A review of latest research findings on the health promotion properties of tea

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.

Bone mineral density, polyphenols and caffeine: a reassessment

Several studies have shown beneficial associations between tea consumption and bone mineral density (BMD) and fracture risk. Current investigations into potential mechanisms of benefit are focused upon the F and polyphenol components of tea. However, previous studies have pointed towards caffeine consumption as a potential risk factor for low BMD and high fracture risk. Tea, therefore, represents an interesting paradox as a mildly caffeinated beverage that may enhance bone health. Fruit and vegetable intake has also been associated with BMD, and it is now apparent that several fruit and vegetable components, including polyphenols, may contribute positively to bone health. Evidence surrounding the function(s) of polyphenol-rich foods in bone health is examined, along with more recent studies challenging the relevance of caffeine consumption to in vivo Ca balance. Plant foods rich in polyphenols such as tea, fruit and vegetables, as significant factors in a healthy diet and lifestyle, may have positive roles in bone health, and the negative role of caffeine may have been overestimated. The present review covers evidence of dietary mediation in positive and negative aspects of bone health, in particular the roles of tea, fruit and vegetables, and of caffeine, flavonoids and polyphenols as components of these foods. Since the deleterious effects of caffeine appear to have been overstated, especially in respect of the positive effects of flavonoids, it is concluded that a reassessment of the role of caffeinated beverages may be necessary.

Theaflavin ameliorates behavioral deficits, biochemical indices and monoamine transporters expression against subacute 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP)-induced mouse model of Parkinson's disease

Evidence from clinical and experimental studies indicates that degeneration of nigrostriatal dopaminergic neurons is a pathological hallmark of Parkinson's disease (PD). The present study was designed to investigate the neuroprotective potential of theaflavin (TF) on oxidative stress, monoamine transporters and behavioral abnormalities in 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP)-induced neurodegeneration. TF, a black tea polyphenol, has been known to possess neuroprotective effects against ischemia, Alzheimer's disease and other neurodegenerative disorders, but the mechanisms underlying its beneficial effects on MPTP-induced dopaminergic neurodegeneration are poorly defined. Administration of MPTP (30 mg/kg bw for four consecutive days) led to increased oxidative stress and reduced behavior patterns (open field, rotarod and hang test), nigrostriatal dopamine transporter (DAT) (immunohistochemistry and Western blot) and vesicular monoamine transporter 2 (VMAT2) (Western blot) expressions. Pre-treatment with TF reduces oxidative stress, improves motor behavior and expression of DAT and VMAT2 in striatum and substantia nigra. These results indicate that TF might be beneficial in mitigating MPTP-induced damage of dopaminergic neurons, possibly via its neuroprotective and its antioxidant potential.

Cavernous antioxidant effect of green tea, epigallocatechin-3-gallate with/without sildenafil citrate intake in aged diabetic rats

This study aimed to assess the cavernous antioxidant effect of green tea (GT), epigallocatechin-3-gallate (EGCG) with/without sildenafil citrate intake in aged diabetic rats. One hundred and four aged male white albino rat were divided into controls that received ordinary chow, streptozotocin (STZ)-induced aged diabetic rats, STZ-induced diabetic rats on infused green tea, induced diabetic rats on epigallocatechin-3-gallate and STZ-induced diabetic rats on sildenafil citrate added to EGCG. After 8 weeks, dissected cavernous tissues were assessed for gene expression of eNOS, cavernous malondialdehyde (MDA), glutathione peroxidase (GPx), cyclic guanosine monophosphate (cGMP), and serum testosterone (T). STZ-induced diabetic rats on GT demonstrated significant increase in cavernous eNOS, cGMP, GPx and significant decrease in cavernous MDA compared with diabetic rats. Diabetic rats on EGCG demonstrated significant increase in cavernous eNOS, cGMP, GPx and significant decrease in cavernous MDA compared with diabetic rats or diabetic rats on GT. Diabetic rats on EGCG added to sildenafil showed significant increase in cavernous eNOS, cGMP and significant decrease in cavernous MDA compared with other groups. Serum T demonstrated nonsignificant difference between the investigated groups. It is concluded that GT and EGCG have significant cavernous antioxidant effects that are increased if sildenafil is added.

Expression of the R2R3-MYB transcription factor TaMYB14 from Trifolium arvense activates proanthocyanidin biosynthesis in the legumes Trifolium repens and Medicago sativa

Proanthocyanidins (PAs) are oligomeric flavonoids and one group of end products of the phenylpropanoid pathway. PAs have been reported to be beneficial for human and animal health and are particularly important in pastoral agricultural systems for improved animal production and reduced greenhouse gas emissions. However, the main forage legumes grown in these systems, such as Trifolium repens and Medicago sativa, do not contain any substantial amounts of PAs in leaves. We have identified from the foliar PA-accumulating legume Trifolium arvense an R2R3-MYB transcription factor, TaMYB14, and provide evidence that this transcription factor is involved in the regulation of PA biosynthesis in legumes. TaMYB14 expression is necessary and sufficient to up-regulate late steps of the phenylpropanoid pathway and to induce PA biosynthesis. RNA interference silencing of TaMYB14 resulted in almost complete cessation of PA biosynthesis in T. arvense, whereas Nicotiana tabacum, M. sativa, and T. repens plants constitutively expressing TaMYB14 synthesized and accumulated PAs in leaves up to 1.8% dry matter. Targeted liquid chromatography-multistage tandem mass spectrometry analysis identified foliar PAs up to degree of polymerization 6 in leaf extracts. Hence, genetically modified M. sativa and T. repens plants expressing TaMYB14 provide a viable option for improving animal health and mitigating the negative environmental impacts of pastoral animal production systems.

