea drinking is not recommended in combination with amoxicillin treatment. Copyright 2009 John Wiley & Sons, Ltd. [source]


    Protective action of aqueous black tea (Camellia sinensis) extract (BTE) against ovariectomy-induced oxidative stress of mononuclear cells and its associated progression of bone loss

    PHYTOTHERAPY RESEARCH, Issue 9 2009
    Asankur Sekhar Das
    Abstract The protective action of aqueous black tea extract (BTE) against ovariectomy-induced oxidative stress of mononuclear cells and its associated progression of bone loss was demonstrated in this study. Eighteen female adult 6-month-old Wistar albino rats were divided into three groups: sham-control (A), bilaterally ovariectomized (B) and bilaterally ovariectomized + BTE supplemented (C). Studies included the measurement of oxidative (nitric oxide, lipid peroxidation) and antioxidative (superoxide dismutase, catalase) markers, inflammatory cytokines (IL-6, TNF- ,), osteoclast differentiation factor (RANKL) and bone resorption markers (tartrate-resistant acid phosphatase and hydroxyproline). Also quantitative histomorphometry and histological studies were undertaken. The bone breaking force was measured. The results indicate that BTE was effective in preserving and restoring skeletal health by reducing the number of active osteoclasts. Such changes with BTE supplementation were steadily linked with the reduced oxidative stress of mononuclear cells, serum levels of bone resorbing cytokines, osteoclast differentiation factor and resorption markers. The results of the bone breaking force, histological and histomorphometric analyses further supported the hypothesis. This study suggests that BTE has both protective and restorative actions against ovariectomy-induced mononuclear cell oxidative stress and associated bone loss. Copyright 2009 John Wiley & Sons, Ltd. [source]


    In vitro anti-adhesive activity of green tea extract against pathogen adhesion

    PHYTOTHERAPY RESEARCH, Issue 4 2009
    Ji-Hye Lee
    Abstract Camellia sinensis polysaccharide has been reported to possess anti-adhesive activity against pathogens. The present study was designed to investigate whether hot water extracts obtained from green tea leaves might inhibit pathogen adhesion to human or mouse cell lines. Green tea extract-4 (CSI-4) with the maximum yield of 4% (w/v) is composed of a major proportion of carbohydrates containing 40% uronic acids, but lack of catechins. It showed strong inhibitory activities against hemagglutination mediated by pathogens Helicobacter pylori, Propionibacterium acnes and Staphylococcus aureus with the minimum inhibitory concentrations of 0.01-0.5 mg/mL. CSI-4 further demonstrated an inhibitory effect on the adhesion of these pathogens to host cell lines with the IC50 values (50% inhibition of adhesion) of 0.14,2.3 mg/mL. It exhibited the highest activity against P. acnes, but no inhibitory effects were observed against Lactobacillus acidophilus, Bifidobacterium bifidum, Escherichia coli, or Staphylococcus epidermidis. Our results suggest that CSI-4 may exert a selective anti-adhesive effect against certain pathogenic bacteria with no adverse effects against beneficial or commensal bacteria. Copyright 2008 John Wiley & Sons, Ltd. [source]


    Antilipogenic effect of green tea extract in C57BL/6J- Lepob/ob mice

    PHYTOTHERAPY RESEARCH, Issue 4 2009
    Hye-Jin Kim
    Abstract The objective of this study was to determine the effects of green tea extract (GTE) on lipid metabolism in obese animal models. Male C57BL/6J- Lepob/ob mice were divided into control and GTE (0.05 g/100 g diet) groups, which were fed a high-fat (20 g/100 g diet) diet for 12 weeks. Supplementation of GTE significantly reduced (p < 0.01) perirenal and total white adipose tissue weights compared with the control group. Also, the plasma HDL-cholesterol level was significantly higher in the GTE group than in the control group, therefore the GTE group showed a higher HDL-cholesterol/total-cholesterol ratio (HTR) and lower atherogenic index (AI) level than the control group. A reduction of hepatic triglyceride content and adipose tissue weight in the GTE group was related to the suppression of enzyme activities for fatty acid synthesis (glucose-6-phosphate dehydrogenase and malic enzyme) without affecting fatty acid oxidation enzyme (, -oxidation and carnitine palmitoyl transferase) activities in hepatic and adipose tissue. The current results showed that supplementation of green tea extract is beneficial for antiobesity by the suppression of lipogenesis via regulation of related enzyme activities in hepatic and adipose tissue. Copyright 2008 John Wiley & Sons, Ltd. [source]


    Effect of green tea and (-)-epigallocatechin gallate on ethanol-induced toxicity in HepG2 cells

