Comparative Flavonoids Contents of Selected Herbs and Associations of Their Radical Scavenging Activity with Antiproliferative Actions in V79-4 Cells

ABSTRACT:  To elucidate the health benefit of herbal teas on the cytotoxicity induced by H₂O₂ in V79-4 cells, herbal extracts and its flavonoids were tested using lactate dehydrogenase release and determining intracellular reactive oxygen species generation and antioxidant activity with superoxide radical scavenging assay. Significant decrease in cell viability was observed on V79-4 cells treated with H₂O₂ (1 mM), while herbal extracts and its flavonoids including catechin and epigallocatechin gallate prevented the LDH release from H₂O₂ cytotoxicity. Total catechin contents of green tea (65.6 mg/g of dry matter) were significantly higher than other herbal teas (35.8 to 1.2 mg/g of DM). The relative concentration of the 4 major tea catechins ranked EGCG > EGC > EC > C. Green tea exhibited the lowest IC₅₀ values (2 g fresh herb/100 mL) of superoxide radical scavenging activity among the tested herbal tea, which indicates powerful antioxidant activity in O₂^·− radicals scavenging, followed by black tea, dandelion, hawthorn, rose hip, chamomile.     

Antimicrobial activities of tea catechins and theaflavins and tea extracts against Bacillus cereus

We evaluated the antimicrobial activities of seven green tea catechins and four black tea theaflavins, generally referred to as flavonoids, as well as the aqueous extracts (infusions) of 36 commercial black, green, oolong, white, and herbal teas against Bacillus cereus (strain RM3190) incubated at 21 degrees C for 3, 15, 30, and 60 min. The results obtained demonstrate that (i) (-)-gallocatechin-3-gallate, (-)-epigallocatechin-3-gallate, (-)-catechin-3-gallate, (-)-epicatechin-3-gallate, theaflavin-3, 3'-digallate, theaflavin-3'-gallate, and theaflavin-3-gallate showed antimicrobial activities at nanomolar levels; (ii) most compounds were more active than were medicinal antibiotics, such as tetracycline or vancomycin, at comparable concentrations; (iii) the bactericidal activities of the teas could be accounted for by the levels of catechins and theaflavins as determined by high-pressure liquid chromatography; (iv) freshly prepared tea infusions were more active than day-old teas; and (v) tea catechins without gallate side chains, gallic acid and the alkaloids caffeine and theobromine also present in teas, and herbal (chamomile and peppermint) teas that contain no flavonoids are all inactive. These studies extend our knowledge about the antimicrobial effects of food ingredients.     

Effects of addition of egg ovotransferrin-derived peptides on the oxygen radical absorbance capacity of different teas

Ovotransferrin-derived peptides showed synergistic effects with vitamin C, epigallocatechin gallate (EGCG), and caffeic acid, but not quercetin in our previous report. In this study, we further investigated the interactions between ovotransferrin-derived peptides and teas, based on the oxygen radical absorbance capacity (ORAC) assay. Our results showed that there was no significant difference in ORAC values among green, oolong, and black teas. For all the samples, 80% methanol extracts possessed better antioxidant capacity than hot water extracts. The antioxidant capacity of teas were improved by adding either ovotransferrin hydrolysate or its purified peptide IRW; however, adding hydrolysate did not improve antioxidant stability of teas. ORAC values of both teas and hydrolysate added teas were decreased during 22weeks of storage, while samples stored at 4°C exhibited higher antioxidant capacity than those stored at room temperature. This suggested that ovotransferrin hydrolysate could be used as functional food ingredients in enhancing antioxidant capacities of foods, which would benefit human nutrition and health.     

Survival of Cronobacter Species in Reconstituted Herbal Infant Teas and their Sensitivity to Bovine Lactoferrin

