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In this study, solid-phase microextraction (SPME) and comprehensive two-dimensional gas chromatography-quadrupole time-of-flight mass spectrometry (GC × GC-Q-TOF-MS) were used for the qualitative and quantitative determination of volatile components in dark tea samples, and the characteristic volatile components of jasmine dark tea were identified by multivariate statistical analysis and their regulatory effects on tea aroma were investigated. The results showed that the scenting process could coordinate the aroma characteristics of dark tea (such as aged, woody and smoky pine aroma), and endow dark tea with the aroma of jasmine, contributing to the aroma quality of jasmine dark tea that is defined as “fresh flowery fragrance, and pure tea-like fragrance”. A total of 366 volatile components were identified in dark tea and jasmine dark tea, of which 38 volatile components such as linalool, α-farnesene, and benzyl acetate were characteristic volatile components to distinguish the aroma quality of dark tea before and after scenting, and most characteristic volatile components were positively correlated with jasmine and fungus fragrance, and negatively correlated with aged woody and smoky pine aroma. These findings led us to conclude that scenting is important for improving the quality of jasmine dark tea. This study provides a theoretical basis for improving the processing technology and quality and regulating the aroma of jasmine dark tea.

This research was performed in order to investigate the alleviative effect of aged Wuyi rock tea on dextran sulfate sodium (DSS)-induced colitis in mice. Fifty C57BL/6JGpt female mice were randomly and equally divided into five groups: control, DSS, DSS + infusion of 20-year-old Wuyi rock tea (DSS + OT01), DSS + infusion of 10-year-old Wuyi rock tea (DSS + OT11) and DSS + infusion of fresh Wuyi rock tea (DSS + OT20). The physiological and histopathological conditions of mice after Wuyi rock tea interventions, and the changes of serum inflammatory factors and cecal microbiota were analyzed. The results showed that aged Wuyi rock tea could significantly alleviate the symptoms of body mass loss, diarrhea, bloody stool, and colon length shortening, reduce inflammatory cell infiltration, and significantly inhibit the secretion of pro-inflammatory cytokines. In addition, aged Wuyi rock tea could alleviate the disorder of the gut microbiota, significantly down-regulate the relative abundance of Proteobacteria, Enterobacteriaceae and Escherichia, and up-regulate the relative abundance of Verrucomicrobia and Akkermansia. In summary, aged Wuyi rock tea can alleviate DSS-induced colitis in mice, and the tea produced in 2011 is more effective than that produced in 2001, which may be due to proper oxidation of catechins such as epigallocatechin gallate to produce thearubigins, with better anti-inflammatory and antioxidant properties. In addition, aged Wuyi rock tea is able to maintain intestinal homeostasis by regulating the relative abundance of Escherichia and Akkermansia in the intestine, which in turn alleviates the symptoms of DSS-induced colitis in mice such as body mass loss, diarrhea, bloody stool, colon length shortening, mucosal and crypt damage, inflammatory cell infiltration, and serum inflammatory factor overexpression.

The current study was performed in order to explore the effect of Eurotium cristatum LJSC.2001 on the fermentation quality of raw dark tea. Golden flower loose tea was produced by using E. cristatum LJSC.2001 to ferment raw dark tea from the cultivars Zhuyeqi, Yuntaidaye and Taoyuandaye provided by representative manufacturers (Yuntaishan, Yunshang, Baishaxi and Junhe) in Anhua, Hunan province, and comparative analysis of their taste and aroma quality was carried out by sensory evaluation, basic physicochemical analysis, analysis of catechin components by high performance liquid chromatography (HPLC), and headspace solid-phase microextraction-gas chromatography-mass spectrometry (HS-SPME-GC-MS). Results showed that after fermentation by E. cristatum LJSC.2001, the dry tea samples were darker in color and fully covered with golden flower; their infusions were darker in color, and had a strong fungal aroma and a mellow and full taste, and the brewed tea was soft. Raw dark tea from Baishaxi had a stronger fungal aroma after fermentation, while retaining a distinct pine smoke-like aroma. The contents of taste compounds including tea polyphenols, free amino acids, soluble carbohydrates, flavonoids, total catechins, myricetin, quercetin, and kaempferol showed an overall decreasing trend. The content of catechins in Yuntaidaye raw dark tea from Yuntaishan and Yunshang declined most. The relative contents of esters and aldehydes increased after fermentation. There were differences in the content of volatile components among the different fermented tea samples, methyl salicylate and (E,E)-2,4-heptadienal being the major ones. Multivariate statistical analysis showed significant differences in volatile composition between golden flower loose tea and raw black tea. There were 19 characteristic volatile components identified including methyl salicylate, (E,E)-2,4-heptadienal, (E)-linalool 3,7-oxide, (E)-furan oxidized linaloa, acetophenone, (E)-2-,(Z)-6-nonadienal, (E)-2-hexenal, (E,E)-3,5-octadien-2-one and n-tridecane. The contents of the nine volatile components increased significantly after fermentation, and they all contributed to the fungal aroma of golden flower loose tea. It can be seen that fermentation by E. cristatum LJSC.2001 can impart a more mellow and fuller taste and a more prominent fungal aroma to raw black tea.

