Effect of green tea (Camellia sinensis) extract and pre-freezing equilibration time on the post-thawing quality of ram semen cryopreserved in a soybean lecithin-based extender

The aim of this study was to determine the effect of Camellia sinensis extract as antioxidant supplement and pre-freezing equilibration times in a soybean lecithin extender for freezing ram semen. In this study, a total of 20 ejaculates were collected from four Ghezel rams and diluted with extenders (1.5% soybean lecithin, 7% glycerol) containing no supplements (control) and Camellia sinensis extract (5, 10, and 15 mg/L) and cryopreserved, immediately after thermal equilibrium was reached at 5 °C (0 h), or 4 h after equilibration. Sperm motility characteristics, membrane integrity, abnormal morphology, mitochondria activity, apoptotic status, MDA and antioxidant activities (GPx, SOD and total antioxidant capacity (TAC)) were evaluated following freeze-thawing. Camellia sinensis extract at level 10 mg/L led to the highest total and progressive motilities percentages, in comparison to other treatments (P < 0.05). Our results showed that Camellia sinensis extract at level of 5 and 10 mg/L led to higher plasma membrane integrity, mitochondria activity and Total antioxidant capacity (TAC) in comparison to the level of 15 mg/L and control group (P < 0.05). Camellia sinensis extract at 10 mg/L level produced the highest percentage of live spermatozoa and the lowest apoptotic spermatozoa in comparison to all treatments (P < 0.05). In addition, level of MDA formation significantly decreased at this concentration, 10 mg/L, compared to all treatments (P < 0.05). No differences (P > 0.05) were observed between equilibration times (0 h vs. 4 h) for sperm samples incubated with or without different concentrations of Camellia sinensis extract. In conclusion, addition of Camellia sinensis extract at level of 10 mg/L can improve post-thawing quality of ram semen cryopreserved in a soybean lecithin extender. However, further research is needed to standardize the process of Camellia sinensis extraction and specially for identifying which compounds are responsible of its beneficial effect on ram sperm cryopreservation.

A tandem mass spectrometry method based on selected ions detects low-abundance phenolics in black tea - theatridimensins as products of the oxidative cascade

RATIONALE

Mixtures of phenolics are widespread in plant-derived food products, for instance black tea. Detailed compositional analysis of phenolics present is important for quality control. Characterization of low-abundance compounds often requires extensive purification; hence, the need for rapid screening methods to annotate compounds in complex mixtures without extensive sample preparation. Opportunities of ultra-high performance liquid chromatography/tandem mass spectrometry (UHPLC/MS) as tool in a rapid screening method are discussed for black tea analysis, with the two-step-oxidation product theatridimensin (T3D) as example.

METHODS

Three MS screening methods were compared for their ability to tentatively annotate two-step-oxidation products in black teas without the need for prior fractionation: (i) full MS; (ii) tandem mass spectrometry (MS/MS) on selected ions; and (iii) selected reaction monitoring (SRM), in combination with post-analysis extracted ion chromatography. A model system of theaflavin (TF), epicatechin (EC) and tyrosinase was used to prepare the two-step-oxidation product T3D, consisting of three oligomerized catechin subunits. Commercial teas were screened for the occurrence of T3Ds.

RESULTS

The MS(2) fragmentation pattern of T3D was compared with that of an isomeric catechin trimer from black tea, TFsEC. MS(2) signature fragments were found to distinguish the two isomers, i.e. m/z 617 for T3D and m/z 563 for TFsEC. The MS screening methods, MS/MS on selected ions and SRM, both enabled monitoring MS(2) data of compounds present in low abundance. The former provided the most complete MS(2) data set, which facilitated the discovery of another isomer, i.e. theaflavate A. T3Ds, TFsECs, and theaflavate A could be tentatively annotated in all tested tea samples.

CONCLUSIONS

When exploring black tea for the occurrence of two-step-oxidation products, the use of MS/MS on selected ions combined with extracted ion chromatography proved to be the most suitable. The occurrence of T3Ds and T3Dgs in various black teas was shown for the first time and the 'oxidative cascade hypothesis' was extended with novel oxidation products. Copyright © 2016 John Wiley & Sons, Ltd.

