Regulation of matrix metalloproteinase secretion by green tea catechins in a three-dimensional co-culture model of macrophages and gingival fibroblasts

ObjectivesElevated levels of matrix metalloproteinases (MMPs) have been associated with the active phases of tissue and bone destruction in periodontitis, an inflammatory disease characterized by a significant breakdown of tooth support. In the present study, we used a three-dimensional (3D) co-culture model of macrophages and gingival fibroblasts to investigate the ability of a green tea extract and its major constituent epigallocatechin-3-gallate (EGCG) to regulate the secretion of MMP-3, -8, and -9.MethodsThe 3D co-culture model was composed of gingival fibroblasts embedded in a type I collagen matrix overlaid with macrophages. Two arbitrary ratios were tested. The ratio composed of 1 macrophage to 10 fibroblasts was used to mimic a slightly inflamed periodontal site while the ratio composed of 10 macrophages to 1 fibroblast was used to mimic a severely inflamed periodontal site. The 3D co-culture model was pre-treated for 2 h with either the green tea extract or EGCG. It was then stimulated with Aggregatibacter actinomycetemcomitans lipopolysaccharide (LPS). The model was also first stimulated with LPS for 2 h and then incubated with the green tea extract or EGCG. The concentrations of secreted MMP-3, -8, and -9 were quantified by enzyme-linked immunoassays.ResultsWhen the 3D co-culture model was stimulated with A. actinomycetemcomitans LPS, the 10:1 ratio of macrophages to gingival fibroblasts was associated with a highest secretion of MMP-3 and -9 and, to a lesser extent, MMP-8, than the 1:10 ratio. Non-cytotoxic concentrations of the green tea extract or EGCG reduced the basal secretion levels of all three MMPs. A 2-h treatment with the green tea extract or EGCG prior to the stimulation with LPS resulted in a dose-dependent decrease in MMP secretion, with MMP-9 showing the most significant decrease. A decrease in MMP secretion was also observed when the green tea extract or EGCG was added following a 2-h stimulation with LPS.ConclusionsOur results suggested that green tea catechins, and more specifically EGCG, offer promising prospects for the development of a novel adjunctive treatment for periodontitis because of their ability to decrease the secretion of MMPs, which are important tissue-destructive enzymes produced by mucosal and immune cells.     

茶油及茶多酚抗炎作用及其机制研究

目的观察茶油及茶多酚对角叉菜胶致大鼠足跖肿胀的模型抗炎作用及其机制。方法建立角叉菜胶致大鼠足跖肿胀的模型,将甘油、茶油、1%茶多酚、0.5%茶多酚、0.25%茶多酚及哈西奈德分别涂抹于大鼠右后足,比较各组药物抑制肿胀的程度,并测定炎症组织中前列腺素E2及丙二醛（M D A）的量,以及超氧化物歧化酶（SO D）活力。结果①建立角叉菜胶所致大鼠足趾肿胀的动物模型。②各组对角叉菜胶所致大鼠足趾肿胀度均有不同程度的抑制作用。其中茶油、0.5%茶多酚和0.25%茶多酚在炎症的后期,均能抑制肿胀。与阴性对照组比较,具有统计学意义（P〈0.05或P〈0.01）;1%茶多酚与哈西奈德具有类似的显著抑制肿胀效果。③哈西奈德和茶多酚,抑制了PG E2的产生,与甘油组比较,具有统计学意义（P〈0.05或P〈0.01）。茶多酚抑制PG E2的产生,作用呈剂量依赖性。④茶油、哈西奈德溶液、1%茶多酚组的SO D活力数值较高,与阴性对照组比较,具有统计学意义（P〈0.05或P〈0.01）。茶油、哈西奈德溶液、茶多酚3个剂量组（1%、0.5%和0.25%）的M D A量降低,与甘油对照组比较,具有统计学意义（P〈0.05或P〈0.01）。结论茶油及茶多酚对角叉菜胶致大鼠的原发性刺激性炎症有抑制作用。     

Epicatechin attenuates atherosclerosis and exerts anti-inflammatory effects on diet-induced human-CRP and NFκB in vivo

Objective

Previous studies investigating flavanol-rich foods provide indications for potential cardioprotective effects of these foods, but the effects of individual flavanols remain unclear. We investigated whether the flavanol epicatechin can reduce diet-induced atherosclerosis, with particular emphasis on the cardiovascular risk factors dyslipidaemia and inflammation.

Methods

ApoE*3-Leiden mice were fed a cholesterol-containing atherogenic diet with or without epicatechin (0.1% w/w) to study effects on early- and late-stage atherosclerosis (8w and 20w). In vivo effects of epicatechin on diet-induced inflammation were studied in human-CRP transgenic mice and NFκB-luciferase reporter mice.