To explore the differences in aroma between compressed dark tea and raw dark tea, headspace solid phase microextraction (HS-SPME) combined with gas chromatography-mass spectrometry (GC-MS) and sensory evaluation were used to analyze and compare the flavor quality and aroma composition of four kinds of Hunan compressed dark tea and raw dark tea stored under the same condition. The results showed that compared with the raw tea, the pine smoke-like aroma and the crude, green, sour and other miscellaneous off-odors of the compressed tea were weaker, the concentration of aroma was higher and more long-lasting, and the stable flavor was more prominent. Furthermore, the contents of 15 unpleasant aroma components such as (E,Z)-2,4-heptadienal, 2,3,5,6-tetramethylpyrazine, and acetic acid in the compressed tea decreased, while the contents of 11 pleasant aroma components such as (E,E)-2,4-heptadienal, saffron aldehyde and butylated hydroxytoluene increased. Through principal component analysis (PCA) and orthogonal partial least squares discriminant analysis (OPLS-DA), 10 characteristic aroma components which could potentially be used to discriminate between compressed dark tea and raw dark tea were identified including acetic acid, 2-butyl-1-octanol, 1,2,3-trimethylbenzene, (Z)-2-decylenaldehyde, linalool, octanol, α-terpineol, 3-tridecanone, (E,Z)-2,6-nonadienol and phenylethanol. These results can provide a reference for further research on the quality formation mechanism of Hunan dark tea and the development of dark tea products.

Fu brick tea (FBT) is a unique compressed dark tea in China. The unique fungal fermentation process creates its unique fungal flavor and special health benefits, so FBT is deeply favored by consumers. This paper reviews the research results on the volatile components contributing to the aroma of FBT and the methods for their evaluation. The reported volatile compounds are systematically classified, and the compounds with high detection frequency are elaborated in detail. The methods for the extraction, qualitative and quantitative analysis of the volatile compounds and the methods for the screening and evaluation of the odor-active compounds of FBT are summarized. Meanwhile, the problems with the current studies and the focus of future research are pointed out.

Hypoxia plays a crucial role in pulmonary vascular remodelling at the early stage of chronic obstructive pulmonary disease (COPD). Circle RNA (circRNA) has been identified to play a critical role in multiple diseases. However, the role of circRNAs in pulmonary vascular remodelling in COPD remains unclear. In this study, we aim to investigate the role of circRNAs in pulmonary arterial smooth muscle cell proliferation and pulmonary vascular remodelling in COPD. COPD patients show lower partial pressure of arterial oxygen and pulmonary arterial remodeling as compared with controls. circRNA microarray and real-time PCR analyses show significantly higher level of circ-BPTF and lower miR-486-5p level in the pulmonary arteries of COPD patients as compared with controls. Hypoxia suppresses miR-486-5p expression but promotes expressions of circ-BPTF and cell migration inducing protein (CEMIP) in human pulmonary arterial smooth muscle cells (PASMCs) in vitro. Loss- and gain-of-function experiments show that circ-BPTF promotes PASMC proliferation in vitro. Moreover, luciferase reporter assay results indicate that circ-BPTF regulates PASMC proliferation by acting as an miR-486-5p sponge. CEMIP is identified as a candidate target gene of miR-486-5p by luciferase reporter assay. Overall, our study shows that circ-BPTF serves as a miR-486-5p sponge to regulate CEMIP and promote hypoxic PASMC proliferation in pulmonary vascular remodelling in COPD.

