O-Methylated Catechins from Tea Leaves Inhibit Multiple Protein Kinases in Mast Cells

Epigallocatechin-3-gallate potentiates curcumin's ability to suppress uterine leiomyosarcoma cell growth and induce apoptosis

BACKGROUND

Uterine leiomyosarcoma (LMS) has an unfavorable response to standard chemotherapeutic regimens. Two natural occurring compounds, curcumin and epigallocatechin gallate (EGCG), are reported to have anti-cancer activity. We previously reported that curcumin reduced uterine LMS cell proliferation by targeting the AKT-mTOR pathway. However, challenges remain in overcoming curcumin's low bioavailability.

METHODS

The human LMS cell line SKN was used. The effect of EGCG, curcumin or their combination on cell growth was detected by MTS assay. Their effect on AKT, mTOR, and S6 was detected by Western blotting. The induction of apoptosis was determined by Western blotting using cleaved-PARP specific antibody, caspase-3 activity and TUNEL assay. Intracellular curcumin level was determined by a spectrophotometric method. Antibody against EGCG cell surface receptor, 67-kDa laminin receptor (67LR), was used to investigate the role of the receptor in curcumin's increased potency by EGCG.

RESULTS

In this study, we showed that the combination of EGCG and curcumin significantly reduced SKN cell proliferation more than either drug alone. The combination inhibited AKT, mTOR, and S6 phosphorylation, and induced apoptosis at a much lower curcumin concentration than previously reported. EGCG enhanced the incorporation of curcumin. 67LR antibody partially rescued cell proliferation suppression by the combination treatment, but was not involved in the EGCG-enhanced intracellular incorporation of curcumin.

CONCLUSIONS

EGCG significantly lowered the concentration of curcumin required to inhibit the AKT-mTOR pathway, reduce cell proliferation and induce apoptosis in uterine LMS cells by enhancing intracellular incorporation of curcumin, but the process was independent of 67LR.

A diet enriched with cocoa prevents IgE synthesis in a rat allergy model

Previous studies in young rats reported the impact of cocoa intake on healthy immune status and allow suggesting it may have a role in the prevention of some immune-mediated diseases. The aim of this study was to ascertain the effect of a cocoa diet in a model of allergy in young rats. Three-week-old Brown Norway rats were immunized by i.p. injection of ovalbumin (OVA) with alum as adjuvant and Bordetella pertussis toxin. During the next 4 weeks rats received either a cocoa diet (containing 0.2% polyphenols, w/w) or a standard diet. Animals fed a standard diet showed high concentrations of anti-OVA IgG1, IgG2a, IgG2b and high anti-OVA IgE titres, which is the antibody involved in allergic response. In contrast, animals fed a cocoa diet showed significantly lower concentrations of anti-OVA IgG1 and IgG2a antibodies. Interestingly, the cocoa diet prevented anti-OVA IgE synthesis and decreased total serum IgE concentration. Analysis of cytokine production in lymph node cells at the end of the study revealed that, in this compartment, the cocoa diet decreased the tumor necrosis factor (TNF)-α and the interleukin (IL)-10 secretion but not IL-4 production. In conclusion, a cocoa-enriched diet in young rats produces an immunomodulatory effect that prevents anti-allergen IgE synthesis, suggesting a potential role for cocoa flavonoids in the prevention or treatment of allergic diseases.

Biochemical basis for functional ingredient design from fruits

Functional food ingredients (nutraceuticals) in fruits range from small molecular components, such as the secondary plant products, to macromolecular entities, e.g., pectin and cellulose, that provide several health benefits. In fruits, the most visible functional ingredients are the color components anthocyanins and carotenoids. In addition, several other secondary plant products, including terpenes, show health beneficial activities. A common feature of several functional ingredients is their antioxidant function. For example, reactive oxygen species (ROS) can be oxidized and stabilized by flavonoid components, and the flavonoid radical can undergo electron rearrangement stabilizing the flavonoid radical. Compounds that possess an orthodihydroxy or quinone structure can interact with cellular proteins in the Keap1/Nrf2/ARE pathway to activate the gene transcription of antioxidant enzymes. Carotenoids and flavonoids can also exert their action by modulating the signal transduction and gene expression within the cell. Recent results suggest that these activities are primarily responsible for the health benefits associated with the consumption of fruits and vegetables.

Development of Expressed Sequence Tag (EST)-based Cleaved Amplified Polymorphic Sequence (CAPS) markers of tea plant and their application to cultivar identification

To develop cleaved amplified polymorphic sequence (CAPS) markers for cultivar identification of the tea leaf, 5 primer pairs designed on the basis of genes that encode proteins related to nitrogen assimilation and 26 primer pairs based on expressed sequence tag (EST) sequences of the root of tea plant were screened. From combinations of primer pair and restriction enzyme that showed polymorphism among tea plants, 16 markers were selected and applied to DNA fingerprinting of Japanese tea cultivars. Sixty-three cultivars, except for a bud sport (Kiraka) and its original cultivar (Yabukita) and a pair that was the progeny of the same crossing parent (Harumoegi and Sakimidori), were distinguished from one another. By combining the 16 markers with previously developed CAPS markers and observing the physical appearance, 67 cultivars were distinguishable. The cultivars involve approximately 95% of total tea cultivating area in Japan; therefore, about 95% of tea leaves produced in Japan can be authenticated by labeling their cultivars.