    PHYTOTHERAPY RESEARCH, Issue 5 2008
    Sang Il Lee
    Abstract Despite the continuing reports supporting the hepatoprotective effects of green tea against ethanol intoxication, there remain controversies regarding the active compound(s) and molecular mechanism. These issues were addressed in the present study using cultured HepG2 cells exposed to a lethal dose of ethanol. Gamma-glutamyl transferase (GGT) was chosen as a marker of ethanol toxicity because it is widely used in clinics. When the cells were treated with ethanol at various concentrations, there was a dose-dependent increase of GGT activity in the culture media and loss of cell viability. Pretreatment of the cells with green tea extract attenuated the changes significantly. Among the green tea constituents, (-)-epigallocatechin gallate (EGCG) attenuated the ethanol cytotoxicity effectively, whereas l -theanine and caffeine had no effects. The ethanol cytotoxicity was also attenuated by alcohol dehydrogenase inhibitor 4-methyl pyrazol and GGT inhibitor acivicin as well as by thiol modulators such as S -adenosyl- l -methionine, N -acetyl- l -cysteine and glutathione. EGCG failed to prevent the intracellular glutathione loss caused by ethanol, but it appeared to be a strong GGT inhibitor. Therefore the cytoprotective effects of green tea could be attributed to the inhibition of GGT activity by EGCG. This study suggests that GGT inhibitors including EGCG may provide a novel strategy for attenuating ethanol-induced liver damage. Copyright 2008 John Wiley & Sons, Ltd. [source]


    Gallic acid is partially responsible for the antiangiogenic activities of Rubus leaf extract

    PHYTOTHERAPY RESEARCH, Issue 9 2006
    Zhijun Liu
    Abstract An aqueous extract of leaves from Rubus suavissimus S. Lee (Rosaceae) or sweet leaf tea was tested for antiangiogenic activity in a human tissue-based ,brin,thrombin clot angiogenesis assay. Further fractionation of this crude extract was performed and the antiangiogenic effect of individual fractions was assessed. The extract was also tested for its oral bioavailability by using the serum of normal rats gavaged with the extract in the assay. At a 0.1% w/v concentration, the extract inhibited initiation of the angiogenic response and subsequent neovessel growth from samples that had already initiated an angiogenic response. Two subfractions of the extract showed signi,cant inhibition of angiogenesis at 0.1% w/w. Gallic acid was elucidated as one of the active angiogenesis inhibitors in one fraction. A 1 mm concentration of gallic acid totally inhibited angiogenesis. In the form of leaf extract, a one-tenth concentration produced the same total inhibition as pure gallic acid. The 10-fold difference in potency suggests the presence of other active compounds contributing to the overall antiangiogenic effect of the extract. The oral absorption of this extract was tested by using serum from rats given the extract orally (gavage) in the angiogenesis assay system. The serum of rats orally administered the sweet leaf tea extract at doses of 0.1% w/w and 0.3% w/w did not signi,cantly inhibit angiogenesis. However, the serum of rats injected intraperitoneally at a dose of 0.1% w/w caused a 41% inhibition of angiogenesis compared with saline injected controls. These preliminary results warrant further bioassay directed identi,cation of other responsible compounds. Copyright 2006 John Wiley & Sons, Ltd. [source]


    Green tea: Health benefits as cancer preventive for humans

    THE CHEMICAL RECORD, Issue 3 2005
    Hirota Fujiki
    Abstract Green tea is an acknowledged cancer preventive in Japan. The aim of this review article is to develop the concept of cancer prevention with green tea beverage for humans, which has largely been our exclusive research territory. This paper briefly reviews several topics, beginning with the introduction of our initial work on penta- O -galloyl-,-D-glucose and (,)-epigallocatechin gallate (EGCG), the main constituent of green tea extract. The mechanisms of EGCG action, particularly the reduction of TNF-, are discussed, and we show how use of 3H-EGCG revealed a wide range of target organs for cancer prevention. The results of an epidemiological study in Saitama Prefecture allowed us to determine the cancer preventive amount of green tea,10 Japanese-size cups per day, about 2.5,g green tea extract,which made it possible for us to introduce the two-stage strategy of cancer prevention with green tea. The first stage is the delay of cancer onset for the general population. The second stage is the prevention of recurrence of cancer for patients following cancer treatment. Combination cancer prevention with green tea and cancer preventive drugs is proving especially beneficial for Japanese, who drink green tea every day. And finally, the stimulating comments of Prof. Jim Watson have encouraged green tea scientists. 2005 The Japan Chemical Journal Forum and Wiley Periodicals, Inc. Chem Rec 5: 119,132; 2005: Published online in Wiley InterScience (www.interscience.wiley.com) DOI 10.1002/tcr.20039 [source]