The Effects of Green Tea Consumption on Incidence of Breast Cancer and Recurrence of Breast Cancer: A Systematic Review and Meta-analysis

Background: Green tea is widely used by women for the prevention and treatment of breast cancer. The authors aimed to determine the efficacy of green tea ingestion on the risk of breast cancer development and the risk of breast cancer recurrence. Methods: The authors conducted a systematic review and meta-analyses of observational studies from systematic searches of 8 electronic data sources and contact with authors. They included studies assessing breast cancer incidence and recurrence. Results from cohort studies and case-control studies were pooled separately using a random effects model with testing of a priori hypotheses to explain heterogeneity. Results: The pooled relative risk (RR) of developing breast cancer for the highest levels of green tea consumption in cohort studies was 0.89 (95% confidence interval [CI], 0.71-1.1; P= .28; I2= 0%), and in case control studies, the odds ratio was 0.44 (95% CI, 0.14-1.31; P= .14; I2= 47%). The pooled RR of cohort studies for breast cancer recurrence in all stages was 0.75 (95% CI, 0.47-1.19; P= .22; I2= 37%). A subgroup analysis of recurrence in stage I and II disease showed a pooled RR in cohort studies of 0.56 (95% CI, 0.38-0.83; P= .004; I2= 0%). Dose-response relationships were evident in only 3 of the 7 studies. Conclusion: To date, the epidemiological data indicates that consumption of 5 or more cups of green tea a day shows a non-statistically significant trend towards the prevention of breast cancer development. Evidence indicates that green tea consumption may possibly help prevent breast cancer recurrence in early stage (I and II) cancers. However, conclusions as to the potential therapeutic application of green tea are currently impossible to make due to the small number of studies conducted, the lack of any clinical trial evidence, the lack of a consistent dose-response relationship, and the potential for interaction with standard care.

Research on dye wastewater decoloration by pulse discharge plasma combined with charcoal derived from spent tea leaves

Pulsed discharge plasma (PDP) combined with charcoal (PDP-charcoal) was employed to treat dye wastewater, with methyl orange (MO) as the model pollutant. The charcoal was prepared using spent tea leaves and was characterized by scanning electron microscopy, Fourier-transform infrared spectroscopy, and Boehm titration to investigate the adsorption and catalytic characteristics before and after adsorption and PDP treatment. The prepared charcoal exhibited a high MO adsorption capacity, and the adsorption process followed the pseudo-second-order kinetic model and the Freundlich model. The MO decoloration efficiency reached 69.8 % within 7.5 min of treatment in the PDP-charcoal system, whereas values of 29.2 and 25.9 % were achieved in individual PDP and charcoal systems, respectively. The addition of n-butanol and H2PO4 (-) presented inhibitive effects on MO decoloration in the PDP system. However, these effects were much weaker in the PDP-charcoal system. In addition, the effects of charcoal on O3 and H2O2 formation were evaluated, and the results showed that both the O3 and H2O2 concentrations decreased in the presence of charcoal. The MO decomposition intermediates were analyzed using UV-Vis spectrometry and GC-MS. 1,4-Benzoquinone, 4-nitrophenol, 4-hydroxyaniline, and N,N'-dimethylaniline were detected. A possible pathway for MO decomposition in this system was proposed.

Risk assessment of mineral and heavy metal content of selected tea products from the Ghanaian market

Food consumption is the most likely route of human exposure to metals. Tea (Camellia sinensis L.) is among the most widely consumed non-alcoholic beverages. Concentrations of heavy metals and minerals in tea from 15 different brands in Kumasi, Ghana were measured to assess the health risk associated with their consumption. The mineral and metal contents (Fe, Cu, Zn, Pb, As, Cd) were analyzed using atomic absorption spectrophotometer (Z-8100 polarized Zeeman). The results revealed that the mean concentrations were in the order: Ca > Fe > As > Cd > Zn > Pb. The average contents of Ca, Fe, Zn, Pb, Cd, and As in the samples were 94.08, 6.15, 0.20, 0.16, 0.36, and 1.66 mg/kg, respectively. All the minerals and heavy metals were below the maximum permissible limits stipulated by the World Health Organization (WHO) and US Pharmacopeia (USP). Metal-to-metal correlation indicated strong correlations between As/Zn, Cd/Zn, Cd/As, and Pb/As pairs. Factor analysis demonstrated a clear separation between minerals, grouped on one side, and heavy metals, clustered on another side. Both the target hazard quotient (THQ) and hazard index (HI) levels in green tea were far below 1, suggesting that consumption of green tea should pose no potential risk to human health. However, carcinogenic risk levels for arsenic were high; R > 10(-6). The results showed that residents in Kumasi consume tea could be at risk from exposure to these heavy metals and minerals.

