Chemical Constituents of Pu-erh Tea and Its Inhibition Effect on α-amylase in vitro

[Objective]The aim was to clarify the chemical substance basis of hypoglycemic and lipid-lowering effects of Pu-erh Tea. [Method]Pu-erh Tea was extracted with 95% ethanol,followed by petroleum ether,chloroform,ethyl acetate and n-butanol extraction,after the further purification and through the NKA-9 macroporous resin and many times of Sephadex column chromatography,two compounds were isolated,in the same time,the effect of Uracil and Gallic acid on α-amylase was studied. [Result]The Uracil and Gallic acid were isolated and identified respectively from Pu-erh Tea and the Uracil was firstly isolated from Pu-erh Tea; Gallic acid had strong inhibition on α-amylase. [Conclusion]It could provide some theories on the hypoglycemic and lipid-lowering effects of Pu-erh Tea.

Study on Pu-erh Tea Methanol Extracts on Antibacterial Activity of Several Plant Pathogens

[Objective] The aim was to study Pu-erh tea methanol extracts on antibacterial activity of several plant pathogens and provide reference for application of Pu-erh tea in agriculture disease prevention and control.[Method]The inhibitive effect of Pu-erh tea methanol extracts on several plant pathogens was studied by adopting mycelium growth rate method.[Result] The results showed that Pu-erh tea methanol extracts had inhibitive effects on Thanatephorus cucomeris(Frank)Donk,Fusarium oxysporum f.sp.niveum,Fusa...

Analysis of α-amylase Inhibitor Content Change in Pu-erh Tea During Pile-fermentation Process

The study was to investigate the changes of α-amylase inhibitor content in Pu-erh tea during pile-fermentation process. Pu-erh tea samples from two regions of Shuangjiang County and Jinggu Dai and Yi Autonomous County of Yunnan Province at various fermentation stages were used as experimental materials to investigate the effect of different fermentation stages on the inhibitory effect to α-amylase; and the change law of the inhibitory effect of c-amylase inhibitor during processing was meanwhile studied by determining the contents of tea polyphenol and amino acid. The results showed that crude meterial of Pu-erh tea presented strong inhibitory effect to α-amylase; this inhibitory effect assumed a de： creasing trend to the minimum at the middle stage of fermentation, whereafter it increased to some extent. Made tea also showed a strong inhibitory effect to α-amylase. During whole processing period, contents of tea polyphenol and amino acid generally assumed a remarkably decreasing trend. Our results provided references for further isolating co-amylase inhibitor from Pu-erh tea and discussing the mechanism of its health care function.

Factors Influencing the Effects of Theabrownin in Pu-erh Tea on Scavenging DPPH Radicals

[Objective] This study aimed to explore factors influencing the effects of theabrownin in Pu-erh tea on scavenging DPPH radicals. [Method] Taking Pu-erh tea as main research object, theabrownin in Pu-erh tea from tea piles with different times of mixture, stored for different years and processed by both the old and new techniques were extracted and isolated. And DPPH method was used to study the effects of theabrownin solution and tea liquor on scavenging radicals and their antioxidant activity. [Result] The result showed that the theabrownin content in Pu-erh tea from tea piles with one to four times of mixture revealed a first declining and subsequently rising trend. Under different pH conditions, the rates of DPPH radical scavenging of 1 mg/ml theabrownin solution made from tea piles with different times of mixture decreased gradually with the increase of pH, and all the rates were lower than that of the control vitamin C solution; the rates of DPPH radical scavenging of theabrownin from tea samples stored for different years and produced by different techniques dropped slowly within pH range 3.0-6.0; when pH was higher than 6.0, the rates of DPPH radical scavenging of theabrownin from tea samples produced by both new and traditional techniques in 2001 declined obviously, while the declining trend was not obvious in either the black tea or the Pu-erh tea produced by new technique in 2005. Under different theabrownin concentrations, the rates of DPPH radical scavenging of theabrownin solution made from tea piles with different times of mixture ascended as the concentration increased and the highest rate occurred in tea pile with four times of mixture, reaching up to 46.56%±0.88%; for tea samples stored for different years and produced by different techniques, the rates of DPPH radical scavenging of theabrownin rose gradually with the increase of the theabrownin concentration; the rate of radical scavenging of theabrownin in the black tea ascended obviously and that in Pu-erh tea was decreasing within the concentration range of 0.04 -0.06 mg/ml. At pH6.0, the DPPH radical scavenging ability of theabrownin in 0.1 mg/ml theabrownin solution and tea liquor containing 0.1mg/ml theabrownin from tea piles with different times of mixture ascended with the time of mixture; solution made from tea samples produced by different techniques in different years, the DPPH radical scavenging ability of theabrownin solution and tea liquor followed： Pu-erh tea produced by the new technique in 2001 ﹥ Pu-erh tea produced by the old technique in 2001﹥ Pu-erh tea produced by the new technique in 2005. And the DPPH radical scavenging ability of theabrownin in tea liquor containing 0.1 mg/ml theabrownin was higher than that in 0.1 mg/ml theabrownin Solution made from tea samples either with different times of mixture or produced by different techniques in different years. The above results indicated that many factor influenced the effects of theabrownin on eliminating DPPH radicals, including the time of fermentation, fermentation technique, years of storage, concentration and pH all had great influence on the effects of theabrownin on eliminating radicals. To ensure a good effect on scavenging radicals, it is better to prepare theabrownin at pH6.0 with concentration between 0.08 and 0.1 mg/ml for drinking. [Conclusion] Results of this study provide a basis for developing functional products of theabrownin from Pu-erh tea in the future.

