ABSTRACT
To explore the volatile profiles and the contents of ten bioactive components (polyphenols and caffeine) of sun-dried Pu-erh tea leaves from ancient tea plants on Bulang Mountain, 17 samples of three tea varieties were analyzed by headspace-solid phase microextraction-gas chromatography-mass spectrometry (HS-SPME-GC-MS) and high-performance liquid chromatography (HPLC). A total of 75 volatile components were tentatively identified. Laomaner (LME), Laobanzhang (LBZ), and other teas on Bulang Mountain (BL) contained 70, 53, and 71 volatile compounds, respectively. Among the volatile compounds, alcohols (30.2%–45.8%), hydrocarbons (13.7%–17.5%), and ketones (12.4%–23.4%) were qualitatively the most dominant volatile compounds in the different tea varieties. The average content of polyphenol was highest in LME (102.1 mg/g), followed by BL (98.7 mg/g) and LBZ (88.0 mg/g), while caffeine showed the opposite trend, 27.3 mg/g in LME, 33.5 mg/g in BL, and 38.1 mg/g in LBZ. Principal component analysis applied to both the volatile compounds and ten bioactive components showed a poor separation of samples according to varieties, while partial least squares-discriminant analysis (PLS-DA) showed satisfactory discrimination. Thirty-four volatile components and five bioactive compounds were selected as major discriminators (variable importance in projection (VIP) >1) among the tea varieties. These results suggest that chromatographic data combined with multivariate analysis could provide a useful technique to characterize and distinguish the sun-dried Pu-erh tea leaves from ancient tea varieties on Bulang Mountain.
ABSTRACT
Objective: To explore the anti-atherosclerosis mechanism of pu-erh tea by reducing the expression and activity of NF-κB and promoting macrophage apoptosis. Methods: ① ApoE-/- mice were fed with pu-erh tea extract for 8 and 16 weeks to observe the positive rate of CD68 and the area of lipid plaque. ② Apoptosis detection kit was used to detect the apoptosis of macrophages. ③ P65 and IkB-β expressions in aortic plaque and macrophages were detected by Real-time quantitative PCR and Western blot; the expressions of inflammatory factors in aortic plaque were detected. Electrophoretic mobility change assay (EMSA) was used to analyze the binding activity of NF-κB DNA. Results: ① The area fraction of lipid plaque in ApoE-/- mice in the 16-week intervention group was significantly reduced (vs. control group, P0.05). The average gray value of NF-κB DNA binding activity in the 8- and 16-week intervention groups decreased respectively (vs. control group, P<0.05). Conclusion: Pu-erh tea may play an anti-atherosclerosis role by inhibiting the expression and activity of NF-κB, promoting the apoptosis of macrophages and reducing the level of inflammation in vivo. This mechanism may not be mediated by I κB.
ABSTRACT
To explore the volatile profiles and the contents of ten bioactive components (polyphenols and caffeine) of sun-dried Pu-erh tea leaves from ancient tea plants on Bulang Mountain, 17 samples of three tea varieties were analyzed by headspace-solid phase microextraction-gas chromatography-mass spectrometry (HS-SPME-GC-MS) and high-performance liquid chromatography (HPLC). A total of 75 volatile components were tentatively identified. Laomaner (LME), Laobanzhang (LBZ), and other teas on Bulang Mountain (BL) contained 70, 53, and 71 volatile compounds, respectively. Among the volatile compounds, alcohols (30.2%-45.8%), hydrocarbons (13.7%-17.5%), and ketones (12.4%-23.4%) were qualitatively the most dominant volatile compounds in the different tea varieties. The average content of polyphenol was highest in LME (102.1 mg/g), followed by BL (98.7 mg/g) and LBZ (88.0 mg/g), while caffeine showed the opposite trend, 27.3 mg/g in LME, 33.5 mg/g in BL, and 38.1 mg/g in LBZ. Principal component analysis applied to both the volatile compounds and ten bioactive components showed a poor separation of samples according to varieties, while partial least squares-discriminant analysis (PLS-DA) showed satisfactory discrimination. Thirty-four volatile components and five bioactive compounds were selected as major discriminators (variable importance in projection (VIP) >1) among the tea varieties. These results suggest that chromatographic data combined with multivariate analysis could provide a useful technique to characterize and distinguish the sun-dried Pu-erh tea leaves from ancient tea varieties on Bulang Mountain.
