Liupao Tea Research Articles

Dark tea extracts: Chemical constituents and modulatory effect on gastrointestinal function

Processing of dark tea varieties, such as Fu brick tea, Liupao tea, Qianliang tea, and Qing brick tea, includes solid-state fermentation involving microorganisms. In this study, we analyzed the major chemical constituents of dark tea extracts and evaluated their modulatory effect on the gastrointestinal function in normal mice, including the improvement of gastrointestinal transit and intestinal microbial, as well as the attenuation of intestinal microbial dysbiosis and intestinal pathological damage, and the adjustment of immune function in antibiotic-treated mice. Substantial differences in major chemical constituents, including total polyphenols, total organic acids, water extract content, 18 free amino acids, gallic acid, and six tea catechins, were observed among Fu brick tea, Qianliang tea, Qing brick tea, and Liupao tea extracts. Extracts from the four dark tea varieties significantly promoted gastrointestinal transit and colonization of beneficial Bifidobacterium and Lactobacillus, and inhibited the growth of harmful Escherichia coli and Enterococcus in normal mice. In addition, Qianliang tea, Qing brick tea, and Liupao tea extracts significantly accelerated the reversal of the ampicillin sodium-induced pathological damage in the ileum, intestinal bacterial dysbiosis (Bifidobacterium, Lactobacillus, E. coli, and Enterococcus), and low immunity.

Amount of Eurotium sp. in Chinese Liupao tea and its relationship with tea quality.

Eurotium sp. are the sexual states of the genus Aspergillus, and their ascospore is a spherical closed capsule with a golden colour. The growth of Eurotium sp. during tea production is a key step in achieving the unique quality of dark tea. This study aimed to evaluate the relationship between Eurotium sp. amount and Liupao tea quality. The amounts of Eurotium sp. in 26 differently aged Liupao tea samples from several factories were studied. Indicators related to the quality of Liupao tea were investigated. The amounts of Eurotium sp. were divided into 0, 105 and 106 levels, and quantitative real-time polymerase chain reaction (qPCR) was performed. Using ultrahigh-performance liquid chromatography and high-performance liquid chromatography, the amounts of emodin and physcion were determined to be closely related to the amount of Eurotium sp. Emodin was not found or occurred in minimal amounts in all raw Liupao tea samples. By contrast, physcion was found in Liupao tea at the 106 level of Eurotium sp. Liupao tea samples with varying levels of Eurotium sp. also exhibited evident differences in aroma and chromaticity. Result of the Pearson correlation test showed that the amount of Eurotium sp. plays a key role in creating the unique quality of Liupao tea. The amount of Eurotium sp. in dark tea detected via qPCR can be used as a quantitative quality indicator for evaluating dark tea. The present study provides an efficient method for identifying the different qualities of dark tea and addressing quality control issues in fermenting dark tea.

Preventive Effect of Liupao Tea Polyphenols on HCl/Ethanol-Induced Gastric Injury in Mice

Liupao tea is a traditional Chinese tea drink. The preventive effect of crude polyphenols in Liupao tea on HCl/ethanol-induced gastric injury was investigated in this study. After a model of gastric injury in mice was established, mouse serum and tissues were analyzed by biochemical and molecular biological methods. The results showed that Liupao tea polyphenols (LTPs) could effectively reduce the area of gastric mucosal lesions, decrease the volume of gastric juice, and increase the pH of gastric juice in mice with gastric injury. Observations of the pathology revealed that LTPs could alleviate cell necrosis and gastric mucosal injury in mice with gastric injury. The SOD activity and GSH level were decreased in mice after gastric injury, while the level of MDA was increased. LTPs could inhibit the changes caused by gastric injury and make the SOD activity, GSH, and MDA levels close to the normal levels. In addition, LTPs could upregulate the mRNA expression of Cu/Zn-SOD, Mn-SOD, CAT, nNOS, and eNOS and downregulate the expression of iNOS in the gastric tissue of mice with gastric injury. Therefore, LTPs can effectively prevent HCl/ethanol-induced gastric injury. HPLC analysis showed that LTP contains six bioactive substances of gallic acid, catechin, caffeine, epicatechin, epigallocatechin gallate, and epicatechin gallate, so the effect of LTP might mainly come from these six components. The effect of a high concentration of LTP is similar to that of ranitidine. LTPs represent a kind of active substance with a protective effect on gastric tissue.

