Oolong tea theasinensins attenuate cyclooxygenase-2 expression in lipopolysaccharide (LPS)-activated mouse macrophages: structure-activity relationship and molecular mechanisms

Changes in amino acids, catechins and alkaloids during the storage of oolong tea and their relationship with antibacterial effect

The storage process has a significant impact on tea quality. Few is known about effect of storage on quality of oolong tea. This study aimed to assess the effect of different storage times on the key chemical components of oolong tea by measuring changes in catechin, free amino acid, and alkaloid content. Variation in the main substances was determined by principal component analysis and heat map analysis. The results revealed notable effects of the storage process on the levels of theanine, epigallocatechin gallate (EGCG), and glutamine. These findings suggest that these compounds could serve as indicators for monitoring changes in oolong tea quality during storage. Additionally, the study observed an increase in the antibacterial ability of tea over time. Correlation analysis indicated that the antibacterial ability against Micrococcus tetragenus and Escherichia coli was influenced by metabolites such as aspartic acid, threonine, serine, gamma-aminobutyric acid, ornithine, alanine, arginine, and EGCG. Overall, this study presents an approach for identifying key metabolites to monitor tea quality effectively with relatively limited data.

Molecular binding mechanism and novel antidiabetic and anti-hypertensive bioactive peptides from fermented camel milk with anti-inflammatory activity in raw macrophages cell lines

The investigation was to determine the effect of camel milk fermented with Limosilactobacillus fermentum KGL4 (MTCC 25515) on ACE-inhibiting, anti-inflammatory, and diabetes-preventing properties and also to release the novel peptides with antidiabetic and anti-hypertensive attributes with molecular interaction studies. Growth conditions were optimised on the basis of total peptide production by inoculating the culture in camel milk at different rates (1.5, 2.0, and 2.5%) along with different incubation periods (12, 24, 36, and 48 h). However, after 48 h of fermentation with a 2.5% rate of inoculum, the highest proteolytic activity was obtained. Reverse phase high-pressure liquid chromatography (RP-HPLC) was used to calculate the % Rpa from permeates of 3 kDa and 10 kDa fractions. Molecular weight distributions of fermented and unfermented camel milk protein fractions were compared using SDS-PAGE. Spots obtained from 2D gel electrophoresis were separated on the basis of pH and molecular weight. Spots obtained from 2D gel were digested with trypsin, and the digested samples were subjected to RP-LC/MS for the generation of peptide sequences. The inhibition of tumour necrosis factor alpha, interleukin-6, and interleukin-1 during fermentation was studied using RAW 264.7 macrophages. In the study, fermented camel milk with KGL4 (CMKGL4) inhibited LPS-induced nitric oxide (NO) production and pro-inflammatory cytokine production (TNF-α, IL-6, and IL-1β) by the murine macrophages. The results showed that the peptide structures (YLEELHRLNK and YLQELYPHSSLKVRPILK) exhibited considerable binding affinity against hPAM and hMGA during molecular interaction studies.

Exploring the potential of Lacticaseibacillus paracasei M11 on antidiabetic, anti-inflammatory, and ACE inhibitory effects of fermented dromedary camel milk (Camelus dromedaries) and the release of antidiabetic and anti-hypertensive peptides