Dispersive cleanup of acetonitrile extracts of tea samples by mixed multiwalled carbon nanotubes, primary secondary amine, and graphitized carbon black sorbents

A method for analysis of 37 pesticide residues in tea samples was developed and validated and was based on reversed-dispersive solid-phase extraction (r-DSPE) cleanup in acetonitrile solution, followed by liquid chromatography-electrospray tandem mass spectrometry determination. Green tea, oolong tea, and puer tea were selected as matrixes and represent the majority of tea types. Acetonitrile was used as the extraction solvent, with sodium chloride and magnesium sulfate enhancing partitioning of analytes into the organic phase. The extract was then cleaned up by r-DSPE using a mixture of multiwalled carbon nanotubes, primary secondary amine, and graphitized carbon black as sorbents to absorb interferences. Further optimization of sample preparation and determination allowed recoveries of between 70% and 111% for all 37 pesticides with relative standard deviations lower than 14% at two concentration levels of 10 and 100 μg kg(-1). Limits of quantification ranged from 5 to 20 μg kg(-1) for all pesticides. The developed method was successfully applied to the determination of pesticide residues in market tea samples.

Green tea ingestion by rats does not affect iron absorption but does alter the composition of the saliva proteome

We tested the hypothesis that rats adapt to the iron absorption inhibitory effects of tea by modifying the expression of salivary proteins. Thirty-six weanling rats were allocated into 6 groups. Two control groups were fed a semipurified diet containing 20 mg Fe(2+)/kg diet. Two groups were fed spray dried green tea infusion mixed into the diet (28.6 g tea/kg diet) and 2 groups were fed the control diet with a twice daily gavage of a tea solution (0.25 g tea/mL). Saliva samples were collected in 3 groups (control, gavage, and oral) on day 8 (acute) and in the remaining groups on day 31 (chronic). Iron absorption was assessed using a (58)Fe(3+) tracer administered on day 1 (acute) and day 24 (chronic). 2D gel electrophoresis and mass spectrometry were used to assess the composition of the saliva proteome. There was no significant difference in iron absorption between the 3 groups on either day 1 or day 24. Salivary proline-rich proteins and submandibular gland secretory protein increased to a greater extent in the oral group than in the gavage group, when compared to control, within the same exposure time period. Amylase, chitinase, deoxyribonuclease, cysteine-rich secretory protein 1, and parotid secretory protein all decreased to a greater extent in the oral tea group, compared to the control, within the same exposure time period. Our results show that green tea did not decrease iron absorption in rats but it did have a marked effect on the saliva proteome when given orally.

Evaluation of antitumour activity of tea carbohydrate polymers in hepatocellular carcinoma animals

Box-Behnken design criterion was applied to identify the significant effects of various extraction parameters such as temperature, time, and solvent-solid ratio on extraction of tea carbohydrate. Among the three variables tested extraction temperature, and solvent-solid ratio were found to have significant effect on tea carbohydrate extraction. The most suitable condition for extraction of tea carbohydrate was found to be a single step extraction at extraction temperature 90°C, extraction time 30 min, and solvent-solid ratio 5:1. At these optimum extraction parameters, the maximum yield of tea carbohydrate obtained experimentally was found to be very close to its predicted value of 3.47% dry weight of root. Then, we have studied the influence of tea carbohydrate on biochemical parameters in hepatocellular carcinoma (HCC) animals. Hepatocellular carcinoma was induced by the injection of 1×10(5) H22 hepatocarcinoma cells into right hind thigh muscle in experimental animals. Tea carbohydrate could inhibit tumour growth and decrease microvessel density in tumour tissue. The altered amount of serum white blood cells (WBC), Interferon-gamma (IFN-γ) and tumor necrosis factor-alpha (TNF-α) in HCC animals were dose-dependently increased, whereas activities of serum alanine transaminase (ALT), aspartate transaminase (AST) and alkaline phosphatase (ALP) were dose-dependently decreased in the drug treated animals. In addition, tea carbohydrate administration could decrease expression of vascular endothelial growth factor (VEGF) and proliferating cell nuclear antigen (PCNA) in H22 tumor tissue. It can be concluded that tea carbohydrate displayed strong antitumour activity in animals.