    GREEN TEA EXTRACT IMPEDES DYSLIPIDAEMIA AND DEVELOPMENT OF CARDIAC DYSFUNCTION IN STREPTOZOTOCIN-DIABETIC RATS

    CLINICAL AND EXPERIMENTAL PHARMACOLOGY AND PHYSIOLOGY, Issue 12 2006
    PV Anandh Babu
    SUMMARY 1The efficacy of green tea extract (GTE) on serum and cardiac lipids was investigated in streptozotocin (STZ)-diabetic rats. 2Diabetes was induced in rats by a single intraperitoneal injection of STZ (60 mg/kg bodyweight). Six weeks after the induction of diabetes, GTE was administered orally for 4 weeks (300 mg/kg bodyweight daily). Bodyweight, heart weight, heart weight : bodyweight ratio, blood glucose, serum and cardiac lipids were determined in experimental rats. 3In diabetic rats, there was a significant decrease in bodyweight with an increase in heart weight : bodyweight ratio and blood glucose. Diabetic rats had significantly increased serum levels of cholesterol, triglycerides, free fatty acids and low-density lipoprotein,cholesterol (LDL-C) and decreased levels of high-density lipoprotein,cholesterol (HDL-C). In the hearts of diabetic rats, there was a significant increase in cholesterol, triglycerides and free fatty acids levels, with an increase in lipoprotein lipase activity. 4The administration of GTE to diabetic rats resulted in significant recovery in bodyweight, heart weight : bodyweight ratio and blood glucose levels. The administration of GTE reduced cholesterol, triglyceride, free fatty acid and LDL-C levels, and increased HDL-C levels, in the serum of diabetic rats. In addition, GTE decreased cholesterol, triglyceride, free fatty acids levels and lipoprotein lipase activity in the myocardium of diabetic rats. These beneficial effects of GTE are ascribed to its antihyperglycaemic and hypolipidaemic activity. In conclusion, green tea can reduce the risk of cardiovascular disease in diabetes with a significant improvement in lipid metabolism. [source]


    THERAPEUTIC EFFECT OF GREEN TEA EXTRACT ON ADVANCED GLYCATION AND CROSS-LINKING OF COLLAGEN IN THE AORTA OF STREPTOZOTOCIN DIABETIC RATS

    CLINICAL AND EXPERIMENTAL PHARMACOLOGY AND PHYSIOLOGY, Issue 4 2006
    Pon Velayutham Anandh Babu
    SUMMARY 1The therapeutic effect of green tea extract (GTE) on the aortic collagen content and its characteristics were investigated in streptozotocin diabetic rats. 2Diabetes was induced in rats by a single intra peritoneal injection of streptozotocin (60 mg/kg bodyweight). Six weeks after diabetes induction, GTE was administered orally for four weeks (300 mg/kg bodyweight daily). Systolic blood pressure, blood glucose, anti-oxidant status, collagen content, extent of glycation, collagen linked fluorescence and aortic collagen solubility pattern were determined in experimental rats. 3At the end of the experimental period, there was a significant increase in the systolic blood pressure and blood glucose in diabetic rats. The lipid peroxides increased whereas glutathione and vitamin C levels were decreased in the serum of diabetic rats. The collagen content, extent of glycation, the advanced glycation end products (AGEs) and degree of cross-linking were increased in the aorta of diabetic rats. 4The oral administration of GTE to diabetic rats significantly reduced the systolic blood pressure and blood glucose. The level of lipid peroxides reduced and the content of glutathione and vitamin C increased in the serum of GTE treated diabetic rats. Green tea extract also impede the accumulation of aortic collagen, extent of glycation, formation of AGEs and cross-linking of collagen in diabetic rats. The antihyperglycemic, anti-oxidant and antiglycating effects of GTE ascribed for these beneficial effects. In conclusion, green tea may have therapeutic effect in the treatment of cardiovascular complications characterized by increased AGE accumulation and protein cross-linking associated with diabetes. [source]


    Green tea extract reduces induction of p53 and apoptosis in UVB-irradiated human skin independent of transcriptional controls