Age and gender differences in the influence of extrinsic product information on acceptability for RTD green tea beverages

BACKGROUND

The introduction of ready-to-drink (RTD) green tea beverage has allowed diverse consumers to consume green teas and related products. Green tea that has been traditionally consumed for its delicate flavor characteristics is also widely consumed for its recognition as a healthy product. Because it is reported that age difference exists in consideration of health-related information, the objective of the study was to investigate how sensory and non-sensory factors, in particular health-related information, price and packaging, would affect the flavor acceptability of green tea beverages, depending on consumers' age and gender.

RESULTS

Regardless of the product information, old consumers preferred products that provided an indication of health beneficial effect. On the other hand, young consumers tended to be influenced by extrinsic product information such as packaging, brand/manufacturer and/or price, though these consumers were not so much influenced by health beneficial information as were the old consumers.

CONCLUSION

The findings of the study implied that the influence of non-sensory information such as health beneficial information in flavor liking differed depending mostly on consumers' age, and little on gender, for RTD green tea beverages.

Stereochemistry of the Black Tea Pigments Theacitrins A and C

Theacitrins A-C are yellow pigments of black tea that are produced by oxidative coupling of gallocatechins, i.e., flavan-3-ols with pyrogallol-type B-rings. However, their stereostructures have not yet been determined. In this study, DFT calculations of NMR chemical shifts of theacitrin C (1) and TDDFT calculations of the ECD spectra of theacitrinin A (5), a degradation product of theacitrin C (1), were used to determine the stereostructure of the theacitrins. Furthermore, the preparation of theacitrins A (4) and C (1) by enzymatic oxidation of an epigallocatechin (7) and epigallocatechin-3-O-gallate (2) mixture confirmed their structural relationship.

Role of nicotine and camellia sinensis on the developing femur of chick

OBJECTIVE

To study the harmful effects of nicotine on the developing femur of chick and to observe the role of antioxidant camellia sinensis in the prevention of these effects.

METHODS

The experimental study was conducted at Army Medical College, Rawalpindi, from November 2, 2011, to November 1, 2012, and comprised fresh fertilised eggs of Fayoumi species at zero hour of incubation of Fayoumi species. The eggs were divided into four equal groups. Control group G1 was given normal saline; G2 was given green tea extract; G3 was given 0.0001% nicotine solution; and G4 was given both 0.0001% nicotine solution and green tea extract. First exposure was at 48 hours of incubation and second at 48 hours of hatching (post-natal dose).At the age of one month, the chicks were sacrifised. The length of the femurs was measured with the help of measuring scale by keeping the ruler between greater trochanter and the lateral condyle. SPSS 16 was used for statistical analysis.

RESULTS

The four groups had 10 eggs each. G3 and G4 showed decreased growth compared to G1 and G2 (p<0.05). In G4, better growth was noticed compared to G3 (p<0.05), but its growth was less in comparison with G1 and G2(p>0.05).

CONCLUSIONS

Camellia sinensis antioxidant property helped to neutralise the oxidative injury by the use of nicotine, but was unable to recover it fully.

[Control of Soil Nutrient Loss of Typical Reforestation Patterns Along the Three Gorges Reservoir Area]

