Antioxidants in tea

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.

Genetic Variation of Flavonols Quercetin, Myricetin, and Kaempferol in the Sri Lankan Tea (Camellia sinensis L.) and Their Health-Promoting Aspects

Flavonol glycosides in tea leaves have been quantified as aglycones, quercetin, myricetin, and kaempferol. Occurrence of the said compounds was reported in fruits and vegetable for a long time in association with the antioxidant potential. However, data on flavonols in tea were scanty and, hence, this study aims to envisage the flavonol content in a representative pool of accessions present in the Sri Lankan tea germplasm. Significant amounts of myricetin, quercetin, and kaempferol have been detected in the beverage type tea accessions of the Sri Lankan tea germplasm. This study also revealed that tea is a good source of flavonol glycosides. The Camellia sinensis var. sinensis showed higher content of myricetin, quercetin, and total flavonols than var. assamica and ssp. lasiocalyx. Therefore flavonols and their glycosides can potentially be used in chemotaxonomic studies of tea germplasm. The nonbeverage type cultivars, especially Camellia rosaflora and Camellia japonica Red along with the exotic accessions resembling China type, could be useful in future germplasm studies because they are rich sources of flavonols, namely, quercetin and kaempferol, which are potent antioxidants. The flavonol profiles can be effectively used in choosing parents in tea breeding programmes to generate progenies with a wide range of flavonol glycosides.

Tea and Risk of Age-Related Cataracts: A Cross-Sectional Study in Zhejiang Province, China

BACKGROUND

The antioxidant properties of tea extracts are considered to be effective in protecting against cataracts. However, there is still insufficient epidemiological knowledge about the protective effects of different types of tea on age-related cataracts.

METHODS

The data was derived from the Zhejiang Major Public Health Surveillance (ZJMPHS) Program on health and related factors in the elderly. The relationships between consumption of different types of tea and risk of age-related cataracts were assessed after adjusting for related covariates.

RESULTS

The prevalence of age-related cataracts in this study population was 4.4% (409/9343). After adjustment for potential confounders, tea drinking was associated with reduced risk of age-related cataracts (adjusted odds ratio [OR] 0.65; 95% confidence interval [CI], 0.47-0.91). Compared to nondrinkers, green tea drinkers had a significantly reduced risk of cataracts (adjusted OR 0.58; 95% CI, 0.40-0.85). Average tea consumption of 14-27 cups (adjusted OR 0.55; 95% CI, 0.33-0.93) and over 28 cups (adjusted OR 0.58; 95% CI, 0.34-0.99) per week had a protective effect against cataracts in comparison to no consumption. In addition, ingesting a moderate concentration of tea significantly decreased the risk of cataract compared to no consumption (adjusted OR 0.43; 95% CI, 0.27-0.71).

CONCLUSIONS

Tea ingestion was associated with reduced risk of age-related cataracts. In light of these findings, we suggest that reasonable tea consumption (ie, favoring green tea and consuming an average of over 500 mL per day at moderate concentration) should offer protection against age-related cataracts.

Improved Quantification of Free and Ester-Bound Gallic Acid in Foods and Beverages by UHPLC-MS/MS

Hydrolyzable tannins are measured routinely during the characterization of food and beverage samples. Most methods for the determination of hydrolyzable tannins use hydrolysis or methanolysis to convert complex tannins to small molecules (gallic acid, methyl gallate, and ellagic acid) for quantification by HPLC-UV. Often unrecognized, analytical limitations and variability inherent in these approaches for the measurement of hydrolyzable tannins include the variable mass fraction (0-0.90) that is released as analyte, contributions of sources other than tannins to hydrolyzable gallate (can exceed >10 wt %/wt), the measurement of both free and total analyte, and lack of controls to account for degradation. An accurate, specific, sensitive, and higher-throughput approach for the determination of hydrolyzable gallate based on ultrahigh-performance liquid chromatography-tandem mass spectrometry (UHPLC-MS/MS) that overcomes these limitations was developed.

Effects of catechins on litter size, reproductive performance and antioxidative status in gestating sows

