Journal of Tea Science

Biochemical and Molecular Biological Basis on The Anticarcinogenic Activity of Tea Polyphenolic Compounds

CHEN Zong-mao

Journal of Tea Science. 2003, 23(2): 83-93. doi:10.13305/j.cnki.jts.2003.02.001

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The progress in the investigation of anticarcinogenic activity of tea polyphenols and its biochemical and molecular biological mechanisms in the world in recent 5 years were analyzed and reviewed in this paper. The mechanism of anticarcinogenic activity was discussed from the following 5 aspects: antioxidative activity, modulation on the key enzymes, blockage of signal transduction, antiangiogenic activity and the apotopsis of cancer cells. The developmental prospect and the investigational tendency of tea polyphenols in the future were discussed.

Research Progress on Resistance Breeding of Tea Plant

WANG Xin-chao，YANG Ya-jun

Journal of Tea Science. 2003, 23(2): 94-98. doi:10.13305/j.cnki.jts.2003.02.002

Abstract ( 442 )

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This paper summarized the progress of cold hardness resistance、drought resistance、resistance to disease and pest on tea breeding in china and abroad，and put forward some further research focal points on these aspects.

Synthesis and Characterization of Highly Pure Theanine

YAN Shou He, Jean-Pierre DUFOUR, Marc MEURENS

Journal of Tea Science. 2003, 23(2): 99-104. doi:10.13305/j.cnki.jts.2003.02.003

Abstract ( 612 )

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An improved synthesis method of L-Theanine, γ - glutamylethylamide was reported as the dehydratation of L-glutamic acid to pyrrolidone carboxylic acid (PCA), then PCA reaction with absolute ethylamine (99%, gas-liquid) with the yield of 92.6%. After re-crystallization in 84% ethanol solution the highest pure theanine (A type) is obtained with a yield of 37.4%. The crystals appear as tetra-rectangular prisms with a silk luster under transmission and scanning electron microscopy (TEM and SEM). The melting point of A theanine is 224°C. The B theanine synthesized from L-PCA shapes as cabbage leaves with curved borders under SEM and with a m. p. of 217 - 218°C as reference data. By using HPLC, it is confirmed that A and B theanine are mix-isomers. The A theanine consists of 47.9% L-theanine and the B theanine consists of 90.9% L-theanine. The rotation (α) of 100% L- theanine was + 8.57°.

Damage of Oxidant-stress and Effect of Epigallocatechin-3-gallate on Vero Cells in Vitro

HU Xiu-fang, CHAI Li-hong, YANG Xian-Qiang

Journal of Tea Science. 2003, 23(2): 105-109. doi:10.13305/j.cnki.jts.2003.02.004

Abstract ( 350 )

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This study was conducted to identify the protection of antioxidant--epigallocatechin-3-gallate(EGCG) to the renal damage by oxidant-stress. H₂O₂ and Cr⁶⁺ were used to induce apoptosis of renal cells-----Vero cells in vitro. With these models of cell apoptosis, the effect of EGCG on apoptosis was investigated through Staining and DNA electrophoresis. As the results, H₂O₂ and Cr⁶⁺ decreased the viability of Vero cells in a dose-dependent manner, and the IC₅₀ was 175.6 and 9.8 mg·L^- respectively. Both 50 mg·L^-1H₂O₂ and 400 mg·L^-/2h Cr⁶⁺caused the apoptosis of Vero cells. 40 mg·L^-EGCG markedly inhibited the apoptosis of Vero cells, and the effect was the same as that of Vc and EDTA in combination, indicating the simultaneous effect of antioxidation and chelating. So, EGCG protected Vero cells from damage through both ROS scavenging and ion-chelating, and this kind of effect is valuable to kidney usually exposed to ROS in clinic.

Effect of Catechin of Different Formulation on Serum Lipid Level in Mice

LIU Xiang-xin, LING Qin-lu, LIU Zikui, YIN Ping, TAN Chao

Journal of Tea Science. 2003, 23(2): 110-114. doi:10.13305/j.cnki.jts.2003.02.005

Abstract ( 334 )

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The effect of catechin in different formnlation and by various administration on serum lipid level in hyperlipidemic mice was conducted. Results shows Catechin in microcapsule formulation could significantly decrease TG, TC, LDL-C level and increase HDL-C level in hyperlipidemic mice. The effect of microcapsule types Catechin is better than free Catechin and i.v. administration is better than o.p.(P<0.05).