Objective To investigate the effect of CPNE3 on the proliferation, migration and invasion of non-small cell lung cancer (NSCLC) cell line A549 and its underlying mechanism. Methods The expression of CPNE3 in NSCLC and its relationship with prognosis were analyzed based on the data from the cancer genome atlas (TCGA) database. Western blotting was used to detect the expression of CPNE3 in normal bronchial epithelial cell line BEAS-2B and lung cancer cell lines. The si-RNAs of CPNE3 were transfected into A549 cells. The abilities of cell proliferation, migration and invasion were detected by CCK-8 assay, colony formation assay, and Transwell assay, respectively, and the expression levels of downstream proteins related to proliferation and metastasis were detected by Western blotting. After the A549 cells with stable overexpression of CPNE3 were established, the cells with overexpression or not were respectively employed to construct lung carcinoma xenograft model in female BALB/c nude mice (n=5 for control and overexpression mice, respectively). Then the tumor growth was observed to determine the effect of CPNE3 overexpression on the tumorigenicity of A549 cells. Results The expression of CPNE3 was increased in NSCLC tissues (P < 0.05), and its high expression was correlated with poor prognosis (P < 0.01). Consistently, the expression of CPNE3 was increased in lung cancer cell lines (P < 0.01). After the knockdown of CPNE3, the proliferation and colony formation (P < 0.001, P < 0.01), and migration and invasion abilities (P < 0.01, P < 0.01) were significantly inhibited in A549 cells, accompanied with decreased phosphorylation levels of AKT, ERK, and EGFR (P < 0.001, P < 0.001, P < 0.01). Overexpression of CPNE3 promoted cell proliferation in vivo (P < 0.001), and upregulated phosphorylation of AKT, ERK, and EGFR (P < 0.05, P < 0.05, P < 0.01). Conclusion Knocking CPNE3 down can inhibit the proliferation, migration and invasion of A549 cells, while its overexpression can promote the proliferation ability of A549 cells in vivo, which may be related to EGFR signaling pathway and downstream AKT/ERK signaling pathway.

EGCG is often regarded as the main active ingredient in tea to protect blood glucose homeostasis. The content of low molecular weight polyphenols such as EGCG in fungus fermented black tea (FFBT) is extremely low, and there are few studies on the hyperglycemic effect of FFBT. To explore the hypoglycemic effects and potential mechanisms of FFBT, GK rats with spontaneous hyperglycemic were given 280 mg⋅kg-1 FFBT extract (equivalent to 9 g of FFBT for daily human consumption) by gavage intervention. The study assessed the effects of FFBT on body weight, glucose homeostasis, regulatory factors related to glucose homeostasis, diabetic complications and liver transcription profiles in hyperglycemic rats. The results indicated that FFBT could obviously reduce the fasting blood glucose level and random blood sugar level of hyperglycemic rats, improve the abnormal glucose metabolism in hyperglycemic rats, maintain glucose homeostasis and alleviate the damage caused by diabetic complications in hyperglycemic rats. In addition, transcriptome analysis revealed that the hypoglycemic properties of FFBT might be related to the regulation of gene expression in the liver, such as Gck, Pklr, Pkm. This study found that FFBT may be a potential hypoglycemic functional beverage, providing a theoretical basis for the development and utilization of fermented tea such as FFBT. [ABSTRACT FROM AUTHOR]

Flavor wheel is a simple and easy method to understand descriptor system, which is convenient for consumers to communicate the sensory flavor attributes of Pu'er tea and Fu brick tea. In this study, by establishing a sensory evaluation team, sensory evaluation was conducted on the flavor of Pu'er tea and Fu brick tea, and the flavor wheels of Pu'er tea and Fu brick tea were drawn from two dimensions: aroma and taste. On this basis, a vocabulary for quantitative sensory description of Pu'er tea and Fu brick tea was established by setting reference samples with different intensities for 23 typical sensory descriptions. Furthermore, using the M-value method combined with analysis of variance and multivariate statistical analysis, the main sensory descriptors that can better describe Pu'er tea and Fu brick tea were selected. A total of 7 aroma descriptors (woody, sweet aroma, herbal, ferment, glutinous, jujube and aged) and 5 flavor descriptors (sweet taste, bitter, astringent, sour and mellow and thick) were selected for Pu'er tea, and 5 aroma descriptors (woody, sweet aroma, herbal, aged and fungal floral) and 5 flavor descriptors (sweet taste, bitter, astringent, sour and mellow and thick) were identified for Fu brick tea, and these descriptors can better evaluate the sensory quality characteristics of Pu'er tea and Fu brick tea samples. The results of this study provide application value for distinguishing and evaluating the sensory flavor characteristics of Pu'er tea and Fu brick tea, as well as in the development of their products. [ABSTRACT FROM AUTHOR]