Quantitative analysis of acylated oleanane-type triterpene saponins, chakasaponins I-III and floratheasaponins A-F, in the flower buds of Camellia sinensis from different regional origins

A quantitative analytical method was developed for the determination of acylated oleanane-type triterpene saponins, chakasaponins I-III (1-3) and floratheasaponins A-F (4-9), found in Camellia sinensis (Theaceae). The practical conditions for separation and detection of these saponins were established on an ODS column with methanol containing 5 mM trifluoroacetic acid as a mobile phase, and the detection and quantitation limits of the method were estimated to be 1.1-3.8 and 3.5-12.5 ng, respectively. The relative standard deviation values of intra- and interday precision were lower than 2.35 and 6.12%, respectively, overall mean recoveries of all saponins being 94.7-108.8%, and the correlation coefficients of all the calibration curves showed good linearity within the test ranges. To approve the validity of the protocol, extracts of 13 kinds of C. sinensis collected in China, Taiwan, Japan, and India were evaluated. The results indicated that the assay was reproducible and precise, and could be readily utilized for the quality evaluation of tea flowers. It was noteworthy that the distinct regional difference was observed with respect to the content of chakasaponins and floratheasaponins, more chakasaponins being contained in the extracts of tea flowers from Fujian and Sichuan provinces, China than those from Japan, Taiwan, and India. Optimum conditions for the extraction process were also established.

Associations between frequency of tea consumption and health and mortality: evidence from old Chinese

Tea consumption may be associated with reduced risk of morbidity and mortality; however, this association is not conclusive and has rarely been investigated among very old adults. The present study examines how self-reported frequency of tea consumption in daily life is associated with health and mortality among very old adults in China. The data are from a national longitudinal data set that included 32 606 individuals (13 429 men and 19 177 women) aged 65 years and older: 11 807 respondents aged 65 to 84 years and 20 799 respondents aged 85 years and older. A total of four measurements between 1998 and 2005 resulted in 51 668 observations. Hazard regressions showed that men who drink tea almost every day have a 10-20 % lower risk of death compared to their counterparts who seldom drink tea, after adjusting for numerous confounders including baseline health. This relationship was stronger in younger male elders aged 65 to 84 years than in the oldest-old men aged 85 years and older. However, frequency of tea consumption was not significantly associated with mortality in women. Our analyses further show that high frequency of tea consumption is significantly associated with reduced OR of disability in activities of daily living, cognitive impairment, self-rated poor health, cumulative health deficits and CVD in both young elders and the oldest-old, and in both men and women. These results suggest that the health benefit of drinking tea is universal. We conclude that frequent tea consumption probably helps one achieve healthy longevity and that men benefit more from such lifestyles.

American Cancer Society Guidelines on nutrition and physical activity for cancer prevention: reducing the risk of cancer with healthy food choices and physical activity

The American Cancer Society (ACS) publishes Nutrition and Physical Activity Guidelines to serve as a foundation for its communication, policy, and community strategies and, ultimately, to affect dietary and physical activity patterns among Americans. These Guidelines, published approximately every 5 years, are developed by a national panel of experts in cancer research, prevention, epidemiology, public health, and policy, and they reflect the most current scientific evidence related to dietary and activity patterns and cancer risk. The ACS Guidelines focus on recommendations for individual choices regarding diet and physical activity patterns, but those choices occur within a community context that either facilitates or creates barriers to healthy behaviors. Therefore, this committee presents recommendations for community action to accompany the 4 recommendations for individual choices to reduce cancer risk. These recommendations for community action recognize that a supportive social and physical environment is indispensable if individuals at all levels of society are to have genuine opportunities to choose healthy behaviors. The ACS Guidelines are consistent with guidelines from the American Heart Association and the American Diabetes Association for the prevention of coronary heart disease and diabetes, as well as for general health promotion, as defined by the 2010 Dietary Guidelines for Americans and the 2008 Physical Activity Guidelines for Americans.

Review of the efficacy of green tea, isoflavones and aloe vera supplements based on randomised controlled trials

We assess the evidence for health benefits of three commonly consumed plant food supplements (PFS), green tea, isoflavone and aloe vera, based on published systematic reviews of randomised controlled trials (RCTs). Whilst the potential benefits of green tea have been reported in a wide range of health areas, it is only in the area of the metabolic syndrome that the number of RCTs is approaching sufficient to judge such efficacy. Isoflavone supplements are widely used, and RCTs indicate that they affect bone resorption at lower doses in postmenopausal women undergoing estrogen-related bone loss, but this is only translated to attenuation of bone loss at higher doses of isoflavones. A systematic review on RCTs concluded that the effects of isoflavones on hot flashes in postmenopausal women were highly variable and no conclusions could be drawn. Despite the popularity of aloe vera as a PFS, the evaluation of its efficacy as a coadjuvant therapy for certain metabolic or digestive pathologies remains scarce; it constitutes a typical example of a naturally occurring ingredient whose efficacy in topical applications presupposes its efficacy in systemic applications. Nevertheless, its possible toxic effects on oral consumption call for caution in its utility as a PFS. Since 2007, efficacy evaluation of PFS in Europe has been covered by European Union Nutrition and Health Claims legislation. The European Food Safety Authority has adopted an approach relying on RCTs, while medicinal effects are accepted based on traditional use. In general, there are insufficient RCTs for claims to be made, and conclusive results on PFS should be obtained in the future by conducting studies with more homogeneous populations, by using supplements with optimised and measured bioavailability, and by conducting larger RCTs.