Annual soil nutrient loss characteristics on typical reforestation patterns in watershed along the Three Gorges Reservoir Area were studied based on runoff plot experiment. Runoff and sediment nutrition content from May to October 2014 of typical reforestation patterns including garden plot (tea garden), forest land (Chinese chestnut) and the original slope farmland were determined and then analyzed. The results showed that: (1) After the Returning Farmland to Forest Project the quantity of annual soil nutrient (nitrogen and phosphorus, the sum of them in sediment and runoff) loss decreased. The output of total nitrogen (TN) was in the order of slope farmland (2 444.27 g x hm(-2)) > tea garden (998.70 g x hm(-2)) > Chinese chestnut forest (532.61 g x hm(-2)), and for total phosphorus (TP) loss was slope farmland (1 690.48 g x hm(-2)) > tea garden (488.06 g x hm(-2)) > Chinese chestnut forest (129.00 g x hm(-2)) . Compared with slope farmland, the load of TN and TP output of reforestation patterns decreased 68.68% and 81.75%, respectively. (2) Compared with slope farmland, available nitrogen loss decreased in reforestation patterns. Total nitrate nitrogen (NO3(-)-N) loss ranked in the order of slope farmland (113.79 g x hm(-2)) > tea garden (73.75 g x hm(-2)) > Chinese chestnut forest (56.06 g x hm(-2)) The largest amount of ammonium nitrogen (NH4(+)-N) was found in tea garden (69.34 g x hm(-2)), then in farmland (52.45 g x hm(-2)), and the least in Chinese chestnut forest (47.23 g x hm(-2)). (3) The main route of NO3(-)-N and NH4(+)-N loss was both through runoff, the quantity of NO3(-)-N and NH4(+)-N output in which accounted for 91.4% and 92.2% of the total, respectively. The quantity of TN and TP in sediment accounted for 86.6% and 98.4% of the total. TN and TP loss showed an extremely significant correlation with sediments, which showed that sediment output was the main approach of TN and TP loss.

[Characteristics of soil pH and exchangeable acidity in red soil profile under different vegetation types]

The characteristics of soil pH and exchangeable acidity in soil profile under different vegetation types were studied in hilly red soil regions of southern Hunan Province, China. The soil samples from red soil profiles within 0-100 cm depth at fertilized plots and unfertilized plots were collected and analyzed to understand the profile distribution of soil pH and exchangeable acidity. The results showed that, pH in 0-60 cm soil from the fertilized plots decreased as the following sequence: citrus orchard > Arachis hypogaea field > tea garden. As for exchangeable acidity content, the sequence was A. hypogaea field ≤ citrus orchard < tea garden. After tea tree and A. hypogaea were planted for long time, acidification occurred in surface soil (0-40 cm), compared with the deep soil (60-100 cm), and soil pH decreased by 0.55 and 0.17 respectively, but such changes did not occur in citrus orchard. Soil pH in 0-40 cm soil from the natural recovery vegetation unfertilized plots decreased as the following sequence: Imperata cylindrica land > Castanea mollissima garden > Pinus elliottii forest ≥ Loropetalum chinensis forest. As for exchangeable acidity content, the sequence was L cylindrica land < C. mollissima garden < L. chinensis forest ≤ P. elliottii forest. Soil pH in surface soil (0-20 cm) from natural forest plots, secondary forest and Camellia oleifera forest were significantly lower than that from P. massoniana forest, decreased by 0.34 and 0.20 respectively. For exchangeable acidity content in 0-20 cm soil from natural forest plot, P. massoniana forest and secondary forest were significantly lower than C. oleifera forest. Compared with bare land, surface soil acidification in unfertilized plots except I. cylindrica land had been accelerated, and the natural secondary forest was the most serious among them, with surface soil pH decreasing by 0.52. However, the pH increased in deep soils from unfertilized plots except natural secondary forest, and I. cylindrica land was the most obvious among them, with soil pH increasing by 0.43. The effects of fertilization and vegetation type on pH and exchangeable acidity decreased with the increasing soil depth from all plots.

Green tea and liver cancer risk: A meta-analysis of prospective cohort studies in Asian populations

OBJECTIVES

The aim of this meta-analysis was to investigate whether an association existed between green tea consumption and the risk for liver cancer in prospective cohort studies in Asian populations.

METHODS

Relevant studies were identified by searching PubMed, EMBASE, ISI Web of Science, and the Chinese Bio-medicine Database published before April 2015. Study-specific risk estimates for the highest versus non- or lowest and increment of daily cup of green tea consumption levels were combined based on fixed- or random-effects models. STATA 11.0 (Stata Corporation, College Station, TX, USA) software was used for statistical analysis.

RESULTS

Nine prospective cohort articles involving 465,274 participants and 3694 cases of liver cancer from China, Japan, and Singapore were included. The summary relative risk (RR) indicated a significant association between the highest green tea consumption and reduced risk for liver cancer (summary RR, 0.88; 95% confidence interval [CI], 0.81-0.97). However, no statistically significant association was observed when analyzing daily consumption of one cup (summary RR, 0.97; 95% CI, 0.95-1.00). When stratified by sex, the protective effect of green tea consumption on risk for liver cancer was observed only in the group of women (summary RR, 0.78; 95% CI, 0.64-0.96), but not in men (summary RR, 0.89; 95% CI, 0.79-1.00).

