Green Tea Preparations Research Articles

Effects of Greenselect Phytosome® on weight maintenance after weight loss in obese women: a randomized placebo-controlled study.

BackgroundMost subjects regain weight after weight loss due to compensatory adaptations finalized to maintain stable body energy stores. Green tea (GT) preparations, which help maintain energy expenditure while dieting could be a useful strategy to facilitate weight maintenance. The usefulness of GT preparations in weight maintenance has been poorly studied so far with conflicting results. This study evaluated if a supplement of GSP and piperine helps obese women to maintain the weight loss obtained with a 3-month lifestyle intervention.MethodsIn a randomized placebo-controlled study, we examined whether a highly bioavailable GT extract may counteract weight regain after weight loss. Forty obese women (age 50.1 ± 10.1 years, Body Mass Index (BMI) 36.3 ± 2.7 kg/m2) underwent a 3-month lifestyle intervention. At the end of the intervention, the women were randomized in two groups for the weight-maintenance phase: 20 of them were prescribed twice a day, for 3 months, with a formula containing 150 mg/dose of Greenselect Phytosome® and 15 mg/dose of pure piperine (GSP group), and 20 were given placebo (P group). Anthropometric measures and body composition were measured before (V-3) and after lifestyle intervention (V0), 1 (V1), 2 (V2), and 3 (V3) months after prescribing supplements and 3 months following the discontinuation of supplements (V6).ResultsLifestyle intervention induced a significant weight reduction in both groups with similar weight change (−6.2 ± 2.6 in GSP group vs. −4.8 ± 3.1 % in P group). In the GSP group, V1 in comparison to V0, had further reduction in weight and fat mass, which remained stable at V2 and V3 and increased at V6. In the P group, weight and fat mass increased from V2 onwards. Weight changes in GSP group and P group from V0 to V3 were −1.0 kg (95 % CI −2.5 to +0.5) and + 0.3 kg (95 % CI −0.9 to +1.6), respectively.The proportion of women with weight loss ≥ 5 % was greater in the GSP group than in the P group (75 % vs. 45 % at V1, and 60 % vs. 30 % at V6, p < 0.05 for both groups).ConclusionsGreenselect Phytosome® devoid of caffeine may have a clinical potential for the maintenance of weight after intentional weight loss.Trial registrationClinicaltrials.gov NCT02542449 (September 2015)Electronic supplementary materialThe online version of this article (doi:10.1186/s12906-016-1214-x) contains supplementary material, which is available to authorized users.

Pomegranate and mint syrup addition to green tea beverage stabilized its polyphenolic content and biofunctional potentials during refrigerated storage.

The chemical stability of the green tea (GT) preparation during refrigerated storage was investigated following the addition of mint (MS) or pomegranate (PS) syrups, a common habit in the Mediterranean countries that improves the savor of this popular beverage. The supernatants recovered by centrifuging GT supplemented or not with mint (GTMS) or pomegranate (GTPS) syrup were examined for their polyphenolic profiles using the high performance liquid chromatography with diode array detection and electrospray ionization-mass spectrometry. Following storage at 4°C for 15days, not-supplemented GT showed a significant decrease (≈92%) of its phenolic content. However, the decrease was relatively lesser in GTPS (≈36%) and in GTMS (≈40%). The observed slight increase of the extractable polyphenolics in PS and MS during the storage might explain in part the relatively limited decrease of GTPS and GTMS total phenolic content. However, chromatographic examination proved that some tea compounds, particularly caffeine, were preserved following PS and MS supplementation. Likewise, syrups'addition to GT significantly (P < 0.5) limited the reduction of its antioxidant capacity as revealed by the DPPH (2,2-diphenyl-1-picrylhydrazyl) and ABTS (2,2'-azino-bis-(3-ethylbenz-thialzoline-6-sulfonic acid)) assays. As expected, the antimicrobial trials showed that Gram (+) Staphylococcus aureus and Staphylococcus epidermidis were the most sensitive strains to tea polyphenols. The syrups supplementation noticeably preserved the tea bacteriostatic and bactericide activities during storage. The obtained analytical results demonstrate that MS or PS addition to green tea beverage stabilized its polyphenolic content and biofunctional properties during refrigerated storage, thus, scientifically supporting this popular practice in the Mediterranean countries.