Results

Epicatechin attenuated atherosclerotic lesion area in ApoE*3-Leiden mice by 27%, without affecting plasma lipids. This anti-atherogenic effect of epicatechin was specific to the severe lesion types, with no effect on mild lesions. Epicatechin mitigated diet-induced increases in plasma SAA (in ApoE*3-Leiden mice) and plasma human-CRP (in human-CRP transgenic mice). Microarray analysis of aortic gene expression revealed an attenuating effect of epicatechin on several diet-induced pro-atherogenic inflammatory processes in the aorta (e.g. chemotaxis of cells, matrix remodelling), regulated by NFκB. These findings were confirmed immunohistochemically by reduced lesional neutrophil content in HCE, and by inhibition of diet-induced NFκB activity in epicatechin-treated NFκB-luciferase reporter mice.

Conclusion

Epicatechin attenuates development of atherosclerosis and impairs lesion progression from mild to severe lesions in absence of an effect on dyslipidaemia. The observed reduction of circulating inflammatory risk factors by epicatechin (e.g. SAA, human-CRP), as well as its local anti-inflammatory activity in the vessel wall, provide a rationale for epicatechin's anti-atherogenic effects.     

Total Anti-Oxidant Capacity,Flavonoid, Phenolic Acid and Polyphenol Content in Ten Selected Species of Zingiberaceae Rhizomes

Background

Natural products such as herbs, fruits, spices, beverages, vegetables are becoming more popular among scientific community and consumers because of their potential to arrest the effect of free radicals in human system. This study determined the total antioxidant capacity of ten selected species of Zingiberaceae (Ginger) used as spices and for medicinal purposes in Southeast Asia.

Materials and Methods

Methanol was used as the extraction solvent, 2,2 - diphenyl-1-picrylhydrazil (DPPH) for free radical scavenging activity and ferric reducing antioxidant power (FRAP) assays. Phenolic compounds were measured using Total flavonoid, Phenolic acid and Polyphenols content assay to evaluate the quality of the antioxidant capacity of the rhizomes and vitamin C as positive control.

Results

The results obtained revealed that Curcuma longa and Zingiber officinale had the highest free radical scavenging capacity of 270.07mg/TE/g DW and 266.95mg/TE/g DW and FRAP assay, Curcuma longa and Zingiber officinale also gave the highest ferric reducing power of 231.73mg/TE/g DW and 176.26mg/TE/g DW respectively. For Phenolic compounds, Curcuma longa and Curcuma xanthorrhiza gave the highest values of flavonoid (741.36mg/NGN/g DW and 220.53mg/NGN/g DW), phenolic acid (42.71mg/GAE/g DW and 22.03mg/GAE/g DW) and polyphenols (39.38mg/GAE/g DW and 38.01mg/GAE/g DW) respectively. Significant and positive linear correlations were found between Total antioxidant capacity and Phenolic compounds (R = 0.65 – 0.96).

Conclusion

This study provides evidence that extracts of Zingiberaceae (Ginger) rhizomes are a potential source of natural antioxidants and could serve as basis for future drugs and food supplements     

Mulberry fruits extracts induce apoptosis and autophagy of liver cancer cell and prevent hepatocarcinogenesis in vivo

Hepatocellular carcinoma (HCC) is one of the most common malignancies in Taiwan. Many risks factors induce liver chronic inflammation, fibrosis, cirrhosis, and hepatocellular carcinoma. Mulberry fruits containing polyphenols to remove free radicals and mitigate inflammation has been reported to not only against gastric cancer, melanoma and leukemia but also prevent liver injury induced by alcohol or CCl₄ in previous researches. The aim of this study is to examine whether Mulberry could inhibit hepatocarcinogenesis. In animal experiment, diethylnitrosamine (DEN) was used to induce hepatic tumorgenesis. After injecting DEN, the rats treated with mulberry water extracts (MWE) had less and smaller tumor than others without MWE. Moreover, MWE reduced the serum ALT and AST, HCC marker, cleavage caspases, Ser-15-p53 and Ser46-p53 induced by DEN. Further, we observed that mulberry polyphenol extracts (MPE) inhibited the cell growth of HepG2 cell and Hep3B cell. By using flow cytometry and western blotting methods, MPE induced HepG2 cell apoptosis by increase subG1 cells and the elevated expression of caspase-3/8/9. Instead of apoptosis, MPE caused Hep3B cells autophagy by inhibiting Akt and mTOR phosphorylation. Comprehensively, mulberry extracts has a potential to be a health supplement to prevent hepatocarcinogenesis in the future.     