This study was conducted to investigate the effects of catechins on reproductive performance, antioxidative capacity and immune function of gestating sows. A total of 60 cross-bred (Landrace × Large White) multiparious sows were blocked by body weight, parity and backfact and randomly allocated to 1 of 5 treatments: 0, 100, 200, 300, or 400 mg/kg catechins. Dietary treatments were imposed from mating to d 40 of gestation of sows. At farrowing, litter total born, born alive, dead, and normal-(healthy piglets, ≥0.85 kg) and low-birth weight piglets (<0.85 kg) were recorded. Within 3.00 ± 0.50 days after farrowing litter size was standardized to 8.00 ± 1.50 piglets within treatment. The piglets were weighed at birth (d 1) and weaning (d 28). Sows serum samples were obtained from blood samples collected on d 40 of gestation for analyses of glutathione peroxidase (GSH-Px), superoxide dismutase (SOD), catalase (CAT), malondialdehyde (MDA), hydrogen peroxide (H₂O₂), nitric oxide synthetase (NOS) and nitrogen monoxide (NO). Our results showed that supplementation of catechins at levels of 200 or 300 mg/kg led to improvements in litter born alive (P < 0.01) and piglet born healthy (P < 0.01) and a decrease in stillborn (P < 0.05) at farrowing when compared with the control. In comparison with the control, catechins at any supplemental levels all enhanced the serum SOD (P < 0.05) and CAT (P < 0.01) activities of sows at farrowing but no obvious differences in the serum GSH-Px and NOS activities were observed in this trial (P > 0.05). Sows received 200 mg catechin per kg diets showed a reduction (P < 0.05) of the serum MDA level at farrowing compared with all other treatments. Sows received all the levels of catechin showed a reduction (P < 0.05) of serum H₂O₂ level compared with sows received the control diet on both d 40 of gestation and farrowing. Our results demonstrated that the catechins may be a potential antioxidant to increase the reproductive performance and antioxidative capacity of sows when it was added into diets during the early gestation.

Antioxidant, Antibacterial, Cytotoxic, and Anti-Inflammatory Potential of the Leaves of Solanum lycocarpum A. St. Hil. (Solanaceae)

Ethanol extract and fractions obtained from leaves of Solanum lycocarpum were examined in order to determine their phenolic composition, antioxidant, antibacterial, anti-inflammatory, and cytotoxic potential. High performance liquid chromatography coupled with DAD analysis indicated that the flavonoids apigenin and kaempferol were the main phenolic compounds present in dichloromethane and ethyl acetate fractions, respectively. The antioxidant activity was significantly more pronounced for dichloromethane, ethyl acetate, and hydroethanol fractions than that of the commercial antioxidant 2,6-di-tert-butyl-4-methylphenol. The hexane and dichloromethane fractions were more active against the tested bacteria. The hydroethanol fraction exhibited significant anti-inflammatory activity at the dose of 75 and 150 mg/kg in the later phase of inflammation. However, the antiedematogenic effect of the higher dose of the ethyl acetate fraction (150 mg/kg) was more pronounced. The ethyl acetate fraction also presented a less cytotoxic effect than the ethanol extract and other fractions. These activities found in S. lycocarpum leaves can be attributed, at least in part, to the presence of phenolic constituents such as flavonoids. This work provided the knowledge of phenolic composition in the extract and fractions and the antioxidant, antibacterial, anti-inflammatory, and cytotoxic activities of leaves of S. lycocarpum.

The effects of N-acetylcysteine and epigallocatechin-3-gallate on liver tissue protein oxidation and antioxidant enzyme levels after the exposure to radiofrequency radiation

PURPOSE

The widespread and sustained use of mobile and cordless phones causes unprecedented increase of radiofrequency radiation (RFR). The aim of this experimental study was to investigate the effect of 900 MHz Global System for Mobile Communications (GSM)-modulated RFR (average whole body Specific Absorption Rate (SAR) of 0.4 W/kg, 10 or 20 min daily for consecutive 7 days) to the liver tissue of guinea pigs and the protective effects of antioxidant treatments.

MATERIALS AND METHODS

Adult male guinea pigs were randomly divided into nine groups as: Group I (sham/saline), Group II (sham/EGCG), Group III (sham/NAC), Group IV (10-min RF-exposure/saline), Group V (20-min RF-exposure/saline), Group VI (10-min RF-exposure/EGCG), Group VII (20-min RF-exposure/EGCG), Group VIII (10-min RF-exposure/NAC), and Group IX (20-min RF-exposure/NAC). Protein oxidation (PCO), advanced oxidation protein products (AOPP) and antioxidant enzyme activities of superoxide dismutase (SOD) were evaluated after the exposure and the treatments with N-acetylcysteine (NAC) and (-)-epigallocatechin-3-gallate (EGCG).

RESULTS AND CONCLUSIONS

Significant decreases in the activities of SOD were observed in the liver of guinea pigs after RFR exposure. Protein damage did not change due to RFR exposure. On the other hand, only NAC treatment induced increased PCO levels, whereas EGCG treatment alone elevated the level of AOPP. Due to antioxidants having pro-oxidant behavior, the well decided doses and treatment timetables of NAC and ECGC are needed.