CONCLUSIONS

The present analysis indicated the preventive effects of green tea intake on the risk for liver cancer in female Asian populations. However, additional studies are needed to make a convincing case for this association.

[Effects of biochar on CO2 and N2O emissions and microbial properties of tea garden soils]

To clarify the effects of biochar addition (0.5%, 1.5%, 2.5%, 3.5%) on the emission of carbon dioxide (CO2) and nitrous oxide (N2O), pH and microbial communities of the tea garden soil, an indoor incubation experiment was conducted using the acidulated tea-planted soil. Results showed that the emissions of CO2 and N2O and the rate of C, N mineralization were increased in a short term after the addition of biochar compared with the control, while the promoting effect was weakened along with increasing the addition of biochar. The pH, dehydrogenase activity and microbial biomass carbon were increased in the biochar treatments. Phospholi-pid fatty acid (PLFA) with different markers was measured and the most PLFA was detected in the group in the 1.5% biochar treatment with significant differences (P<0.05) compared with the control. In addition, the higher levels of 16:0, 14:0 (bacteria), 18:lω9c (fungi), l0Me18:0 (actinomycetes) groups were observed and there were significant differences (P <0.05) in individual phospholipid fatty acid among the different treatments. Taken together, the acidulated tea-planted soil, soil microbial biomass and microbial number were improved after addition of biochar.

Tea, but not coffee consumption, is associated with components of arterial pressure. The Observation of Cardiovascular Risk Factors study in Luxembourg

There is uncertainty regarding the impact of tea and coffee consumption on arterial blood pressure. The present study aimed to examine the association between blood pressure (BP) components, namely, systolic BP (SBP), diastolic BP, mean arterial pressure, and pulse pressure (PP), and tea or coffee consumption, taking into account simultaneous consumption. The study population was derived from a national cross-sectional stratified sample of 1352 individuals aged 18 to 69 years, recruited between November 2007 and January 2009 to participate in the Observation of Cardiovascular Risk Factors in Luxembourg study. We hypothesized that greater tea consumption would be independently associated with lower BP. Tea and coffee consumptions in deciliters per day were obtained from a semiquantitative food frequency questionnaire. Participants were classified into 3 groups: nonconsumers, ≤3-dL/d consumers, and >3-dL/d consumers of each beverage separately. After exclusion of subjects taking antihypertensive medications, several general linear models were performed to investigate the independent relationship between tea/coffee consumption and BP components. Tea consumers (36.3%) were more likely to be younger women, nonsmokers, with better cardiometabolic profiles, and less frequent chronic pathologies, whereas the reverse was true for coffee consumers (88%). Greater tea consumption was associated with lower SBP and PP values, after adjustment for age, sex, education, lifestyle, and dietary confounding factors, including coffee drinking. No association between BP components and coffee consumption was observed. Daily consumption of 1 dL of tea was associated with a significant reduction of SBP by 0.6 mm Hg and PP by 0.5 mm Hg. Given the widespread consumption of tea and coffee throughout the world, together with the major cardiovascular disease risk, our findings have important implications for human health.

Protective effect of kombucha on rats fed a hypercholesterolemic diet is mediated by its antioxidant activity

CONTEXT

Kombucha (KT) is claimed to have various beneficial effects on human health, but there is very little scientific evidence available in the literature.

OBJECTIVE

The present study investigates the effects of Camellia sinensis (GT) Linn. (Theaceae) and KT, two natural drinks, on cholesterol and antioxidant status using a hypercholesterolemia rat model.

MATERIALS AND METHODS

The present study compared the free-radical scavenging abilities and polyphenol levels of GT and KT. Wistar rats fed cholesterol-rich diets were given KT or GT (5 mL/kg body weight per day, po) for 16 weeks, then fasted overnight and sacrificed. The plasma lipid levels, thiobarbituric acid reactive substances (TBARS) and aspartate aminotransferase (AST), alanine aminotransferase (ALT), and γ-glutamyl transpeptidase (GGT) serum levels, antioxidant activities of superoxide dismutase (SOD) and catalase (CAT), and creatinine and urea rats were examined.