Enhancement of antimicrobial activities of whole and sub-fractionated white tea by addition of copper (II) sulphate and vitamin C against Staphylococcus aureus; a mechanistic approach

BACKGROUND

Enhancement of antimicrobial plant products e.g. pomegranate extract by copper (II) sulphate is known. Such combinations have applications in various settings, including the identification of novel compositions to study, treat and control infection.

METHODS

A combination of white tea (WT) (made allowing 10 minutes infusion time at 100°C) was combined with 4.8 mM copper (II) sulphate and tested for antimicrobial effect on the viability of Staphylococcus aureus NCTC 06571. Comparisons were made with green (GT) and black (BT) teas. A WT sub-fraction (WTF < 1000 Da) was tested with copper (II) sulphate and 4.8 mM vitamin C. pH measurements of samples were taken for controls and to observe any changes due to tea/agent interaction. Catalase was used to investigate hydrogen peroxide release. UV-vis. was used to compare WT and WTF.

RESULTS

A 30 minute incubation at room temperature of copper (II) sulphate alone and combined with WT reduced the viability of S. aureus NCTC 06571 by c.a 1 log10 cfu mL-1. GT and BT with copper (II) sulphate negated activity to buffer values. Combined with copper (II) sulphate, vitamin C, WTF and, vitamin C plus WTF all reduced the viability of S. aureus NCTC 06571 by c.a. 3.5 log10 cfu mL-1. Independent experiments showed the results were not due to pH effects. Adding WT or WTF to copper (II) sulphate resulted in increased acidity. Copper (II) sulphate alone and combined with WT required c.a 300 μg mL-1 (final concentration) catalase to restore S. aureus viability, WTF with copper (II) sulphate and added vitamin C required c.a 600 μg mL-1. WT and WTF UV-visible spectra were similar.

CONCLUSIONS

WT showed no efficacy in the combinations tested. WTF was enhanced with copper (II) sulphate and further with vitamin C. WT and WTF increased acidity of copper (II) sulphate possibly via the formation of chemical complexes. The difference in WT/WTF absorbance possibly represented substances less concentrated or absent in WTF. Investigations to establish which WTF component/s and in what proportions additives are most effective against target organisms are warranted.

Theaflavin, a black tea polyphenol, protects nigral dopaminergic neurons against chronic MPTP/probenecid induced Parkinson's disease

Parkinson's disease (PD) is a progressive neurodegenerative disorder, characterized by loss of dopominergic neurons in substantia nigra pars compacta, and can be experimentally induced by the neurotoxin 1-methyl-4-phenyl-1, 2, 3, 6-tetrahydropyridine (MPTP). Chronic administration of MPTP/probenecid (MPTP/p) leads to oxidative stress, induction of apoptosis, and loss of dopominergic neurons which results in motor impairments. Epidemiological studies have shown an inverse relationship between tea consumption and susceptibility to PD. Theaflavin is a black tea polyphenol, which possess a wide variety of pharmacological properties including potent anti oxidative, anti apoptotic and anti inflammatory effects. The current study is aimed to assess the effect of theaflavin against MPTP/p induced neurodegenaration in C57BL/6 mice. We found that the theaflavin attenuates MPTP/p induced apoptosis and neurodegeneration as evidenced by increased expression of nigral tyrosine hydroxylase (TH), dopamine transporter (DAT) and reduced apoptotic markers such as caspase-3, 8, 9 accompanied by normalized behavioral characterization. This may be due to anti oxidative and anti apoptotic activity and these data indicate that theaflavin may provide a valuable therapeutic strategy for the treatment of progressive neurodegenerative diseases such as PD.

Mutagenicity and safety evaluation of the water extract of Camellia oleifera Abel

The purpose of this study was to evaluate the mutagenicity and safety of water extract of the fruit hull of Camellia oleifera Abel (WECO), which was prepared using hot-reflux method. The oral maximum tolerated dose (MTD) of WECO was above 20 g/kg body weight both in rats and in mice, which can be regarded as virtually nontoxic. No mutagenicity was found in Ames test, mouse bone marrow cell micronucleus test and mouse sperm abnormality test. In the subacute study, the SD rats were administered orally at 0.5, 1, or 2 g/kg/BW for 30 d. There were no treatment-related toxic effects from WECO. No significant differences were found in parameters of body weight, hematology value, clinical chemistry value, and organ/body weight ratio. The level of no observed adverse effect level (NOAEL) for WECO was 2 g/kg/BW for subacute toxicity study.

PRACTICAL APPLICATION

  With the gradual increase in tea oil production, it was in urgent need of dealing with Camellia fruit hull, which was always discarded because of low economic benefits. Camellia fruit hull has been shown to have significant antioxidant effects including DPPH radical-scavenging ability and ferric-reducing antioxidant power (Zhang and others 2010). Toxicological evaluation of WECO provided a safety assurance of WECO for developing dietary supplements and functional foods.

