Inhibitory mechanism of angiotensin-converting enzyme inhibitory peptides from black tea.

The aim of this work is to discover the inhibitory mechanism of tea peptides and to analyse the affinities between the peptides and the angiotensin-converting enzyme (ACE) as well as the stability of the complexes using in vitro and in silico methods. Four peptide sequences identified from tea, namely peptides I, II, III, and IV, were used to examine ACE inhibition and kinetics. The half maximal inhibitory concentration (IC50) values of the four peptides were (210.03±18.29), (178.91±5.18), (196.31±2.87), and (121.11±3.38) µmol/L, respectively. The results of Lineweaver-Burk plots showed that peptides I, II, and IV inhibited ACE activity in an uncompetitive manner, which requires the presence of substrate. Peptide III inhibited ACE in a non-competitive manner, for which the presence of substrate is not necessary. The docking simulations showed that the four peptides did not bind to the active sites of ACE, indicating that the four peptides are allosteric inhibitors. The binding free energies calculated from molecular dynamic (MD) simulation were -72.47, -42.20, -52.10, and -67.14 kcal/mol (1 kcal=4.186 kJ), respectively. The lower IC50 value of peptide IV may be attributed to its stability when docking with ACE and changes in the flexibility and unfolding of ACE. These four bioactive peptides with ACE inhibitory ability can be incorporated into novel functional ingredients of black tea.

Identification of Similar Chinese Congou Black Teas Using an Electronic Tongue Combined with Pattern Recognition.

It is very difficult for humans to distinguish between two kinds of black tea obtained with similar processing technology. In this paper, an electronic tongue was used to discriminate samples of seven different grades of two types of Chinese Congou black tea. The type of black tea was identified by principal component analysis and discriminant analysis. The latter showed better results. The samples of the two types of black tea distributed on the two sides of the region graph were obtained from discriminant analysis, according to tea type. For grade discrimination, we determined grade prediction models for each tea type by partial least-squares analysis; the coefficients of determination of the prediction models were both above 0.95. Discriminant analysis separated each sample in region graph depending on its grade and displayed a classification accuracy of 98.20% by cross-validation. The back-propagation neural network showed that the grade prediction accuracy for all samples was 95.00%. Discriminant analysis could successfully distinguish tea types and grades. As a complement, the models of the biochemical components of tea and electronic tongue by support vector machine showed good prediction results. Therefore, the electronic tongue is a useful tool for Congou black tea classification.

The association between dietary protein intake and colorectal cancer risk: a meta-analysis.

BACKGROUND: Association between dietary protein intake and colorectal cancer risk has not been fully quantified, while the results were controversial. This study aimed to evaluate the role of protein intake in the development of colorectal cancer. METHODS: PUBMED and EMBASE were searched up to December 2016. Two independent reviewers independently extracted data from eligible studies. Relative risk (RR) with 95% confidence intervals (CI) was pooled using random-effects model to estimate the result. Besides, publication bias and sensitivity analysis were conducted. RESULTS: Thirteen articles involving 21 studies comprising 8187 cases were included in this report. The pooled RR of colorectal cancer was 1.006 (95% CI = 0.857-1.179) indicating that there is no significant association between dietary protein intake and colorectal cancer risk. Furthermore, the pooled RRs for colon cancer and rectum cancer were 1.135(95% CI = 0.871-1.480) and 0.773(95% CI = 0.538-1.111), respectively, with the highest category of dietary protein intake. The association was not significant either in subgroup analysis of study design, protein type (animal protein or vegetable protein), sex, and or geographic locations. CONCLUSIONS: The present study indicated that the highest category compared to the lowest category of protein intake had no significant association on colorectal cancer risk. Dose-response analysis was not conducted due to limited information provided. Therefore, more studies with large cases and participants as well as detailed amounts of dietary protein intake are wanted to confirm this result.

Ethanol extract of gardenia fruit alleviates renal interstitial fibrosis induced by unilateral ureteral obstruction in rats.

Gardenia fruit has been used in traditional Chinese medicine for thousands of years. A previous study by the present authors indicated that the ethanol extract of gardenia fruits (EEG) primarily contains eight constituents. In the present study, the potential effects of EEG on unilateral ureteral obstruction (UUO)-induced renal interstitial fibrosis were observed in rats. A total of 30 rats were randomly divided into three groups (n=10 each): Sham group, UUO group, and EEG group, which were administered with EEG (200 mg/kg/day) or the same volume of distilled water as a vehicle. UUO were established by ligating left ureter at two points and cut between the ligatures. All rats were sacrificed at 14 days after UUO operation. the present results demonstrated that EEG significantly elevated the expressions of vascular endothelial growth factor and E-cadherin induced by UUO (both P<0.05), and reduced levels of hypoxia-inducible factor-1α, transforming growth factor-ß1, connective tissue growth factor and α-smooth muscle actin (all P<0.05). The present findings suggest that EEG is a potential novel renoprotective compound for renal fibrosis through inhibiting epithelial-to-mesenchymal transition.

Two-year observation of the clinical efficacy in treating chronic hepatitis B Patients with Ganxian recipe and lamivudine.

OBJECTIVE: To evaluate the clinical efficacy of Ganxian recipe (GXR) and lamivudine (LVD) in a two-year treatment of chronic hepatitis B (CHB). METHODS: One hundred and twenty patients with CHB were randomly divided into the combinedly treated group (combined group) of 40 CHB patients who were treated with GXR combined with LVD. Another 40 CHB patients were treated with LVD alone (WM group), and still another 40 CHB patients were treated with GXR alone (TCM group). All these cases were randomly controlled and observed for two years. RESULTS: Comprehensive efficacy: Total effective rate of the combined group (complete response and partial response) was 92.5%, while that of the WM group was 67.5% and TCM group 57.5%, respectively, with the difference between them was significant (P < 0.01); after treatment, the hepatic functions (AST, ALT, SB) of the three groups were all reduced, and the reduction in the combined group was particularly significant in comparison with the WM group or TCM group, P < 0.05 or P < 0.01 respectively, suggesting that the effect in the combined group was better than that in the other two groups; the rate of tyrosine-methionine-aspartate-aspartate (YMDD) virus mutation: it was 7.5% in the combined group, 40.0% in the WM group, and 5.0% in the TCM group; liver fibrosis improvement parameter: after treatment, the results in the combined group got better than those in the other two groups. CONCLUSION: GXR could inhibit the appearance of YMDD after long-term application of LVD, and combined use has marked synergism.