Occurrence of Free Base of Phytosphingosine in Candida intermedia (IFO 0761)

The aroma concentrates from Vietnamese green tea and lotus tea were prepared and analyzed. Characterization of the components were carried out using coupled gas chromatography and mass spectrometry and infrared spectrometry, besides gas chromatographic retention data.

Anethole and 1,4-dimethoxybenzene have been identified for the first time as the flavor constituents in green tea. Linalool, two linalooloxides (cis and trans, five membered), 3,7-dimethyl-1,5,7-octatriene-3-ol, 2,5 (or 2,6)-dimethylpyrazine and 1-ethyl-2-formylpyrrole were the predominant components in Vietnamese green tea.

1,4-Dimethoxybenzene has been identified as the main component in lotus tea. The compound was also isolated from both dried and fresh lotus pollen.     

Genoprotection and genotoxicity of green tea (Camellia sinensis): Are they two sides of the same redox coin?

Abstract

Objectives

Regular intake of green tea associates with lower DNA damage and increased resistance of DNA to oxidant challenge. However, in vitro pro-oxidant effects of green tea have been reported. Both effects could be mediated by hydrogen peroxide (H₂O₂) which is generated by autoxidation of tea catechins. In large amounts, H₂O₂ is genotoxic, but low concentrations could activate the redox-sensitive antioxidant response element (ARE) via the Keap-1/Nrf2 redox switch, inducing genoprotective adaptations. Our objective was to test this hypothesis.

Methods

Peripheral lymphocytes from healthy volunteers were incubated for 30 minutes at 37°C in freshly prepared tea solutions (0.005, 0.01, 0.05%w/v (7, 14, 71 µmol/l total catechins) in phosphate buffered saline (PBS), with PBS as control) in the presence and absence of catalase (CAT). H₂O₂ in tea was measured colorimetrically. Oxidation-induced DNA lesions were measured by the Fpg-assisted comet assay.

Results

H₂O₂ concentrations in 0.005, 0.01, and 0.05% green tea after 30 minutes at 37°C were, respectively, ～3, ～7, and ～52 µmol/l. Cells incubated in 0.005 and 0.01% tea showed less (P < 0.001) DNA damage compared to control cells. Cells treated with 0.05% green tea showed ～50% (P < 0.001) more DNA damage. The presence of CAT prevented this damage, but did not remove the genoprotective effects of low-dose tea. No significant changes in expression of ARE-associated genes (HMOX1, NRF2, KEAP1, BACH1, and hOGG1) were seen in cells treated with tea or tea + CAT.

Conclusion

Genoprotection by low-dose green tea could be due to direct antioxidant protection by green tea polyphenols, or to H₂O₂-independent signalling pathways.     

Studies on the Flavor of Green Tea

The essential oil from manufactured green tea was separated into carboxylic, phenolic, carbonyl and alcoholic fractions and analysed by gas chromatography.

Seventeen alchols, two carbonyls, seven acids and two phenolic compounds were identified on the basis of their relative retention times and aroma of effluents by comparing with authentic compounds.

The quantities of these compounds were also determined by gas chromatography.

Four alcohols (present in rather high amounts), two caronyls, three esters and two phenols have remained unidentified.     

Simultaneous Determination of S-Methylmethionine,Vitamin U and Free Amino Acids in Extracts of Green Tea with an HPLC-Amino Acid Analyzer

Free amino acids and S-methylmethionine (MMS, an anti-ulcer factor, Vitamin U) in green tea extracts were simultaneously determined with an HPLC-amino acid analyzer using lithium citrate buffers.

Rapid analysis of MMS and free amino acids was achieved with a high resolution column, MCI Gel CK-10U 0.46 </> × 15 cm, within 180 min. MMS in the column eluates was identified as dimethyl sulfide by a gas-chromatographic method with a flame photometric detector. The contents of MMS and free amino acids in various green teas were determined and compared with respect to the quality of commercial teas, blended teas and non-blended teas, and the place of cultivation of the tea. The described method is rapid and useful for checking the quality of green tea.     

Volatile Flavor Components of Dried Bonito (Katsuobushi). I. On Basic,Acidic and Weak Acidic Fractions

The aqueous extract of dried bonito (Katsuobushi) was distilled by using a thin film evaporator. The resulting distillate was extracted with diethyl ether, and the extract was separated into basic, acidic, weak acidic, and neutral fractions.

The basic, acidic, and weak acidic fractions were analyzed by gas chromatography and gas chromatography-mass spectrometry.

Seventy-four compounds, including 24 acids, 24 phenols, 8 pyridines, 12 pyrazines, 3 thiazoles, and 3 other compounds were identified. Thirty-six of these compounds were newly identified as volatile flavor compounds of Katsuobushi.     