六堡茶茶褐素对小鼠肠道菌群结构的影响

六堡茶茶褐素对小鼠肠道菌群结构的影响

Liupao tea extract alleviates diabetes mellitus and modulates gut microbiota in rats induced by streptozotocin and high-fat, high-sugar diet

Liupao tea, a popular dark tea, exhibited anti-diabetic activity in Chinese tea culture. However, the bioavailability of the main active components is low. Therefore, the relationship between the anti-diabetic activity and the modulation of gut microbiota was investigated in this study for the first time. Liupao tea extract (LTE) could significantly alleviate hyperglycemia, insulin-resistance, and plasma lipid profiles. The hypoglycemic effect of high-dose LTE was comparable to that of metformin. Importantly, LTE exhibited beneficial effect on modulating the diabetic-induced disorder of gut microbiota, such as increasing Bacteroidetes/Firmicutes ratio and up-regulating putative short-chain fatty acid (SCFA)-producing bacteria, including Prevotella and Bacteroides. Moreover, 29 key phylotypes were significantly correlated with at least one diabetic index. In conclusion, LTE could be developed into an anti-diabetic functional beverage and its beneficial effects is likely to be associated with the prebiotic effects for increasing the level of SCFAs and the relative abundance of SCFA-producing bacteria.

Liupao Tea Extract Alleviates Diabetes Mellitus and Modulates Gut Microbiota in Rats Induced by Streptozotocin and High‐fat, High‐sugar Diet

Liupao tea, a popular dark tea in China, has anti-diabetic activity in Chinese tea culture. However, the bioavailability of the main active components was low. Therefore, the relationship between the anti-diabetic activity of Liupao tea and the modulation of gut microbiota was investigated in this study for the first time. The chemical composition of Liupao tea extract (LTE) was profiled by UPLC/Q-TOF MS. The diabetic rats were treated with LTE for 6 weeks, and major diabetic indices were measured. Then, the gut microbiota were investigated on the sequencing analysis of 16S rRNA (V3+V4 regions). The contents of the short chain fatty acids (SCFAs) were determined with gas chromatography. The LTE could significantly alleviate hyperglycemia, insulin-resistance, and plasma lipid profiles. At the end of study, hypoglycemic effect of high-dose LTE was close to that of metformin. Importantly, LTE showed its beneficial effect on modulating the diabetic-induced disorder of gut microbiota, such as increasing Bacteroidetes/Firmicutes ratio and up-regulating some putative SCFA-producing bacteria, including Prevotella and Bacteroides. Moreover, 29 key phylotypes were significantly correlated with at least one diabetic index. In conclusion, the LTE could modulate the composition of gut microbiota and might be an anti-diabetic functional beverage by its role as a prebiotic for increasing SCFA-producing bacteria and SCFAs. Support or Funding Information This study was supported by the National Natural Science Foundation of China (No. 81773867). This abstract is from the Experimental Biology 2019 Meeting. There is no full text article associated with this abstract published in The FASEB Journal.

