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.

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.

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.

三种植物提取物对Ⅱ型糖尿病小鼠糖脂代谢改善作用研究

通过建立Ⅱ型糖尿病小鼠模型,以血糖值的变化确定南瓜多糖、葛根黄酮、普洱茶褐素提取物降血糖的最佳剂量。在该基础上,通过对其空腹血糖值(FBG)、胰岛素(INS)、甘油三酯(TG)、胆固醇(TC)、高密度脂蛋白(HDL)、低密度脂蛋白(LDL)的测定,表明3种提取物单一组分及两两联合对Ⅱ型糖尿病小鼠糖脂代谢紊乱均有明显的改善作用,在FBG、INS、IR、HDL、LDL指标上联合组显著优于单一组分(P<0.05)。析因分析结果表明,当3种物质两两联合时具有交互作用;协同试验发现,南瓜多糖与葛根黄酮联合或与茶褐素联合在降低TG含量上均与多糖组差异显著(P<0.05);茶褐素与葛根黄酮联合在降低FBG、TC、LDL含量上效果显著优于黄酮组,在TG、INS方面效果显著优于茶褐素组和黄酮组(P<0.05)。分子机制试验表明,3种物质单一组分和两两联合在PI3K/Akt蛋白通路表达方面均有增强作用。

3种植物活性成分联合改善2型糖尿病小鼠氧化应激效果研究

建立2型糖尿病小鼠模型,测定FBG、TG、TC、HDL、LDL、INS、FFA、MDA、ROS等,分析南瓜多糖、葛根黄酮、普洱茶褐素提取物单一及联合对糖脂代谢和氧化应激的作用效果及氧化应激与糖脂代谢的相关性。研究表明提取物单一及联合干预均对糖脂代谢和氧化应激指标有显著的改善(P<0.05)。其中多糖与黄酮联合组对改善FFA、MDA的效果显著优于多糖组、黄酮组,对改善TG的效果显著优于多糖组(P<0.05);多糖与茶褐素联合组较多糖组可显著降低TG、LDL、INS的水平(P<0.05);茶褐素与黄酮联合组对TG、TC、LDL、FBG、INS、FFA的作用效果显著优于黄酮组,对TG的作用效果显著优于茶褐素组(P<0.05)。利用主成分分析可知,联合与单一成分在改善糖、脂代谢及氧化应激指标上权重贡献率不尽相同,说明其作用机制的靶点和通路存在差异性。同时,通过线性相关分析法可知氧化应激与糖脂代谢具有极显著的正相关关系,提取物对T2DM小鼠糖脂代谢的改善与降低氧化应激水平有关。

红碎茶发酵过程中多酚类物质含量变化的研究

用云南大叶群体种作材料,控制在一定温湿度等环境条件下,用仿制C. T. C揉切机切碎。每隔20min取一次发醇叶烘干,然后对不同处理的茶样进行生化测定,测定出茶多酚(多酚类化合物)总量、儿茶素的总量都是随着发酵时间的延长而逐渐减少,儿茶素的次级氧化产物茶黄素(TF)、茶红素(TR)的含量是随着发酵时间延长而逐渐增加,当含量积累到高峰期时,又随着发酵时间的延长而降低。茶红素含量高峰期后于茶黄素。茶褐素(TB)的含量是随着发酵时间的廷长而逐渐增加,从茶化分析结合感官审评的结果,温度在22～26℃,相对湿度在90％以上,发醇时间在80min左右,制出的红碎茶品质最好。

An overview of Pu-erh tea and its health-promoting effects of lipid-lowering and anti-obesity

As a dark tea,Pu-erh tea(PET)is produced from sun-dried leaves of Camellia sinensis var.assamica mainly in Yunnan Province of China.Many microorganisms are involved in the fermentation of PET.Among them,Aspergillus niger is most important.It is believed that the longer the preservation period,the better is the quality and taste of PET,which is commercially available as loose,compressed or instant tea leaves.Chemical components of PET include flavones,flavanols,flavonols,phenolic acids,alkaloids and methylxanthines.In this overview,the lipid-lowering and anti-obesity effects of PET were discussed based on animal models and human trials,and our study provided some insights into possible mechanisms of bioactive compounds,such as theabrownin,catechins,lovastatin and gallic acid.Other bioactivities of PET and some information on Fuzhuan brick tea were also included.Sources of information cited were from Google Scholar,Pub Med,Pub Med Central,Science Direct,J-Stage,Pub Chem,Directory of Open Access Journals(DOAJ),and China National Knowledge Infrastructure(CNKI).

Flavanols from the Camellia sinensis var.assamica and their hypoglycemic and hypolipidemic activities

α-Glucosidase and lipase inhibitors play important roles in the treatment of hyperglycaemia and dyslipidemia. To identify novel naturally occurring inhibitors, a bioactivity-guided phytochemical research was performed on the pu-erh tea. One new flavanol, named(–)-epicatechin-3-O-(Z)-coumarate(1), and 16 known analogs(2–17) were isolated from the aqueous extract of the pu-erh tea. Their structures were determined by spectroscopic and chemical methods. Furthermore, the water extract of pu-erh tea and its fractions exhibited inhibitory activities against α-glucosidases and lipases in vitro;compound 15 showed moderate inhibitory effect against sucrase with an IC_(50) value of 32.5 μmol/L and significant inhibitory effect against maltase with an IC_(50) value of 1.3 μmol/L. Compounds 8, 10, 11 and15 displayed moderate activity against a lipase with IC_(50) values of 16.0, 13.6, 19.8, and 13.3 μmol/L,respectively.