Analysis of Monosaccharide Composition of Pu-erh Tea Polysaccaride by Pre-column Derivatization HPLC

[Objective] This study aimed to establish a pre-column derivatization HPLC method for the identification and analysis of monosaccharide composition of Pu-erh tea polysaccharide. [Method] Pu-erh tea polysaccharide was extracted using the wa- ter extraction method, further isolated and purified by DEAE cellulose-52 columns. The obtained tea polysaccharide and four components TPS1, TPS2, TPS3 and TPS, were first derived by 1-phenyl-3-methyl-5-pyrazolone （PMP）, and then the PMP derivatives of monosaccharide were analyzed by high performance liquid chromatog- raphy （HPLC）. [Result] Pu-erh tea polysaccharide contained eight kinds of monosac- chaddes （mannose, rhamnose, glucuronic acid, galacturonic acid, grucose, galactose, arabinose, fucose）, without xylose; so it was the same with TPS1; each of TPS2, TPS3 and TPS4 contained seven monosaccharides, while no fucose. [Conclusion] This method is simplified and rapid, which can be used to determine the monosac- charide composition of Pu-erh tea polysaccharide and monosaccharide content.

Characterization of aroma compounds of Pu-erh ripen tea using solvent assisted flavor evaporation coupled with gas chromatography-mass spectrometry and gas chromatography-olfactometry

Pu-erh ripen tea becomes popular worldwide owing to its unique taste and aroma.In the present study,volatile compounds from Pu-erh ripen tea were extracted using a solvent assisted flavor evaporation(SAFE)and analyzed with a gas chromatography-mass spectrometry(GC-MS)and a gas chromatography olfactometry(GC-O).Results demonstrated that 58 major volatile compounds and 24 aroma active substances of Pu-erh ripen tea were identified by GC-MS and GC-O analysis.Among volatile compounds identified,methoxyphenyl compounds were considered as the dominate compounds in the aroma of Pu-erh ripen tea.Further investigation showed that 6 methoxybenzenes were responsible for the aging aroma in Pu-erh ripen tea;α-ionone,3,4-dimethoxytoluene,1,3-dimethoxybenzene,etc.were responsible for the wood-like aroma.Linalool,α-terpineol,α-ionone,β-ionone,and benzeneacetaldehyde were responsible for the floral odor.Compared the odor detection threshold(ODT)among the 8 methoxyphenyl compounds in water,1,2,3-trimethoxybenzene showed the highest ODT,followed by 3,4-dimethoxyphenol.1,3-dimethoxybenzene(105μg/L)and 1,2,3-trimethoxy-5-methylbenzene(100μg/L)were present at relatively low odor threshold values.The result indicated that methoxyphenyl compounds play a vital role in the unique flavor of Pu-erh ripen tea.

Reducing oxidative stress and hepatoprotective effect of water extracts from Pu-erh tea on rats with high-fat diet

Reducing oxidative stress and hepatoprotective effect of Pu-erh tea water extracts on rats fed with high-fat diet were researched for explaining health care of Pu-erh tea.Fifty SD rats were divided into five groups.The body weight was measured once a day.The malondialdehyde(MDA)and glucose(Glu)levels and the activities of alanine aminotransferase(ALT),aspartate aminotransferase(AST),nitric oxide synthase(NOS),and pyruvate kinase(PK)in serum were determined.Furthermore,the hepatic glycogen level(HGL)and the activities of hepatic total superoxide dismutase(T-SOD),catalase(CAT),and glutathione peroxidase(GSH-Px)were also measured after continuous administration for 12 weeks.The result demonstrated that Pu-erh extract caused the decreases in body weight,fat index,MDA and NOS levels,and the increases in hepatic T-SOD,CAT and GSH-Px activities,indicating that the extract may be due to inhibiting the increases of body weight and fat index,reducing oxidant stress state and inhibiting lipid peroxidation,thus decreasing the activities of ALT and AST,and protecting the liver in rat.Meanwhile,the extracts could increase the production of hepatic glycogen and the activity of PK,and reduce glucose level,protecting the liver from the diseases associated with type II diabetes.