ABSTRACT:  Cronobacter  is a new genus containing 5 species previously known as  Enterobacter sakazakii . The popularity of "natural" substances and alternative medicine has extended the use of natural antimicrobials and herbs to foods, and some herbs are claimed to relieve gastric disturbances in infants. The present study investigated the antimicrobial activity of bovine lactoferrin (LF) and  Cronobacter  survival in commercial herbal infant teas (HITs) reconstituted with water at different temperatures.  Cronobacter  cells were able to grow in all reconstituted HITs at 37 or 21 °C after 6 h. A 4-log reduction in  Cronobacter  was achieved by reconstituting herbal infant tea at ≥ 60 °C. LF was able to reduce  Cronobacter  species viability in herbal infant tea. No viable cells were recovered after 4 h at 37 °C in the presence of ≥5mg LF/mL. The bactericidal activity of LF was reduced at lower concentrations and lower temperatures. This study demonstrates that if present in reconstituted herbal infant tea,  Cronobacter  can grow and this may compromise the safety of these products. Therefore, addition of LF to reconstituted HIT may be a promising approach for the effective control of this organism.
Practical Application:  Cronobacter  species can be isolated from herbal teas, and these products are claimed to relieve gastric disturbances in infants. This study demonstrates that  Cronobacter  cells present in reconstituted herbal infant teas (HITs) can grow if not held at acceptable temperatures. It was shown that reconstitution of these tea formulas with ≥ 60 °C water reduced the potential risk from  Cronobacter . Furthermore, use of lactoferrin (LF) may be a promising approach for effective control of these organisms in HIT held at nonrefrigeration temperatures (10 to 37 °C) for short periods.     

Antioxidative and anti-hydrogen peroxide activities of various herbal teas

Herbal teas, i.e., extracts of herbs, are popular because of their fragrance and antioxidative activity. Since the antioxidative activity comes mainly from polyphenols, total polyphenol concentrations and 1,1-diphenyl-2-picrylhydrazyl (DPPH) radical-scavenging activities in herbal teas were measured and compared. Levels of H₂O₂ in the teas were also examined, since the production of H₂O₂ in beverages such as coffee and green tea, has been reported. Only a small amount of H₂O₂ was detected in the herbal teas just after their preparation with hot water. However, H₂O₂ was gradually produced during incubation at 25 °C after extraction with hot water, especially when the teas were incubated in phosphate buffer at pH 7.4. To examine the anti-H₂O₂ activity of herbal teas, various teas were added to a catechin-enriched green tea, which produce much H₂O₂, and they were incubated at 25 °C for one day. Addition of hibiscus and thorn apple tea decreased the production of H₂O₂ in the catechin-enriched green tea, possibly because of a lowering of the pH of the mixture.     

Comparison of NO-scavenging and NO-suppressing activities of different herbal teas with those of green tea

Oxidative stress caused by the production of excess nitric oxide (NO) during infection or inflammation has been implicated in the pathogenesis of several diseases, including cancer, diabetes and renal disease. Accordingly, the scavenging of NO radical or/and suppression of NO production by mitogen-activated cells may be promising indicators in screening healthy food. In this work, the NO-scavenging and NO-suppressing activities of different herbal teas were determined and compared with those of green tea. All of the tested herbal teas revealed NO-scavenging and NO-suppressing activities. The NO-scavenging activity of herbal teas can be ranked by the IC₅₀, the concentration of the tested herbal tea required to quench 50% of NO radicals released by sodium nitroprusside. The activities follow the order: green tea > rosemary, sweet osmanthus, rose and lavender > jasmine, lemongrass and daisy. The NO-suppressing activity was evaluated, based on the suppressing effect of herbal teas on the production of NO by LPS-activated RAW 264.7 macrophages. Experimental results indicated that green tea and rosemary had IC₅₀ values of less than 500 μg/ml, and were proven to be good NO-suppressors, whereas lavender, sweet osmanthus, lemongrass, rose, daisy and jasmine had IC₅₀ values that exceeded 500 μg/ml, and were classified as rather poor NO-suppressors. In conclusion, consumption of herbal teas promotes the NO-scavenging and NO-suppressing activities of the diet, even though their activities are weaker than that of green tea.     

Antimicrobial activity of tea as affected by the degree of fermentation and manufacturing season.

Bacillus subtilis, Escherichia coli, Proteus vulgaris, Pseudomonas fluorescens, Salmonella sp. and Staphylococcus aureus were used to test the antimicrobial activity of tea flush extract and extracts of various tea products. Among the six test organisms, P. fluorescens was the most sensitive to the extracts, while B. subtilis was the least sensitive. In general, antimicrobial activity decreased when the extents of tea fermentation increased. The antimicrobial activities of tea flush extract and extracts of tea products with different extents of fermentation varied with test organisms. Tea flush and Green tea, the unfermented tea, exerted the strongest antimicrobial activity followed by the partially fermented tea products such as Longjing, Tieh-Kuan-Ying, Paochung, and Oolong teas. On the other hand, Black tea, the completely fermented tea, showed the least antimicrobial activity. It was also noted that extracts of Oolong tea prepared in summer exhibited the strongest antimicrobial activity, followed by those prepared in spring, winter and fall.     