Camellia sinensis Mediated Enhancement of Humoral Immunity to Particulate and Non-particulate Antigens.

The most common drinking beverage in large portion of the world is Camellia sinensis (green tea). In the present study, we evaluated the adjuvant effect of green tea and tea polyphenols to particulate and non-particulate antigens. BALB/c mice were immunized with particulate and non-particulate antigens. Modulation of immunoglobulin-secreting splenocytes, IgG-mediated and IgM-mediated immunity, was evaluated by hemolytic plaque assay and enzyme-linked immunosorbent assay, respectively. Dose-dependent response of tea polyphenols was also assayed. Phenolic content was measured in crude preparations of green tea. We observed a stimulatory effect of green tea preparations on humoral immune response mediated by the increased number of antibody-secreted cells in spleen. A significant increase in IgM-mediated and IgG-mediated immune response to non-particulate antigen was also observed in green tea-treated animals. A dose-dependent adjuvant effect was seen in the case of tea polyphenols for a longer period of time compared with crude tea preparations. This study indicates polyphenols as major constituents responsible for the enhanced and sustained adjuvant activity of green tea. We suggest that tea polyphenols might be considered for real-life evaluation during adjuvant-mediated vaccination trial programs.

Polifenóis totais e flavonoides em amostras de chá verde (Camellia sinensis L.) de diferentes marcas comercializadas na cidade de Salvador-BA

RESUMO Camellia sinensis é amplamente conhecida por seus efeitos benéficos à saúde humana. Dentre as diversas formas de processamento desta erva, o chá verde e chá preto são os mais populares. Neste trabalho objetivou-se avaliar os teores de fenólicos totais e flavonoides em amostras de 25 diferentes marcas disponíveis à venda em farmácias e supermercados de Salvador-Ba. Os resultados obtidos apresentaram diferenças significativas na concentração dos compostos fenólicos entre as marcas de chá verde estudadas. No estudo também ficou comprovado que, no preparo do chá verde, as amostras obtidas por infusão aquosa com agitação mecânica apresentaram maiores teores de polifenóis e flavonoides em relação àquelas que não foram submetidas à agitação.

Additional benefit of higher dose green tea in lowering postprandial blood glucose

Background: Green tea contains catechins that have inhibitory effects on amylase, sucrase, and sodium-dependent glucose transporter (SGLT) which result in lowering of postprandial blood glucose (PBG). This beneficial effect has been widely demonstrated using the usual dose (UD) of green tea preparation. Our study was aimed to explore futher lowering of PBG using high dose (HD) of green tea in healthy adolescents.&#x0D; Methods: 24 subjects received 100 mL infusion of either 0.67 or 3.33 grams of green tea with test meal. Fasting, PBG at 30, 60, 120 minutes were measured. Subjects were cross-overed after wash out. PBG and its incremental area under the curve (IAUC) difference between groups were analyzed with paired T-test. Cathecin contents of tea were measured using high-performance liquid chromatography (HPLC).&#x0D; Results: The PBG of HD group was lower compared to UD (at 60 minutes =113.70 ± 13.20 vs 124.16 ± 8.17 mg/dL, p = 0.005; at 120 minutes = 88.95 ± 6.13 vs 105.25 ± 13.85 mg/dL, p &lt; 0.001). The IAUC of HD was also found to be lower compared to UD (2055.0 vs 3411.9 min.mg/dL, p &lt; 0.001).&#x0D; Conclusion: Additional benefit of lowering PBG can be achieved by using higher dose of green tea. This study recommends preparing higher dose of green tea drinks for better control of PBG.

Can green tea preparations help with weight loss?

Can green tea preparations help with weight loss?