In order to explore the effect of fermented loose tea technology with Eurotium cristatum LJSC.2005 on the quality of primary dark tea, the major part of Hunan Fu tea, the sensory evaluation, biochemical composition analysis and head-space solid-phase micro-extraction (HS-SPME) coupled with gas chromatography-mass spectrometry (GC-MS) technologies were used to analyze its effect on the primary dark teas made from six main tea cultivars in Hunan Province. The sensory evaluation results show that, compared with the primary dark tea, the loose tea sample after fermentation had golden flowers, deeper color, more flat and tight strips and deeper tea soup color. Its taste changed from astringency to mellow and its aroma changed from the flowery and fruity aroma of sun-dried dark tea and the smoky pine aroma of the seven-star stove to the strong and pure fungus aroma. Biochemical component analysis shows that the contents of taste components such as flavonoids, tea polyphenols, free amino acids, catechins and quercetin in fermented loose tea were generally lower than that of primary dark tea, and the soluble sugar and myricetin show a downward trend. HS-SPME/GC-MS analysis shows that there were a total of 71 aroma components in the tea samples, including 14 hydrocarbons, 16 alcohols, 10 aldehydes, 10 ketones, 6 esters, 4 phenols, 1 lactone, 6 nitrogen compounds and 4 oxygen compounds. Styrene and geraniol isobutyrate were the common aroma components of the primary dark tea. (E)-linalool 3,7-oxide, isophytol and acetophenone were the common aroma components of the fermented loose tea. Compared with the aroma components of primary dark tea, 16 components such as methyl salicylate, (E)-oxidized linalool (furan), (E)-linalool 3,7- oxide, β-ionone and geraniol isobutyrate were the characteristic aroma components of the loose tea fermented by Eurotium cristatum LJSC.2005. [ABSTRACT FROM AUTHOR]

Metabolic syndrome (MS) is an abnormal multi-metabolic disease that comprises a combination of various diseases such as hypertension, abnormal blood sugar, dyslipidemia and obesity. Tea polyphenols (TPs) are the characteristics secondary metabolites in tea leaves. The latest studies show that TPs can improve the disorder of gut flora (GF) and modulate the co-metabolism of Host-GF by the intervention & treatment to achieve the goal of improving MS. This paper systematically summarized the absorption and metabolism of TPs and the effects of TPs on GF in in vitro fermentation models, animal experiments, and clinical trials. The underlying mechanism among TPs-GF-Host was described, which would facilitate further exploring the effects of TPs on human health based on the theory of intestinal flora and developing functional products of TPs. In addition, it also provided theoretical foundation for developing functional products associating with TPs. [ABSTRACT FROM AUTHOR]

In order to understand the characteristic taste chemicals of Hunan black tea, representative samples of Hunan black tea and typical samples from other provinces were selected. The taste and chemical constituents of black tea samples were evaluated by electronic tongue and high performance liquid chromatography. Visual pattern recognition method such as Principal component analysis (PCA) and partial least squares discriminant analysis (OPLS-DA) were used to compare the characteristic chemical compositions of Hunan black tea in different tenderness grades and flavor types. The results show that: (1) The contents of water extraction, glucose, maltose, tea polyphenols, theabrownin, amino acid, delicious amino acid, theanine and theaflavins could be used as the main flavor components to distinguish Hunan black tea from other black tea as water extraction, glucose, maltose and theaflavins in Hunan black tea are significantly higher. (2) Most of the contents of taste components in the first grade of Hunan black tea soup were lower than those in other grades. Except for amino acids and thearubigins, other main flavor components were significantly lower than those of second grade tea. The contents of water extracts, tea polyphenols, caffeine, amino acids, theaflavins, thearubin were rich in the second grade tea soup. The contents of catechins, carbohydrates, theaflavins, thearubin and other compounds in the third grade tea was relatively high, while the contents of tea polyphenols, amino acids, thearubin and other compounds were relatively low. (3) The contents of caffeine, catechins, non-ester catechins, EGC and theaflavins in the "sweet and delicious" tea soup were significantly lower than those in the "slightly bitter (strong)" tea soup. The research results provided a reference for the classification and identification of Hunan black tea products and the evaluation of taste quality. [ABSTRACT FROM AUTHOR]