RESULTS

KT had a phenolic compound of 955 ± 0.75 mg GAE/g) followed, by GT (788.92 ± 0.02 mg GAE/g). The free radical scavenging activity of KT was higher than GT. Compared with GT, KT induced lowered serum levels of TC, TG, VLDL-C, and LDL-C by 26, 27, 28, and 36%, respectively, and increased the serum level of high-density lipoprotein cholesterol (HDL-C). KT induced a 55% decrease of TBARS level in liver and 44% in kidney, compared with those of rats fed a cholesterol-rich diet alone. Moreover, CAT and SOD activities were reduced by 29 and 33%, respectively, in liver and 31 and 35%, respectively, in kidney, after oral administration of KT, compared with those of HCD-fed rats.

CONCLUSION

The findings revealed that KT administration induced attractive curative effects on hypercholesterolemic, particularly in terms of liver-kidney functions in rats. Its effect on humans needs to be studied further.

Analyzing organic tea certification and traceability system within the Taiwanese tea industry

BACKGROUND

We applied game theory to the organic tea certification process and traceability system used by the Taiwanese tea industry to elucidate the strategic choices made by tea farmers and organic tea certification agencies. Thus, this paper clarifies how relevant variables affect the organic certification process and traceability system used within the tea industry.

RESULTS

The findings indicate that farmers who generate high revenues experience failures regarding tea deliveries, cash outflow, damage compensation, and quasi-rent. An additional problem included the high costs yielded when tea farmers colluded with or switched organic tea certification agencies. Furthermore, there could be decreasing levels of personal interest in planting non-organic tea and lowering the costs of planting organic tea and the managerial accounting costs of building comprehensive traceability systems; thus, the analysis yielded strong results and a superior equilibrium.

CONCLUSION

This research is unprecedented, using an innovative model and providing a novel analysis structure for use in the tea industry. These results contribute to the field of literature and should serve as a valuable reference for members of the tea industry, government, and academia.

Harmonizing the assessment of biodiversity effects from land and water use within LCA

Addressing biodiversity impacts in life cycle assessment (LCA) has recently been significantly improved. Advances include the consideration of several taxa, consideration of vulnerability of species and ecosystems, global coverage and spatial differentiation. To allow a comparison of biodiversity impacts of different stressors (e.g., land and water use), consistent approaches for assessing and aggregating biodiversity impacts across taxa are needed. We propose four different options for aggregating impacts across taxa and stressors: equal weight for species, equal weight for taxa and two options with special consideration of species' vulnerability. We apply the aggregation options to a case study of coffee, tea and sugarcane production in Kenya for the production of 1 kg of crop. The ranking between stressors (land vs water use) within each crop and also of the overall impact between crops (coffee>sugarcane>tea) remained the same when applying the different aggregation options. Inclusion of the vulnerability of species had significant influence on the magnitude of results, and potentially also on the spatial distribution of impacts, and should be considered.

A case-control study of stomach cancer in relation to Camellia sinensis in China

OBJECTIVE

The purpose of our study was to investigate the association between green tea (Camellia sinensis) drinking habits and risk of stomach cancer in China.

METHOD

A 1:2 matched hospital-based case-control study including 160 cases and 320 controls was conducted. A self-designed questionnaire was used to collect information on possible risk factors of stomach cancer, and to assess the green tea drinking habit. Conditional logistic regression was used to calculate odds ratios (ORs) and corresponding 95% confidence intervals (CIs).

RESULT

Our study proposed that green tea was associated with risk of stomach cancer. Regular drinking (OR = 0.72), larger amount of consumption (≥35 g/week) (OR = 0.53) were protective factors. Among regular tea drinkers, lower temperature and longer interval between tea being poured and drunk also reduced the risk. Moreover, a strong agreement was found between temperature at which tea was drunk and tea interval (Correlation coefficient p value = 0.73).

CONCLUSION

Habits of green tea drinking, including regular drinking, larger amount of consumption, lower temperature and longer interval were strongly associated with a lower risk of stomach cancer.

Inhibitory effect of black tea and its combination with acarbose on small intestinal α-glucosidase activity

ETHNOPHARMACOLOGICAL RELEVANCE

It is said that black tea is effective against type 2 diabetes mellitus because it can help modulate postprandial hyperglycemia. However, the mechanism underlying its therapeutic and preventive effects on type 2 diabetes mellitus is unclear. In this study, we focused on the effect of black tea on the carbohydrate digestion and absorption process in the gastrointestinal tract. We examined whether black tea can modulate postprandial hyperglycemia.