Protective Role of Black Tea Extract against Nonalcoholic Steatohepatitis-Induced Skeletal Dysfunction

Aim. This paper aimed to examine the chemoprotective actions of aqueous black tea extract (BTE) against nonalcoholic steatohepatitis- (NASH-) induced skeletal changes in rats. Material. Wistar rats (body wt. 155-175 g) of both sexes, aged 4-5 months, were randomly assigned to 3 groups; Group A (control), Group B (60% high-fat diet; HFD), and Group C (HFD + 2.5% BTE). Methods. Several urinary (calcium, phosphate, creatinine, and calcium-to-creatinine ratio) serum (alkaline phosphatase and serum tartrate-resistant acid phosphatase), and molecular markers of bone turnover (receptor activator of NF-κB ligand (RANKL), osteoprotegerin (OPG), and estrogen) were tested. Also, several bone parameters (bone density, bone tensile strength, bone mineral content, and bone histology) and calcium homeostasis were checked. Results. Results indicated that HFD-induced alterations in urinary, serum, and bone parameters as well as calcium homeostasis, all could be significantly ameliorated by BTE supplementation. Conclusion. Results suggest a potential role of BTE as a protective agent against NASH-induced changes in bone metabolism in rats.

Tentative identification, quantitation, and principal component analysis of green pu-erh, green, and white teas using UPLC/DAD/MS

Tea (Camellia sinensis L.), an important drink and a natural medicine for thousands of years, contains many health beneficial compounds. Growing season, geographical region, and fermentation methods create many variations in tea compositions, which contribute to each tea's uniqueness. In this study, a simple, rapid, and efficient ultra-performance liquid chromatography (UPLC) method combined with diode array detector (DAD) and mass spectroscopic (MS) detection and chemometrics analysis was used to analyse three different types of teas (green pu-erh, green tea, white tea). Using the developed method, 68 compounds were identified and 54 were quantified based on retention times, UV spectra, and MS spectra by referencing to available standards and data in the literatures. The results showed the chemical differences between the tested teas. Principal component analysis (PCA) was applied to classify and distinguish between tea samples.

Inhibition of angiotensin converting enzyme (ACE) activity by polyphenols from tea (Camellia sinensis) and links to processing method

The focus of this study was to investigate Angiotensin Converting Enzyme (ACE) inhibiting activity across 34 teas (Camellia sinensis) produced by 5 different processing methods including green (GT), oolong (OT), white (WT), black (BT) and dark (DT) teas. In vitro ACE inhibitory activity was affected by the tea processing method with IC(50) values for ACE inhibition: green < oolong < white < black < dark teas. Substrate-dependence of the reaction kinetics was studied for GT and BT polyphenolic size fractions either < or > 3 kDa and also Green Tea Polyphenolic Isolate (GTPI), and revealed that enzyme velocity curves fitted allosteric, not Michaelis-Menten, relationships. Inhibition was weakly dependent on substrate concentration for GT fraction >3 kDa and independent of substrate concentration for all other GT and BT size fractions and GTPI. Furthermore, evidence for direct inactivation of ACE by GTPI was demonstrated. Overall, the results suggest that tea polyphenolics exert a mixed mode of in vitro inhibition of ACE, mostly of a kinetically uncompetitive type. The results are discussed in the context of in vivo and epidemiological evidence for regulation of blood pressure by tea consumption.

Mechanochemical-assisted extraction and antioxidant activities of kaempferol glycosides from Camellia oleifera Abel. meal

A mechanochemical-assisted extraction (MCAE) method was proposed and investigated for the fast extraction of two kaempferol glycosides (kaempferol-3-O-[2-O-β-D-galactopyranosyl-6-O-α-L-rhamnopyranosyl]-β-D-glucopyranoside and kaempferol-3-O-[2-O-β-D-xylopyranosyl-6-O-α-L-rhamnopyranosyl]-β-D-glucopyranoside) from Camellia oleifera Abel. meal. The effects of operating parameters in terms of NaOH content, grinding time, extraction time, and ratio of solution to solid were evaluated by means of response surface methodology (RSM). Under the optimal conditions with a ratio of material to NaOH of 20:1 (g/g), a milling time of 15 min, and a ratio of solution to solid of 20:1 (mL/g) for 60 min, the maximum extraction yields of the two kaempferol glycosides reached 13.34 and 13.83%, respectively. The antioxidant activity of kaempferol glycosides extract was assessed by 2,2-diphenyl-1-picrylhydrazyl (DPPH) radical-scavenging assay and ferric thiocyanate (FTC) assay. Compared with the heat reflux extraction (HRE) method, the yield and the antioxidant activities of the extracts from MCAE with water as solvent were higher and stronger.