Inhibitory effect of Chinese green tea on cigarette smoke-induced up-regulation of airway neutrophil elastase and matrix metalloproteinase-12 via antioxidant activity

Abstract

Our recent study has indicated that Chinese green tea (Lung Chen), in which epigallocatechin-3-gallate (EGCG) accounts for 60% of catechins, protected cigarette smoke-induced lung injury. We now hypothesized that Lung Chen tea may also have potential effect on lung oxidative stress and proteases/anti-proteases in a smoking rat model. Sprague–Dawley rats were exposed to either sham air (SA) or 4% cigarette smoke (CS) plus 2% Lung Chen tea or water by oral gavage. Serine proteases, matrix metalloproteinases (MMPs) and their respective endogenous inhibitors were determined in bronchoalveolar lavage (BAL) and lung tissues by gelatin/casein zymography and biochemical assays. Green tea consumption significantly decreased CS-induced elevation of lung lipid peroxidation marker, malondialdehyde (MDA), and CS-induced up-regulation of neutrophil elastase (NE) concentration and activity along with that of α₁-antitrypsin (α₁-AT) and secretory leukoproteinase inhibitor (SLPI) in BAL and lung. In parallel, significant elevation of MMP-12 activity was found in BAL and lung of the CS-exposed group, which returned to the levels of SA-exposed group after green tea consumption but not CS-induced reduction of tissue inhibitor of metalloproteinase (TIMP)-1 activity, which was not reversed by green tea consumption. Taken together, our data supported the presence of local oxidative stress and protease/anti-protease imbalance in the airways after CS exposure, which might be alleviated by green tea consumption through its biological antioxidant activity.     

Antimutagenic activity of selenium-enriched green tea toward the heterocyclic amine 2-amino-3-methylimidazo[4,5-f]quinoline

Both selenium and green tea have been reported to exhibit antigenotoxic and cancer chemopreventive properties. We compared the antimutagenic activities of regular green tea and selenium-enriched green tea obtained from Hubei Province, China, toward the heterocyclic amine, 2-amino-3-methylimidazo[4,5-f]quinoline (IQ) in the Salmonella assay. Selenium-enriched green tea obtained by foliar application of selenite exhibited concentration-dependent inhibition of IQ-induced mutagenesis in the presence of rat liver S9 and was significantly more effective than regular green tea tested under the same conditions. Analytical studies revealed no major differences in the polyphenol or caffeine content between regular green tea and selenium-enriched green tea, but the latter tea contained approximately 60-fold higher concentrations of selenium compared with regular green tea. The only soluble form of selenium was identified as selenite. The antimutagenic effects of certain individual tea constituents, such as epicatechin gallate and catechin, were enhanced by the addition of selenite to the Salmonella assay. Sodium selenite, sodium selenate, seleno-dl-cysteine, seleno-l-methionine, and l-Se-methylselenocysteine were not antimutagenic toward IQ when tested alone, but augmented significantly the inhibitory potency of green tea. The results suggested an enhancing (“coantimutagenic”) effect of selenium in combination with green tea in vitro, but in vivo studies are needed to assess whether there is a synergistic effect of tea and selenium to protect against heterocyclic amine-induced mutagenesis and carcinogenesis.     

Flavor of Black Tea

Acidic fraction of the essential oil of black tea has a characteristic odor and affects the tea flavor. Eight aliphatic acids were identified by gas chromatography with the authentic samples known as the constituents of tea flavor. Two unknown substances were separated and identified as cis-3-hexenoic acid and trans-2-hexenoic acid respectively.

Three kinds of black tea (i.e. Assam, Shan and Benihomare) have same acidic components and the percent composition of these acids is different among them.     

Enzymatic tannase treatment of green tea increases in vitro inhibitory activity against N-nitrosation of dimethylamine

In vitro experiments were performed to test inhibition of nitrite-mediated N-nitrosation by individual catechins, green tea, and tannase-treated green tea extracts. The extent of inhibition was measured via nitrosamine formation. Green tea with or without tannase treatment was examined to study nitrosation inhibition in order to evaluate the inhibitory activities with the structural changes of catechins present in the extracts. The results showed that the tannase-treated green tea had a greater ability to inhibit the nitrosation than green tea and ascorbic acid did. The tannase-treated green tea strongly inhibited the formation of N-nitrosodimethylamine (NDMA). Among four major catechins tested, epigallocatechin blocked the N-nitrosation efficiently, and epigallocatechin gallate was more unstable than epigallocatechin at pH 2.0 or 8.0. These results suggest that the consumption of tannase-treated green tea can reduce NDMA formation.     