The Main Active Component of Lipophilic Tea Polyphenols and in vitro Inhibition Activity on Ovarian Cancer Cells HO-8910

CHEN Ping，ZHONG Jian-hua，SUN Dong

Journal of Tea Science. 2003, 23(2): 115-118. doi:10.13305/j.cnki.jts.2003.02.006

Abstract ( 338 )

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A single-substitution long-chain lipophilic catechin was isolated and purified from lipophilic tea polyphenols by high-speed countercurrent chromatography (HSCCC). Its molecular structure was elucidated as epigallocatechin-3-O-gallate-4'-palmitate by elemental analysis, IR, MS and 1H-NMR. The in vitro inhibition activity of the lipid-soluble epigallocatechin-3-O-gallate-4'-palmitate on ovarian cancer cells HO-8910 was investigated and compared with that of green tea polyphenols and lipophilic tea polyphenols. The results demonstrated that the inhibition activity of the single-substitution EGCG palmitate was almost corresponding to green tea polyphenols, and more effective than lipophilic tea polyphenols.

Effects of Tea Catechins on Lead-induced Lipid Peroxidation Damage in HepG2 Cells and Tea Polyphenol on the Content of Lead in Lead-exposed Mice

PIAO Zai-ri, Wang Yue-fei, YANG Xian-qiang, CHEN Liu-ji, YANG Yong, ZHAO Bao-lu, JIAO Hong-li, ZHOU Dang-yi

Journal of Tea Science. 2003, 23(2): 119-123. doi:10.13305/j.cnki.jts.2003.02.007

Abstract ( 340 )

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The effects of tea catechins on lead-induced lipid peroxidation damage in HepG2 cells and tea polyhenol on the content of lead in lead-exposed mice were investigated.HepG2 cell viability was determined using the MTT method,lipid peroxidation was assayed by detetmining the production rate of thibarbiturie acid reactive substance(TBARS)which was expressed as malondialdehyde(MDA)equivalents.The content of lead in lead-exposed mice was determined using hydride atomic fluorescence spectroscopic method. Results showed that tea catechins had protective effects on lead-exposed HepG2 cell viability and inhibitory effects on TBARS formation in HepG2 cells.All the indices of the mice in the exposed groups were significantly higher than those in the control.Tea polyphenol was able to accelerate the removal of lead from liver,but the same effects were not found in blood、kidney, brain and thigbones.

Chemiluminescence of Tea Polyphenols

YU Hai-ning, HONG Jun, SHEN Sheng-rong

Journal of Tea Science. 2003, 23(2): 124-128. doi:10.13305/j.cnki.jts.2003.02.008

Abstract ( 360 )

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The chemiluminescence of tea polyphenols was investigated under different concentrations, different pH value , and in the presence of different metal ions(Cu²⁺、Zn²⁺ or Fe²⁺) .Results showed that concentrations of tea polyphenols could not obviously affect their chemiluminescence intensity and the higher the pH value,the more the chemiluminescence intensity of tea polyphenols was; Cu²⁺ suppressed the photoactivities of tea polyphenols,but Fe²⁺ promoted it,and Zn²⁺ had no effects on their chemiluminescence。

Study on Literatures of Tea Medicine in China

ZHU Yong-xing, DENG Jun-qi

Journal of Tea Science. 2003, 23(2): 129-135. doi:10.13305/j.cnki.jts.2003.02.009

Abstract ( 432 )

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1060 tea medical literatures were collected from more than 7000 Chinese periodicals. These literatures were written by 653 authors (the first author) from 352 institutions, and were published in 399 periodicals. Cao Jin was the author who wrote the highest amounts of academic papers on tea medical thesis, the institution that possessed the highest amounts of such kind of papers was Zhejiang (Agricultural) University, and the periodical that published the highest amounts of such kind of papers was JOURNAL OF TEA SCIENCE. There are 13 kinds of components with medical values in tea. These components possess 7 kinds of effect concerning human health, such as anti-oxidation, metabolizing modulation, providing important nutrition etc, and by which tea was concerned to prevention and cure of more than twenty kinds of diseases such as diseases on liver, kidney, lung, tummy, the five sense organs and tumors. Following aspects were also statistically analyzed and discussed in the paper: the developing law and trend of tea medical literatures, the distribution and composition of authors, institutions and journals of which the literatures were published.