White tea (Camellia sinensis Kuntze) exerts neuroprotection against hydrogen peroxide-induced toxicity in PC12 cells

Tea is a popular beverage whose consumption is associated with prevention of certain disorders. The objective of the study was to investigate the potential neuroprotective effect of white tea extract (WTE) on hydrogen peroxide induced toxicity in PC12 cells. Cells were treated with various doses of WTE (10-250 μg/ml) before exposition to 250 μM hydrogen peroxide and cell survival was determined through the MTT and LDH assays. Oxidative stress was quantified in the cells after treatments as intracellular reactive oxygen species (ROS) production and the antioxidant activity of the extract was assessed in a cell free system in terms of free radical scavenging capacity. Results showed that WTE has a significant protective effect in the PC12 cell line against hydrogen peroxide as cell survival was significantly superior in WTE-treated cells compared to hydrogen peroxide-treated cells. A reduction on intracellular oxidative stress as well as radical scavenging properties were produced by WTE. Results suggest that WTE protects PC12 cells against H(2)O(2)-induced toxicity, and that an antioxidant mechanism through ROS scavenging may be in part responsible for cells neuroprotection.

Safety evaluation of tea (Camellia sinensis (L.) O. Kuntze) flower extract: assessment of mutagenicity, and acute and subchronic toxicity in rats

ETHNOPHARMACOLOGICAL RELEVANCE

Tea (Camellia sinensis (L.) O. Kuntze, Theaceae) flowers possess many physiological functions and have been used in traditional medicines for deodorization, skin care, cough suppressant and expectorant in China. However, there is a little information about its possible toxicity.

AIM OF THE STUDY

The present investigation was carried out to evaluate the safety of tea flower extract by mutagenicity and acute and subchronic toxicity studies.

MATERIALS AND METHODS

Mutagenicity of tea flower extract was evaluated by the Ames test in Salmonella typhimurium strains TA97, TA98, TA100 and TA102 at concentrations of 0.008, 0.04, 0.2, 1.0, 5.0 mg/plate. In the acute toxicity study, Sprague-Dawley rats were administered a single dose of 12.0 g/kg of body weight by gavage, and were monitored for 14 days. In the subchronic toxicity study, tea flower extract was administered by gavage at doses of 1.0, 2.0 and 4.0 g/kg body weight daily for 13 weeks to Sprague-Dawley rats.

RESULTS

In the Ames test, there was no mutagenic effect of tea flower extract (up to 5.0 mg/plate) towards four tested strains (TA97, TA98, TA100, TA102), with or without metabolic activation (S9). In the acute toxicity study, all animals gained weight and appeared active and normal, so the LD(50) value must be >12.0 g/kg body weight. In the subchronic toxicity study, no dose-related effects on survival, growth, hematology, blood chemistry, organ weights, or pathologic lesions were observed.

CONCLUSION

These results indicate that tea flower extract does not possess mutagenic potential, and that both acute and subchronic toxicity towards animals is very low. A no-observed adverse-effect level (NOAEL) for tea flower extract is 4.0 g/kg bw/day for rats under the conditions of this study.

Cytotoxic and genotoxic investigation on barbatimão [Stryphnodendron adstringens (Mart: ) Coville, 1910] extract

Stryphnodendron adstringens (Mart.) Coville, 1910 is a small tree, distributed widely throughout the Cerrado region of Brazil and named "barbatimão" by the Tupi-Guarani tribes, which presents astringent properties. Its ethnopharmacological uses comprise, among others, anti-inflammatory and wound healing action, and it is used in the treatment of diarrhea and gynecological problems. The phytotherapeutic use of 'barbatimão' is largely related to its tannin content, which is abundant in its bark. The main goal of the present study was to evaluate the cytotoxic, mutagenic, and genotoxic potential of the lyophilized solution of the stem bark of S. adstringens, using the Ames test, the SOS-Inductest and the SOS-Chromotest. S. adstringens presented cytotoxic activity in all tested systems, did not present mutagenic activity detectable by the Ames test and SOS-Chromotest, and showed some genotoxic effect on the SOS-Inductest. However, the metabolization of the extract by S9 fraction attenuated its genotoxic and cytotoxic activities.

Black tea and theaflavins assist healing of indomethacin-induced gastric ulceration in mice by antioxidative action

The healing activities of black tea (BT) and the theaflavins (TF) against the indomethacin-induced stomach ulceration were studied in a mouse model. Indomethacin (18 mg/kg, p.o.) administration induced maximum ulceration in the glandular portion of the gastric mucosa on the 3rd day, accompanied by increased lipid peroxidation and protein oxidation, depletion of thiol-defense and mucin, as well as reduced expressions of cyclooxygenases (COX) and prostaglandin (PG) E synthesis in the gastric tissues, and plasma total antioxidant status of mice. Treatment with BT (40 mg/kg), TF (1 mg/kg), and omeprazole (3 mg/kg) produced similar (74%-76%) ulcer healing, as revealed from the histopathological studies. Treatment with all the above samples reversed the adverse oxidative effects of indomethacin significantly. BT and TF also enhanced the PGE synthesis by augmenting the expressions of COX 1 and 2, but did not modulate acid secretion.