ABSTRACT
To establish a robust method for the determination of mycotoxins in tea samples, and to provide means for the quality and safety control of tea products. Samples of 20 tea products acquired from international market were extracted by organic solvents (acetonitrile containing 0.1% formic acid) or hot water, respectively. The extracts were analyzed by UPLC-MS/MS.A good linear regression was achieved in a range of 39.1 to 5 000 ng•L⁻¹ for aflatoxin B1 (AFB1) and aflatoxin G1 (AFG1), 117 to 15 000 ng•L⁻¹ for aflatoxin B2 (AFB2) and aflatoxin G2 (AFG2), 2.44 to 313 ng•L⁻¹ for fumonisin B1 (FB1), fumonisinB2 (FB2) and fumonisin B3 (FB3), and 3 125 to 5 000 ng•L⁻¹ for deoxynivalenol, with recovery rates between 85.7% and 99.6%. The coefficient of the linear equation for all standards was greater than 0.999 0, and the RSD value was less than 10%. Mycotoxins were detected in several tea samples using the two extraction methods but with different outcomes. The levels of mycotoxins detected ranging from 0.15 to 7.31 μg•kg⁻¹ were well below the State or US FDA regulation limits of mycotoxins in food products. Both methods are simple, accurate, and sensitive, and thus, suitable for the quantitative determination of mycotoxins in different food products. The method with the 80 ℃ hot-water extraction is more appropriate to determine the trace amounts of mycotoxins in tea leaves that are likely to be present in brewed tea liquor, while organic solvent method is more suitable for the detection of mycotoxins in ingestible foods.
ABSTRACT
-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---coumarate (), andknown analogs (-) 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-glucosidases and lipases; compoundshowed moderate inhibitory effect against sucrase with an ICvalue of 32.5 μmol/L and significant inhibitory effect against maltase with an ICvalue of 1.3 μmol/L. Compounds,,anddisplayed moderate activity against a lipase with ICvalues of 16.0, 13.6, 19.8, and 13.3 μmol/L, respectively.
ABSTRACT
Pu-erh tea has gradually aroused general concern with social development and people's enhanced awareness of health. Pu-erh tea is rich in multiple active constitute such as flavonoids, catechins, phenolic acids, flavanols polymer, purine alkaloids, and hydrolysable tannin as a microbial-fermented tea.It is reported that Pu-erh tea have a variety of pharmacologically activities, such as anti-hyperlipidemic, anti-diabetic, anti-oxidative, anti-tumor, anti-bacterial, anti-inflammatory, and anti-viral effects. In this paper, the main pharmacological effects of Pu-erh tea are reviewed. We wish this work will provide some references and clues for further research of Pu-erh tea.
ABSTRACT
Objective To examine the effect of Pu-Erh tea extract(PTE) on genes expression of lipogenesis in white adipose tissue of rats fed high fat diet.Method Thirty male SD rats were randomly divided into three groups(n=10):the control group(basal diet);the high fat group(high fat diet);the PTE group(high fat diet + Pu-Erh tea extract).Body weight and adipose tissue were measured.Expression of genes regulating lipid metabolism was assessed in adipose tissue.Results PTE supplementation prevented diet-induced increases in body weight and adipose tissue.Diacylglycerol acyltransferase-1(DGAT1),stearoyl-CoA desalurase-1(SCD1) and sterol regulatory element binding protein-1c(SREBP-1c) mRNA levels were markedly decreased in adipose tissue of rats fed PTE.Conclusion This study shows for the first time that Pu-Erh tea extract prevents diet-induced obesity,and this effect is partly mediated via a direct influence on adipose tissue.
ABSTRACT
Objective To study the effect of gallic acid isolated from Pu-erh Tea on the peroxisome proliferators activated receptors function.Method The appropriate concentration of gallic acid added to three cell models was decided to be 50 ?g/ ml,and the activity of gallic acid on peroxime prolipevators activated receptors PPAR?,PPAR?,PPAR? was studied.Results Gallic acid could activate PPAR?,as high as 2.436 fold and the effect corresponded to that of positive drug which value was 2.438.gallic acid had no effect on PPAR? and PPAR?.Conclusion Gallic acid in Pu-erh Tea had good activity on PPAR? and this could offer scientific basis for study of the anti-diabetes and anti-hyperlipidenmia mechanism of Pu-erh Tea.