The goal of this investigation was to find antidiabetic peptides and inhibit angiotensin converting enzyme (ACE) in Lacticaseibacillus paracasei (M11) fermented dromedary camel milk (Camelus dromedaries). According to the findings, the rate of antidiabetic activity increased along with the incubation periods and reached its peak after 48 hr of fermentation. The inhibitions of α-amylase, α-glucosidase, and lipase were 80.75, 59.62, and 65.46%, respectively. The inhibitory activity of ACE was 78.33%, and the proteolytic activity was 8.90 mg/mL. M11 at 0.25 mg/mL effectively suppressed LPS-induced pro-inflammatory cytokines and their mediators such as NO, TNF-α, IL-6, and IL-1β in RAW 264.7 cells. The rate of inoculum in the optimization phase was 1.5-2.5%, and the greatest proteolytic activity was observed after 48 hr of fermentation. The investigation of the above property in the ultrafiltered fermented milk exhibited the highest antidiabetic and ACE inhibition activities in the 3 kDa than 10 kDa fractions. The molecular weight was determined employing SDS-PAGE, and the six-peptide sequences were identified using 2D gel electrophoresis. Due to its high proteolytic activity, the L. paracasei strain has been reported to be useful in the production of ACE-inhibitory and antidiabetic peptides. Amino acid sequences such from ɑ1, ɑ2, and β-caseins have been identified within fermented camel milk by searching on online databases, including BIOPEP (for antidiabetic peptides) and AHTPDB (for hypertension peptides) to validate the antidiabetic and ACE-inhibitory actions of several peptides. PRACTICAL APPLICATIONS: The study aims to identify antidiabetic peptides and inhibit ACE in dromedary camel milk fermented with Lacticaseibacillus paracasei M11. Maximum antidiabetic and ACE-inhibitory actions of the fermented camel milk were observed in 3 kDa permeate fractions. Fermented camel milk significantly reduced the excessive TNF-α, IL-6, and IL-1β production in LPS-activated RAW 264.7 cells. RP-LC/MS was used to identify 6 bioactive peptides from dromedary fermented camel milk. This fermented camel milk could be used for the management of hypertension and diabetic related problems.

Cellular Uptake of Epigallocatechin Gallate in Comparison to Its Major Oxidation Products and Their Antioxidant Capacity In Vitro

Depletion of reactive oxygen species and reduction of oxidative stress have been identified as key parameters in the prevention of cellular aging. In previous in vitro studies, the tea catechin epigallocatechin gallate (EGCG) was found to have both pro- and antioxidant properties, disregarding the low stability under cell culture conditions. Besides hydrogen peroxide, theasinensin dimers amongst other oxidation products are formed. Exact quantities, cellular uptake and antioxidant capacities of these dimeric oxidation products remain unknown. Via high-performance liquid chromatography (HPLC) coupled with tandem mass spectrometry (MS/MS), formation kinetics and cellular uptake of EGCG and its major oxidation products are quantified. The antioxidant capacity is determined on a cellular level using a modified dichlorofluorescein (DCF) approach. As a first result, oxidation product quantities of up to 21 µM each are measured after incubation of 50 µM EGCG. While EGCG is taken up equimolarly, its major oxidation products are accumulated in hepatocarcinoma HepG2 cells at millimolar concentrations, especially theasinensin A (TSA). Lastly, the oxidation products show higher antioxidant properties than the monomer EGCG. In correlation with cellular uptake, TSA displays the highest capacity of all tested analytes. The findings reveal the strong influence of EGCG oxidation products on its bioactivity in vitro.

Gut Microbiota as a Novel Tool to Dissect the Complex Structures of Black Tea Polymers

Thearubigins, polymers of tea catechins, account for more than 20% of the black tea polyphenols and have been reported to be the active components in black tea. However, the chemical structures and underlying mechanisms regarding how the thearubigins, being poorly bioavailable, generate in vivo health benefits are still largely unknown. Using germ-free and specific pathogen-free husbandry conditions combined with LC/MS-based nontargeted and targeted metabolomic analyses, we investigated the role of intestinal bacteria in thearubigin metabolism. Theaflavins and theasinensins were identified as the major microbial metabolites of thearubigins, suggesting that these molecules are the building units for the complex thearubigins. To further confirm this, thearubigin depolymerization was done using menthofuran in an acidic condition. Menthofuran-conjugated theaflavins, theasinensins, and catechins as well as their free forms were detected as the major degradation products of thearubigins. This indicated that theaflavins and theasinensins could be further polymerized through B-type proanthocyanidin linkages. Furthermore, four microbial degradation products were able to be detected in urine samples, suggesting that they can be absorbed into the circulatory system. Using the combination of microbial degradation, metabolomics, and chemical degradation, our results demonstrate that thearubigins are the complex polymers of theaflavins, theasinensins, and catechins and can be metabolized by gut microbiota to their corresponding bioactive and bioavailable smaller molecular metabolites.