Tea polyphenols alleviate motor impairments, dopaminergic neuronal injury, and cerebral α-synuclein aggregation in MPTP-intoxicated parkinsonian monkeys

Tea polyphenols (TPs) are bioactive flavanol-related catechins that have been shown to protect dopaminergic (DAergic) neurons against neurotoxin-induced injury in mouse Parkinson's disease (PD) models. However, the neuroprotective efficacy of TP has not been investigated in nonhuman PD primates, which can more accurately model the neuropathology and motor impairments of human PD patients. Here, we show that oral administration of TP alleviates motor impairments and DAergic neuronal injury in the substantia nigra in N-methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP)-intoxicated PD monkeys, indicating an association between protection against motor deficits and preservation of DAergic neurons. We also show a significant inhibition of MPTP-induced accumulation of neurotoxic α-synuclein (α-syn) oligomers in the striatum and other brain regions, which may contribute to the neuroprotection and improved motor function conferred by TP. The association between reduced α-syn oligomerization and neuroprotection was confirmed in cultured DAergic cells. The most abundant and bioactive TP in the mixture used in vivo, (-)-epigallocatechin-3-gallate, reduced intracellular levels of α-syn oligomers in neurons treated with α-syn oligomers, 1-methyl-4-phenylpyridiniumion, or both, accompanied by increased cell viability. The present study provides the first evidence that TP can alleviate motor impairments, DAergic neuronal injury, and α-syn aggregation in nonhuman primates.

Alternative therapies for diabetes and its cardiac complications: role of vanadium

It is now well known that a cardiomyopathic state accompanies diabetes mellitus. Although insulin injections and conventional hypoglycemic drug therapy have been of invaluable help in reducing cardiac damage and dysfunction in diabetes, cardiac failure continues to be a common cause of death in the diabetic population. The use of alternative medicine to maintain health and treat a variety of diseases has achieved increasing popularity in recent years. The goal of alternative therapies in diabetic patients has been to lower circulating blood glucose levels and thereby treat diabetic complications. This paper will focus its discussion on the role of vanadium on diabetes and the associated cardiac dysfunction. Careful administration of a variety of forms of vanadium has produced impressive long-lasting control of blood glucose levels in both Type 1 and Type 2 diabetes in animals. This has been accompanied by, in many cases, a complete correction of the diabetic cardiomyopathy. The oral delivery of vanadium as a vanadate salt in the presence of tea has produced particularly impressive hypoglycemic effects and a restoration of cardiac function. This intriguing approach to the treatment of diabetes and its complications, however, deserves further intense investigation prior to its use as a conventional therapy for diabetic complications due to the unknown long-term effects of vanadium accumulation in the heart and other organs of the body.

Alternative therapies for diabetes and its cardiac complications: role of vanadium

It is now well known that a cardiomyopathic state accompanies diabetes mellitus. Although insulin injections and conventional hypoglycemic drug therapy have been of invaluable help in reducing cardiac damage and dysfunction in diabetes, cardiac failure continues to be a common cause of death in the diabetic population. The use of alternative medicine to maintain health and treat a variety of diseases has achieved increasing popularity in recent years. The goal of alternative therapies in diabetic patients has been to lower circulating blood glucose levels and thereby treat diabetic complications. This paper will focus its discussion on the role of vanadium on diabetes and the associated cardiac dysfunction. Careful administration of a variety of forms of vanadium has produced impressive long-lasting control of blood glucose levels in both Type 1 and Type 2 diabetes in animals. This has been accompanied by, in many cases, a complete correction of the diabetic cardiomyopathy. The oral delivery of vanadium as a vanadate salt in the presence of tea has produced particularly impressive hypoglycemic effects and a restoration of cardiac function. This intriguing approach to the treatment of diabetes and its complications, however, deserves further intense investigation prior to its use as a conventional therapy for diabetic complications due to the unknown long-term effects of vanadium accumulation in the heart and other organs of the body.

Reduced risk of dyslipidaemia with oolong tea consumption: a population-based study in southern China

Experimental studies have suggested that tea consumption could lower the risk of dyslipidaemia. However, epidemiological evidence is limited, especially in southern China, where oolong tea is the most widely consumed beverage. We conducted a population-based case-control study to evaluate the association between consumption of tea, especially oolong tea, and risk of dyslipidaemia in Shantou, southern China, from 2010 to 2011. Information on tea consumption, lifestyle characteristics and food consumption frequency of 1651 patients with newly diagnosed dyslipidaemia and 1390 controls was obtained using a semi-quantitative questionnaire. Anthropometric variables and serum biochemical indices were determined. Drinking more than 600 ml (2 paos) of green, oolong or black tea daily was found to be associated with the lowest odds of dyslipidaemia risk (P< 0.001) when compared with non-consumption, but only oolong tea consumption was found to be associated with low HDL-cholesterol levels. A dose-response relationship between duration of tea consumption and risk of dyslipidaemia (OR 0.10, 95% CI 0.06, 0.16), as well as that between amount of dried tea leaves brewed and risk of dyslipidaemia (OR 0.34, 95% CI 0.24, 0.48), was found. Moreover, consumption of oolong tea for the longest duration was found to be associated with 3.22, 11.99 and 6.69% lower blood total cholesterol, TAG and LDL-cholesterol levels, respectively. In conclusion, the present study indicates that long-term oolong tea consumption may be associated with a lower risk of dyslipidaemia in the population of Shantou in southern China.

