Preparation of chitosan-Epigallocatechin-3-O-gallate nanoparticles and their inhibitory effect on the growth of breast cancer cells

In this paper,we prepared the nanoparticle drug carrier system between nanoparticles chitosan and Epigallocatechin-3 O-gallate(EGCG)for breast cancer cell inhibiting application.For this drug carrier system,chitosan acts as a carrier and EGOG as a drug.Which were systematically characterized and thoroughly evaluated in terms of their inhibition rate and biocompatibility.We also did a cell scratch test and the result indicated that the chitosan EGCG nanoparticles have inhibitory effect on the growth of breast cancer cells.The inhibition rate could reach up to 21.91%.This work revealed that the modification of nanopartidles paved a way for specific biomedical applications.

Electrochemical properties of La_(0.8)Sr_(0.2)FeO_(3-δ) based composite cathode for intermediate temperature SOFC

La0.8Sr0.2FeO3-δ is a new kind of cathode material for intermediate SOFC, but its electrochemical activity is relative poor for the lanthanum gallate based solid oxide fuel cell. In this paper, a novel composite cathode of La0.8Sr0.2FeO3-δ/La0.9Sr0.1Ga0.8Mg0.2O3-δ was prepared on the LSGM electrolyte substrate by screen-printing method. The results of cathodic polarization measurements show that the overpotential decreases significantly when the composite cathode is used instead of the La0.8Sr0.2FeO3-δ single layer cathode. The cathodic overpotential of the composite La0.8Sr0.2FeO3-δ/La0.9Sr0.1Ga0.8Mg0.2O3-δ cathode is 150 mV at the current density of 0.2 A·cm-2 at 800 ℃, while the cathodic overpotential of the La0.8Sr0.2FeO3-δ single layer cathode is higher than 260 mV at the same condition. The electrochemical impedance spectroscopy was employed to investigate the polarization resistance of the cathode. The polarization resistance of the composite cathode is 1.20 Ω·cm2 in open circuit condition, while the value of the single La0.8Sr0.2FeO3-δ cathode is 1.235 Ω·cm2.

A Novel Flavane from Carapa guianensis

Seven compounds were isolated from the EtOH extraction of the twig of Carapa guianensis Aubl. (Meliaceae). On the basis of spectroscopic methods, their structures were elucidated as (-)-epicatechin-3-O-(3' , 5'-di-O-methyl) gallate (1), (-)-catechin (2), sciadopitysin (3), cleomiscosin B (4), photogedunin (5), chisocheton compound F (6) and odoratone (7), respectively. Among them compound 1 was a new flavane, compounds 2-7 were firstly obtained from this plant, and compound 5 was assigned the C-13-NMR data for the first time. Compound 7 exhibited strong antifeedant activity against Pieris brassicae, and compound 2 exhibited moderate activity, while the n-BuOH portion showed weak activity.

The epigallocatechin gallate derivative Y_6 reverses drug resistance mediated by the ABCB1 transporter both in vitro and in vivo

Previously, we reported that Y_6, a new epigallocatechin gallate derivative, is efficacious in reversing doxorubicin(DOX)–mediated resistance in hepatocellular carcinoma BEL-7404/DOX cells. In this study, we evaluated the efficacy of Y_6 in reversing drug resistance both in vitro and in vivo by determining its effect on the adenosine triphosphate-binding cassette protein B1 transporter(ABCB1 or P-glycoprotein, P-gp). Our results showed that Y_6 significantly sensitized cells overexpressing the ABCB1 transporter to anticancer drugs that are ABCB1 substrates. Y_6 significantly stimulated the adenosine triphosphatase activity of ABCB1. Furthermore, Y_6 exhibited a higher docking score as compared with epigallocatechin gallate inside the transmembrane domain of ABCB1. In addition, in the nude mousetumor xenograft model, Y_6(110 mg/kg, intragastric administration), in combination with doxorubicin(2 mg/kg, intraperitoneal injection), significantly inhibited the growth of BEL-7404/DOX cell xenograft tumors, compared to equivalent epigallocatechin gallate. In conclusion, Y_6 significantly reversed ABCB1-mediated multidrug resistance and its mechanisms of action may result from its competitive inhibition of the ABCB1 drug efflux function.