The synergistic potential of various teas,herbs and therapeutic drugs in health improvement: a review

Tea is one of the most widely consumed non‐alcoholic beverages in the world next to water. It is classified as Camellia sinensis and non‐Camellia sinensis (herbal teas). The common bioactive compounds found mainly in green teas are flavan‐3‐ols (catechins) (also called flavanols), proanthocyanidins (tannins) and flavonols. Black tea contains theaflavins and thearubigins and white tea contains l ‐theanine and gamma‐aminobutyric acid (GABA), while herbal teas contain diverse polyphenols. Phytochemicals in tea exhibit antimicrobial, anti‐diabetic and anti‐cancer activities that are perceived to be helpful in managing chronic diseases linked to lifestyle. Many of these phytochemicals are reported to be biologically active when combined. Knowledge of the synergistic interactions of tea with other teas or herbs in terms of biological activities will be of benefit for therapeutic enhancement. There is evidence that various types of teas act synergistically in exhibiting health benefits to humans, improving consumer acceptance and economic value. Similar observations have been made when teas and herbs or medicinal drugs were combined. The aim of this review is to highlight potential beneficial synergies between combinations of different types of teas, tea and herbs, and tea and medicinal drugs. © 2017 Society of Chemical Industry     

Comparison of the effects of black and green tea on in vitro lipoprotein oxidation in human serum

Lipoprotein oxidation is a process thought to be involved in atherogenesis. Dietary antioxidants that prevent or inhibit oxidative damage to lipoproteins may help to prevent atherosclerosis. Both black and green teas can be major dietary sources of flavonoids and other phenolics with antioxidant activity. Results of previous studies suggest that green tea may have a greater antioxidant potential than black tea. The aim of this study was to assess and compare the effects of black and green tea on in vitro lipoprotein oxidation. The tea extracts were prepared using a method similar to that used to prepare infusions of tea for drinking. Antioxidant activities of seven black teas and four green teas were assessed using an in vitro assay that measures Cu²⁺ ‐induced oxidation of lipoproteins in human serum. All tea extracts inhibited in vitro lipoprotein oxidation in human serum to a similar extent. No significant difference in antioxidant activity was found between black and green tea. Caffeine prepared to a comparable concentration to that found in tea had no effect on lipoprotein oxidation. Further studies are required to determine the importance of these findings in relation to possible protective effects of black and green tea consumption against atherogenesis and cardiovascular disease. © 1999 Society of Chemical Industry     

Pyrrolizidine and tropane alkaloids in teas and the herbal teas peppermint,rooibos and chamomile in the Israeli market

Dehydro pyrrolizidine alkaloids (dehydro PAs) are carcinogenic phytotoxins prevalent in the Boraginaceae, Asteraceae and Fabaceae families. Dehydro PAs enter the food and feed chain by co-harvesting of crops intended for human and animal consumption as well as by carry-over into animal-based products such as milk, eggs and honey. Recently the occurrence of dehydro PAs in teas and herbal teas has gained increasing attention from the EU, due to the high levels of dehydro PAs found in commercially available teas and herbal teas in Germany and Switzerland. Furthermore, several tropane alkaloids (TAs, e.g. scopolamine and hyoscyamine) intoxications due to the consumption of contaminated herbal teas were reported in the literature. The aim of the present study was to determine the dehydro PAs and TAs levels in 70 pre-packed teabags of herbal and non-herbal tea types sold in supermarkets in Israel. Chamomile, peppermint and rooibos teas contained high dehydro PAs levels in almost all samples analysed. Lower amounts were detected in black and green teas, while no dehydro PAs were found in fennel and melissa herbal teas. Total dehydro PAs concentrations in chamomile, peppermint and rooibos teas ranged from 20 to 1729 μg/kg. Except for black tea containing only mono-ester retrorsine-type dehydro PAs, all other teas and herbal teas showed mixed patterns of dehydro PA ester types, indicating a contamination by various weed species during harvesting and/or production. The TA levels per teabag were below the recommended acute reference dose; however, the positive findings of TAs in all peppermint tea samples warrant a more extensive survey. The partially high levels of dehydro PAs found in teas and herbal teas present an urgent warning letter to the regulatory authorities to perform routine quality control analysis and implement maximum residual levels for dehydro PAs.     