Cigarette smoke-induced biochemical perturbations in human erythrocytes and attenuation by epigallocatechin-3-gallate--tea catechin

The protective effect of epigallocatechin-3-gallate (EGCG) against cigarette smoke (CS) induced alterations in human erythrocyte was studied using an in vitro model. Hemolysis, carboxyhemoglobin, osmotic fragility, hemin, lipid peroxidation (LPO), protein thiol, protein carbonyl, glutathione, antioxidant enzymes, membrane bound ATPases and erythrocyte ghost protein were assessed to investigate the effect of EGCG. Erythrocytes were incubated with CS and/or 10 μM EGCG under physiological conditions of temperature and pH for 2 h. CS significantly increased the percentage of hemolysis, carboxyhemoglobin, hemin, LPO and osmotic fragility in human erythrocytes whereas EGCG pretreatment significantly reduced all the above parameters. The levels of protein carbonyls significantly increased whereas the level of protein thiol decreased significantly in erythrocytes incubated with CS. EGCG pretreatment significantly decreased the levels of carbonyls and increased the level of protein thiol. The level of glutathione, antioxidant enzyme and membrane bound ATPases were decreased significantly in erythrocytes incubated with CS. However, EGCG pretreatment significantly increased the activities of GSH, antioxidant enzymes and membrane bound ATPases. CS incubated erythrocytes showed a progressive loss of the cytoskeleton proteins and formation of low molecular weight bands and protein aggregates. EGCG pretreatment of CS incubated erythrocytes showed a near normal protein profile compared to that of control erythrocytes. The present study divulges that EGCG can reduce the abnormalities of cigarette smoking by ameliorating the oxidative stress. This finding raises the possibility that EGCG may provide protection from CS induced toxicity.

Wound-healing evaluation of ointment from Stryphnodendron adstringens (barbatimão) in rat skin

This study evaluated the cicatrizant effect of an ointment containing 1% of the ethyl-acetate fraction extracted from the stem bark of "barbatimão" (Stryphnodendron adstringens), in wounds made in the skin of rats, after 4, 7 and 10 days of treatment. Control wounds were treated with a base ointment without extract. The proliferation of keratinocytes in the area of reepithelialization was evaluated by counting the number of epithelial cells that were blocked in metaphase by vincristine sulfate. The length of the reepithelialized margin and the contraction of the wound were measured. Topical application of the "barbatimão" ointment stimulated proliferation of the keratinocytes, but had no effect on the length of the epithelium or on the contraction of the wounds.

Prediction and interpretation of the antioxidant capacity of green tea from dissimilar chromatographic fingerprints

Previously, multivariate calibration techniques have been successfully applied to model and predict the antioxidant activity of green tea from its chromatographic fingerprint. Since the selectivity differences between dissimilar chromatographic systems have already been valuably used in several applications, in this paper it is studied whether combining the complementary information contained in two dissimilar fingerprints can improve the predictive capacity of the multivariate calibration model. The simplest way of combining the data is concatenating both fingerprints for each sample. The resulting matrix can then be subjected to Orthogonal Projections to Latent Structures (O-PLS). Unfortunately, this approach resulted in a more complex model with a prediction error of about the average of the errors obtained with the individual fingerprints. Secondly, only the peaks with high loading and low orthogonal loading from both chromatograms were included in the O-PLS model. This resulted in a reduced complexity, but not in better predictions, probably due to a lack of complementarity of the information concerning the antioxidant capacity. Finally, the concatenated fingerprints were subjected to stepwise multiple linear regression (MLR) in order to build a model based on the variables most correlated with the antioxidant capacity. The obtained prediction error was lower than those of both previous approaches, but still higher than the error of the model based on a single analysis. This is probably again caused by a lack of complementarity in the variables. Nevertheless, it was advantageous to develop fingerprints on dissimilar system, because it enables to choose the most suited chromatographic profile to build a multivariate calibration model for the considered purpose. In contrast to what was expected, the study showed that the most simple (so the worst separated) fingerprints resulted in the best predictions. On the other hand, a more complex fingerprint in which more compounds are separated is still important to improve the interpretability of the model.

Phytoceuticals: the new 'physic garden' for asthma and chronic obstructive pulmonary disease

Phytoceuticals (non-nutritional but beneficial plant chemicals) merit investigation as pharmacotherapy for asthma and chronic obstructive pulmonary disease (COPD). Although asthma is mostly treated adequately, COPD is not. Thus, there is a need for new drugs with improved therapeutic benefit, especially in COPD. Recent interest in herbal remedies has redirected attention towards plants as sources of improved treatments for lung disease. Phytoceuticals from a variety of plants and plant products, including butterbur, English ivy, apples, chocolate, green tea and red wine, demonstrate broad-spectrum pharmacotherapeutic activities that could be exploited in the clinic. Well-designed clinical trials are required to determine whether these beneficial activities are reproduced in patients, with the prospect that phytoceuticals are the new physic garden for asthma and COPD.