MATERIALS AND METHODS

The freeze-dried powder of the aqueous extract of black tea leaves (JAT) was used for in vitro studies of α-amylase activity, α-glucosidase activity, and glucose uptake by glucose transporters in Caco-2 cells; ex vivo studies of small intestinal α-glucosidase activity; and in vivo studies of oral sugar tolerance in GK rats, an animal model of nonobese type 2 diabetes mellitus.

RESULTS

Half maximal inhibitory concentration values indicated that JAT significantly reduced α-glucosidase activity, but weakly reduced α-amylase activity. Kinetic studies of rat small intestinal α-glucosidase activity revealed that the combination of JAT and the α-glucosidase inhibitor, acarbose, showed a mixed-type inhibition. JAT had no effect on the uptake of 2'-deoxy-d-glucose by glucose transporter 2 (GLUT2) and the uptake of α-methyl-d-glucose by sodium-dependent glucose transporter 1 (SGLT1). In the oral sucrose tolerance test in GK rats, JAT reduced plasma glucose levels in a dose-dependent manner compared with the control group. The hypoglycemic action of JAT was also confirmed: JAT, in combination with acarbose, produced a synergistic inhibitory effect on plasma glucose levels in vivo. In contrast to the oral sucrose tolerance test, JAT showed no effect in the oral glucose tolerance test.

CONCLUSIONS

JAT was demonstrated to inhibit the degradation of disaccharides into monosaccharides by α-glucosidase in the small intestine. Thereby indirectly preventing the absorption of the dietary source of glucose mediated by SGLT1 and GLUT2 transporters localized at the apical side of enterocytes in the small intestine. The results indicate that black tea could be useful as a functional food in the dietary therapy for borderline type 2 diabetes mellitus that could modulate postprandial hyperglycemia.

High-resolution assessment of land use impacts on biodiversity in life cycle assessment using species habitat suitability models

Agricultural land use is a main driver of global biodiversity loss. The assessment of land use impacts in decision-support tools such as life cycle assessment (LCA) requires spatially explicit models, but existing approaches are either not spatially differentiated or modeled at very coarse scales (e.g., biomes or ecoregions). In this paper, we develop a high-resolution (900 m) assessment method for land use impacts on biodiversity based on habitat suitability models (HSM) of mammal species. This method considers potential land use effects on individual species, and impacts are weighted by the species' conservation status and global rarity. We illustrate the method using a case study of crop production in East Africa, but the underlying HSMs developed by the Global Mammals Assessment are available globally. We calculate impacts of three major export crops and compare the results to two previously developed methods (focusing on local and regional impacts, respectively) to assess the relevance of the methodological innovations proposed in this paper. The results highlight hotspots of product-related biodiversity impacts that help characterize the links among agricultural production, consumption, and biodiversity loss.

Preliminary Clinical Evidence of the Antiplaque, Antigingivitis Efficacy of a Mouthwash Containing 2% Green Tea - A Randomised Clinical Trial

PURPOSE

To assess the efficacy of a mouthwash containing 2% green tea as compared to a placebo mouthwash for the control of plaque and gingivitis.

MATERIALS AND METHODS

A randomised controlled clinical trial was conducted on 110 male subjects 18-60 years of age. The inclusion criteria were having a minimum of 20 sound natural teeth, a plaque index (PI) of at least 1.5 and a gingival index (GI) of at least 1.0. The subjects were randomised into two parallel groups, test and control. Subjects in the test group and control group were instructed to rinse twice daily for 1 min with 10 ml of test (mouthwash containing 2% green tea) and placebo mouthwash, respectively. After 28 days of using the mouthwash, inter- and intragroup differences for mean plaque index and gingival index scores were analysed.

RESULTS

There was a significant (p < 0.05) reduction in mean GI and PI scores among the test group from baseline to 28 days, whereas it was not significant in the control group. A statistically significant (p < 0.05) reduction was found in the mean difference in GI scores in the test group (0.67 ± 0.22) as compared to the control group (0.05 ± 0.11) and a statistically significant (p < 0.05) reduction was observed in the mean difference in PI scores in the test group (1.65 ± 0.68) compared to the control group (0.45 ± 0.99).

CONCLUSION

The results showed that the green tea mouthwash was effective in the reduction of plaque and gingivitis scores.