The effect of oolong tea as an adjunct to nonsurgical management of chronic periodontitis: A randomized controlled clinical trial

Introduction: Oolong tea, a functional food, has numerous therapeutic benefits owing to the presence of bioactive polyphenols, theasinensins (TS) and catechins. The present study aimed to evaluate the influence of systemic administration of oolong tea as an adjunct to nonsurgical periodontal therapy (NSPT) in the management of chronic periodontitis (CP).Methods: A total of 60 subjects with mild to moderate CP were randomly divided into two groups of tests (n = 30) and the controls (n = 30). They underwent NSPT with adjunctive oolong tea supplementation in the test group only. At baseline, 1, and 3 months, their gingival index (GI), plaque index (PI), probing pocket depth (PPD), clinical attachment loss (CAL), percentage of sites with bleeding on probing (BOP), and lobene stain index (LSI) were recorded. Furthermore, the levels of glutathione peroxidase (GPx), total antioxidants (TAO), and malondialdehyde (MDA) were also estimated in gingival crevicular fluid (GCF), saliva and serum. Additionally, colony-forming units (CFUs) of selective supra and subgingival plaque bacteria were estimated in the plaque samples.Results: In both groups, at 1 month, the GI, PI, BOP, GPx, and TAO levels were improved with a reduction in the levels of MDA and CFU’s and no staining of teeth (P < 0.05). The results were maintained in the test group at 3-month recall visit.Conclusion: Adjunctive administration of oolong tea with NSPT reduced the local and systemic oxidative burden and rapidly resolved the inflammation in CP. This would be specifically beneficial in CP subjects with systemic conditions.

Assessment of Antioxidant, Immunomodulatory Activity of Oxidised Epigallocatechin-3-Gallate (Green Tea Polyphenol) and Its Action on the Main Protease of SARS-CoV-2—An In Vitro and In Silico Approach

Owing to the instability of Epigallocatechin Gallate (EGCG), it may undergo auto-oxidation and form oxidised products or dimers. In the present study, we aimed to evaluate the therapeutic effects, including antioxidation and immunomodulatory action, of the Oxidised Epigallocatechin Gallate (O-EGCG) as compared to native EGCG and the action of these compounds on main protease (Mpro) docking against SARS-CoV-2. HCT-116 (Human Colon Cancer) cell lines were used to estimate the total antioxidant capacity and lipid peroxidation levels and pro-inflammatory markers (human IL-6, IL-1β, TNF-α). Further, molecular docking analysis was performed by AutoDock and visualised in Discovery studio. Improved antioxidant capacity of O-EGCG was observed, and there was a significant decrease in the inflammatory markers (IL-1β, IL-6, and TNF-α) when O-EGCG was applied as compared to EGCG. The O-EGCG was shown to be strongly associated with the highest docking score and active site residues of IL-1, IL-6, and TNF- α, as well as the Mpro of SARS-CoV-2, according to in silico approach. The in vitro and in silico analyses indicate an improved therapeutic action of the oxidised form of EGCG. The effective inhibitory action of O-EGCG against SARS-CoV-2 suggests further exploration of the compound against COVID-19 and its efficacy. However, in vivo studies and understanding of the mechanism of action of O-EGCG may yield a better opinion on the use of O-EGCG and future human clinical trials.

Updates on the chemistry, processing characteristics, and utilization of tea flavonoids in last two decades (2001-2021)

Tea flavonoids are widely recognized as critical flavor contributors and crucial health-promoting bioactive compounds, and have long been the focus of research worldwide in food science. The aim of this review paper is to summarize the major progress in tea flavonoid chemistry, their dynamics of constituents and concentrations during tea processing as well as storage, and their health functions studied between 2001 and 2021. Moreover, the utilization of tea flavonoids in the human body has also been discussed for a detailed understanding of their uptake, metabolism, and interaction with the gut microbiota. Many novel tea flavonoids have been identified, including novel A- and B-ring substituted flavan-3-ol derivatives, condensed and oxidized flavan-3-ol derivatives, and glycosylated and methylated flavonoids, and are found to be closely associated with the characteristic color, flavor, and health benefits of tea. Flavoalkaloids exist widely in various teas, particularly 8-C N-ethyl-2-pyrrolidinone-substituted flavan-3-ols. Tea flavonoids behave significantly difference in constituents and concentrations depending on tea cultivars, plantation conditions, multiple stresses, the tea-specified manufacturing steps, and even the long-term storage period. Tea flavonoids exhibit multiple health-promoting effects, particularly their anti-inflammatory in alleviating metabolic syndromes. Interaction of tea flavonoids with the gut microbiota plays vital roles in their health function.