Simultaneous determination of theanine,gallic acid,purine alkaloids,catechins, and theaflavins in black tea using HPLC

In the present study, we employed high performance liquid chromatography with an amide‐C₁₆ column to determine the eighteen major active ingredients in black tea, including theanine, gallic acid, four purine alkaloids, eight catechins and four theaflavins. The method was successfully used to analyse two new kinds of black teas from the leaves of Camellia ptilophylla and Camellia kucha in China and several other world‐ famous black teas. Forty percentage ethanol was chosen as the extraction solvent for preparing tea extracts. All of the eighteen compounds could be separated within 86 min with a gradient elution system. Excellent linearity was observed for all the standard calibration curves, and correlation coefficients were above 0.9991. The developed method is accurate and sensitive enough for the determination of active components in black tea.     

网购凉茶中非法添加抗风湿类药物状况分析及对策探讨

目的 对网购凉茶非法添加的抗风湿类药物进行检测分析, 了解其非法添加抗风湿类药物添加情况, 并进行对策探讨。方法 通过高效液相色谱质谱法检测凉茶中39种非法添加抗风湿类药物, 并对69批次网购凉茶进行检测分析。结果 69批次样品中发现7批次呈阳性, 检出成分为对乙酰氨基酚、氨基比林、地塞米松、醋氯芬酸和双氯芬酸钠药物。结论 网购凉茶中存在非法添加抗风湿类药物的情况, 特别是产品包装上信息不全, 功能宣称较夸张的卖家销售的产品, 检出非法添加药物情况较为突出。今后应建立网购食品, 特别是有功能声称的食品的长效监管机制, 提高网购食品安全水平。     

Metabonomics: a developing platform for better understanding Chinese herbal teas as a complementary therapy

Chinese herbal teas (CHTs) have gained increasing attention throughout the world as a complementary therapy. Due to the multicomponent composition in herbal teas, the molecular mechanisms of their causality in health effects are still elusive and becoming the main obstacles for their application. There is a pressing need for a more systematic study about their molecular mechanisms to substantiate the health effects of CHTs. With the particular feature of measuring the real metabolic phenotype resulted from molecular interplay between host and environmental factors, metabonomics is especially suited to inspect metabolic responses to CHT intake and provide insights into health effects. Application of metabonomics to uncover the effects of CHTs on human health is foreseen as providing deeper insights of the complicated molecular mechanisms of CHTs by explaining relatively subtle and different effects of herbal tea intervention, classifying the metabolic responses to herbal tea, depicting synergistic effects of CHTs and evaluating the safety of CHTs intake.     

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

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

Antioxidant capacity of herbal infusions and tea extracts: A comparison of ORAC-fluorescein and ORAC-pyrogallol red methodologies

Oxygen radical absorbance capacity (ORAC) values have been obtained for a series of teas and herbal infusions employing 2,2′-azo-bis(2-amidinopropane) as free radical source, and fluorescein and pyrogallol red as target molecules. The amounts of phenols in the extracts were evaluated by Folin’s methodology. ORAC values are extremely dependent upon the employed target molecule. Even more, relative ORAC values measured for different infusions depend upon the employed methodology. For example, ORAC-fluorescein value of Aloysia citriodora is larger than that of green tea, while if pyrogallol red is employed as target molecule green tea appears as nearly nine times more efficient. Similarly, for extracts with comparable amounts of phenols, herbal infusions are more efficient than teas by ORAC-fluorescein, while opposite conclusions are obtained if ORAC-pyrogallol red values are considered. Extreme care must then be taken for conclusions obtained from ORAC values estimated by employing a single target molecule.     

不同储存时间对普洱茶有机溶剂萃取物清除自由基活性的影响

本文以半数抑制浓度IC50的大小研究了十种茶叶（不同年份的生普和熟普）有机溶剂萃取物的体外抗氧化活性。结果表明,生茶有机溶剂萃取层清除DPPH自由基、羟基自由基、超氧自由基的IC50最小分别可达0.339 mg/mL、0.074 mg/mL、1.206 mg/mL,熟茶清除DPPH自由基、羟基自由基、超氧自由基的IC50最小分别可达0.554 mg/mL、0.164 mg/mL、1.927 mg/mL,生茶的抗氧化能力明显优于熟茶;各种普洱茶对自由基的清除能力主要取决于各萃取液中的多酚和黄酮含量。生茶乙酸乙酯层的茶多酚萃取量最多,在7.33-9.57%之间,正丁醇层的黄酮类物质的萃取量最多在7.08-10.99%之间,熟茶正丁醇层的茶多酚含量和黄酮类物质的含量在个有机溶剂层中均是最高的,分别在3.62-5.73%之间和4.75-5.83%之间,乙酸乙酯层和正丁醇层的萃取化合物具有较多的羟基,具有较强的清除自由基的能力;茶叶的储存时间对各萃取液的抗氧化能力无显著影响。     