Cancer prevention trial of a synergistic mixture of green tea concentrate plus Capsicum (CAPSOL-T) in a random population of subjects ages 40-84

BackgroundExperts agree that one of the more promising strategies in cancer management is early detection coupled with early intervention. In this study, we evaluated an early cancer detection strategy of cancer presence based on serum levels of the cancer-specific transcript variants of ENOX2 in serum coupled with an ENOX2-targeted nutraceutical preparation of green tea concentrate plus Capsicum (Capsol-T®) as a strategy of Curative Prevention® involving early detection coupled with early intervention in early stage cancer when in its most susceptible and manageable stages.Experimental designOne hundred ten (110) subjects were tested for cancer presence using the ONCOblot® Tissue of Origin 2-D gel/western blot protocol for detection of serum presence of transcript variants of the ENOX2 protein. Subjects testing positive for ENOX2 received 350 mg of Capsol-T® in capsule form every 4 h including during the night for periods of at least 3 to 6 months or longer after which they were again tested for ENOX2 presence using the ONCOblot® Tissue of Origin Cancer Test protocol.ResultsOf the 110 subjects, both male and female, ages 40 to 84, with no evidence of clinical symptoms of cancer, 40% were positive for ENOX2 presence in the ONCOblot® Tissue of Origin Cancer Test. After completion of 3 to 17 months of Capsol-T® use, 94% of subjects subsequently tested negative for ENOX2 presence.ConclusionsOral Capsol-T® is well tolerated and, for ENOX2 presence in serum in the absence of clinical cancer symptoms, is consistently effective in reducing the serum ENOX2 levels to below detectable limits.

Epigallocatechin gallate effectively ameliorates fluoride-induced oxidative stress and DNA damage in the liver of rats

Environmental exposure to sodium fluoride (NaF) compounds is a worldwide health concern. Epigallocatechin gallate (EGCG) is a green tea catechin found in a variety of green tea preparations. The intention of this study was to investigate the hepatoprotective role of EGCG in NaF-intoxicated rats. Rats were orally treated with NaF alone (25 mg·(kg body mass)(-1)·day(-1)) or plus EGCG at different doses (20, 40, and 80 mg·(kg body mass)(-1)·day(-1)) for 4 weeks. Hepatotoxicity of NaF was determined by increased levels of serum hepatospecific markers and total bilirubin, along with increased levels of thiobarbituric acid reactive substances, lipid hydroperoxides, protein carbonyl content, and conjugated dienes. The hepatotoxic nature of NaF was further evidenced by the decreased activity of enzymatic and nonenzymatic antioxidant levels in liver. NaF-treated rats also showed increased DNA damage and fragmentation in hepatocytes. Administration of EGCG (40 mg·(kg body mass)(-1)) to NaF-intoxicated rats significantly recuperated the distorted biochemical indices, DNA damage, and pathological changes in the liver tissue. Thus, the results of the present study clearly demonstrate that EGCG has strong free radical scavenging, antioxidant, and antigenotoxic properties that protect against NaF-induced oxidative hepatic injury in rats.