Citrinin produced using strains of Penicillium citrinum from Liupao tea

The ability of a strain to produce citrinin was analysed in the growth inhibition zone using HPLC and UHPLC–MS. A total of 12 Penicillium citrinum strains isolated from Liupao tea were inoculated onto tea leaves and their capability for citrinin production were studied using different water content (15–45%) and temperatures (15–40 °C). The results provided a theoretical base for the safe manufacture of Liupao tea. Five strains of P. citrinum produced a clear growth inhibition zone with diameters of 11–22 mm. The citrinin contents in the liquid cultures of the 12 strains of P. citrinum ranged from 0.03 to 14.5 μg/mL. The citrinin contents of the teas with initial water content of 15 and 25% and those inoculated with P. citrinum were below the limit of detection during the fermentation. The citrinin content of the teas with initial water contents of 35 and 45% at 25 °C increased rapidly at first and then decreased during the fermentation. Similarly, the citrinin contents of the teas at 15 and 25 °C rapidly increased and then decreased. Meanwhile, P. citrinum was unable to produce citrinin at 35 and 40 °C. The optimum conditions were 45% water and 25 °C, generating the highest citrinin yield of 181 ng/g, which was higher than the limit of 50 ng/g citrinin in red yeast rice that can cause harm to human health. The highest citrinin yield in tea fermented for 50 days was 34.8 ng/g for stored teas with proper conditions. Therefore, storing teas with a low water content and temperature can reduce the content of citrinin.

响应面分析法优化六堡茶茶多糖提取工艺的研究

响应面分析法优化六堡茶茶多糖提取工艺的研究

Polysaccharides from Chinese Liupao dark tea and their protective effect against hyperlipidemia

SummaryPolysaccharides‐rich dark tea is believed to be beneficial to health in Southeast Asian. However, the hypolipidemic effect of Chinese Liupao tea polysaccharides (CLTPS) has not been investigated. Here, the potential mechanism by which the oral administration of CLTPS affects lipid metabolism was evaluated using high‐fat diet‐induced hyperlipidemia rats. In rats supplemented with CLTPS, a suppressive effect on body weight was observed after 4 weeks of intervention. CLTPS significantly improved the levels of lipid profiles, the oxidation of lipids and antioxidant enzyme activity in a dose‐dependent manner. The cholesterol‐lowering action was paralleled by the stimulation of cholesterol converted to bile acids along with a 1.5‐fold increase in faecal excretion. Besides, the prolongation of coagulation factors and the reduction in fibrinogen content showed that CLTPS regulated the coagulation initiated through the intrinsic pathway. With current findings, CLTPS may be valuable as a natural hypolipidemic nutraceutical for human consumption.

Analyses of fungal community by Illumina MiSeq platforms and characterization of Eurotium species on Liupao tea, a distinctive post-fermented tea from China

Liupao tea is a distinctive Chinese dark tea obtained by indigenous tea fermentation facilitated by the symbiotic association of bacteria and fungi. The composition of fungal community in 4 Liupao tea samples stored for several years under natural microbial fermentation was evaluated by MiSeq sequencing. Taxonomic analysis revealed 3 phyla, 6 families, 8 genera. The genera Eurotium and Aspergillus were dominant fungi in almost all the samples. A total of 85 strains found in 41 other tea samples were species of Eurotium. amstelodami, Eurotium. niveoglaucum, Eurotium. repens, Eurotium. rubrum, Eurotium. tonophilum and Eurotium. cristatum by culture-dependent method. Of these species, E. repens, E. rubrum and E. tonophilum have not been previously associated with Liupao tea. This report is the first to reveal fungal flora composition using Illumina-based sequencing and provide useful information for relevant studies on the isolation of Eurotium species in Liupao tea. The predominant molds are Eurotium species, and the comparison of fungal diversity in dark teas is worth considering. The taxonomic analysis of the microbial community would also aid the further study of functional genes and metabolic pathways of Liupao tea fermentation.

New phenolic compounds from Camellia sinensis L. fermented leaves

Two new phenolic compounds (1 and 2, named as teasperol and teasperin, respectively) were isolated from fermented tea (Camellia sinensis L.) products, together with known phenolic compounds. Teasperol (1) was isolated from Chinese traditional post-fermented tea leaves (Liu-pao tea) and teasperin (2) was from a Japanese tea product which was selectively fermented with Aspergillus sp. The chemical structures of 1 and 2 were elucidated based on the analyses of their spectroscopic data.