Progress in catechins oxidation products and their formation mechanism / 中国中药杂志

Catechins are the key components of tea and have a great impact on its quality. Catechins can be oxidized to form a new black tea polyphenols, some of which have better pharmacological effect. However, the formation mechanism of these new polyphenols is still unclear. In this paper, oxidation products coming from catechins and the formation mechanism of the new compounds are reviewed.It is the base of further study on theaflavins, thearubigins and theabrownines.

Advance in anticancer studies on catechins and their derivatives / 中国中药杂志

Experimental studies on animals discovered that catechins have a notable inhibitory effect on the formation and development of tumors in different organs. Studies on their mechanism showed that catechins could inhibit cancer cell invasion and proliferation, angiogenesis and metastasis and induce cancer cell apoptosis through anti-oxidation and by inhibiting related enzyme activities and cancer cell signal transmission. This essay provides an overview of correlation between tea drinking and cancer prevention, various mechanisms of catechins and their derivatives such as biochemical cancer prevention and anticancer and looks into the future of catechins.

Synthesis of 8-alkyl-13-bromo-berberine hydrochloride derivatives and their effect on proliferation of human HepG2 cell line / 中草药

Objective: To study the antitumor activity of berberine which was alkylated based on the development of new antitumor drug. Methods: The alkylation and bromination of berberine were performed with Grignard reagent and bromine respectively to give 8-alkyl-13-bromo-berberine derivatives in good to excellent yields. The chemical structures of the derivatives were identified by UV, IR, 1H-NMR, and elemental analysis. The antiproliferative effect of the derivatives on human hepatoma cell line HepG2 was evaluated by MTT after 48 h incubation. Results: The results showed that the length of carbon chain of the derivatives was highly correlated with the tumor cell sensitivity and 8-octyl-13-bromo-berberine showed the remarkable activity. Its inhibitory rate was 96. 82% at the concentration of 32 μg/mL and IC50 was 3.33 μg/mL. Conclusion: Known from IC50, the antitumor activity could be enhanced within eight carbon atoms as the bromide side chain extension.

Roles of theaflavins in inflammatory airway mucus hypersecretion / 上海第二医科大学学报

Objective To investigate the roles of theaflavins(TFs) in airway mucus hypersecretion induced by human neutrophil elastase(HNE). Methods Human lung adenocarcinoma cell A549 was stimulated by HNE for mucus hypersecretion,and TF monomers(TF1,TF2 and TF3) were used for intervention.The effects of TF monomers on viability of A549 cells were examined by MTT method.After the effective doses of TFs were determined,A549 cells were divided into 4 groups for experiment.In control group,A549 cells were cultured with serum-free medium.In HNE treatment group,A549 cells were treated with HNE(50 nmol/L) for 24 h.In TF monomer intervention groups,A549 cells were pre-treated with TF1,TF2 or TF3(50,100 or 200 ?g/mL) for 24 h,and were then treated with HNE for another 24 h.In AG1478 intervention group,A549 cells were pre-treated with AG1478(5 ?mol/L),an epidermal growth factor receptor blocker for 30 min,and were then treated with HNE for another 24 h.The changes in mucin(MUC) after treatment by different doses of TF1,TF2 and TF3,and by TF3(200 ?g/mL) for different time(12 h,24 h and 36 h) were detected.The changes in MUC5AC mRNA expression and MUC5AC protein expression were detected by RT-PCR and ELISA,respectively. Results The MUC5AC mRNA expression and protein expression in HNE treatment group were significantly higher than those in control group(P