The Critical Control of Microbiological Sanitary Quality of Black Tea in the Course of Process

LI Ping, WAN Xiao-chun, XIA Tao

Journal of Tea Science. 2003, 23(2): 136-140. doi:10.13305/j.cnki.jts.2003.02.010

Abstract ( 321 )

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The microbiological sanitary quality of black tea is one of the main problems in exportation. In order to investigate the sanitary quality of black tea, the samples were random sampled during tea processing. The total number of bacteria, coliform most probable number (MPN) and total number of molds were analyzed so as to found out the critical control segment in the process of black tea and put forward the measure in improving the sanitary quality of black tea.

Acute Toxicity Evaluation of Pu’er Tea

LIU Qin-jin, CHEN Wen-pin, BAI Wen-xiang, LI Qing-ze

Journal of Tea Science. 2003, 23(2): 141-145. doi:10.13305/j.cnki.jts.2003.02.011

Abstract ( 306 )

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The acute toxicity of three kinds of typical Pu’er tea and one kind of baked green tea from Yunnan province were evaluated in this investigation. The tested mice were feed with tea infusion. The LD₅₀ of the three kinds of Pu’er Tea was 9.7βg/kg, 11.2 βg/kg and 12.2 βg/kg respectively, while that of the baked green tea was 7.5βg/kg. None of tested mice died 14 days later, when single feeding dose of four kinds of tea was less than 5βg/kg. Most tested mice showed excitement when the feeding dose less than 1/2 of LD₅₀. The tested mice revealed symptoms of restrained nervous 10 minutes late with the feed dose increased. There was only one peak of the acute lethal time in the case of Pu'er tea, and two peaks appeared in the case of baked green tea. The authors regarded that the death of tested mice was attributed to the high concentration of caffeine and polyphenols. It is concluded that all four kinds of tea are highly safe for drinking according to LD₅₀. However , scientific drinking methods should be mentioned first.

Genetic Diversity of Two Sexual Tea Cultivars Detected by RAPD Markers

LI Bin, YIN Yi, ZHOU Ying, DENG Pei-qing, YANG Hong-wei

Journal of Tea Science. 2003, 23(2): 146-150. doi:10.13305/j.cnki.jts.2003.02.012

Abstract ( 342 )

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RAPD markers analysis on the genome DNA of two sexual cultivars of Yunnadaye and Nankunshan maoyecha were studied by amplifying with 36 arbitrary 10-mer primers in order to defect the genetic diversity and relationship. Among the two sexual tea cultivars, 4382 loci were amplified, 109.55 loci per cultivars. In the total 315 DNA bands, 294 bands were polymorphic, the genetic diversity was 93.33%. It has been proved that Yunnadaye possess much higher genetic diversity than Nankunshan maoyecha on DNA molecular level. According to the cluster analysis, the two sexual cultivars might be divided into two groups by UPGMA method. 20 plants of Yunnadaye were classified as one group and 20 plants of Nankunshan maoyecha were classified as another group.

Study on the Frozen Storage of De-enzyming Leaf of Quality-tea

Wang Wen-jie

Journal of Tea Science. 2003, 23(2): 151-158. doi:10.13305/j.cnki.jts.2003.02.013

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The changes of main biochemical components and aroma in de-enzyming leaf of quality-tea were studied during its frozen storage. Results indicated that changes of its total amino acids and its tea polyphenols reached distinct or extremely distinct levels during the frozen storage. It is consistent with the changes of the biochemical components in made tea, but the changing speed, especially the tea polyphenols, is slower in de-enzyming leaf than in those in made tea. This expressed that the biochemical reaction within tea leaves is lower in de-enzyming leaf than that in made tea. After stored six months, the remaining percentage of aromas is 26.86% higher in de-enzyming leaf than those in made tea. The frozen storage of de-enzyming leaf is particularly favorable to the preserving of aromatic compounds. This probably related to a lot of the precursor of aroma was stored in de-enzyming leaf during the storage. The late processing of the frozen de-enzyming leaf, unfreezing for example, influenced the biochemical components and aroma of tea. Quick unfreezing with microwave is more favorable the tea quality.