Inhibitory effect of epigallocatechin gallate (EGCG), resveratrol, and curcumin on proliferation of human retinal pigment epithelial cells in vitro

PURPOSE

To investigate potential inhibitory effects of three polyphenolic agents, epigallocatechin gallate (EGCG; from green tea), resveratrol (from red wine), and curcumin (from turmeric), on the proliferation of human retinal pigment epithelial (RPE) cells and to elucidate unwanted effects.

METHODS

ARPE19 cells and primary human RPE cells were cultured in the presence of various concentrations of EGCG, resveratrol, or curcumin, and compared with controls. The number of viable cells was determined after 24, 48, and 72 hr by flow cytometrical enumeration. Furthermore, cell division was measured by dye dilution assay using carboxyfluorescein succinimidyl ester (CFSE), cell death by Hoechst 33258 staining, and apoptosis by staining for active caspase 3/7 and 8.

RESULTS

The three drugs inhibited the increase of RPE cell numbers at all time points, with resveratrol being the most efficient and curcumin being the least efficient. EGCG inhibited cell proliferation with intermediate efficiency, and showed little induction of cell death. Resveratrol almost completely suppressed cell proliferation, and induced RPE cell necrosis and caspase 3/7- and caspase 8-dependent apoptosis. Curcumin inhibited RPE cell increase exclusively by inducing caspase 3/7-dependent but caspase 8-independent cell death and necrosis.

CONCLUSIONS

All three polyphenols tested reduced the absolute number of cells, but had different effects on cell proliferation, apoptosis, and necrosis. Resveratrol was most potent and EGCG induced the least cell death. These polyphenols may aid treatment of proliferative vitreoretinopathy (PVR).

Effect of green tea powder (Camellia sinensis L. cv. Benifuuki) particle size on O-methylated EGCG absorption in rats; The Kakegawa Study

Tea polyphenols, e.g., (-)-epigallocatechin-3-O-(3-O-methyl gallate (EGCG3"Me), (-)-epigallocatechin-3-O-gallate (EGCG), (-)-epigallocatechin (EGC), (-)-epicatechin-3-O-gallate (ECG), and (-)-epicatechin (EC), are believed to be responsible for the beneficial effects of tea. 'Benifuuki', a tea (Camellia sinensis L.) cultivar grown in Japan, is rich in the anti-allergic molecule epigallocatechin-3-O-(3-O-methyl) gallate (EGCG3"Me). Pulverized Benifuuki green tea powder (BGP) is more widely distributed than leaf tea in Japan. Japanese people mix their pulverized tea with water directly, whereas it is common to drink leaf tea after extraction. However, few studies of the effects of BGP particle size on polyphenol bioavailability have been performed. This study was conducted to investigate the absorption of catechins in rats after the intragastric administration of Benifuuki green tea. Therefore, we assessed the plasma concentrations of catechins following the ingestion of BGP with different mean particle sizes (2.86, 18.6, and 76.1 μm) or Benifuuki green tea infusion (BGI) as a control in rats. The bioavailabilities of EGCG3"Me, EGCG, ECG, EGC, and EC were analyzed after the oral administration of a single dose of Benifuuki green tea (125 mg/rat) to rats. The plasma concentrations of tea catechins were determined by HPLC analysis combined with of electrochemical detection (ECD) using a coulometric array. The AUC (area under the drug concentration versus time curve; min μg/mL) of ester-type catechins (EGCG3"Me, EGCG, and ECG) for the BGP 2.86 μm were significantly higher than those in the infusion and 18.6 and 76.1 μm BGP groups, but the AUC of free-type catechins (EGC and EC) showed no differences between these groups. Regarding the peak plasma level of EGCG3"Me adjusted for intake, BGP 2.86 μm and BGI showed higher values than the BGP 18.6 and 76.1 μm groups, and the peak plasma levels of the other catechins displayed the same tendency. The present study demonstrates that the bioavailability of ester-type catechins (EGCG and ECG) can be improved by reducing the particle size of green tea, but the plasma level of EGCG3"Me in the BGI group was similar to that in the BGP 2.86 μm group. This result suggests that drinking Benifuuki green tea with a particle size of around 2 μm would deliver the anti-allergic EGCG3"Me and the anti-oxidant EGCG efficiently.

Green tea polyphenol sensing

Green tea polyphenols have emerged over the past two decades as an important dietary factor for health promotion. There is considerable evidence that tea polyphenols, in particular (-)-epigallocatechin-3-gallate (EGCG) inhibit carcinogenesis. However, the mechanisms for the cancer-preventive activity of EGCG are not completely characterized and many features remain to be elucidated. Recently we have identified a cell-surface EGCG receptor and the relating molecules that confer EGCG responsiveness to many cancer cells at physiological concentrations. Here, we review some of the reported mechanisms for the cancer chemopreventive action of EGCG and provide an overview of several molecules that sense and manage the physiological functions of EGCG.