Adsorption Equilibrium and Thermodynamics of Tea Theasinensins on HP20-A High-Efficiency Macroporous Adsorption Resin

The separation and preparation of theasinensins have been hot spots in the field of tea chemistry in recent years. However, information about the mechanism of efficient adsorption of tea theasinensins by resin has been limited. In this study, the adsorption equilibrium and thermodynamics of tea theasinensins by a high-efficiency macroporous adsorption HP20 resin were evaluated. The adsorption of theasinensin A, theasinensin B, and theasinensin C on HP20 resin were spontaneous physical reaction processes. Adsorption processes were exothermic processes, and lowering the temperature was beneficial to the adsorption. The Freundlich model was more suitable to describe the adsorption of tea theasinensins. The adsorption equilibrium constant and maximum adsorption capacity of theasinensin A were significantly higher than theasinensin B and theasinensin C, which indicated that the adsorption affinity of theasinensin A was stronger than that of theasinensin B and theasinensin C. The phenolic hydroxyl groups and intramolecular hydrogen bonds of theasinensin A were more than those of theasinensin B and theasinensin C, which might be the key to the resin's higher adsorption capacity for theasinensin A. The HP20 resin was very suitable for efficient adsorption of theasinensin A.

Antimelanogenesis Effects of Theasinensin A

Theasinensin A (TSA) is a major group of catechin dimers mainly found in oolong tea and black tea. This compound is also manufactured with epigallocatechin gallate (EGCG) as a substrate and is refined after the enzyme reaction. In previous studies, TSA has been reported to be effective against inflammation. However, the effect of these substances on skin melanin formation remains unknown. In this study, we unraveled the role of TSA in melanogenesis using mouse melanoma B16F10 cells and normal human epidermal melanocytes (NHEMs) through reverse transcription polymerase chain reaction (RT-PCR), Western blotting analysis, luciferase reporter assay, and enzyme-linked immunosorbent assay analysis. TSA inhibited melanin formation and secretion in α-melanocyte stimulating hormone (α-MSH)-induced B16F10 cells and NHEMs. TSA down-regulated the mRNA expression of tyrosinase (Tyr), tyrosinase-related protein 1 (Tyrp1), and Tyrp2, which are all related to melanin formation in these cells. TSA was able to suppress the activities of certain proteins in the melanocortin 1 receptor (MC1R) signaling pathway associated with melanin synthesis in B16F10 cells: cyclic adenosine monophosphate (cAMP) response element-binding protein (CREB), protein kinase A (PKA), tyrosinase, and microphthalmia-associated transcription factor (MITF). We also confirmed α-MSH-mediated CREB activities through a luciferase reporter assay, and that the quantities of cAMP were reduced by TSA in the enzyme linked immunosorbent assay (ELISA) results. Based on these findings, TSA should be considered an effective inhibitor of hyperpigmentation.

Significant Inactivation of SARS-CoV-2 In Vitro by a Green Tea Catechin, a Catechin-Derivative, and Black Tea Galloylated Theaflavins

Potential effects of tea and its constituents on SARS-CoV-2 infection were assessed in vitro. Infectivity of SARS-CoV-2 was decreased to 1/100 to undetectable levels after a treatment with black tea, green tea, roasted green tea, or oolong tea for 1 min. An addition of (-) epigallocatechin gallate (EGCG) significantly inactivated SARS-CoV-2, while the same concentration of theasinensin A (TSA) and galloylated theaflavins including theaflavin 3,3'-di-O-gallate (TFDG) had more remarkable anti-viral activities. EGCG, TSA, and TFDG at 1 mM, 40 µM, and 60 µM, respectively, which are comparable to the concentrations of these compounds in tea beverages, significantly reduced infectivity of the virus, viral RNA replication in cells, and secondary virus production from the cells. EGCG, TSA, and TFDG significantly inhibited interaction between recombinant ACE2 and RBD of S protein. These results suggest potential usefulness of tea in prevention of person-to-person transmission of the novel coronavirus.