Long Non-coding RNAs Expression Profile in HepG2 Cells Reveals the Potential Role of Long Non-coding RNAs in the Cholesterol Metabolism

Background：Green tea has been shown to improve cholesterol metabolism in animal studies,but the molecular mechanisms underlying this function have not been fully understood.Long non-coding RNAs （lncRNAs） have recently emerged as a major class of regulatory molecules involved in a broad range of biological processes and complex diseases.Our aim was to identify important lncRNAs that might play an important role in contributing to the benefits of epigallocatechin-3-gallate （EGCG） on cholesterol metabolism.Methods：Microarrays was used to reveal the lncRNA and mRNA profiles in green tea polyphenol（-）-epigallocatechin gallate in cultured human liver （HepG2） hepatocytes treated with EGCG and bioinformatic analyses of the predicted target genes were performed to identify lncRNA-mRNA targeting relationships.RNA interference was used to investigate the role of lncRNAs in cholesterol metabolism.Results：The expression levels of 15 genes related to cholesterol metabolism and 285 lncRNAs were changed by EGCG treatment.Bioinformatic analysis found five matched lncRNA-mRNA pairs for five differentially expressed lncRNAs and four differentially expressed mRNA.In particular,the lncRNA4 T102202 and its potential targets mRNA-3-hydroxy-3-methylglutaryl coenzyme A reductase （HMGCR） were identified.Using a real-time polymerase chain reaction technique,we confirmed that EGCG down-regulated mRNA expression level of the HMGCR and up-regulated expression ofAT102202.After AT102202 knockdown in HepG2,we observed that the level of HMGCR expression was significantly increased relative to the scrambled small interfering RNA control （P 〈 0.05）.Conclusions：Our results indicated that EGCG improved cholesterol metabolism and meanwhile changed the lncRNAs expression profile in HepG2 cells.LncRNAs may play an important role in the cholesterol metabolism.

Isolation and Purification of a Novel Long-chain Acyl Catechin from Lipophilic Tea Polyphenols

Lipophilic tea polyphenols (LTP) was prepared by esterification of green tea polyphenols (GTP) with hexadecanoyl chloride. A novel long-chain acyl catechin was isolated and purified from LTP by high-speed countercurrent chromatography (HSCCC). Its molecular structure was elucidated as epigallocatechin-3-O-gallate-4'-O-hexadecanate by elemental analysis, IR, MS and H-1 NMR spectra.

Excretion of Four Catechins in Tea Polyphenols in Rats

Objective To investigate excretion profiles of the four major anti-oxidant active catechins, (-) epigallo-catechin-3-gallate (EGCG), (-) epicatechin-3-gallate (ECG), (-) epigallocatechin (EGC), and epicatechin (EC) in tea polyphenols (TP) in rats in order to provide experimental data for clinical uses and development of TP as a novel drug. Methods The above four catechins in urine, bile, and feces were simultaneously determined by high performance liquid chromatography coupled with ultraviolet absorption detector (HPLC-UV) assay with a binary gradient elution. The samples were extracted by ethyl acetate prior to HPLC. The quantification was carried out by peak area internal standard method. Following iv dosing TP 100 mg/kg to rats, the samples were collected at different time intervals up to 8 h (urine and bile) and 24 h (feces). Results The urinary Ae, 0-8 h (cumulative excretion amount over 8 h) of EGCG, ECG, EGC, and EC were, on the average, 150.83, 30.75, 116.69, and 254.56 μg, corresponding to fe, 0-8 h (cumulative excretion fraction of dose over 8 h) of 1.45%, 0.84%, 7.88%, and 10.73%, respectively; the biliary Ae, 0-8 h were 12.61, 42.64, 6.61, and 1.24 μg, corresponding to the fe, 0-8 h of 0.12%, 1.16%, 0.45%, and 0.053%,respectively. For fecal excretion, only EGCG and EGC were detected with Ae, 0-24 h of 7.38 μg (fe, 0-24 h of 0.07%) and 157 μg (fe, 0-24 h of 9.99 %), respectively. The fe, total (the total fe of 3 excretory routes) were 18.32%, 10.78%, 2.00%, and 1.64% for EGC, EC, ECG, and EGCG, respectively. Conclusion EGCG and EC are mainly excreted in urine, ECG in bile, and EGC in feces by reference to their Ae and fe. The excretion of the four catechins based on fe, total is ranked in order of EGC > EC > ECG > EGCG. Only small amount of four catechins are recovered in urine, bile, and feces, indicating an extensive metabolic conversion of catechins in the rat body.