The characterization of caffeine and nine individual catechins in the leaves of green tea (Camellia sinensis L.) by near-infrared reflectance spectroscopy

Near-infrared reflectance spectroscopy (NIRS) was used to determine the contents of caffeine and nine individual catechins in tea leaves. A total of 665 samples were scanned by NIRS, and also by high performance liquid chromatography coupled to a diode array detector to determine the contents of caffeine and nine individual catechins. The calibration models for caffeine, EGC, C, EGCG, EC, ECG, and total catechins had high r(2) (more than 0.90) and RSP (the ratio of standard deviation of reference data to SEP(C) in the external validation set) values (more than 4.1), indicating a good correlation between reference values and NIRS predicted values. In contrast, the calibration models of GC and EGCG-3Me had low r(2) and RSP values (below 0.8 and 2.0). Therefore, these results suggest that NIRS could be applied for the rapid determination of the contents of caffeine, EGC, C, EGCG, EC, ECG, and total catechins in tea leaves for breeding programs that develop high-quality tea plants.

Membrane clarification of tea extracts

The ready-to-drink (RTD) tea beverages are becoming increasingly popular owing to the health benefits associated with tea polyphenols, but instability due to development of haze and formation of tea cream is a common problem encountered in the product. Membrane technology provides a scope to produce natural, additive-free RTD teas while overcoming the major disadvantages associated with the conventional decreaming methods. Approaches employing membranes for the clarification of extracts from black and green tea have been discussed together with their relative advantages and limitations. The article also outlines the concerns to be addressed in the future attempts employing membrane technology.

A solution spectroscopy study of tea polyphenol and cellulose: effect of surfactants

Catechin, a bioflavonoid, found in green tea leaves has various applications in the food and pharmaceutical industries.

Applying transcriptomic and proteomic knowledge to Parkinson's disease drug discovery

It is recognised that in both genetic and sporadic cases of Parkinson's disease (PD), the basis of its etiopathology resides in the particular vulnerability of the dopaminergic neurons of the substantia nigra pars compacta (SNpc) to oxidative stress and in the failure to adequately remove abnormal proteins. These observations have been confirmed recently by microarray transcriptomic studies in human SN from PD brains and have extended understanding of the molecular pathways underlying the PD pathology. This article reviews recent gene expression profiling studies in sporadic PD postmortem SN and highlights gene candidates as putative molecular signatures for early disease diagnosis. In addition, the application of transcriptomics and proteomics in the quest for multifunctional neuroprotective-neurorescue drugs that might possess disease-modifying action is discussed.

Phytochemistry, pharmacology and medicinal properties of Carthamus tinctorius L

Carthamus tinctorius L. is commonly known as Safflower. C. tinctorius extracts and oil are important in drug development with numerous pharmacological activities in the world. This plant is cultivated mainly for its seed, which is used as edible oil. For a long time C. tinctorius has been used in traditional medicines as a purgative, analgesic, antipyretic and an antidote to poisoning. It is a useful plant in painful menstrual problems, post-partum hemorrhage and osteoporosis. C. tinctorius has recently been shown to have antioxidant, analgesic, anti-inflammatory and antidiabetic activities. Carthamin, safflower yellow are the main constituents in the flower of C. tinctorius. Carthamidin, isocarthamidin, hydroxysafflor yellow A, safflor yellow A, safflamin C and luteolin are the main constituents which are reported from this plant. Caryophyllene, p-allyltoluene, 1-acetoxytetralin and heneicosane were identified as the major components for C. tinctorius flowers essential oil. Due to the easy collection of the plant and being widespread and also remarkable biological activities, this plant has become both food and medicine in many parts of the world. This review presents comprehensive analyzed information on the botanical, chemical and pharmacological aspects of C. tinctorius.

Antioxidant and antibacterial properties of green, black, and herbal teas of Camellia sinensis

Background:

The role of non-polymeric phenolic (NP) and polymeric tannin (PT) constituents in the antioxidant and antibacterial properties of six brands of green, black, and herbal teas of Camellia sinensis were investigated.

Materials and Methods:

Total phenolic content (TPC) and ascorbic acid equivalent antioxidant capacity (AEAC) were assessed using the Folin-Ciocalteu and 2,2-diphenyl-1-picrylhydrazyl (DPPH) assays, respectively. Minimum inhibitory dose (MID) against Gram-positive Micrococcus luteus, Staphylococcus aureus, and Bacillus cereus, and Gram-negative. Escherichia coli, Salmonella typhi, and Pseudomonas aeruginosa was assessed using the disc-diffusion method. Teas were extracted with hot water successively three times for one hour each time. The extracts were fractionated using Sephadex LH-20 column chromatography to obtain the NP and PT constituents.