Anti-allergic activity of standardized extract of Albizia lebbeck with reference to catechin as a phytomarker

BACKGROUND AND AIM

The major groups of phytonutrients found in plants include polyphenols, flavonoids, terpenes, amines, etc., all of which are observed to have potential anti-allergic activity. In this study, we evaluated the anti-allergic activity of the standardized extract of Albizia lebbeck with respect to the catechin, a polyphenolic phytomarker.

MATERIAL AND METHODS

The percentage of catechin in the ethanolic extract was found to be 14.72 mg/g. We administered Albizia lebbeck (50-300 mg/kg) and 50 mg/kg of catechin to mice to evaluate the mast cell stabilization and estimation of histamine elevation in the plasma.

RESULTS AND CONCLUSION

Results support the conclusion that Albizia lebbeck at different concentrations has got potent mast cell stabilizing property and the IC(50) value of Albizia lebbeck was found to be 85 microg/ml. This inhibitory potential of catechin from Albizia lebbeck is perhaps due to modulation of two important effector's functions, histamine release and cytokine expression of antigen -IgE activated mast cells.

Cloning of a novel O-methyltransferase from Camellia sinensis and synthesis of o-methylated EGCG and evaluation of their bioactivity

The gene of a novel O-methyltransferase was isolated from tea cultivars (Camellia sinensis L.). Using the recombinant enzyme, O-methylated (-)-epigallocatechin-3-O-gallate (EGCG) in all cases were synthesized. EGCG and the synthesized O-methylated EGCGs including (-)-epigallocatechin-3-O-(3-O-methyl)-gallate (EGCG3''Me), (-)-epigallocatechin-3-O- (4-O-methyl)-gallate(EGCG4''Me), (-)-epigallocatechin-3-O-(3,5-O-dimethyl)-gallate (EGCG3'',5''diMe), and (-)-3-O-methyl-epigallocatechin-3-O-(3,5-O-dimethyl)-gallate (EGCG3',3'',5''triMe) were assayed using the 1,1-diphenyl-2-picrylhydrazyl (DPPH) radical scavenging assay and antibacterial activity. EGCG was the most effective of the O-methylated EGCGs. The antiallergic effects of EGCG and the other O-methylated EGCGs were measured by conducting histamine release assays using bone marrow-derived mouse mast cells, and the order of potency was EGCG3',3'',5''triMe = EGCG3'',5''diMe > EGCG3''Me > EGCG. These results indicated that reducing the number of hydroxyl groups decreases the effectiveness of DPPH radical scavenging and antibacterial activity. In contrast, the inhibition of histamine release was potentiated by an increase in the number of methyl groups in EGCG, especially in the galloyl moiety.

Antihypertensive effect of Benifuuki tea containing O-methylated EGCG

Benifuuki is a tea cultivar with an antiallergic effect stronger than that of Yabukita tea, the most popular green tea cultivar consumed in Japan. The effective compound is (-)-epigallocatechin-3-O-(3-O-methyl)gallate (EGCG3''Me), an O-methylated derivative of EGCG. This study examined the antihypertensive effects of EGCG3''Me and Benifuuki tea. First, it was determined that EGCG3''Me has a significant inhibitory effect on the activity of angiotensin I-converting enzyme (ACE). Second, clinical trials showed that Benifuuki tea suppressed high blood pressure to a greater extent than green tea that did not contain EGCG3''Me after equal amounts of tea catechins were consumed for 8 weeks. The effect of Benifuuki tea on human hypertension is mainly the result of the strong inhibitory effect of EGCG3''Me on ACE activity, its high rate of absorption, and its stability in the blood.

Identifications of inhibitors of IgE production by human lymphocytes isolated from 'Cha Chuukanbohon Nou 6' tea leaves

BACKGROUND

Tea (Camellia sinensis L.) is consumed all over the world and in especially large quantities in Japan and China, where it has been used not only as a daily beverage but also for medicinal purposes for thousands of years. Tea has been found to exhibit various bioregulatory activities, including antiallergic, anticarcinogenic, antimetastatic, antioxidative, antihypertensive, antihypercholesterolemic, anti-dental caries and antibacterial effects, and to influence intestinal flora.

RESULTS

Cha Chuukanbohon Nou 6 is a tea cultivar improved by the National Institute of Vegetable and Tea Science (NIVTS) in Japan. On comparing chemical constituents of 11 varieties of tea leaves by high-performance liquid chromatography, we found two new major compounds in Cha Chuukanbohon Nou 6. Nuclear magnetic resonance spectroscopy revealed these compounds to be theogallin and 1,2-di-O-galloyl-4,6-O-(S)-hexahydroxydiphenoyl-beta-D-glucopyranose. The two were similar in chemical structure to strictinin, an inhibitor of immunoglobulin (Ig) production. Thus their effects on the production of Igs by peripheral blood lymphocytes were tested. Both compounds, like strictinin, inhibited IgE production.