Inhibition of Ca2+-activated Cl- channels by gallotannins as a possible molecular basis for health benefits of red wine and green tea

TMEM16A was found recently to be a calcium-activated Cl(-) channel (CaCC). CaCCs perform important functions in cell physiology, including regulation of epithelial secretion, cardiac and neuronal excitability, and smooth muscle contraction. CaCC modulators are of potential utility for treatment of hypertension, diarrhea, and cystic fibrosis. Screening of drug and natural product collections identified tannic acid as an inhibitor of TMEM16A, with IC(50) ∼ 6 μM and ∼100% inhibition at higher concentrations. Tannic acid inhibited CaCCs in multiple cell types but did not affect CFTR Cl(-) channels. Structure-activity analysis indicated the requirement of gallic or digallic acid substituents on a macromolecular scaffold (gallotannins), as are present in green tea and red wine. Other polyphenolic components of teas and wines, including epicatechin, catechin, and malvidin-3-glucoside, poorly inhibited CaCCs. Remarkably, a 1000-fold dilution of red wine and 100-fold dilution of green tea inhibited CaCCs by >50%. Tannic acid, red wine, and green tea inhibited arterial smooth muscle contraction and intestinal Cl(-) secretion. Gallotannins are thus potent CaCC inhibitors whose biological activity provides a potential molecular basis for the cardioprotective and antisecretory benefits of red wine and green tea.

Electrochemical and antioxidant properties of rutin

The mechanism of electrochemical oxidation of rutin on a glassy carbon electrode was studied at different pH by using several electrochemical techniques (cyclic, linear sweep, differential pulse and square-wave voltammetry) in order to give deeper insight into the mechanism of electrochemical oxidation of rutin and adsorption of its oxidation products on a glassy carbon electrode. It was determined that the rutin oxidation process on a glassy carbon electrode is reversible, pH dependent and includes the transfer of 2 e– and 2 H+. The products of electrochemical oxidation strongly adsorb on the electrode surface. Maximum surface coverage, Γmax, decreased with increasing scan rate from 3.4 × 10–9 mol cm–2 at scan rate 20 mV s–1 to 1.5 × 10–9 mol cm–2 at scan rate 100 mV s–1 and adsorption equilibrium constant was log K = 4.57 ± 0.05. Antioxidant properties of rutin were investigated by a Trolox equivalent antioxidant capacity (TEAC) assay. It was found that the TEAC values of rutin depend on concentration and the EC50 value of rutin amounted 0.23.

Toxic and essential mineral elements content of black tea leaves and their tea infusions consumed in Iran

The metal contents of eleven black tea samples, four cultivated in Iran and seven imported, and their tea infusions were determined. Twelve elements consisting toxic metals (Al, As, Pb, Cr, Cd, and Ni) and essential mineral elements (Fe, Zn, Cu, Mn, Ca, and Mg) were analyzed using inductively coupled plasma atomic emission spectroscopy (ICP-AES). Al, Ca, Mg, and Mn ranged in black tea leaves at mg g(-1) levels, while Cr, Fe, Ni, Cu, Zn were at microg g(-1) levels. Analysis of variance showed no statistically significant differences among most elements determined in cultivated and imported black teas in Iran except for Ni and Cu. The extraction efficiency of each element into tea infusions was evaluated. The solubility of measured metals in infusion extracts varied widely and ranged from 0 to 59.3%. Among the studied elements, Cr, Pb, and Cd showed the lowest rates of solubility and Ni had the highest rates of solubility. The amount of toxic metals and essential mineral elements that one may take up through consumption of black tea infusion was estimated. The amount of realizing each element into tea infusions and acceptable daily intake, for safety consumption of black tea, was compared.

Quality of Life and Related Factors in the Older Rural and Urban Chinese Populations in Zhejiang Province

The aim of this study was to evaluate the quality of life (QoL) in the older rural and urban Chinese populations in Zhejiang province. An analysis of the association between potential factors and QoL for these two groups was conducted. A cross-sectional study was conducted from October to December 2007. The total sample consisted of 2,441 rural and 2,554 urban participants. A Chinese version of the 36-item Short Form Health Survey (SF-36) was used to quantify the QoL of participants. A comparison between the QoL of rural and urban participants was made. The association between potential factors and QoL was performed using a multiple linear regression model. The study revealed all scale scores of SF-36 in the rural population were significantly lower than those in the urban population except general health (GH; p < .001). The common factors associated with high QoL in both older rural and urban populations were gender (male), tea consumption, income, and consumption of alcohol. Age and the number of chronic diseases an individual suffered from were negatively associated with QoL. In addition, the study revealed the perception that giving up smoking cigarettes and drinking alcohol were negatively associated with QoL for participants living in rural areas, whereas educational level and regular exercise were positively associated with QoL for participants living in urban areas. Intervention programs for decreasing chronic diseases, establishing security mechanisms of the pension, and spreading the knowledge of healthy lifestyles may improve QoL for the older populations in Zhejiang province, especially in rural areas.

Estimation of antioxidative properties of tea leaves by abrasive stripping electrochemistry using paraffin-impregnated graphite electrode

Electrooxidation potentials of powdered green and black teas were determined by abrasive stripping voltammetry. A circular surface of paraffin-impregnated graphite rod was contaminated with tea microparticles and used as a chemically prepared working electrode in square-wave voltammetric experiments. The responses are ascribed to electrooxidation of flavanols in teas. Low oxidation potentials of some green teas were observed. An advantage of the proposed method is that no extraction of electroactive components is necessary.