Results:

Extraction yields ranged from 12 to 23%. Yields of NP fractions (70–81%) were much higher than those of PT fractions (1–11%), suggesting that the former are the major tea components. Ranking of antioxidant properties of extracts was green tea>black tea>herbal tea. For all six teas, antioxidant properties of PT fractions were significantly higher than extracts and NP fractions. Extracts and fractions of all six teas showed no activity against the three Gram-negative bacteria. Green teas inhibited all three Gram-positive bacteria with S. aureus being the least susceptible. Black and herbal teas inhibited the growth of M. luteus and B. cereus, but not S. aureus. The most potent were the PT fractions of Boh Cameron Highlands and Ho Yan Hor with MID of 0.01 and 0.03 mg/disc against M. luteus.

Conclusion:

Results suggested that NP constituents are major contributors to the antioxidant and antibacterial properties of teas of C. sinensis. Although PT constituents have stronger antioxidant and antibacterial properties, they constitute only a minor component of the teas.

Prevention of coronary heart disease and cancer by tea, a review

Biomedical research has uncovered the mechanisms whereby tea promotes good health and lowers the risk of major chronic diseases, such as heart disease and many types of cancer. The active components in tea are polyphenols, epigallocatechin gallate in green tea, theaflavins and thearubigins in black tea. Green and black tea and the polyphenols have similar beneficial effects. The mechanisms are categorized into 5 groups. 1) Tea polyphenols are powerful antioxidants. They decrease the oxidation of LDL cholesterol and lower the risk of heart disease, and also inhibit action of reactive oxygen species mediating the oxidation of DNA associated with carcinogenesis 2) Tea polyphenols induce detoxifying enzymes, glucuronosyl transferases, eliminating active forms of carcinogens and other toxicants, accounting for the lower cancer risk. 3) Tea polyphenols lower duplication rates of cancer cells and inhibit the growth of cancer, increase apoptosis and lower angiogenesis. 4) Tea polyphenols alter the intestinal bacterial flora, suppressing undesirable bacteria and favoring growth of beneficial bacteria. 5) Aging phenomena, and diseases associated with the formation of reactive oxygen species (ROS) are inhibited.

Recent developments on new formulations based on nutrient-dense ingredients for the production of healthy-functional bread: a review

Bread is one of the oldest functional foods which its health effects have been investigated in many studies. The current communication presents a review of published studies in recent years on the topic and looks at possible future trends in the improved nutritional and health qualities which have been applied in the bakery industry, directing it further to the formulation design and production of functional breads. The results show that many beneficial ingredients such as dietary fibers, phenolic antioxidants, marine ingredients, and n-3 fatty acids can be used in the bread industry to increase its functionality and result in healthy products, low in calories, cholesterol and celiac disease. Moreover, the use of psyllium seed, amaranth seed, chestnut flour and prebiotics in gluten-free bread (GFB) baking may be the promising frontier to improve overall appearance, quality, sensory properties, and shelf-life of GFB.

Effects of oxygen and antioxidants on the lipid oxidation and yellow discolouration of film from red tilapia mince

BACKGROUND

Generally, biodegradable films from fish muscle protein become yellow after preparation. This discolouration is more likely associated with lipid oxidation and can be prevented by minimising the oxidation in the films. Thus, the effects of oxygen and antioxidants on lipid oxidation and yellow discolouration of film from red tilapia mince during storage were investigated.

RESULTS

Both films prepared at pH 3 and 11, and kept under atmosphere containing 100% N(2) had the lowest TBARS value with the concomitant lowest b* and ΔE* values during storage (P < 0.05), when compared with other films kept in air and a 100% O(2) atmosphere. Films prepared at pH 3 and incorporated with antioxidants (Trolox and catechin) at all levels (100, 200 and 400 mg L(-1) film-forming solution) had the lowest TBARS value, b* and ΔE* values during storage, indicating the retardation of lipid oxidation and yellow discolouration in films. Nevertheless, films prepared at pH 11 had no difference in TBARS values, in comparison with control film, regardless of antioxidant incorporation. Coincidentally, increases in b* and ΔE* values were observed in those films.

CONCLUSIONS

Lipid oxidation was the main factor inducing yellow discolouration of film exposed to oxygen and the incorporation of antioxidants in film prepared at acidic pH was able to prevent yellow discolouration of resulting film.