Dose-dependent green tea effect on decrease of inflammation in human oral gingival epithelial keratinocytes: in vitro study

Objectives

This in vitro study aimed to analyze the anti-inflammatory and wound healing potential of green tea extract (GTE) in human gingival epithelial keratinocytes (HGEK) treated with lipopolysaccharides (LPS).

Materials and methods

A cell viability assay was conducted using MTT to determine nontoxic levels of GTE on immortalized HGEK. Cells were concomitantly treated with LPS (1 μg/ml) and GTE (1 mg/ml, 2.5 mg/ml, 5 mg/ml, and 10 mg/ml) to assess inflammation. Gene expression levels of inflammatory markers IL-β1, IL-6, and TNFα were measured by RT-PCR and their protein production was assessed by ELISA. The scratch wound healing assay was used to investigate the effects of different concentrations of GTE on cell migration. We also explored the effect of GTE on the induction of the Nrf2/HO-1 pathway in the cells with or without LPS.

Results

GTE at concentrations of 2.5 mg/ml, 5 mg/ml, and 10 mg/ml significantly enhanced cell viability (p < 0.05). And IL-β1, IL-6, and TNFα gene expression presented up to 10-fold decrease compared with LPS-treated cells, which was also similarly found on the protein levels. At the same concentrations, cell migration increased.

Conclusions

The mechanism results showed that GTE produced the anti-inflammatory response by activating the nuclear factor erythroid 2-related factor 2 (Nrf2) pathway and increasing the level of anti-oxidant protein heme oxygenase-1 (HO-1).

Clinical relevance

GTE may be potentially used as oral rinse anti-inflammatory drug for treatment and prevention of oral inflammatory diseases, which is shown here by the ability to reduce the inflammation and increase in cell migration in a dose-dependent manner.

Chemical characterization and bioactivity of phenolics from Tieguanyin oolong tea

Phenolics are the main bioactive components in tea and greatly contribute to human health. Three phenolic-enriched extracts, the ethyl acetate fraction (TEF), n-butanol fraction (TBF), and water fraction (TWF), were obtained from Tieguanyin oolong tea, which is considered a typical type of semi-fermented tea. The chemicals in the extracts and their antioxidant activity and cytotoxicity against 4T1 breast cancer cells were investigated in the present work. TEF was found to have the highest contents of phenolics, flavonoids, procyanidins, sugars, and catechin monomers. Meanwhile, TEF exhibited the strongest antioxidant capacity, which may be due to its abundant bioactive compounds, as validated by Pearson correlation and hierarchical clustering analysis. Furthermore, TEF showed greater inhibition of the growth of 4T1 murine breast cancer cells than TBF and TWF. PRACTICAL APPLICATIONS: Fermentation during the processing of oolong tea causes many alterations in polyphenols, leading to different bioactivities. In the present work, three phenolic-enriched extracts, the ethyl acetate fraction (TEF), n-butanol fraction (TBF), and water fraction (TWF), were obtained from Tieguanyin oolong tea. Further tests showed that TEF and TBF from Tieguanyin oolong tea possessed remarkable antioxidant activity and inhibitory potential inhibition of the growth of 4T1 murine breast cancer cells in vitro due to their main bioactive compounds, including phenolics and flavonoids. Thus, the phenolic-enriched extracts from Tieguanyin tea are expected to have a potential application in the food and pharmaceutical industries after further study.

Polyphenols in Health and Disease

Deadly diseases, such as cardiovascular diseases and cancer, remain the major health problems worldwide. Research in cardiovascular diseases and genome-wide association studies were successful in indentifying the gene loci associated with these threatening diseases. Yet, a substantial number of casual factors remain unexplained. Over the last decade, a better understanding of molecular and biochemical mechanisms of cardiac diseases led to developing a rationale for combining various protective agents, such as polyphenols, to target multiple signaling pathways. The present review article summarizes recent advances of the use of polyphenols against diseases, such as cardiac diseases.

Protective effects of theasinensin A against carbon tetrachloride-induced liver injury in mice

TSA markedly reduced the CCl₄-induced liver injury in mice.