Studies on Aroma Composition of Huangdan Fresh Shoots and Distribution of Its Aroma Precursor of Glucoside

MIAO AI-qing, JIANG He-yuan, LI Jia-xian, HU Hai-tao, HE Yu-mei, HAN Bao-yu

Journal of Tea Science. 2003, 23(2): 159-162. doi:10.13305/j.cnki.jts.2003.02.014

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The content of free essential oil in stems was higher than that in leaves and whole shoots of Huangdan cultivar. The detected amount in stems was 20.95 mg / kg, the amount in shoots was 12.42 mg / kg, whereas the amount in leaves was only 8.15 mg / kg. Furthermore, the detected amount of free alcohol in stems was 14.87 mg / kg, and was 3.46 and 5.65 times of that from shoots and leaves, respectively. The aroma components in tea shoots was the most, and thirty-six components were detected. And twenty-four and nineteen components were respectively identified in stems and leaves. The characteristic aroma profile of Chinese Oolong tea had been measured in the experimented fresh shoots, and the most of these components was contained in large amount in stems. The numeral distribution of bound aroma procuror of glucoside from stems, leaves and shoots were reversed to those of free aroma.

Study on the Status of Lead Content in Tea Gardens of Zhejiang Province

SHI Yuan-zhi, MA Li-feng, HAN Wen-yan, RUAN Jian-yun

Journal of Tea Science. 2003, 23(2): 163-166. doi:10.13305/j.cnki.jts.2003.02.015

Abstract ( 320 )

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The Lead content in tea leaves from main tea producing areas of Zhejiang Province and its affecting factors have been investigated. The results showed that the air deposit was one of the main sources for lead in tea leaves coming from. It could decrease the lead content to a certain extent when fresh leaves were washed. The lead contents in tea leaves had a significantly positive relationship with the available lead contents in the soil, therefore, reducing the available lead content in the soil would be one of the effective ways to reduce the lead content in tea leaves.

Properties of Rhizosphere Soil of Tea Plants and The Impact of Nitrogen Fertilizer

RUAN Jian-yun, MA Li-feng, SHI Yuan-zhi

Journal of Tea Science. 2003, 23(2): 167-170. doi:10.13305/j.cnki.jts.2003.02.016

Abstract ( 280 )

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The properties of rhizosphere soil of pot-cultured tea plants were investigated. The rhizosphere soil was collected by removing the soil adhering to plant roots and other soil was referred as bulk soil. N fertilization with NH₄⁺ (urea or (NH₄)₂SO₄) significantly reduced soil pH, the contents of exchangeable Ca, K, Mg and base saturation whereas raised extractable Al levels. Compared to bulk soil, rhizosphere soil showed lower pH, exchangeable Ca, Mg and base saturation but a higher exchangeable K. The contents of soil solution Al, exchangeable Al and absorbed hydroxy Al were much higher in the rhizosphere soil than those in the bulk soil. The results showed that the acidification of rhizosphere soil increased the availability of Al, which might be of importance for tea plants capable of taking up a large amount of Al.

Effect of Heat Sterilization and Storage on Quality Attributes of Fresh Green Tea Beverages

ZHANG Ling-yun, LIANG Yue-rong, SUN Qi-fu, SUN Qing-lei, LU Jian-liang, E.G. Mamati

Journal of Tea Science. 2003, 23(2): 171-176. doi:10.13305/j.cnki.jts.2003.02.017

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Effect of heat sterilization and storage on quality attributes of fresh green tea beverages was studied. The results showed that the lightness and greenness of the infusions decreased with the treatments of heat sterilization and storage whereas the yellowness increased. The concentration of tea polyphenols and amino acids did not correspondingly change with the colors, but the concentration of caffeine in the beverage decreased during storage. Among the major catechins, EGCG、ECG、EGC decreased, and GCG、CG、GC increased with heat sterilization and storage treatments. The changes in quality attributes of the different beverages could be due to variation in content of tea catechins, amino acid and caffeine.

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