Detection of composition of functional component theabrownins in Pu-erh tea by degradation method

Habitual tea consumption can reduce the risk of ASCVD morbidity and mortality and all-cause mortality in China,and long-term adherence to this habit can provide greater protection.Pu-erh tea is one of the representatives of post-fermented teas,and the polymers in Pu-erh tea have anti-cancer and anti-hyperlipidemic activities,but their chemical composition is still unknown.In this study,the chemical composition of Pu-erh tea was investigated in detail and eight(1–8)known compounds were isolated.The polymers in Pu-erh tea were also degraded by thiol degradation,and the fragments of quercetin and(–)-epicatechin-3-O-gallate were found in the thiol degradation products of Pu-erh tea polymers by UPLC observation and separation and purification.This is the first time that this fragment was obtained in Pu-erh tea polymer.

Inhibitory Effects of Pu-erh Tea Leaves on Mouse Type IV Allergy

Pu-erh tea is one of post fermented tea manufactured through oxidative maturing by microorganisms. We investigated the preventive effects of pu-erh tea extract on oxazolone-induced type IV allergy in male (ICR) mice. Oral administration of 50 mg/kg water extract of pu-erh tea leaves resulted in significant preventive effects against mouse type IV allergy. The hydrophilic Theabrownin-like fraction (TBW-ND), with a high molecular weight of approximately 12,000 or higher, was prepared from pu-erh tea leaves by a solvent-extraction method, followed by Diaion HP-20 column chro-matography and dialysis. Oral and percutaneous administrations of TBW-ND at doses of 18.7 mg/kg and 0.037 mg/ear also resulted in significant preventive effects, which included preventing increases in levels of the proinflam-matory cytokine interleukin-12. The anti-allergic ingredients in TBW-ND were predicted to be highly complex compounds containing of polyphenols, polysaccharides and/or proteins. The results suggest pu-erh tea leaves could be a beneficial food for protecting against delayed-type allergy.

Anti-Obesity, Anti-Atherosclerotic and Anti-Oxidant Effects of Pu-Erh Tea on a High Fat Diet-Induced Obese Rat Model

Pu-erh tea, a traditional Chinese beverage, has been believed to have many benefits to human health and without side effects. In this study, we systematically analyzed the main active components of Pu-erh tea and investigated its anti-obesity, anti-atherosclerotic and anti-oxidant effects using an obese rat model. Obesity was induced by feeding a high-fat diet and subsequently the experimental obese mice were fed with high-fat diet supplemented with low (2.5%), medium (5%) or high (7.5%) doses of Pu-erh tea powder for 6 weeks respectively. As result, the body weight gain of the rats was decreased by medium and high doses of Pu-erh tea treatments. Furthermore, the levels of serum total cholesterol (TC), triglyceride (TG) and atherosclerosis index (AI) were significantly lowered by Pu-erh tea compared to the control group. Conversely, high density lipoproteincholesterol (HDL-C) level of the rats was significantly elevated by Pu-erh tea treatments. In addition, Pu-erh tea treatments increased the activities of anti-oxidative enzymes such as superoxide dismutase (SOD) and glutathione peroxides (GSH-Px), whereas reduced the level of lipid peroxidation product malondialdehyde (MDA) in obese rats. Collectively, our find-ings revealed that Pu-erh tea exerts comprehensive benefits in anti-obesity, anti-atherosclerotic and anti-oxidant effects, therefore can be used as a promising functional food in obesity management.

Pu-erh tea: A review of a healthful brew

Pu-erh tea has been used for thousands of years to treat metabolic diseases.Recognized in Shen Nong's Herbal Classic,a compendium kept by the first traditional Chinese practitioners,it is still highly valued for its hypocholesterolemic and hypolipidemic effects.This review reports the processing and bioactive components of pu-erh tea.Recent human and animal studies of pu-erh tea and its potential therapeutic mechanisms have also been summarized.The interaction of liver and gut microbiome regulates the puerh tea biotransformation and endogenous metabolism,and thus contributes to the health benefits.