CONCLUSION

The results suggest Cha Chuukanbohon Nou 6 to be the basis of an antiallergic beverage.

The efficacy of early treatment of seasonal allergic rhinitis with benifuuki green tea containing O-methylated catechin before pollen exposure: an open randomized study

BACKGROUND

We previously reported that 'benifuuki' green tea containing O-methylated catechin significantly relieved the symptoms of perennial or seasonal rhinitis compared with a placebo green tea that did not contain O-methylated catechin in randomized double-blind clinical trials. In this study we assessed the effects of 'benifuuki' green tea on clinical symptoms of seasonal allergic rhinitis.

METHODS

An open-label, single-dose, randomized, parallel-group study was performed on 38 subjects with Japanese cedar pollinosis. The subjects were randomly assigned to long-term (December 27, 2006-April 8, 2007, 1.5 months before pollen exposure) or short-term (February 15, 2007: after cedar pollen dispersal--April 8, 2007) drinking of a 'benifuuki' tea drink containing 34 mg O-methylated catechin per day. Each subject recorded their daily symptom scores in a diary. The primary efficacy variable was the mean weekly nasal symptom medication score during the study period.

RESULTS

The nasal symptom medication score in the long-term intake group was significantly lower than that of the short-term intake group at the peak of pollen dispersal. The symptom scores for throat pain, nose-blowing, tears, and hindrance to activities of daily living were significantly better in the long-term group than the short-term group. In particular, the differences in the symptom scores for throat pain and nose-blowing between the 2 groups were marked.

CONCLUSIONS

We conclude that drinking 'benifuuki' tea for 1.5 months prior to the cedar pollen season is effective in reducing symptom scores for Japanese cedar pollinosis.

Inhibitory effect of carotenoids on the degranulation of mast cells via suppression of antigen-induced aggregation of high affinity IgE receptors

Carotenoids have been demonstrated to possess antioxidative and anti-inflammatory effects. However, there is no report that the effects of carotenoids on degranulation of mast cell is critical for type I allergy. In this study, we focused on the effect of carotenoids on antigen-induced degranulation of mast cells. Fucoxanthin, astaxanthin, zeaxanthin, and beta-carotene significantly inhibited the antigen-induced release of beta-hexosaminidase in rat basophilic leukemia 2H3 cells and mouse bone marrow-derived mast cells. Those carotenoids also inhibited antigen-induced aggregation of the high affinity IgE receptor (Fc epsilonRI), which is the most upstream of the degranulating signals of mast cells. Furthermore, carotenoids inhibited Fc epsilonRI-mediated intracellular signaling, such as phosphorylation of Lyn kinase and Fyn kinase. It suggests that the inhibitory effect of carotenoids on the degranulation of mast cells were mainly due to suppressing the aggregation of Fc epsilonRI followed by intracellular signaling. In addition, those carotenoids inhibited antigen-induced translocation of Fc epsilonRI to lipid rafts, which are known as platforms of the aggregation of Fc epsilonRI. We assume that carotenoids may modulate the function of lipid rafts and inhibit the translocation of Fc epsilonRI to lipid rafts. This is the first report that focused on the aggregation of Fc epsilonRI to investigate the mechanism of the inhibitory effects on the degranulation of mast cells and evaluated the functional activity of carotenoids associated with lipid rafts.

Efficient procedure for isolating methylated catechins from green tea and effective simultaneous analysis of ten catechins, three purine alkaloids, and gallic acid in tea by high-performance liquid chromatography with diode array detection

Monomers of (-)-epigallocatechin (EGC), (-)-epigallocatechin gallate (EGCG), (-)-epicatechin (EC), (-)-epicatechin gallate (ECG), (-)-epigallocatechin 3-O-(3-O-methyl) gallate (EGCG3''Me) and (-)-3-O-methyl epicatechin gallate (ECG3'Me) (purity, >97%) were successfully prepared from extract of green tea by two-time separation with Toyopearl HW-40S column chromatography eluted by 80% ethanol. In addition, monomers of (-)-catechin (C), (-)-gallocatechin (GC), (-)-gallocatechin gallate (GCG), and (-)-catechin gallate (CG) (purity, >98%) were prepared from EC, EGC, EGCG, and ECG by heat-epimerization and semi-preparative HPLC chromatography. With the prepared catechin standards, an effective and simultaneous HPLC method for the analysis of gallic acid, tea catechins, and purine alkaloids in tea was developed in the present study. Using an ODS-100Z C(18) reversed-phase column, fourteen compounds were rapidly separated within 15min by a linear gradient elution of formic acid solution (pH 2.5) and methanol. A 2.5-7-fold reduction in HPLC analysis time was obtained from existing analytical methods (40-105min) for gallic acid, tea catechins including O-methylated catechins and epimers of epicatechins, as well as purine alkaloids. Detection limits were generally on the order of 0.1-1.0ng for most components at the applied wavelength of 280nm. Method replication generally resulted in intraday and interday peak area variation of <6% for most tested components in green, Oolong, black, and pu-erh teas. Recovery rates were generally within the range of 92-106% with RSDs less than 4.39%. Therefore, advancement has been readily achievable with commonly used chromatography equipments in the present study, which will facilitate the analytical, clinical, and other studies of tea catechins.