Antioxidant activity assay based on the inhibition of oxidation and photobleaching of L-cysteine-capped CdTe quantum dots

Quantum dots (QDs) have recently been the focus of attention of many investigators for development of diagnostic tools in many research areas. In this work, we established a new QD-based assay to evaluate the antioxidant/polyphenolic activity. This assay is based on measurement of the inhibitory effect of the antioxidant/polyphenolic compounds on the UV-induced bleaching of CdTe QDs with L-cysteine capping. QDs exhibited excellent photostability without any UV exposure, while they bleached rapidly under UV irradiation. Generation of reactive oxygen species (ROS) under UV irradiation is probably the main cause of the photobleaching of QDs. By comparing the photostability of QDs in buffer solution in the absence and presence of sodium azide, as a known (1)O(2) quencher, the involvement of (1)O(2) in photobleaching of QDs was confirmed. The photobleaching effect induced by ROS could be reduced in the presence of antioxidant/polyphenolic compounds. We tested several antioxidant/polyphenolic compounds as well as known antioxidants such as trolox and 4 different types of tea. The results obtained by the QD-based assay revealed a very good correlation with the data acquired by Folin-Ciocalteu assay. Furthermore, a deeper understanding of the mechanism and the solution for photobleaching of QDs under UV irradiation might be very meaningful in promoting their clinical applications.

Reduction of oxidative stress in liver cancer patients by oral green tea polyphenol tablets during hepatic arterial infusion chemotherapy

Hepatic arterial infusion chemotherapy (HAI) using an implanted port system is the standard regimen for primary and metastatic liver cancers (MLCs). However, there have been few studies concerning HAI-induced oxidative stress and damage to the liver or other organs. The aim of the present study was to investigate the ability of green tea polyphenols (GTPs) to reduce the oxidative stress or increase the biological antioxidative potential in HAI-treated patients. A total of 19 patients with inoperable hepatocellular carcinoma (HCC) or MLC from colorectal malignancy were eligible for HAI with cisplatin (CDDP) and 5-fluorouracil (5FU). The study subjects were randomly assigned to either a 3 or a 6 oral GTP tablets per day group. Each tablet had a GTP content equivalent to 79 mg of epigallocatechin-3-gallate. The oxidative stress was assessed by measuring the levels of derivatives of reactive oxygen metabolites (d-ROMs) and the biological antioxidative potential (BAP) values in patient plasma using the Free Radical Analytical System 4 (FRAS4), and correlating the results with clinical laboratory data for the patients. The levels of d-ROMs were significantly reduced by the oral intake of 6 GTP tablets for 6–9 months (P=0.0463) but were not significantly reduced by the oral intake of 3 GTP tablets daily. BAP values remained constant in the 3 and 6 tablet groups for 6–9 months during the follow-up study. The total serum bilirubin (T-bil) levels increased significantly at 3 (P=0.028) and 9 (P=0.0151) months and the red blood cell (RBC) count decreased at 6 months (P=0.0458) after intake for the 6 GTP tablet group. Alkaline phosphatase (ALP) levels increased significantly at 9 months (P=0.0298). Cholinesterase (ChE) decreased significantly at 9 (P= 0.0127) and 12 (P= 0.0207) months after intake for the 3 GTP tablet group. The results indicate that the daily intake of 6 GTP tablets containing 474 mg polyphenols significantly reduces HAI-induced oxidative stress in HCC or MLC patients while the antioxidative potentials of the patients remain constant.

Selective determination of catechin among phenolic antioxidants with the use of a novel optical fiber reflectance sensor based on indophenol dye formation on nano-sized TiO₂

The optical sensor for "tea catechins" was built by immobilizing 2,2'-(1,4-phenylenedivinylene)bis-8-hydroxyquinoline (PBHQ) on TiO₂ nanoparticles (NPs). The sensor worked by "indophenol blue" dye formation on PBHQ-immobilized TiO₂ NPs as a result of p-aminophenol (PAP) autoxidation with dissolved O₂ at pH 10. Among quercetin, rutin, naringenin, naringin, gallic acid, caffeic acid, ferulic acid, p-coumaric acid, catechin, epicatechin, epicatechin gallate, epigallocatechin, epigallocatechin gallate, and trolox, only catechin group antioxidants delayed the color formation on NPs, as measured by the reflectance signal at 710 nm. For quantitative analysis, reflectance signal versus time was recorded, and the difference between the areas under curve (ΔAUC) in the presence and absence of catechin was correlated (r = 0.98) to catechin concentration. The selectivity of the sensor for catechins was shown in tea infusions compared to other plant extracts and was ascribed to the nonplanar structure of catechin interfering with the formation of perfectly conjugated indophenol blue on TiO₂ surface.

Green tea polyphenol epigallocatechin-3-gallate shows therapeutic antioxidative effects in a murine model of colitis

BACKGROUND AND AIMS

Leukocyte infiltration, up-regulation of proinflammatory cytokines and severe oxidative stress caused by increased amounts of reactive oxygen species are characteristics of inflammatory bowel disease. The catechin (2R,3R)-2-(3,4,5-Trihydroxyphenyl)-3,4-dihydro-1(2H)-benzopyran-3,5,7-triol-3-(3,4,5-trihydroxybenzoate), named epigallocatechin-3-gallate, EGCG, has been demonstrated to exert anti-inflammatory and antioxidative properties, reducing reactive oxygen species in the inflamed tissues. The aim of this study was to evaluate the therapeutic effects of EGCG in a murine model of colitis induced by oral administration of dextran sodium sulfate.