超声波辅助定量卤制对茶香味卤煮牛肉品质的影响

为探究超声波辅助定量卤制对茶香味配方的牛肉品质的影响,本文设置不同超声功率(0、600、800、1000、1200 W)辅助定量煮制方法卤制茶香味牛肉,测定了牛肉的出品率、肉色、质构、电子鼻、游离氨基酸以及呈味核苷酸等。结果表明,超声波辅助定量卤制可以提高茶香味卤制牛肉的出品率,其中800 W的超声功率处理的牛肉出品率达到80.77%,且改善了卤制牛肉的质构特性,对卤牛肉的a^(*)值和b^(*)值无显著影响(P>0.05)。当超声功率大于800 W时会使卤牛肉的a^(*)值和L^(*)值显著减少,b^(*)值显著增加(P<0.05)。此外,电子鼻的主成分分析表明超声处理和未经超声处理之间的香气风味存在差异,不同功率处理组的茶香味卤煮牛肉风味也各有特色。不同超声功率处理卤牛肉中甘氨酸含量随超声功率的增加整体上呈先降低后增加趋势,精氨酸随超声功率的增加呈先上升后下降的趋势,且在1000 W时达到最大值。超声处理对茶香味卤煮牛肉的呈味核苷酸含量存在显著影响(P<0.05),尤其是肌苷含量在800 W时达到了最大值。另外,800 W超声处理组的感官评价得分也高于其他组别。综上,在超声波功率800 W时,定量卤制的茶香味卤牛肉具有最好的品质。

氧化型粗茶褐素制备工艺优化及其抗氧化活性分析

以普洱生茶为原料制备氧化型粗茶褐素。以茶褐素含量为指标,在单因素试验基础上通过正交试验优化氧化型粗茶褐素的制备工艺,并与熟茶水提物对比分析其抗氧化活性。结果表明:氧化型粗茶褐素的最佳制备工艺为料液比1∶20(g/mL)、pH 8.5、通气时间14 h,在此条件下制得的氧化型粗茶褐素中茶褐素含量为77.12%。抗氧化试验结果表明,氧化型粗茶褐素与熟茶水提物的抗氧化能力相近,均具有较好的抗氧化活性。

Development of the fingerprints of crude Pu-erh tea and ripened Pu-erh tea by high-performance liquid chromatography

A simple and accurate high-performance liquid chromatography（HPLC）method to generate the fingerprints of crude Pu-erh tea（CPT）and ripened Pu-erh tea（RPT）is described.A suitable chromatographic system was established using a linear gradient elution with acetonitrile and water containing 0.6% formic acid as the mobile phase and a detection wavelength of 300 nm.HPLC analysis identified 24 common peaks among RPT and 21 common peaks among CPT.This study revealed that crude Pu-erh tea and ripened Pu-erh tea contained some similar major constituents,but with distinctive peaks,which may be caused by the difference in the fermentation process.This HPLC fingerprint method could be used to evaluate and authenticate crude Pu-erh tea and ripened Pu-erh tea.

Influence of the post-fermentation by four Aspergillus strains on the aroma of pu-erh tea

Aroma is one of the most important factors for the flavor, taste, and quality of pu-erh tea, and the post-fermentation process has an important influence on the aroma of pu-erh tea. In the present study, the influence of fungi fermentation on the flavor of pu-erh tea was investigated and compared. Volatile compounds from pu-erh tea fermented by four Aspergillus strains, including A. niger, A. oryzae, /1. awamori, and A. glaueus, were extracted and analyzed using ultrasound-assisted extraction-dispersive liquid-liquid microextraction-gas chromatography-mass spectrometry （UAE-DLLME-GC-MS）, and a total of 63 volatile compounds were identified. In comparison with the sun-dried green tea, fermented pu-erh tea contained high levels of methoxyphenolic compounds, such as 1,2,3-trimethoxybenzene, which was the most abundant one. Our results confirmed that the characteristic methoxyphenolic compounds were produced by the activity of Aspergillus during the post-fermentation process, and A. niger and A. awamori were the most important strains for the formation of aroma quality of pu-erh tea.