Procyanidin C1 from apple extracts inhibits Fc epsilon RI-mediated mast cell activation

BACKGROUND

Polyphenol-enriched fractions, which are extracted from unripe apples (Rosaceae, Malus spp.), consisting of procyanidins (polymers of catechins) are known to have an anti-allergenic effect on patients with various allergic diseases. Although it has been reported that apple extracts inhibit histamine release from mast cells, the molecular mechanisms for this anti-allergenic effect are not well understood. To elucidate the molecular mechanisms by which apple extracts induce their anti-allergenic effects, the effects of purified apple extract components on high-affinity receptors for IgE (Fc epsilon RI)-mediated mast cell activation were investigated.

METHODS

The anti-allergic effect of oral administration of apple procyanidin extracts on passive cutaneous anaphylactic responses of BALB/c mice was assessed. We evaluated the effects of procyanidin C1 (PC1) [epicatechin-(4beta-->8)-epicatechin-(4beta-->8)-epicatechin], a component of the procyanidin fraction, on mouse bone-marrow-derived mast cell degranulation, cytokine production, protein tyrosine phosphorylation and on the generation of intracellular reactive oxygen species (ROS) of cells stimulated by Fc epsilon RI cross-linking in vitro.

RESULTS

In an in vivo study, oral administration of the procyanidin fraction suppressed the mast-cell-dependent allergic reaction. In in vitro studies, PC1 dose-dependently decreased Fc epsilon RI-mediated degranulation and cytokine production of mast cells. Furthermore, PC1 inhibited tyrosine phosphorylation of Syk and linker for activation of T cells, and the ROS generation in stimulated mast cells.

CONCLUSIONS

PC1 suppresses Fc epsilon RI-mediated mast cell activation by inhibiting intracellular signaling pathways. These observations provide evidence for the anti-allergenic effects of the procyanidin-enriched apple extract.

Tea catechins have dual effect on mast cell degranulation induced by compound 48/80

Green tea catechins are emerging as one of the most efficient and safest ingredient in health promoting food. We investigated catechin's effects on intracellular ROS generation in mast cell activation and degranulation. Compound 48/80, receptor mimetic basic secretagogues for mast cell, induced ROS generation dose-dependently with bell-shaped degranulation pattern in canine cutaneous mastocytoma cells (CM-MC). When intracellular ROS level was relatively low, catechins decreased both ROS and the degranulation. However, when intracellular ROS level was remarkably high, catechins decreased ROS level but increased the degranulation paradoxically. Gallocatechins showed the stronger effects than non-gallated catechins. Exogenous H(2)O(2) also shows dual effect on degranulation dose-dependently. EGCG shows the dual effect on the tyrosine and threonine phosphorylation depending on the concentration of compound 48/80. Particularly, 60 kDa protein tyrosine-phosphorylated by EGCG with 3 microg/ml of compound 48/80 might be a negative regulator for the degranulation. Taken together, there is an optimal level of ROS for the degranulation, and the catechins have a dual function by controlling ROS level.

The impact of the 67kDa laminin receptor on both cell-surface binding and anti-allergic action of tea catechins

Here, we investigated the structure-activity relationship of major green tea catechins and their corresponding epimers on cell-surface binding and inhibitory effect on histamine release. Galloylated catechins; (-)-epigallocatechin-3-O-gallate (EGCG), (-)-gallocatechin-3-O-gallate (GCG), (-)-epicatechin-3-O-gallate (ECG), and (-)-catechin-3-O-gallate (CG) showed the cell-surface binding to the human basophilic KU812 cells by surface plasmon resonance analysis, but their non-galloylated forms did not. Binding activities of pyrogallol-type catechins (EGCG and GCG) were higher than those of catechol-type catechins (ECG and CG). These patterns were also observed in their inhibitory effects on histamine release. Previously, we have reported that biological activities of EGCG are mediated through the binding to the cell-surface 67kDa laminin receptor (67LR). Downregulation of 67LR expression caused a reduction of both activities of galloylated catechins. These results suggest that both the galloyl moiety and the B-ring hydroxylation pattern contribute to the exertion of biological activities of tea catechins and their 67LR-dependencies.

In vitro and in vivo anti-allergic effects of 'benifuuki' green tea containing O-methylated catechin and ginger extract enhancement