Green tea for weight loss and weight maintenance in overweight or obese adults

Preparations of green tea are used as aids in weight loss and weight maintenance. Catechins and caffeine, both contained in green tea, are each believed to have a role in increasing energy metabolism, which may lead to weight loss. A number of randomised controlled trials (RCTs) evaluating the role of green tea in weight loss have been published; however, the efficacy of green tea preparations in weight loss remains unclear. To assess the efficacy and safety of green tea preparations for weight loss and weight maintenance in overweight or obese adults. We searched the following databases from inception to specified date as well as reference lists of relevant articles: The Cochrane Library (Issue 12, 2011), MEDLINE (December 2011), EMBASE (December 2011), CINAHL (January 2012), AMED (January 2012), Biological Abstracts (January 2012), IBIDS (August 2010), Obesity+ (January 2012), IPA (January 2012) and Web of Science (December 2011). Current Controlled Trials with links to other databases of ongoing trials was also searched. RCTs of at least 12 weeks' duration comparing green tea preparations to a control in overweight or obese adults. Three authors independently extracted data, assessed studies for risk of bias and quality, with differences resolved by consensus. Heterogeneity of included studies was assessed visually using forest plots and quantified using the I(2) statistic. We synthesised data using meta-analysis and descriptive analysis as appropriate; subgroup and sensitivity analyses were conducted. Adverse effects reported in studies were recorded. Due to the level of heterogeneity among studies, studies were divided into two groups; those conducted in Japan and those conducted outside Japan. Study length ranged between 12 and 13 weeks. Meta-analysis of six studies conducted outside Japan showed a mean difference (MD) in weight loss of -0.04 kg (95% CI -0.5 to 0.4; P = 0.88; I(2) = 18%; 532 participants). The eight studies conducted in Japan were not similar enough to allow pooling of results and MD in weight loss ranged from -0.2 kg to -3.5 kg (1030 participants) in favour of green tea preparations. Meta-analysis of studies measuring change in body mass index (BMI) conducted outside Japan showed a MD in BMI of -0.2 kg/m(2) (95% CI -0.5 to 0.1; P = 0.21; I(2) = 38%; 222 participants). Differences among the eight studies conducted in Japan did not allow pooling of results and showed a reduction in BMI ranging from no effect to -1.3 kg/m(2) (1030 participants), in favour of green tea preparations over control. Meta-analysis of five studies conducted outside Japan and measuring waist circumference reported a MD of -0.2 cm (95% CI -1.4 to 0.9; P = 0.70; I(2) = 58%; 404 participants). Differences among the eight studies conducted in Japan did not allow pooling of results and showed effects on waist circumference ranging from a gain of 1 cm to a loss of 3.3 cm (1030 participants). Meta-analysis for three weight loss studies, conducted outside Japan, with waist-to-hip ratio data (144 participants) yielded no significant change (MD 0; 95% CI -0.02 to 0.01). Analysis of two studies conducted to determine if green tea could help to maintain weight after a period of weight loss (184 participants) showed a change in weight loss of 0.6 to -1.6 kg, a change in BMI from 0.2 to -0.5 kg/m(2) and a change in waist circumference from 0.3 to -1.7 cm. In the eight studies that recorded adverse events, four reported adverse events that were mild to moderate, with the exception of two (green tea preparations group) that required hospitalisation (reported as not associated with the intervention). Nine studies reported on compliance/adherence, one study assessed attitude towards eating as part of the health-related quality of life outcome. No studies reported on patient satisfaction, morbidity or cost. Green tea preparations appear to induce a small, statistically non-significant weight loss in overweight or obese adults. Because the amount of weight loss is small, it is not likely to be clinically important. Green tea had no significant effect on the maintenance of weight loss. Of those studies recording information on adverse events, only two identified an adverse event requiring hospitalisation. The remaining adverse events were judged to be mild to moderate.

Complementary and Alternative Medicines in Prostate Cancer: From Bench to Bedside?

Complementary and alternative medicine (CAM) use is common among adults, and recent reports suggest that 25%-50% of prostate cancer (PCa) patients use at least one CAM modality. The most common CAM modalities used by PCa patients are vitamin and herbal preparations with purported antitumor effects despite only modest underlying preclinical or clinical evidence of efficacy. In this review we provide a brief overview of the basic scientific and clinical studies underlying the most common herbal and vitamin preparations including common antioxidants, pomegranate extract, green tea, turmeric, resveratrol, silibinin, and herbal combination preparations. When available, prostate cancer clinical trial data are reviewed. Importantly, we have compared the concentration of these agents used in in vitro experiments to that likely to be achievable in humans. From the available data we conclude that there is insufficient evidence to support the use of CAMs for the treatment of prostate cancer patients outside of a clinical trial. The purpose of this review is to more rigorously evaluate CAM therapy in prostate cancer and educate oncologists and patients. This review focuses on examples from the general classes of agents in common use.