    EXPERIMENTAL DERMATOLOGY, Issue 1 2009
    Christian D. Mnich
    Abstract:, Ultraviolet (UV) irradiation plays a pivotal role in human skin carcinongenesis. Preclinically, systemically and topically applied green tea extract (GTE) has shown reduction of UV-induced (i) erythema, (ii) DNA damage, (iii) formation of radical oxygen species and (iv) downregulation of numerous factors related to apoptosis, inflammation, differentiation and carcinogenesis. In humans, topical GTE has so far only been tested in limited studies, with usually very high GTE concentrations and over short periods of time. Both chemical stability of GTE and staining properties of highly concentrated green tea polyphenols limit the usability of highly concentrated green tea extracts in cosmetic products. The present study tested the utility of stabilized low-dose GTE as photochemopreventive agents under everyday conditions. We irradiated with up to 100 mJ/cm2 of UVB light skin patches which were pretreated with either OM24 -containing lotion or a placebo lotion. Biopsies were taken from both irradiated and un-irradiated skin for both immunohistochemistry and DNA microarray analysis. We found that while OM24 treatment did not significantly affect UV-induced erythema and thymidine dimer formation, OM24 treatment significantly reduced UV-induced p53 expression in keratinocytes. We also found that OM24 treatment significantly reduced the number of apoptotic keratinocytes (sunburn cells and TUNEL-positive cells). Carefully controlled DNA microarray analyses showed that OM24 treatment does not induce off-target changes in gene expression, reducing the likelihood of unwanted side-effects. Topical GTE (OM24) reduces UVB-mediated epithelial damage already at low, cosmetically usable concentrations, without tachyphylaxis over 5 weeks, suggesting GTE as suitable everyday photochemopreventive agents. [source]


    HPLC Analysis of Catechins, Theaflavins, and Alkaloids in Commercial Teas and Green Tea Dietary Supplements: Comparison of Water and 80% Ethanol/Water Extracts

    JOURNAL OF FOOD SCIENCE, Issue 6 2006
    Mendel Friedman
    ABSTRACT:, To help meet the needs of consumers, producers of dietary tea supplements, and researchers for information on health-promoting tea compounds, we compared the following conditions for the extraction of tea leaves and green tea-containing dietary supplements: 80% ethanol/water at 60 C for 15 min and boiled water for 5 min. The following 7 catechins, 4 theaflavins, and 3 alkaloids were separated in a 70-min single HPLC analysis: (,)-epigallocatechin, (,)-catechin, (+)-epicatechin, (,)-epigallocatechin-3-gallate, (,),gallocatechin-3-gallate, (,)-epicatechin-3-gallate, (,)-catechin-3-gallate, theaflavin, theaflavin-3-gallate, theaflavin-3,-gallate, theaflavin-3,3,-digallate, caffeine, theobromine, and theophylline. The following ranges of concentrations of flavonoids (catechins plus theaflavins) in the tea leaves extracted with 80% ethanol were observed (in mg/g): in 32 black teas, 19.8 to 115.1; in 24 green teas, 12.3 to 136.3; in 14 specialty teas, 4.9 to 118.5; in 7 herbal teas, 0 to 46.0. Total alkaloids in all teas ranged from 0 to 32.6 mg/g. Significantly greater amounts of flavonoids were extracted from the tea leaves with aqueous ethanol than with boiled water. Levels of tea catechins in 10 capsules sold as dietary supplements were about 50 to 75% lower than the amounts listed on the labels. Catechin content of 4 commercial green tea extracts ranged from 96 to 696 mg/g. The results make it possible to maximize the extraction of tea compounds to better relate the flavonoid and alkaloid content of teas and dietary tea supplements to their health-promoting effects. [source]


    Effects of green tea extract on the quality of bread made from unfrozen and frozen dough processes

    JOURNAL OF THE SCIENCE OF FOOD AND AGRICULTURE, Issue 6 2006
    Rong Wang
    Abstract Two different green tea extracts (GTE-A and -B) as a rich source of tea catechins were incorporated into a no-time bread-making process, where bread made from the unfrozen and frozen dough processes was compared by specific volume and texture profile. GTE-A and -B both exhibited significant effects on bread volume and firmness, but to a different extent. GTE-A with higher content of tea catechins (73%) at a level of 1.5 g kg,1 flour was found to lead to a significant reduction in bread volume in unfrozen dough process and an increment in firmness during storage for 4 days at ambient temperature (22 C). GTE-B, with a lower content of catechins (60%), had relatively mild effects on the bread quality. Significantly negative effects were evident starting at a higher level of 5.0 g kg,1 flour in unfrozen dough process. Frozen storage showed more predominant deteriorating effects than the GTEs over a period of 9 weeks frozen storage at ,20 C. Copyright 2006 Society of Chemical Industry [source]