'Benifuuki', a tea (Camellia Sinensis L.) cultivar in Japan, is rich in anti-allergic epigallocatechin-3-O-(3-O-methyl) gallate (EGCG3''Me). 'Benifuuki' green tea and simultaneous addition of ginger extract remarkably suppressed cytokine (TNF-alpha and MIP-1alpha) secretion from mouse bone marrow-derived mast cells after antigen stimulation and, as expected, suppressed delay-type allergy. After drinking 'benifuuki' green tea containing 43.5 mg of EGCG and 8.5 mg of EGCG3''Me, the AUC (area under the drug concentration time curve; min mug/ml) of EGCG was 6.72 +/- 2.87 and EGCG3''Me was 8.48 +/- 2.54 in healthy human volunteers. Though the dose of EGCG was 5.1 times the dose of EGCG3''Me, the AUC of EGCG3''Me was higher than that of EGCG. A double blind clinical study on subjects with Japanese cedar pollinosis was carried out. At the 11th week after starting the study, in the most severe cedar pollen scattering period, symptoms, i.e., blowing the nose and itching eyes, were significantly relieved in the 'benifuuki' intake group compared with the placebo group, and blowing the nose, itching eyes and nasal symptom score, and at the 11th and 13th weeks, stuffy nose, throat pain and the nasal symptom medication score were significantly relieved in the 'benifuuki' containing ginger extract group compared with the placebo group. These results suggested that over one consecutive month, drinking 'benifuuki' green tea was useful to reduce some of the symptoms from Japanese cedar pollinosis, and did not affect any normal immune response in subjects with seasonal rhinitis, and the ginger extract enhanced the effect of 'benifuuki' green tea.

Determination of theaflavins including methylated theaflavins in black tea leaves by solid-phase extraction and HPLC analysis

A quantitative method for four theaflavins and two methylated theaflavin derivatives in black tea leaves was developed by solid-phase extraction and a high-performance liquid chromatographic method with photodiode array detection. The theaflavins in black tea leaves were extracted three times with 40 vol 50% aqueous ethanol (mg dry tea powder/mL) containing 2% ascorbic acid. The ethanol extracts were diluted 4-fold with distilled water. All diluted extracts were directly applied to the solid-phase C18 cartridge column without concentration. The fraction of theaflavins was obtained by 40% ethanol extraction after rinsing with water followed with 15% ethanol extraction. An aliquot of theaflavins after concentration was injected onto an ODS C18 reversed-phase column, and four theaflavins and two methylated theaflavins were sufficiently separated by a linear gradient system using distilled water and acetonitrile with 0.5% acetic acid. This analytical method is sensitive for the determination of a small amount of methylated theaflavins, since various interfering substances produced during the fermentation process were eliminated in advance by solid-phase extraction. Using this analytical method, we also demonstrated that methylated theaflavins were easily produced during the manufacture of black tea.

Relationship between the biological activities of methylated derivatives of (-)-epigallocatechin-3-O-gallate (EGCG) and their cell surface binding activities

It was previously reported that (-)-epigallocatechin-3-O-gallate (EGCG) suppresses the expression of the high-affinity IgE receptor FcepsilonRI in human basophilic cells and that this suppressive effect is associated with EGCG binding to the cell surface. This study examined the effects of five methylated derivatives of EGCG, (-)-epigallocatechin-3-O-(3-O-methyl)gallate (EGCG 3' 'Me), (-)-epigallocatechin-3-O-(4-O-methyl)gallate (EGCG 4' 'Me), (-)-4'-O-methyl-epigallocatechin-3-O-gallate (EGCG 4'Me), (-)-epigallocatechin-3-O-(3,4-O-methyl)gallate (EGCG 3' '4' 'diMe), and (-)-4'-O-methyl-epigallocatechin-3-O-(4-O-methyl)gallate (EGCG 4'4' 'diMe) on FcepsilonRI expression and ERK1/2 phosphorylation, and each of their cell surface binding activities was measured. Of these five methylated derivatives, three that are methylated at the 3' '- and/or 4' '-position, EGCG 3' 'Me, EGCG 4' 'Me, and EGCG 3' '4' 'diMe, suppressed FcepsilonRI expression and ERK1/2 phosphorylation, although the suppressive effects were lower than that of EGCG. EGCG 4'Me and EGCG 4'4' 'diMe, both of which are methylated at the 4'-position, did not demonstrate a suppressive effect. Furthermore, it was found that EGCG 3' 'Me, EGCG 4' 'Me, EGCG 3' '4' 'diMe, and EGCG 4'Me, which are methylated at the 3' '- and/or 4' '-positions or the 4'-position, could bind to the cell surface even though their binding activities were lower than that of EGCG. Only EGCG 4'4' 'diMe, which is methylated at both the 4'- and 4' '-positions, could not bind. These results suggest that the trihydroxyl structure of the B ring is essential for EGCG to exert the suppressive effects and that the hydroxyl groups on both the 4'-position in the B ring and the 4' '-position in the gallate are crucial for the cell surface binding activity of EGCG.

Epigallocatechin gallate suppresses expression of receptor activator of NF-κB ligand (RANKL) in Staphylococcus aureus infection in osteoblast-like NRG cells

Catechin, a constituent of tea, possesses various bioactivities. In particular, the most abundant catechin in tea is epigallocatechin gallate (EGCg), which has an anti-inflammatory effect. In the present study, the usability of EGCg for osteomyelitis treatment was examined. Osteomyelitis is a difficult disease to cure, partly due to bone lysis caused by infected osteoblasts. Since bone lysis is promoted by proinflammatory cytokines and the receptor activator of NF-κB ligand (RANKL), osteoblasts were infected with Staphylococcus aureus and the effect of EGCg on the production of cytokines was examined. It was found that the production of interleukin 6 and RANKL was suppressed in the osteoblasts treated with EGCg, which indicated an inflammation suppression effect of EGCg in osteomyelitis treatment.