茶多酚在卤肉制品保鲜中的应用

为了研究茶多酚对卤肉制品冷藏过程中品质变化的影响,将经卤制、添加茶多酚(0.6g/kg)、真空包装、灭菌的自制卤肉制品于4℃贮藏,定期测定其pH值、菌落总数、挥发性盐基氮(TVB-N)、过氧化值(POV)、二苯基苦味肼基自由基(DPPH.)清除率和感官评价指标,以不添加茶多酚作为对照组。结果表明,试验组各个指标都低于对照组,即茶多酚能够明显降低贮藏期间卤肉制品的pH值、TVB-N值、POV值,抑制细菌生长繁殖,使感官品质的下降减缓,有效清除DPPH.。茶多酚对于冷藏卤肉制品具有良好的抗氧化和抑菌作用,可应用于卤肉制品的保鲜。

煮制时间与二次煮制对紫娟普洱茶抗氧化性的影响

分析不同煮制时间以及二次煮制对紫娟普洱茶中主要活性成分浸出情况的影响。测定茶汤的总花青素、总酚及总黄酮等抗氧化成分含量,分析茶汤的·OH清除能力、DPPH自由基清除能力、总抗氧化性、还原能力与这些抗氧化成分的相关性。结果表明,紫娟普洱茶汤中的抗氧化成分随煮制时间延长而增加,第一次煮制7min后,各活性成分总含量的增加大多趋于平缓;第二次煮制后,各类活性成分总含量下降显著(p<0.05)。紫娟普洱茶汤的·OH清除能力、总抗氧化性与其活性成分含量呈线性正相关,且与总花青素、总酚含量的相关性更加明显(R2>0.8)。

茶多酚和维生素C对腌制猪肉亚硝酸盐残留量和脂肪氧化的影响

以腌制猪肉模型为材料,研究不同含量的茶多酚和维生素C对色泽、残留亚硝酸盐含量以及脂肪氧化TBARS值的影响。结果表明,茶多酚和维生素C都在一定程度上降低了腌制模型中亚硝酸钠的残留量,维生素C的作用效果要显著强于茶多酚(p<0.05)。腌制过程中TBARS值呈逐渐增加的趋势,茶多酚和维生素C有降低TBARS值的作用,茶多酚的作用效果要强于维生素C。在腌制过程中,维生素C组的色泽显著高于茶多酚组(p<0.05),而蒸煮后各组之间色泽差异不显著(p>0.05)。

广东省居民饮用凉茶及煲汤与鼻咽癌发病关系的流行病学研究

目的:探讨在广东鼻咽癌高发地区居民饮用凉茶及煲汤与鼻咽癌发病的关系,为制定高发区鼻咽癌预防措施提供依据。方法:选取广东肇庆地区在2010年至2013年新诊断的1 245例鼻咽癌为病例组。并按照居住地、性别、年龄为匹配条件,选取同时期1 293名健康对照。开展包括饮用凉茶及煲汤在内的生活饮食习惯的问卷调查。采用单因素以及多因素Logistic回归分析,计算各生活环境因素与鼻咽癌发病风险的比值比(odds ratio,OR)。结果:凉茶与煲汤与鼻咽癌的发病风险呈负相关。与不饮用凉茶人群相比,每年饮用凉茶与每月饮用凉茶的人群其发病风险均降低,OR值分别为0.65和0.74;与不煲汤的人群相比,煲汤频率为每月一次以及每周一次时,其OR分别为0.55与0.51,P<0.05。进一步对30种煲汤常用中药材进行调查,发现有7种具有保护作用,其中中药花旗参的保护作用最明显,其OR=0.18, 95%CI:0.05～0.73。结论:广东地区居民经常饮用凉茶及煲汤可降低鼻咽癌的发病风险,煲汤中的部分中药材的使用可能成为预防鼻咽癌的有效措施。

普洱熟茶中黄酮醇类物质杨梅素、槲皮素和山奈酚的分离纯化

本文以云南普洱熟茶为实验材料,以不同浓度乙醇水溶液为洗脱液,利用MCI GEL CHP 20P（75~150μm）树脂色谱柱和SephadexTMLH-20葡聚糖凝胶色谱柱,并结合高效液相色谱（HPLC）法,对普洱熟茶中主要黄酮醇类物质进行了分离和定性。结果表明：普洱熟茶提取液浓缩后过MCI GEL CHP 20P（75~150μm）树脂色谱柱,经不同浓度（10%,30%,50%,70%,90%）乙醇溶液洗脱分离后,将获得的70%和90%的洗脱液过SephadexTMLH-20葡聚糖凝胶色谱柱,70%的洗脱液经90%乙醇溶液洗脱分别获得了HPLC纯度为96.0%的杨梅素和HPLC纯度为98.5%的槲皮素;90%的洗脱液经70%的乙醇溶液洗脱获得了HPLC纯度为95.6%的山奈酚。