Flavonoids, total phenolics and antioxidant capacity: comparison between commercial green tea preparations

The potential health benefits attributed to green tea and its catechins such as antioxidant effects, cancer chemoprevention, and weight loss have led to a huge increase of green tea products in the food market. The objectives of this work were to analyze and compare these products in terms of phenolic contents and in vitro antioxidant capacity including tea bags, dehydrated leaves, and ready-to-drink preparations after standardization of the infusion preparation procedure. Total phenolics content in 1 cup of the different teas varied from 90 to 341 mg of catechin equivalents, and the highest and the lowest values were both those of the ready-to-drink products. Infusions prepared from tea bags had contents varying from 96 to 201 mg.200 mL-1, and there were no significant differences among batches. The DPPH radical scavenging and the Oxygen Radical Absorbing Capacities (ORAC) varied largely among the different tea preparations, from 23 to 131 mmoles of Trolox Equivalents (TE).200 mL-1 (DPPH), and from 1.2 to 5.1 mmoles of TE.200 mL-1 (ORAC), but again there were no differences among infusions or ready-to-drink commercial preparations. However, the antioxidant capacity of ready-to-drink products was partially due to the presence of other non-phenolic compounds such as ascorbic acid

The influence of domestic culinary processes on the Trolox Equivalent Antioxidant Capacity of green tea infusions

This paper presents an investigation into the influence of several culinary factors, such as water temperature, infusion time, stirring and dosage form, on polyphenol content and antioxidant capacity (TEAC values) during the domestic preparation of green tea. The results obtained show that water temperature and infusion time strongly influence total polyphenol levels and the antioxidant capacity of green tea. Temperatures of 70–80 °C together with infusion times of 3–5 min produced greatest effect, in this respect. At 90 °C, extraction was faster and more effective. However, prolonged infusion at this temperature may cause a loss of polyphenol compounds and, consequently, of antioxidant capacity. Factors such as agitation and dosage form do not seem to have much influence. Furthermore, it was found that pure green tea infusions have higher antioxidant properties than do blends of green tea with aromatic herbs and fruits.

Effect of deep sea water on the antioxidant activity and catechin content of green tea

Application of deep sea water (DSW) on preparation of green tea was evaluated. Green tea leaves were soaked in desalinated deep sea water (DSW) at 75°C for 10 min, and were evaluated for antioxidant activity and catechin content. DSW green tea showed higher antioxidant activity than green tea prepared with distilled water (DW). The 2,2-diphenyl-1-picrylhydrazyl (DPPH) radical scavenging activities and reducing power of DW and DSW green teas were 57.88 and 83.98%, and their optical densities were 0.99 and 1.14, respectively. Nitrite scavenging activity was also higher in DSW green tea than in DW green tea. Overall amounts of catechins and caffeine were also greater in DSW green tea. For example, epigallocatechin gallate content in DW and DSW green teas were 13.20 and 17.97 mg/g, respectively. However, there was no significant colour difference between the two tea preparations. These results indicated that the chemical properties of green tea are significantly affected by DSW and that DSW results in high quality green tea. Key words: Green tea, deep sea water, antioxidant activity, catechins.

Possible green tea-induced thrombotic thrombocytopenic purpura

A case of a patient who developed thrombotic thrombocytopenic purpura (TTP) after consuming a weight-loss product containing green tea is reported. A 38-year-old, 68-kg Caucasian woman arrived at the emergency department with a one-week history of malaise, fatigue, and petechiae of the skin. She had no symptoms of infection and denied illegal drug use. Her medical history included hypothyroidism, for which she was treated with levothyroxine 150 microg daily for the past four years. She reported that she had been using a green tea preparation for the two months before admission to lose body weight. The daily preparation contained 200 mg of green tea extract 5:1, equivalent to 1 g of natural green tea. On clinical examination, the patient appeared acutely ill and was afebrile, with pallor, petechiae, and purpura of the extremities. Laboratory test results at the time of admission revealed that the patient had anemia and marked thrombocytopenia. A peripheral blood smear demonstrated a feature of microangiopathic hemolytic anemia. Immunoglobulin G autoantibodies against ADAM metallopeptidase with thrombospondin type 1 motif, 13 were detected. On hospital day 3, the patient appeared confused and exhibited aphasia that was initially transient but then recurrent. Brain computerized tomography did not exhibit focal pathology. Over the next few days, her neurologic symptoms subsided and her platelet count and hematocrit value gradually increased. Plasmapheresis was performed (12 procedures). Corticosteroid treatment was also initiated. After 20 days of hospitalization, the patient was discharged. A 38-year-old woman developed TTP after consuming a weight-loss product containing green tea extract for two months.