Simultaneous analysis of catechins, gallic acid, strictinin, and purine alkaloids in green tea by using catechol as an internal standard

We developed a high-performance liquid chromatography-based method for simultaneous analysis of nine catechins, gallic acid, strictinin, caffeine, and theobromine in green tea by using catechol as an internal standard. Although the high cost and instability of the catechin reference standards limit the application of this method, the addition of ascorbic acid to the standard stock solution preserved the stability of the reference standards in the solution for 1 year when stored at -30 degrees C. Furthermore, we found that the slopes of the calibration curves plotted were stable for a run time of 2000 h. Our method proved to be appropriate for quantification and yielded good correlation coefficients, detection levels, repeatability, reproducibility, and recovery rates. Quantitative data revealed that the contribution of only 200 mL of brewed tea to the total dietary catechins was approximately 220-420 mg, while that of 500 mL of bottled tea was approximately 170-900 mg.

Epigallocatechin-3-Gallate Inhibits Secretion of TNF-α, IL-6 and IL-8 through the Attenuation of ERK and NF-κB in HMC-1 Cells

BACKGROUND

Epigallocatechin-3-gallate (EGCG) is a major form of tea catechin and has a variety of biological activities. In the present study, we investigated the effect of EGCG on the secretion of TNF-alpha, IL-6 and IL-8, as well as its possible mechanism of action by using the human mast cell line (HMC-1).

METHODS

EGCG was treated before the activation of HMC-1 cells with phorbol 12-myristate 13-acetate (PMA) plus calcium ionophore (A23187). To investigate the effect of EGCG on PMA+A23187-stimulated HMC-1 cells, ELISA, Western blot analysis, electrophorectic mobility shift assay and luciferase assay were used in this study.

RESULTS

EGCG (100 microM) inhibited PMA+A23187-induced TNF-alpha, IL-6 and IL-8 expression and production. EGCG inhibited the intracellular Ca(2+) level. EGCG attenuated PMA+A23187-induced NF-kappaB and extracellular signal-regulated kinase (ERK1/2) activation, but not that of c-Jun N-terminal kinase or p38 mitogen-activated protein kinase.

CONCLUSION

EGCG inhibited the production of TNF-alpha, IL-6 and IL-8 through the inhibition of the intracellular Ca(2+) level, and of ERK1/2 and NF-kappaB activation. These results indicate that EGCG may be helpful in regulating mast-cell-mediated allergic inflammatory response.

The involvement of the 67 kDa laminin receptor-mediated modulation of cytoskeleton in the degranulation inhibition induced by epigallocatechin-3-O-gallate

Recently, we have reported that (-)-epigallocatechin-3-O-gallate (EGCG) acts as an inhibitor of degranulation. However, the inhibitory mechanism for degranulation is still poorly understood. Here we show that suppression of exocytosis-related myosin II regulatory light chain phosphorylation and alteration of actin remodeling are involved in the inhibitory effect of EGCG on the calcium ionophore-induced degranulation from human basophilic KU812 cells. Surface plasmon resonance assay also revealed that EGCG binds to the cell surface, and the disruption of lipid rafts resulted in reduction of EGCG's ability. We have previously identified the raft-associated 67kDa laminin receptor (67LR) as an EGCG receptor on the cell surface. Treatment of the cells with anti-67LR antibody or RNA interference-mediated downregulation of 67LR expression abolished the effects of EGCG. These findings suggest that EGCG-induced inhibition of the degranulation includes the primary binding of EGCG to the cell surface 67LR and subsequent modulation of cytoskeleton.

Regulation of IL-1-induced selective IL-6 release from human mast cells and inhibition by quercetin

Mast cells are involved in allergic reactions, but also in innate immunity and inflammation. Crosslinkage of mast cell Fc immunoglobulin E receptors (FcvarepsilonRI) by multivalent antigen triggers secretion of granule-stored mediators, as well as de novo synthesis of cytokines, including interleukin (IL)-6. We showed recently that the proinflammatory cytokine IL-1 stimulates human leukemic mast cells (HMC-1) and human umbilical cord blood-derived cultured mast cells (hCBMCs) to release newly synthesized IL-6 without tryptase in the absence of degranulation. Here, we investigated several signal-transduction pathways activated by IL-1 leading to IL-6 production by HMC-1 and hCBMCs. We also investigated the effect of the flavonol quercetin that was recently shown to strongly inhibit IL-6 secretion in response to allergic stimulation from hCBMCs.IL-1 stimulated p38, but did not activate extracellular signal-regulated kinase (ERK) or c-jun N-terminal kinase (JNK); it also did not activate protein kinase C (PKC) isozymes alpha, beta, mu and zeta, except for PKC-theta, which was phosphorylated. The p38 inhibitor SB203580 and the PKC inhibitors Calphostin C and Gö6976 completely inhibited IL-1-induced IL-6 production. Quercetin 1-100 microM inhibited IL-1-induced IL-6 secretion, p38 and PKC-theta phosphorylation in a dose-dependent manner. These results indicate that IL-1-stimulated IL-6 production from human mast cells is regulated by biochemical pathways distinct from IgE-induced degranulation and that quercetin can block both IL-6 secretion and two key signal transduction steps involved.