    Effect of selenium spraying on green tea quality

    JOURNAL OF THE SCIENCE OF FOOD AND AGRICULTURE, Issue 14 2001
    Qiuhui Hu
    Abstract This research was conducted to determine the effects of different selenium treatments on the sensory and chemical qualities of green tea harvested in the summer tea-producing season. Green tea was produced from fresh tea leaves sprayed with sodium selenite or organically bound selenium solution. The results showed that the sweetness and aroma of green tea extracts were significantly increased and the astringent taste and bitterness were significantly reduced by selenium spraying during the summer tea-producing season. Significant differences in astringent taste, bitterness and sweetness of green tea extracts were found between sodium selenite and organically bound selenium treatments. The total amino acid and vitamin C contents of green tea were significantly increased and the ratio of polyphenols and amino acids was significantly decreased by selenium spraying. The vitamin C content of green tea during storage was more stable as a result of selenium treatment. No significant difference was found between sodium selenite and organically bound selenium treatments. These results demonstrate that the sensory and chemical qualities of green tea were significantly improved by selenium spraying. 2001 Society of Chemical Industry [source]


    Acute liver failure induced by green tea extracts: Case report and review of the literature

    LIVER TRANSPLANTATION, Issue 12 2006
    Michele Molinari
    In industrialized countries, over-the-counter dietary supplements have become popular in preventing and treating an expanding list of medical conditions. Although most commercially available supplements have not been rigorously tested for safety and efficacy, they have found an enlarging market because they are considered natural. Oral supplements containing green tea extract have been marketed as effective for weight loss and to prevent and cure some solid tumors. Although there is little scientific evidence of the effectiveness of green tea extracts to improve the quality of health of regular consumers, there is an increasing body of medical literature supporting the hypothesis that they can cause serious side effects. Our experience adds to previous reports of acute liver toxicity observed in individuals consuming supplements containing green tea extract. We highlight the importance of obtaining a detailed history of dietary supplement consumption when evaluating a patient presenting with acute liver dysfunction. Liver Transpl 12:1892,1895, 2006. 2006 AASLD. [source]


    Cyclooxygenase-2 Expression in Murine and Human Nonmelanoma Skin Cancers: Implications for Therapeutic Approaches,

    PHOTOCHEMISTRY & PHOTOBIOLOGY, Issue 1 2002
    Kathy P. An
    ABSTRACT Inflammatory stimuli result in the production of cutaneous eicosanoids, which are known to contribute to the process of tumor promotion. Cyclooxygenase (COX), the rate-limiting enzyme for the production of prostaglandins (PG) from arachidonic acid, exists in at least two isoforms, COX-1 and COX-2. COX-1 is constitutively expressed in most tissues and plays various physiological roles, whereas increased COX-2 expression is known to occur in several types of epithelial neoplasms. Enhanced PG synthesis is a potential contributing factor in UVB-induced nonmelanoma skin cancers (NMSC). Increased COX-2 staining occurs in murine skin neoplasms after chronic exposure to carcinogenic doses of UVB. In this study, immunohistochemical and Western blot analyses were employed to assess longitudinally COX-2 expression in a standard mouse UVB complete carcinogenesis protocol and in human basal cell carcinomas (BCC) and squamous cell carcinomas (SCC). During UVB irradiation of mice, COX-2 expression consistently increased in the hyperplastic skin, the benign papillomas and the SCC. COX-2 expression was also increased in human actinic keratoses, SCC and BCC as well as in murine SCC and BCC. The pattern of COX-2 expression was quite variable, occurring in a patchy distribution in some lesions with staining confined mainly to suprabasal cell layers. In general, COX-2 expression progressively became more extensive in benign papillomas and well-differentiated murine SCC. The staining was predominantly cytoplasmic and perinuclear in some focal areas in tissue stroma around both murine and human tumors. Western blot analysis confirmed negative COX-2 expression in normal skin, whereas acute UVB exposure resulted in increased enzyme expression, which continued to increase in developing papillomas and SCC. Because of the evidence indicating a pathogenic role for eicosanoids in murine and human skin neoplasms, we performed studies to assess the anti-inflammatory and anticarcinogenic effects of green tea extracts, which are potent antioxidants. Acute exposure of the human skin to UVB (minimum erythema dose 4) caused a transient enhancement of the COX-2 expression, which reverted to baseline within hours; however, in murine skin the expression persisted for several days. Pretreatment with the topically applied green tea extract (1 mg/cm2) largely abrogated the acute COX-2 response to UVB in mice or humans. In summary, enhanced COX-2 expression serves as a marker of epidermal UVB exposure for murine and human NMSC. These results suggest that COX-2 inhibitors could have potent anticarcinogenic effects in UVB-induced skin cancer. [source]