[Ecological stoichiometry of soil carbon, nitrogen and phosphorus within soil aggregates in tea plantations with different ages]

This study selected 4 tea plantations with different ages (12-15, 20-22, 30-33 and >50 year-old) located in Ya' an, Sichuan Province, China to investigate the distribution patterns of soil organic carbon (SOC), total nitrogen (TN) and total phosphorus (TP) , and to examine the ecological stoichiometric characteristics of C, N and P within soil aggregates. The results showed that the coefficients of variation of SOC, TN and TP were 17.5%, 16.3% and 9.4%, respectively in the 0-20 cm soil layer and were 24.0%, 21.0% and 9.2%, respectively in the 20-40 cm soil layer. The spatial variation of TP was lower than that of SOC and TN but there were significant positive correlations among them. SOC and TN were distributed in the small-size aggregates and both of them had the greatest values in the >50 year-old tea plantation, however, the distribution of TP was relatively uniform among aggregates and ages. The coefficients of variation of C/N, C/P, and N/P were 9.4%, 14.0% and 14.9%, respectively in the 0-20 cm soil layer and were 7.4%, 24.9% and 21.8%, respectively in the 20-40 cm soil layer. Variation of C/N was lower than that of C/P and N/P. Averaged C/P and N/P values in the small-size aggregates were higher than in aggregates of other sizes, and the maximum values were in the >50 year-old plantation. C/N, C/P and N/P had good indication for soil organic carbon storage.

[Responses of rhizosphere nitrogen and phosphorus transformations to different acid rain intensities in a hilly red soil tea plantation]

Tea (Camellia sinensis) plantation in hilly red soil region has been long impacted by acid deposition, however its effects on nitrogen (N) and phosphorus (P) transformations in rhizosphere soils remain unclear. A 25-year old tea plantation in a typical hilly red soil region was selected for an in situ simulation experiment treated by pH 4.5, pH 3.5, pH 2.5 and control. Rhizosihere and bulk soils were collected in the third year from the simulated acid deposition experiment. Soil mineral N, available P contents and major enzyme activities were analyzed using the chemical extraction and biochemical methods, and N and P mineralization rates were estimated using the indoor aerobic incubation methods. Our results showed that compared to the control, the treatments of pH 4.5, pH 3.5 and pH 2.5, respectively decreased 7.1%, 42.1% and 49.9% NO3(-)-N, 6.4%, 35.9% and 40.3% mineral N, 10.5%, 41.1% and 46.9% available P, 18.7%, 30.1% and 44.7% ammonification rate, 3.6%, 12.7% and 38.8% net N-mineralization rate, and 31.5%, 41.8% and 63.0% P mineralization rate in rhizosphere soils; however, among the 4 treatments, rhizosphere soil nitrification rate was not significantly different, the rhizosphere soil urease and acid phosphatase activities generally increased with the increasing intensity of acid rain (P<0.05). In bulk soil, compared with the control, the treatments of pH 4.5, pH 3.5 and pH 2.5 did not cause significant changes in NO3(-)-N, mineral N, available P as well as in the rates of nitrification, ammonification, net N-mineralization and P mineralization. With increasing the acid intensity, the rhizosphere effects of NH4+-N, NO3(-)-N, mineral N, ammonification and net N-mineralization rates were altered from positive to negative effects, those of urease and acid phosphatease showed the opposite trends, those of available P and P mineralization were negative and that of nitrification was positive. In sum, prolonged elevated acid rain could reduce N and P transformation rates, decrease their availability, alter their rhizosphere effects, and have impact on nutrient cycling in tea plantation.

[Soil pH buffer capacity of tea garden with different planting years]

In order to investigate the effects of long-term tea planting on soil pH buffer capacity (pHBC), the variation of pHBC and its influence factors were investigated in tea gardens of 10, 15, 20, 25 and 30 years in Langxi and Qimen of Anhui Province. The results showed that the acid-base titration method was suitable for the determination of soil pHBC of tea gardens. The amount of acid-base added had approximate linear relationship with soil pH value in specific section (pH 4.0-6.0) of acid-base titration curves, so the soil pHBC could be calculated by linear regression equation. Soil pHBC in the tea gardens from the two regions showed a downward trend with increasing the planting years, which decreased at rates of 0.10 and 0.06 mmol · kg(-1) · a(-1) in Langxi and Qimen tea gardens, respectively. Soil pHBC had significant positive correlation with CEC, soil organic matter, base saturation and physical clay content, and significant negative correlation with exchangeable acid and exchange H+.