Origin of sennosides in health teas including Malva leaves

The aim of this study is to clarify whether sennosides are contained in the leaf of Malva verticillata L., and then to clarify the source of sennosides in health teas including malva leaves. The identification and determination of sennosides were performed with thin layer chromatography and high performance liquid chromatography. The leaf of Malva verticillata L. did not contain sennosides A or B and could be easily distinguished from senna leaf. Our previous report showed that sennosides are contained in weight-reducing herbal teas including malva leaves, and that senna leaf is a herbal component in some teas. Furthermore, in 10 samples of health tea including malva leaves that were bought last year, the smallest amount of sennosides was 6.1 mg/bag, and all health teas including malva leaves contained the leaf and midrib of senna. We suggest that sennosides A and B are not contained in the leaf of Malva verticillata L., and that the sennosides in health teas including malva leaves are not derived from malva leaf but from senna leaf.     

White and Green Teas (Camellia sinensis var. sinensis): Variation in Phenolic,Methylxanthine, and Antioxidant Profiles

Abstract: Recent investigations have associated white teas with anti-carcinogenic, immune-boosting, and antioxidative properties that may impact human health in a manner comparable to green teas. An in-depth chemical analysis of white tea types was conducted to quantify polyphenols and antioxidant potential of 8 commercially available white teas, and compare them to green tea. Extraction and HPLC protocols were optimized and validated for the quantification of 9 phenolic and 3 methylxanthine compounds to examine inter- and intra-variation in white and green tea types and subtypes. A sampling strategy was devised to assess various subtypes procured from different commercial sources. Variation in antioxidant activity and total phenolic content (TPC) of both tea types was further assessed by the 1-1-diphenyl-2-picrylhydrazyl (DPPH) and Folin–Ciocalteau (F–C) assays, respectively. Total catechin content (TCC) for white teas ranged widely from 14.40 to 369.60 mg/g of dry plant material for water extracts and 47.16 to 163.94 mg/g for methanol extracts. TCC for green teas also ranged more than 10-fold, from 21.38 to 228.20 mg/g of dry plant material for water extracts and 32.23 to 141.24 mg/g for methanol extracts. These findings indicate that statements suggesting a hierarchical order of catechin content among tea types are inconclusive and should be made with attention to a sampling strategy that specifies the tea subtype and its source. Certain white teas have comparable quantities of total catechins to some green teas, but lesser antioxidant capacity, suggesting that white teas have fewer non-catechin antioxidants present. Practical Application: In this investigation white and green teas were extracted in ways that mimic common tea preparation practices, and their chemical profiles were determined using validated analytical chemistry methods. The results suggest certain green and white tea types have comparable levels of catechins with potential health promoting qualities. Specifically, the polyphenolic content of green teas was found to be similar to certain white tea varieties, which makes the latter tea type a potential substitute for people interested in consuming polyphenols for health reasons. Moreover, this study is among the first to demonstrate the effect subtype sampling, source of procurement, cultivation, and processing practices have on the final white tea product, as such analysis has previously been mostly carried out on green teas.     

In vitro antimicrobial activities against cariogenic streptococci and their antioxidant capacities: A comparative study of green tea versus different herbs

The antimicrobial activity against cariogenic bacteria, total antioxidant capacity and phenolic constituents of methanolic extracts from 11 herbs were investigated and compared with those of green tea (Camellia sinensis). Among the 12 tested herbs, eight herbal extracts could inhibit the growth of Streptococcus sanguinis. Jasmine, jiaogulan, and lemongrass were the most potent, with minimum inhibitory concentrations (MIC) of 1 mg/ml, while green tea was less effective, with a MIC of 4 mg/ml. Among them, only rosemary could inhibit the growth of S. mutans at a MIC of 4 mg/ml. Total antioxidant capacities of herbal extracts were analyzed by three different assays, including 2,2-diphenyl-1-picrylhydrazyl (DPPH·) radical scavenging activity, trolox equivalent antioxidant capacity (TEAC) and oxygen radical absorbance capacity (ORAC). Regardless of the assays used, green tea exhibited the highest antioxidant capacity, followed by osmanthus. Wide variations in total phenolics and total flavonoids of herbal tea extracts were observed. Chlorogenic acid was detected in high amount in honeysuckle and duzhong. These data suggest that rosemary is a potent inhibitor of oral streptococci, and green tea and osmanthus may be effective potential sources of natural antioxidants.