Effects of Methylated Derivatives of Luteolin Isolated from Cyperus alopecuroides in Rat H4IIE Hepatoma Cells*

Polyphenols are ubiquitous substances in human diet. Their antioxidative, antiinflammatory and antiviral effects are of interest for human health, and polyphenols such as luteolin are used at high concentrations in food supplements. Luteolin is metabolized to glucuronides, but also to methylated derivatives. For example, O-methylation of the catechol group mediated by the catechol-O-methyl transferase, is an important step in flavonoid metabolism. The aim of this project was to determine the effect of O-methylation on antioxidative capacity and cytotoxicity of luteolin in H4IIE rat hepatoma cells. Therefore we analyzed the effects of luteolin 5,3'-dimethylether, isolated from the flowers of foxtail flatsedge (Cyperus alopecuroides) and luteolin 5,7,3',4'-tetramethylether compared to the non-methylated flavonoid luteolin. The antioxidative potential of luteolin was lowered by methylation, an effect that seems to be mediated by masking of the catechol moiety in the B ring. The cytotoxic potential of luteolin 5,3'-dimethylether is comparable to luteolin, but the tetramethylether showed no cytotoxic effect. The cytotoxic effect of luteolin but not luteolin 5,3'-dimethylether was mediated via apoptosis (caspase-3 activation). We conclude that the O-methylation of luteolin led to a decreased radical-scavenging activity and to a reduction in the apoptotic potential of the flavonoid.

Polymeric grape-seed procyanidins, but not monomeric catechins and oligomeric procyanidins, impair degranulation and membrane ruffling in RBL-2H3 cells

Grape-seed proanthocyanidins (GSPs) are catechin polymers that are predicted to form helices in their global minimum-energy conformation and to have a mean degree of polymerization of seven (mDP = 7). The highly polymerized GSP-H fraction (mDP = 10) was found to impair degranulation in RBL-2H3 cells after stimulation with an antigen (Ag) and treatment with the Ca-ATPase inhibitor thapsigargin (Tg). In addition, GSP-H affected actin cytoskeleton and inhibited membrane ruffling in these cells, resulting in the suppression of exocytosis. By contrast, monomeric epicatechin, the dimeric procyanidins PA-1, PA-2, and PB-2, and the oligomerized GSP-L (mDP = 3) had no effect on membrane ruffling and degranulation. These findings indicate that the molecular size and length of GSP-H are needed for the inhibition of membrane ruffling and degranulation in RBL-2H3 mast-cell lines.

Mechanisms of action of green tea catechins, with a focus on ischemia-induced neurodegeneration

Catechins are dietary polyphenolic compounds associated with a wide variety of beneficial health effects in vitro, in vivo and clinically. These therapeutic properties have long been attributed to the catechins' antioxidant and free radical scavenging effects. Emerging evidence has shown that catechins and their metabolites have many additional mechanisms of action by affecting numerous sites, potentiating endogenous antioxidants and eliciting dual actions during oxidative stress, ischemia and inflammation. Catechins have proven to modulate apoptosis at various points in the sequence, including altering expression of anti- and proapoptotic genes. Their anti-inflammatory effects are activated through a variety of different mechanisms, including modulation of nitric oxide synthase isoforms. Catechins' actions of attenuating oxidative stress and the inflammatory response may, in part, account for their confirmed neuroprotective capabilities following cerebral ischemia. The versatility of the mechanisms of action of catechins increases their therapeutic potential as interventions for numerous clinical disorders. However, more epidemiological and clinical studies need to be undertaken for their efficacy to be fully elucidated.

Costimulation of mast cells by 4-1BB, a member of the tumor necrosis factor receptor superfamily, with the high-affinity IgE receptor

Mast cells are the major effector-cell type for immediate hypersensitivity and other forms of allergic reactions. Expression of 4-1BB, a member of the tumor necrosis factor receptor superfamily, is induced at mRNA and protein levels on stimulation through the high-affinity receptor for immunoglobulin E (IgE; FcepsilonRI). In this study, we present evidence that agonistic anti-4-1BB antibodies can enhance FcepsilonRI-induced cytokine production and secretion. Consistent with this, 4-1BB-deficient mast cells exhibit reduced degranulation and cytokine production on FcepsilonRI stimulation. Analysis of 4-1BB ligand (4-1BBL)-deficient cells supported this notion. As a potential mechanism for these defects, we identified a defect in Ca2+ flux induced by FcepsilonRI stimulation. The defective Ca2+ flux could be accounted for by the reduced activity of Lyn/Btk/phospholipase C-gamma2 pathway and constitutive interactions between 4-1BB and Lyn. Therefore, FcepsilonRI-inducible 4-1BB plays a costimulatory function together with FcepsilonRI stimulation.