Green tea preparation and its influence on the content of bioactive compounds

Abstract The effect of different extraction conditions and storage time of prepared infusions on the content of bioactive compounds of green teas and their antioxidant capacity were investigated. The content of total phenols, total flavonoids and total non-flavonoids in green teas was determined spectrophotometrically, while 7 flavan-3-ols, 6 phenolic acids and 3 methylxanthines were identified and quantified by using high performance liquid chromatography (HPLC–PDA). Among the tested green teas bagged green tea Twinings of London was recognized as the richest source of phenolic compounds (3585 mg/L GAE of total phenols). The most abundant phenolic constituents of green tea were flavan-3-ols, of which EGCG was prevailing in all teas (94.54–357.07 mg/L). The highest content of caffeine, as the most abundant methylxanthine, was determined in powdered green tea. The findings of this investigation suggest that extraction efficiency of studied bioactive compounds from green tea depends on the extraction conditions and that maximum extraction efficiency is achieved during aqueous extraction at 80 °C, for 5′ (powder), 15′ (bagged) and 30′ (loose leaf). In order to determine the antioxidant capacity of teas the DPPH, ABTS and FRAP assays were applied. Regardless of the extraction conditions all green teas exhibited significant antioxidant capacity in vitro, which was in correlation with their phenolic content, confirming that green tea is one of the best dietary sources of antioxidants.

Effects of olfactory dysfunction on sensory evaluation and preparation of foods

Aim of this study was to investigate the impact of olfactory dysfunction on behavior during sensory evaluation and self-preparation, as well as on sensory perception and pleasantness of green tea and coffee. We compared the intensities of overall odor, flavor, and bitter taste, respectively, and the pleasantness ratings for three different concentrations of green teas and coffees between three groups: young ( n = 30) and elderly ( n = 30) with normal olfactory function and elderly ( n = 30) with olfactory dysfunction. In addition, we compared the subject groups’ behavior during sensory testing and preparation of green tea or coffee. As expected, elderly subjects with olfactory dysfunction rated the overall odor intensity less intense than subjects with normal olfactory function. Also, elderly subjects with olfactory dysfunction rated the intensities of overall flavor and bitter taste significantly lower rather than subjects with normal olfactory function in green tea, whereas this result was not obtained in coffee. Compared to young subjects with normal olfactory function, elderly with olfactory dysfunction used more green tea powder to optimize their own green tea. Moreover, olfactory function scores assessed by the “Sniffin’ Sticks” test were positively related with sniffing frequency for green tea and with sniffing time for coffee during sensory evaluation. During preparation of the green tea, compared to elderly subjects, young healthy subjects tried to adjust the green tea more frequently by adding green tea powder or water. Such behavioral differences were not present during coffee preparation. In conclusion, our findings demonstrate that olfactory dysfunction affects odor perception and sniffing behavior. However, under the current conditions, it appeared to have no effect on hedonic ratings and self-preparation behaviors.

The Relation between Green Tea Consumption and Cardiovascular Disease as Evidenced by Epidemiological Studies

Although substantial evidence from in vitro and animal studies indicates that green tea preparations inhibit cardiovascular disease processes, the possible protective role of green tea consumption against this disease in humans remains unclear. We conducted a population-based prospective cohort study (the Ohsaki Study) to examine the association between green tea consumption and mortality from cardiovascular disease (CVD), cancer, and all causes with 40,530 persons in Miyagi prefecture, in northern Japan. Previously published work has shown that green tea consumption was inversely associated with mortality from CVD and all causes. The inverse association of mortality from CVD was more pronounced in women (P = 0.08 for interaction with sex). In women, the multivariate hazard ratios (95% confidence intervals) of CVD mortality across increasing green tea consumption categories were 1.00, 0.84 (0.63–1.12), 0.69 (0.52–0.93), 0.69 (0.53–0.90) (P for trend = 0.004). Within CVD mortality, the stronger inverse association was observed for stroke mortality. Because our observational study has found the inverse association, I report here the results of a review of epidemiological evidence from randomized controlled trials (RCT) of the association between green tea or green tea extracts and CVD risk profiles. More than half of the RCT have demonstrated the beneficial effects of green tea on CVD risk profiles. These results from RCT suggest a plausible mechanism for the beneficial effects of green tea and provide substantial support for our observations.