Condensed catechins and their potential health-benefits

Condensed catechins are commonly present in fermented tea, and are produced by the oxidation of monomeric catechins. Due to their auto-oxidation, catechins have diverse structural features, including different binding modes and degrees of polymerization. Because of their structural complexity, their physiological functions and possible health-benefits have not yet been fully investigated. This review focuses on the physiological potentials of dimeric and trimeric catechins in the intestine (regulation of absorption across the intestinal membrane), blood vessels (vasorelaxation in vessel regulation), and muscle organs (promotion of glucose uptake resulting in an anti-diabetic effect). Furthermore, the roles of non-absorbable theaflavins (dimeric catechins), absorbable theasinensins (dimeric catechins), and absorbable procyanidins (dimeric and trimeric catechins) on target organs are discussed.

Anti-inflammatory activity and molecular mechanism of Oolong tea theasinensin

Oolong tea theasinensins are a group of tea polyphenols different from green tea catechins and black tea theaflavins, and they are considered as bioactive compounds in Oolong tea. In the present study, based on the properties of theasinensin and information about inflammatory processes, we investigated the anti-inflammatory activity and molecular mechanisms of theasinensin A (TSA) in both cell and animal models. In the cell model, TSA reduced the levels of pro-inflammatory mediators including inducible nitric oxide synthase (iNOS), nitric oxide (NO), interleukin-12 (IL-12) (p70), tumor necrosis factor alpha (TNF-α), and monocyte chemotactic protein-1 (MCP-1) induced by lipopolysaccharide (LPS). Cellular signaling analysis revealed that TSA downregulated MAPK/ERK kinase (MEK)-extracellular signal-regulated kinase (ERK) signaling. Pull-down assay and affinity data revealed that TSA might directly bind to MEK-ERK for the inhibitory action. In the animal model, TSA suppressed the production of IL-12 (p70), TNF-α, and MCP-1 and attenuated mouse paw edema induced by LPS.

Auto-oxidation products of epigallocatechin gallate activate TRPA1 and TRPV1 in sensory neurons

The sensation of astringency is elicited by catechins and their polymers in wine and tea. It has been considered that catechins in green tea are unstable and auto-oxidized to induce more astringent taste. Here, we examined how mammalian transient receptor potential V1 (TRPV1) and TRPA1, which are nociceptive sensors, are activated by green tea catechins during the auto-oxidation process. Neither TRPV1 nor TRPA1 could be activated by any of the freshly prepared catechin. When one of the major catechin, epigallocatechin gallate (EGCG), was preincubated for 3h in Hank's balanced salt solution, it significantly activated both TRP channels expressed in HEK293 cells. Even after incubation, other catechins showed much less effects. Results suggest that only oxidative products of EGCG activate both TRPV1 and TRPA1. Dorsal root ganglion (DRG) sensory neurons were also activated by the incubated EGCG through TRPV1 and TRPA1 channels. Liquid chromatography-mass spectrometry revealed that theasinensins A and D are formed during incubation of EGCG. We found that purified theasinensin A activates both TRPV1 and TRPA1, and that it stimulates DRG neurons through TRPV1 and TRPA1 channels. Results suggested a possibility that TRPV1 and TRPA1 channels are involved in the sense of astringent taste of green tea.

Investigation of isomeric flavanol structures in black tea thearubigins using ultraperformance liquid chromatography coupled to hybrid quadrupole/ion mobility/time of flight mass spectrometry

Ultra performance liquid chromatography (UPLC) when coupled to ion mobility (IMS)/orthogonal acceleration time of flight mass spectrometry is a suitable technique for analyzing complex mixtures such as the black tea thearubigins. With the aid of this advanced instrumental analysis, we were able to separate and identify different isomeric components in the complex mixture which could previously not be differentiated by a conventional high performance liquid chromatography/tandem mass spectrometry. In this study, the difference between isomeric structures theasinensins, proanthocyanidins B-type and rutin (quercetin-3O-rutinoside) were studied, and these are present abundantly in many botanical sources. The differentiation between these structures was accomplished according to their acquired mobility drift times differing from the traditional investigations in mass spectrometry, where calculation of theoretical collisional cross sections allowed assignment of the individual isomeric structures. The present work demonstrates UPLC-IMS-MS as an efficient technology for isolating and separating isobaric and isomeric structures existing in complex mixtures discriminating between them according to their characteristic fragment ions and mobility drift times. Therefore, a rational assignment of isomeric structures in many phenolic secondary metabolites based on the ion mobility data might be useful in mass spectrometry-based structure analysis in the future.