METHODS

Mice received a daily oral administration of 6.9 mg/kg body weight EGCG or Piper nigrum (L.) alkaloid (2E,4E)-5-(1,3-benzodioxol-5-yl)-1-piperidin-1-ylpenta-2,4-dien-1-one, named piperine (2.9 mg/kg body weight) or the combination of the both - piperine was used in this combination to enhance the bioavailability of EGCG.

RESULTS

In vivo data revealed the combination of EGCG and piperine to significantly reduce the loss of body weight, improve the clinical course and increase overall survival in comparison to untreated groups. The attenuated colitis was associated with less histological damages to the colon and reduction of tissue concentrations of malondialdehyde, the final product of lipid peroxidation. Neutrophils accumulation indicator myeloperoxidase was found to be reduced in colon tissue, while antioxidant enzymes like superoxide dismutase and glutathione peroxidase showed an increased activity. In vitro, the treatment with EGCG plus piperine enhanced the expression of SOD as well as GPO and also reduced the production of proinflammatory cytokines.

CONCLUSION

These data support the concept of anti-inflammatory properties of EGCG being generally beneficial in the DSS-model of colitis, an effect that may be mediated by its strong antioxidative potential.

Protective effects of green and white tea against benzo(a)pyrene induced oxidative stress and DNA damage in murine model

In the current investigation, the ameliorative effect of green tea (GT) and white tea (WT) against benzo(a)pyrene (BaP) induced oxidative stress and DNA damage has been studied in the livers and lungs of Balb/c mice. A single dose of BaP (125 mg/kg, b.w. orally) increased the levels of lipid peroxidation (LPO) and decreased endogenous antioxidants such as superoxide dismutase (SOD), glutahione reductase (GR), catalase (CAT), and glutathione (GSH) significantly. Pretreatment with GT and WT for 35 days before a single dose of BaP elevated the decreased activity of GR, SOD, and CAT in liver tissue and also tended to normalize the levels of GSH and LPO in both hepatic and pulmonary tissues. The percentage of DNA in comet tail and 8-hydroxy-2'-deoxyguanosine levels reflected the decreasing pattern of DNA damage from the BaP-treated group to the groups that received pretreatment with GT and WT. Our study concludes that both GT and WT are effective in combating BaP induced oxidative insult and DNA damage. However, WT was found to be more protective than GT with respect to CAT (only in the liver), percentage of DNA in comet tail (only in the lungs), GST activity, and GSH content in both the tissues.

Coffee, tea, and sugar-sweetened carbonated soft drink intake and pancreatic cancer risk: a pooled analysis of 14 cohort studies

BACKGROUND

Coffee has been hypothesized to have pro- and anticarcinogenic properties, whereas tea may contain anticarcinogenic compounds. Studies assessing coffee intake and pancreatic cancer risk have yielded mixed results, whereas findings for tea intake have mostly been null. Sugar-sweetened carbonated soft drink (SSB) intake has been associated with higher circulating levels of insulin, which may promote carcinogenesis. Few prospective studies have examined SSB intake and pancreatic cancer risk; results have been heterogeneous.

METHODS

In this pooled analysis from 14 prospective cohort studies, 2,185 incident pancreatic cancer cases were identified among 853,894 individuals during follow-up. Multivariate (MV) study-specific relative risks (RR) and 95% confidence intervals (CI) were calculated using Cox proportional hazards models and then pooled using a random-effects model.

RESULTS

No statistically significant associations were observed between pancreatic cancer risk and intake of coffee (MVRR = 1.10; 95% CI, 0.81-1.48 comparing ≥900 to <0 g/d; 237g ≈ 8oz), tea (MVRR = 0.96; 95% CI, 0.78-1.16 comparing ≥400 to 0 g/d; 237g ≈ 8oz), or SSB (MVRR = 1.19; 95% CI, 0.98-1.46 comparing ≥250 to 0 g/d; 355g ≈ 12oz; P value, test for between-studies heterogeneity > 0.05). These associations were consistent across levels of sex, smoking status, and body mass index. When modeled as a continuous variable, a positive association was evident for SSB (MVRR = 1.06; 95% CI, 1.02-1.12).

CONCLUSION AND IMPACT

Overall, no associations were observed for intakes of coffee or tea during adulthood and pancreatic cancer risk. Although we were only able to examine modest intake of SSB, there was a suggestive, modest positive association for risk of pancreatic cancer for intakes of SSB.

Effect of green tea catechin, a local drug delivery system as an adjunct to scaling and root planing in chronic periodontitis patients: A clinicomicrobiological study

Background:

Evaluate the adjunctive use of locally delivered green tea catechin with scaling and root planing, as compared to scaling and root planing alone in the management of chronic periodontitis.