Green tea polyphenols inhibit colorectal aberrant crypt foci (ACF) formation and prevent oncogenic changes in dysplastic ACF in azoxymethane-treated F344 rats

Green tea and its constituents have shown cancer-preventive activities in many animal models. In order to prepare for a human trial on the inhibition of colon carcinogenesis, we conducted a study with green tea polyphenols as the preventive agent in an azoxymethane (AOM)-induced rat colon cancer model using aberrant crypt foci (ACF) as an end point. F344 rats were given two weekly injections of AOM (15 mg/kg), and then fed a 20% high-fat diet with or without 0.12 or 0.24% Polyphenon E (PPE, a standardized green tea preparation consisting 65% of (-)-epigallocatechin-3-gallate and 22% of other catechins) for 8 weeks. Colorectal ACF were analyzed under a microscope after methylene blue staining. Dietary PPE administration was found to significantly and dose dependently decrease the total number of ACF per rat and the total number of aberrant crypt per rat. Moreover, treatment with 0.24% PPE also significantly decreased the percentage of large ACF (four or more crypts) and the percentage of ACF with high-grade dysplasia in total ACF. The high-grade dysplastic ACF from 0.24% PPE-treated group had increased apoptosis and decreased nuclear expression levels of beta-catenin and cyclin D1. Retinoid X receptor (RXR)alpha expression was reduced in high-grade dysplastic ACF, adenoma and adenocarcinoma during AOM-induced colon carcinogenesis, and the PPE treatment partially prevented the loss of RXRalpha expression in high-grade dysplastic ACF. Taken together, our results strongly suggest the colon cancer-preventive activity of PPE and identified possible molecular markers for future colon cancer prevention studies.

Quality Evaluation of the Green Tea Extract Containing Capsules and Investigation of their Antioxidant Activity

Green tea preparations are currently widely used in Lithuania, and therefore capsules with dry green tea extract were chosen with the aim of determination of their polyphenol and caffeine contents and antioxidant activity, as well as for the evaluation of the correlation between possible indicators. The amount of polyphenolic compounds was determined using the Foulin - Ciocalteau reagent, standard galic acid, and following spectrophotometry. Qualitative and quantitative determination of the caffeine was performed using high performance liquid chromatography. Antioxidant activity was determined by applying the 2,2-diphenyl-1-picrylhydrazyl (DPPH) radical binding method and inhibition of tyrosine nitration technique. The study showed that the amount of polyphenols and caffeine in the extract depends not only on the quality of the vegetal stock, but also on the technological parameters of processes applied in the production of dry extract. Antioxidant activity directly correlated with the amount of polyphenols in the extract. The quality of the green tea extract capsules was evaluated and, the allowable amounts of polyphenols (not less than 150 mg) and caffeine (not less than 16 mg) per capsule were established.

ANALISIS EPIGALOKATEKIN GALAT DALAM MINUMAN TEH HIJAU SIAP SAJI

Epigallocatechin gallat (EGCg) is a polyphenol constituent in tea that has antioxidant effect. The purpose of this research was to identify and examine qualitative and quantitative EGCg in green tea preparations which were stored in different condition, that was in a refrigerator and in an open air. The results showed that all samples containing EGCg. The examination of EGCg concentration in the sample was done by thin layer chromatography densitometric method using cellulose plate. N-propanol - acetic acid - water (1:1:5) was the selected eluent. Linear regression equation from calibration curve was y = -1204.071 + 7.495 x, with correlation factor (r) = 0.99911. EGCg concentration from sample that stored in refrigerator sample number one was 0.00293% w/v, sample number two was 0.00298% w/v, and sample number three was 0.00328% w/v. EGCg concentration from sample that stored in open air was lower than LOD.