Tea extracts differentially inhibit Streptococcus mutans and Streptococcus sobrinus biofilm colonization depending on the steeping temperature

Abstract

This study aimed to evaluate the effects of tea extracts on oral biofilm colonization depending on steeping temperature. S. mutans and S. sobrinus were cultured and treated with green or black tea extracts prepared under different steeping conditions. Biofilm formation, glucosyltransferase (GTF) levels, bacterial growth, and acidogenicity were evaluated. Biofilms were also assessed by gas chromatography-mass spectrometry and confocal laser scanning microscopy. All extracts with hot steeping showed higher inhibitory effects on biofilm formation and cell viability and lower GTF levels compared with those with cold steeping (p?<?0.05). Hot steeping significantly reduced bacterial growth (p?<?0.05) and maintained the pH. Catechins were only identified from hot steeping extracts. Within the limits of this study, extracts with cold steeping showed lower inhibitory effects on oral biofilms. The different effects between steeping extracts may be attributed to the difference in catechins released from tea extracts under the different steep conditions.     

Determination of S-Methylmethionine,Vitamin U,in Various Teas

S-Methylmethionine (MMS, an anti-ulcer factor, Vitamin u) was determined in the extracts of various kinds of teas, such as green teas, black teas and oolong teas, using an amino acid analyzer for physiological-fluid analysis or for rapid analysis. MMS in the column eluates was confirmed to be dimethyl sulfide by a gas-chromatographic method with a flame photometric detector. The quantity of MMS obtained from the various green teas depended on the quality and the freshness, i.e.fresh, high-quality gyokuro, 15.7 to 24.5 mg%; fresh sen-cha, 7.0 to 10.3 mg%; and the other green teas 1 to 6mg%. Oolong tea and black tea did not contain MMS.

The extraction conditions for and the heat-stability of MMS were also discussed.     

Inhibition of Camellia sinensis (L.) O. Kuntze on Microcystis aeruginosa and isolation of the inhibition factors

Low concentration of tea (Camellia sinensis (L.) O. Kuntze) was shown to inhibit the growth of the toxic cyanobacterium Microcystis aeruginosa. The inhibition efficiency was 40 % at 0.1 g dry tea/L and 90 % at 0.2 g/L after a 12-day culture. All varieties of tea used in the test could inhibit Microcystis growth, in which the inhibitory effect of green tea was greater than that of black tea. Antialgal allelochemicals were isolated from tea by solvent extraction, gel-chromatography and high performance liquid chromatography. Two algal-inhibition compounds were identified by liquid chromatography/mass spectrometry as epigallocatechin-3-gallate, epicatechin-3-gallate respectively. These are the main polyphenols in tea that have inhibitory effects on the growth of cyanobacteria. The combined effect of these polyphenols makes tea a promising source of algicide to inhibit the growth of algal blooms.     

Small molecule-sensing strategy and techniques for understanding the functionality of green tea

Various low-molecular-weight phytochemicals in green tea (Camellia sinensis L.), especially (–)-epigallocatechin-3-O-gallate (EGCG), are known to be involved in health promotion and disease risk reduction. However, the underlying mechanism has remained elusive because of the absence of an analytical technique that can easily detect the precise behavior of such a small molecule. Recently, we have identified a cell-surface EGCG-sensing receptor and the related signaling molecules that control the physiological functions of EGCG. We also developed a novel in situ label-free imaging technique for visualizing spatially resolved biotransformations based on simultaneous mapping of EGCG and its phase II metabolites. Furthermore, we established a chemometric method capable of evaluating the functionality of multicomponent green tea extracts by focusing on their compositional balances. This review highlights our proposed small molecule-sensing techniques for detecting the complex behavior of green tea components and linking such information to an enhanced understanding of green tea functionality.     

Green tea aroma fraction reduces β-amyloid peptide-induced toxicity in Caenorhabditis elegans transfected with human β-amyloid minigene

Green tea is a popular world-wide beverage with health benefits that include preventive effects on cancer as well as cardiovascular, liver and Alzheimer’s diseases (AD). This study will examine the preventive effects on AD of a unique aroma of Japanese green tea. First, a transgenic Caenorhabditis elegans (C. elegans) CL4176 expressing human β-amyloid peptide (Aβ) was used as a model of AD. A hexane extract of processed green tea was further fractionated into volatile and non-volatile fractions, named roasty aroma and green tea aroma fractions depending on their aroma, by microscale distillation. Both hexane extract and green tea aroma fraction were found to inhibit Aβ-induced paralysis, while only green tea aroma fraction extended lifespan in CL4176. We also found that green tea aroma fraction has antioxidant activity. This paper indicates that the green tea aroma fraction is an additional component for prevention of AD.     