Materials and Methods:

Fourteen patients with two sites in the contralateral quadrants with probing pocket depth of 5–8mm were selected. Each of the sites was assessed for the plaque index, gingival index, and probing pocket depth at baseline and 21 days and for microbiological analysis at baseline, 1 week and 21 days. Test sites received scaling and root planing along with green tea catechin strips and control sites received scaling and root planning alone.

Results:

The result showed intercomparison of the plaque index and gingival index for test and control groups at 21 days was not significant with P>0.05, whereas the probing depth at 21 days was significant with P<0.001. Intercomparison between microbial results demonstrated a considerable reduction of occurrence of Aggregatibacter actinomycetemcomitans, Prevotella intermedia, Fusobacterium species and Capnocytophaga in test.

Conclusion:

Green tea catechin local delivery along with scaling and root planing is more effective than scaling and root planing alone.

Protective effect of Melissa officinalis aqueous extract against Mn-induced oxidative stress in chronically exposed mice

Manganese (Mn) is an essential element for biological systems; however occupational exposure to high levels of this metal may lead to neurodegenerative disorders, resembling Parkinson's disease (PD). While its mechanisms of neurotoxicity have yet to be fully understood, oxidative stress plays a critical role. Thus, the main goal of this study was to investigate the efficacy of aqueous extract of Melissa officinalis in attenuating Mn-induced brain oxidative stress in mice. Sixteen male mice were randomly divided into two groups and treated for 3 months: the first group consumed tap water (control group) and the second group was treated with Mn (50 mg/kg/day for habituation during the first 15 days followed by 100 mg/kg/day for additional 75 days) in the drinking water. After 3 months both groups were sub divided (n=4 per group) and treated for additional 3 months with Mn and/or M. officinalis in the drinking water. The first group (control) was treated with water and served as control; the second group (M. officinalis) was treated with M. officinalis (100 mg/kg/day); the third group was treated with Mn (100 mg/kg/day); the fourth group (Mn+M. officinalis) was treated with both Mn and M. officinalis (100 mg/kg/day each). Mn-treated mice showed a significant increase in thiobarbituric acid reactive species (TBARS) levels (a marker of oxidative stress) in both the hippocampus and striatum. These changes were accompanied by a decrease in total thiol content in the hippocampus and a significant increase in antioxidant enzyme activity (superoxide dismutase and catalase) in the hippocampus, striatum, cortex and cerebellum. Co-treatment with M. officinalis aqueous extract in Mn-treated mice significantly inhibited the antioxidant enzyme activities and attenuated the oxidative damage (TBARS and decreased total thiol levels). These results establish that M. officinalis aqueous extract possesses potent antioxidative properties, validating its efficacy in attenuating Mn-induced oxidative stress in the mouse brain.

Antioxidant activity in the extracts of two edible aroids

Two neglected species of Araceae, Alocasia macrorhiza (Linn.) G. Don and Alocasia fornicata (Roxb.) Schott are important as food and ethno medicine in Asia and Africa. Their bioefficacy is documented in the Ayurveda. The solvent extracts of different edible parts of these two species like rhizomes, leaves, roots and stolons were screened for in vitro antioxidant properties using standard procedures. The successive extracts in hexane, benzene, toluene, chloroform, diethyl ether, ethyl acetate and water fraction exhibited IC₅₀ values in the following order, roots>rhizome>leaves for Alocasia macrorhiza and leaves>stolon for Alocasia fornicate, respectively in 2,2-diphenyl-1-picryl hydrazyl antioxidant inhibition assay. Maximum antioxidant activity was observed in diethyl ether extracts for both species. The IC₅₀ values were comparable with those of quercetine and ascorbic acid as standards. These results suggest that the two aroid species have antioxidant activity in their edible parts and should be extracted using diethyl ether solvent.

Characterization of tea cultivated at four different altitudes using 1H NMR analysis coupled with multivariate statistics

The taste of black tea differs according to the different areas in which the tea is grown, even for the same species of tea. A combination of (1)H NMR spectroscopy and partial least-squares discriminate analysis (PLS-DA) was used to assess the quality differences of tea leaves from four cultivation areas with different elevations, RAN > 1800 m, UDA = 1200 m, MEDA = 600 m, and YATA < 300 m, in Sri Lanka. As a result of a statistical analysis, PLS-DA showed a separation between high- and low-quality black teas derived from the four different tea cultivation areas. RAN from the highest elevation showed characteristic trends in the levels of theaflavin and theaflavin 3,3'-digallate that were found only in RAN, and the levels of theanine and caffeine were higher, and the levels of thearubigins, especially thearubigin 3,3'-digallate, were lower in RAN than in UDA, MEDA, and YATA. The structures of these components were determined by 1D and 2D NMR analyses. These results demonstrate that this method can be used to evaluate black tea quality according to the chemical composition or metabolites, which are characteristic of the tea leaves cultivated in four regions with different elevations in Sri Lanka.