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AIM: To investigate t h e impacts of theaflavins (TFs) on neuronal apoptosis and blood-brain barrier (BBB) by regulating the calcium/calmodulin-dependent protein kinase kinase 2 (CaMKK2)/5 '-adenosine monophosphate-activated protein kinase (AMPK) signaling pathway. METHODS: Ninety rats were randomly separated into sham operation group, model group, low-dose TFs group (20 mg/kg TFs), high-dose TFs group (40 mg/kg TFs), and high-dose TFs + STO-609 group (40 mg/kg TFs + 10 ΜL CaMKK2 inhibitor-STO-609), positive control group (2 mg/kg nimodipine injection), with 15 rats in each group. A rat model of intracerebral hemorrhage was induced by collagenase type VII. The behavior of rats and the water content of brain tissue were detected; the serum of rats was isolated, and the levels of inflammatory factors-vascular cell adhesion molecule-1 (VCAM-1), tumor necrosis factor-α (TNF-α), and intercellular adhesion molecule-1 (ICAM-1) were detected; brain tissue around the hematoma was collected to detect neuronal apoptosis, BBB permeability parameter-EB level, and expressions of p-CaMKK2/CaMKK2, p-AMPK/AMPK and apoptosis-related protein Bax. RESULTS: Compared with the sham operation group, the mNSS score, ICAM-1, TNF-α, VCAM-1, brain tissue water content, apoptosis rate, EB level and Bax protein expression in the model group were all increased, both pCaMKK2/CaMKK2 and p-AMPK/AMPK were decreased (P < 0.05); compared with the model group, the mNSS score, ICAM-1, TNF-α, VCAM-1, brain water content, apoptosis rate, EB level and Bax expression in the low- and high-dose TFs groups and the positive control group were all lower than those in the model group, both pCaMKK2/CaMKK2 and p-AMPK/AMPK were increased (P < 0.05); compared with the high-dose TFs group, the mNSS score, ICAM-1, TNF-α, VCAM-1, brain tissue water content, apoptosis rate, EB level and Bax expression were all increased in the high dose TFs + STO-609 group, both p-CaMKK2/CaMKK2 and p-AMPK/AMPK were decreased (P < 0.05). CONCLUSION: TFs can reduce neuronal apoptosis, inflammatory response, BBB permeability, and play a protective role in rats with cerebral hemorrhage injury. Its mechanism is related to the activation of CaMKK2/AMPK signaling pathway.
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Theaflavins are a class of natural products extracted from black tea or green tea, with significant anti-tumor effects on gastric cancer, liver cancer, breast cancer and other tumors. Theaflavins were once considered as the new products for anticancer therapy. However, the anti-tumor mechanism of theaflavins involves a variety of biological processes, and the regulation is complex. Therefore, this article summarizes the role of theaflavins in promoting tumor cell apoptosis, inducing tumor cell mitotic arrest and regulating tumor immunity, and reviews the inhibition of tumorigenesis and growth through MAPK, PI3K/AKT, Hedgehog, NF-κB, JAK/STAT and Wnt/β-Catenin signal pathways, in order to provide new ideas for cancer treatment and anti-cancer drug development.
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BACKGROUND Drinking tea has antioxidant, anti-inflammatory and anti-carcinogenic properties. In addition, tea is also considered beneficial for cardiovascular health and oral health. Health benefits of green tea are attributed to its polyphenol content. Catechins are the major polyphenols in green tea and in black tea the catechins are oxidized to theaflavins. Polyphenols present in tea have exhibited antimicrobial effects against a wide range of pathogenic bacteria. Studies have shown that green tea catechins are bioavailable in both plasma and urine. The aim of the present study is to evaluate the antibacterial activity of black tea extract against standard strains of S. mutans, S. aureus, L. acidophilus, Klebsiella and E. coli.METHODSBlack tea extract was prepared by boiling black tea leaves in distilled water. It was then filtered, and the filtrate was treated with chloroform and ethyl acetate. The ethyl acetate was evaporated in a rotary evaporator and a brown coloured residue was obtained. Its antibacterial activity was studied against standard strains of five common bacteria i.e.; S. mutans, L. acidophilus, S. aureus, Klebsiella spp, and E. coli and the MIC of the black tea extract was determined using serial dilution method.RESULTSBlack tea extract showed sufficient antibacterial activity against the tested bacteria. The MIC of black tea extract was lowest against Staphylococcus aureus.CONCLUSIONSTea extracts have significant antimicrobial activity at varying concentrations against different bacterial pathogens.
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Theaflavins are a category of natural compounds characterized with the benzotropolone skeleton. Theaflavins have many pharmacological actions, such as antioxidant, regulating blood-lipid, hypoglycemic, antiviral, anti-inflammation, hypouricemic, anti-bacterial, anti-tumor, anti-osteoporosis. Theaflavins is one of the research focuses of natural active ingredients in tea, and it is more and more widely used in the development of terminal products with health food, medicine, cosmetics, animal feed, plant pesticide, and so on. Based on the literatures review of theaflavins in recent years, taking the theaflavins structure as the starting point, the biological activities of theaflavins were reviewed, the research and application of theaflavins in health food, medicine and other fields were focused on, in order to provide reference for the application and development of theaflavins.
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Objective To investigate the protective effect of theaflavins on thymus injury caused by total body irradiation (TBI).Methods Twenty-five C57BL/6 mice were randomly divided into 5 groups:control group,4 Gy TBI group,4 Gy TBI + 25 mg/kg theaflavins group,4 Gy TBI + 50 mg/kg theaflavins group and 4 Gy TBI + 100 mg/kg theaflavins group.Thymus index and total number of thymocytes were detected at the 14th d post-irradiation to determine the optimal dose of theaflavins.According to this optimal dose,32 C57BL/6 mice were randomly divided into 4 groups:control group,theaflavins group,4 Gy TBI group and 4 Gy TBI + theaflavins group.Thymus histomorphology,CD4CD8 T cell subsets,and reactive oxygen species (ROS) in thymocytes were examined at the 14th d post-irradiation.Results The irradiated thymus exhibited decreased thymus index and total number of thymocytes (P ＜ 0.05),aberrant histomorphology and T cell subsets (P ＜ 0.05),and increased ROS level in thymocytes (P ＜ 0.05).Compared with 4 Gy TBI group,the thymus index and total number of thymocytes were significantly increased in 4 Gy TBI + 50 mg/kg theaflavins group (P ＜ 0.05).The total number of thymocytes was significantly higher in 4 Gy TBI + 50 mg/kg theaflavins group than that in 4 Gy TBI + 25 mg/kg theaflavins group (P ＜ 0.05).Therefore,50 mg/kg theaflavins was chosen as the optimal dose for subsequent experiments.Moreover,the aberrant histomorphology of irradiated thymus was alleviated by theaflavins.A decline in the percentage of CD4-CD8-T cells and an elevation of CD4+CD8-and CD4+CD8+ T cells were found in irradiated mice administered with theaflavins (P ＜ 0.05).Compared with 4 Gy TBI group,the ROS level was significantly decreased in 4 Gy TBI + theaflavins group (P ＜ 0.05).Conclusion Theaflavins exhibits a protective effect on radiation-induced thymus injury.
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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