Polyphenol‐rich apple extract inhibits dexamethasone‐induced sebaceous lipids production by regulating SREBP1 expression

Sebum production and excretion is a primary function of the sebaceous glands, but abnormally increased sebum production is a major cause of acne vulgaris. To identify a new candidate that regulates sebum production, we investigated the possible inhibitory effects of apple polyphenols (APP) purified from unripe apples on primary cultured human sebocytes and in patients with acne vulgaris. Dexamethasone (Dex) increased lipid synthesis and expression of the sterol response element‐binding protein 1 (SREBP 1) and its target enzymes, acetyl‐CoA carboxylase (ACC) and fatty acid synthase (FAS), in the sebocytes. However, APP inhibited Dex‐induced lipid production and expression of SREBP‐1, ACC and FAS. APP also inhibited the increase in the expression and activation of glucocorticoid receptor in the sebocytes. Taken together, these results suggest that APP may be useful to regulate sebum production and may alleviate sebum‐involved skin disease, such as acne vulgaris.     

Enteric microbiota leads to new therapeutic strategies for ulcerative colitis

Ulcerative colitis(UC) is a leading form of inflammatory bowel disease that involves chronic relapsing or progressive inflammation. As a significant proportion of UC patients treated with conventional therapies do not achieve remission, there is a pressing need for the development of more effective therapies. The human gut contains a large, diverse, and dynamic population of microorganisms, collectively referred to as the enteric microbiota. There is a symbiotic relationship between the human host and the enteric microbiota, which provides nutrition, protection against pathogenic organisms, and promotes immune homeostasis. An imbalance of the normal enteric microbiota composition(termed dysbiosis) underlies the pathogenesis of UC. A reduction of enteric microbiota diversity has been observed in UC patients, mainly affecting the butyrateproducing bacteria, such as Faecalibacterium prausnitzii, which can repress pro-inflammatory cytokines. Many studies have shown that enteric microbiota plays an important role in anti-inflammatory and immunoregulatory activities, which can benefit UC patients. Therefore, manipulation of the dysbiosis is an attractiveapproach for UC therapy.Various therapies targeting a restoration of the enteric microbiota have shown efficacy in treating patients with active and chronic forms of UC.Such therapies include fecal microbiota transplantation,probiotics,prebiotics,antibiotics,helminth therapy,and dietary polyphenols,all of which can alter the abundance and composition of the enteric microbiota.Although there have been many large,randomized controlled clinical trials assessing these treatments,the effectiveness and safety of these bacteria-driven therapies need further evaluation.This review focuses on the important role that the enteric microbiota plays in maintaining intestinal homeostasis and discusses new therapeutic strategies targeting the enteric microbiota for UC.     

An antioxidant resveratrol significantly enhanced replication of hepatitis C virus

AIM:To elucidate the effect of antioxidants,resveratrol (RVT)and astaxanthin(AXN),on hepatitis C virus(HCV) replication. METHODS:We investigated the effect of recent popular antioxidant supplements on replication of the HCV replicon system OR6.RVT is a strong antioxidant and a kind of polyphenol that inhibits replication of various viruses.AXN is also a strong antioxidant.The replication of HCV RNA was assessed by the luciferase reporter assay.An additive effect of antioxidants on antiviral effects of inter...     

Inhibition of thrombin-induced signaling by resveratrol and quercetin: effects on adenosine nucleotide metabolism in endothelial cells and platelet-neutrophil interactions

BACKGROUND: Thrombin downregulates endothelial ectonucleotidase activity resulting in high levels of adenosine diphosphate (ADP) and adenosine triphosphate (ATP) which lead to platelet, leukocyte and endothelial activation. Depending on adenosine nucleotide levels, resting platelets inhibit and thrombin-activated platelets increase respiratory burst of neutrophils. Whether the red wine polyphenols quercetin and resveratrol affect thrombin-dependent adenosine nucleotide, metabolism and thrombin-induced signaling is unknown. MATERIALS AND METHODS: ATP and ADP secretion by platelets, the impact on subsequent oxidative burst activity in neutrophils and CD39/ATPdase function in endothelial cells (ECs)was studied. Cell migration was measured in modified Boyden chambers; adenosine metabolites were quantified by high-performance liquid chromatography (HPLC). Signal transduction was studied by Western blotting. RESULTS: Quercetin and resveratrol inhibited thrombin-induced ADP and ATP secretion from platelets in a concentration-dependent manner. Augmented respiratory burst of neutrophils in response to thrombin-activated platelets was also inhibited by the two polyphenols as was neutrophil migration toward thrombin-induced supernatants of platelets. Quercetin and resveratrol restored the decreased CD39/ATPdase activity in human umbilical vein endothelial cells, in response to thrombin as demonstrated by adenosine monophosphate (AMP) and adenosine increases in endothelial culture supernatants. Both polyphenols inhibited thrombin-induced MAPK, JNK and focal adhesion kinase activities in endothelial cells. CONCLUSION: Quercetin and resveratrol interfere with the proinflammatory signaling of thrombin resulting in the inhibition of adenosine nucleotide secretion from activated platelets and decreased neutrophil function. Moreover, the polyphenols protect endothelial adenosine nucleotide metabolism when downregulated by thrombin. These observations may explain cardioprotective effects of grape products.