Pyrazines Responsible for the Potatolike Odor Produced by Some Serratia and Cedecea Strains

The pyrazines responsible for the potatolike odor produced by some Serratia and Cedecea cultures were identified by gas-liquid chromatography (with flame ionization and thermoionic ionization detectors) and mass spectrometry. Alkylpyrazines were produced by the six strains studied irrespective of their odors. The major alkyl-methoxypyrazine produced by Cedecea davisae was 3-sec-butyl-2-methoxypyrazine, and that produced by odoriferous Serratia strains (S. rubidaea, S. odorifera, and S. ficaria) was 3-isopropyl-2-methoxy-5-methyl-pyrazine. Other pyrazines produced by some strains were 3-isopropyl-2-methoxypyrazine, 3-isobutyl-2-methoxypyrazine, 3-sec-butyl-2-methoxy-5-methylpyrazine, and 3-isobutyl-2-methoxy-6-methylpyrazine. Some of these pyrazines had not previously been found as natural products or to be produced by bacteria.     

Aroma Components Characteristic of Spring Green Tea

To investigate the aroma components characteristic of spring green tea, analysis of the aroma concentrates of green tea and fresh tea-leaves was accomplished. The research on the changes in aroma constituents of spring green tea and the aroma concentrate from fresh tea-leaves during storage, showed that cis-3-hexenylhexanoate and cis-3-hexenyl-trans-2-hexenoate contributed to the typical fresh aroma of spring green tea. Twelve isomers of hexenol esters were synthesized for comparison of the fresh green note.     

Dietary supplementation of a high-temperature-processed green tea extract attenuates cognitive impairment in PS2 and Tg2576 mice

ABSTRACT

Green tea intake is generally recognized as an effective supplement that promotes mental clarity and cognitive function. These health benefits of green tea have been attributed mainly to its effective component, epigallocatechin gallate (EGCG). Because various catechin derivatives potently enhance these health benefits, we manipulated the extraction process with a high-temperature intervention. High-temperature-processed green tea extract (HTP-GTE) showed an elevated proportion of gallocatechin gallate (GCG) content. To investigate the preventive effects of HTP-GTE on cognitive decline, we found its neuroprotective effects against amyloid β (Aβ)-induced neurotoxicity in neurons and clarified that GCG significantly inhibited Aβ aggregation in vitro. Moreover, we showed that HTP-GTE intake attenuated several cognitive-decline phenotypes in a model mouse of Alzheimer’s disease. These beneficial effects of HTP-GTE against cognitive decline were due to the distinctive composition of the extract and suggest the possibility that HTP-GTE supplementation could attenuate cognitive decline of Alzheimer’s disease.     

Application of a new high-performance liquid chromatographic method for measuring selected polyphenols in human plasma

We developed a method to measure plasma levels of selected polyphenols before and after ingestion of green tea. Blood samples were obtained from four healthy women before and 30 and 50 min after the ingestion of 300 ml of green tea infusion. A 1-ml volume of plasma was hydrolysed with 0.5 M HCl-methanol (1:1, v/v) for 30 min at room temperature, extracted with ethyl acetate and separated by reversed-phase chromatography. Polyphenols were identified on the basis of their retention times and by spectrum analysis. Green tea caffeine has the same retention times as caffeic acid. Consumption of green tea produces a notable increase in the plasma levels of caffeine plus caffeic acid and the appearance of measurable levels of epigallocatechingallate. In conclusion, the method was found to have the requisite features of specificity and sensitivity for monitoring plasma levels of selected tea polyphenols.     

Stereocontrolled Synthesis of Pyridazine,Pyrazine, and Triazine 2′-DEOXY-β-Nucleosides by Means of Intramolecular Glycosylation

Abstract

The stereocontrolled synthesis of 2′-deoxynucleoside analogs was explored by intramolecular glycosylation of pyridazine, pyrazines and triazines. These heterocycles were temporarily connected to the 5-O position in 1-thioglycoside via ethereal linkage.     

Effects of green tea consumption on human fecal microbiota with special reference to Bifidobacterium species

Green tea is one of the most popular beverages in the world. Its beneficial health effects and components have been extensively reviewed. However, little is known about the influence of green tea consumption on the human intestinal microbiota (HIM), which plays a crucial role in human health. Ten volunteers who did not usually consume green tea, drank it for 10 days and then stopped drinking it for 7 days. Their fecal samples were collected at three time points: before beginning the 10‐day green‐tea regime, at the conclusion of that 10 days, and 7 days after stopping the regime. Their fecal samples were analyzed by terminal restriction fragment length polymorphism with specific primer‐restriction enzyme systems for HIM and by using a real‐time PCR method for the Bifidobacterium species. Although the HIM of each subject was relatively stable, the proportion of Bifidobacterium species played an important role in the classification of their fecal microbiota. Although there were inter‐individual differences in the Bifidobacterium species, an overall tendency for the proportion of bifidobacteria to increase because of green tea consumption was noted. However, little change was observed in the composition of Bifidobacterium species in each sample. This suggests that the change in proportion was induced, not by an inter‐species transition, but by an intra‐species increase and/or decrease. In conclusion, green tea consumption might act as a prebiotic and improve the colon environment by increasing the proportion of the Bifidobacterium species.