Antioxidant and anti-inflammatory effects in RAW264.7 macrophages of malvidin, a major red wine polyphenol

Background

Red wine polyphenols can prevent cardiovascular and inflammatory diseases. Resveratrol, the most extensively studied constituent, is unlikely to solely account for these beneficial effects because of its rather low abundance and bioavailability. Malvidin is far the most abundant polyphenol in red wine; however, very limited data are available about its effect on inflammatory processes and kinase signaling pathways.

Methods & Findings

The present study was carried out by using RAW 264.7 macrophages stimulated by bacterial lipopolysaccharide in the presence and absence of malvidin. From the cells, activation of nuclear factor-kappaB, mitogen-activated protein kinase, protein kinase B/Akt and poly ADP-ribose polymerase, reactive oxygen species production, mitogen-activated protein kinase phosphatase-1 expression and mitochondrial depolarization were determined. We found that malvidin attenuated lipopolysaccharide-induced nuclear factor-kappaB, poly ADP-ribose polymerase and mitogen-activated protein kinase activation, reactive oxygen species production and mitochondrial depolarization, while upregulated the compensatory processes; mitogen-activated protein kinase phosphatase-1 expression and Akt activation.

Conclusions

These effects of malvidin may explain the previous findings and at least partially account for the positive effects of moderate red wine consumption on inflammation-mediated chronic maladies such as obesity, diabetes, hypertension and cardiovascular disease.

Dichloromethane fraction of Laminaria japonica ethanolic extract inhibits lipopolysaccharide-induced nitric oxide synthase and cyclooxygenase-2 expression in RAW 264.7 cells via NF-κB pathway

Strong anti-inflammatory activity has been found in Laminaria japonica dichloromethane fraction (LDF); however, the molecular mechanisms underlying its anti-inflammatory activity are not reported. Our results indicated that LDF inhibited LPS-induced nitric oxide and prostaglandin E(2) production in a dose-dependent manner and suppressed the expression of inducible nitric oxide synthase (iNOS) and cyclooxygenase 2 (COX-2) in RAW 264.7 cells. Also, levels of pro-inflammatory cytokines such as tumor necrosis factor-α, interleukin (IL)-1β and IL-6 were remarkably reduced by LDF in LPS-treated RAW 264.7 cells. LDF greatly inhibited promoter activity of nuclear factor-κB (NF-κB) and translocation of NF-κB subunits by prevention of the degradation of inhibitor κB-α in LPS-treated RAW 264.7 cells (p < 0.05). Moreover, LDF inhibited activation of mitogen-activated protein kinases and AKT in LPS-treated RAW 264.7 cells. These results indicate that the LDF downregulates iNOS and COX-2 expressions through the suppression of NF-κB pathway associated with inhibition of multiple signaling proteins.

Transepithelial transport of theasinensins through Caco-2 cell monolayers and their absorption in Sprague-Dawley rats after oral administration

The aim of this study is to illustrate the in vivo and in vitro absorption of theasinensins B and A that are (-)-epigallocatechin-3-O-gallate (EGCG)-(-)-epigallocatechin (EGC) dimer and EGCG dimer, respectively, and their transport pathway across the intestinal membrane. Our animal study by a single oral administration to rats demonstrated the intact absorption of theasinensins into the blood system, which was estimated to be a >10-fold lower absorption amount than EGCG. The in vitro absorption study indicated that theasinensins can be transported across Caco-2 cell monolayers, while their permeability coefficients were also >10-fold lower than those of EGCG and EGC. Transport experiments using cytochalasin D or quercetin as a tight junction (TJ) modulator and a non-saturable permeation revealed that theasinensins were transported across Caco-2 cells in a TJ paracellular diffusion route. In conclusion, the dimers of condensed catechins, theasinensins B and A, can be absorbed intact into rat blood and transported across Caco-2 cell monolayers probably through a TJ paracellular pathway.