Effects of flavonoids on immune and inflammatory cell functions

Quercetin does not alter lipopolysaccharide-induced fever in rats

Fever is considered an important component of the acute phase response of the body in defence against invading organisms such as bacteria. Quercetin, an important representative of the flavonoid class, has been extensively studied as an anti-inflammatory agent. In the present study, we investigated the effect of quercetin, administered orally (5, 25 and 50 mg kg−1) or intraperitoneally (50 mg kg−1), on the febrile response induced by either intraperitoneally (50 μg kg−1) or intravenously (5 μg kg−1) injected lipopolysaccharide (LPS from Escherichia coli) in rats. In contrast with the well known anti-inflammatory activity of quercetin, the results demonstrate that quercetin, at the doses used, did not alter the fever induced by LPS, regardless of the route of administration.

Suppressive effects of T-412, a flavone on interleukin-4 production in T cells

Interleukin (IL)-4 has been suggested as a molecular therapeutic target to prevent and/or treat various allergic diseases and several flavonoids have been suggested as anti-allergic agents suppressing IL-4 production. In an effort to find novel candidates for anti-allergic agents from natural sources, we screened several flavonoids affecting on IL-4 production. In this study, we showed that 7,8,4'-trihydroxyflavone (T-412) significantly decreased IL-4 production both in phorbol 12-myristate 13-acetate (PMA) and ionomycin (PI)-activated EL-4 T cells and concanavalin A (ConA)-activated murine CD4(+) T cells in a dose- and time-dependent manner. The PI-induced increase of IL-4 mRNA expression was dramatically suppressed by T-412 at 6 h, indicating the suppression is regulated at transcriptional level. T-412 also significantly inhibited IL-4 gene promoter activity in EL-4 T cells transiently transfected with luciferase reporter plasmid containing IL-4 promoter (pGL4.14-IL-4). Western blot analysis of the transcription factors revealed that T-412 suppressed the nuclear expression of nuclear factor of activated T cells (NF-AT)c1, c-Jun and c-Maf, but not c-Fos and nuclear factor kappa B (NF-kappaB). Our data suggested that T-412 might have potential as a candidate for anti-allergic agent having suppressive effects on IL-4 production in activated T cells by controlling the transcription of IL-4.

Antibody response to hepatitis B vaccine in substance use disorder patients

The objectives of this study were to assess the prevalence of prognostic factors previously known to be associated with poor antibody response to hepatitis B vaccination in a sample of veterans presenting for substance use disorders treatment at a Veterans Health Administration (VA) Medical Center, assess vaccination response, and identify markers for poor response in this population. Results indicated that most participants had multiple prognostic factors previously known to be associated with poor antibody response including male gender, age over 40, smoking, and obesity. The rate of seroconversion in this sample was 51.9%. This is substantially lower than seen in healthy adults. Alcohol dependence was the only significant independent negative predictor of seroconversion in this sample. Substance use disorders treatment providers who are considering adding hepatitis B vaccination services to their clinics should be aware that the antibody response to the hepatitis B vaccination is inconsistent and that patients with particular demographic characteristics may be at heightened risk of poor antibody response.

Structural characterization of flavonoid glycosides by multi-stage mass spectrometry

Flavonoids are secondary plant metabolites of great structural variety and high medicinal significance. The search for new chemical entities and the quality control of flavonoid containing natural products require easy-to-use but reliable and robust analytical methodologies. For structural elucidation of flavonoids and their glycosides, nuclear magnetic resonance (NMR) and mass spectroscopy (MS) are the generally used techniques. In phytochemical analyses, however, high amounts of flavonoids are difficult to isolate for NMR, thus low sample volume requiring MS based methods are emerging. This review summarizes and compares currently available methods for structural elucidation of flavonoids by LC-MS and LC-MS(n), and focuses on the identification options of unknown flavonoid glycosides in complex samples (e.g., plant extracts) with the emphasis on the differentiation of isomeric compounds.

NMR of a series of novel hydroxyflavothiones

Alkylated hydroxyflavothiones, namely flavothione, 5-hydroxyflavothione, 5,7-dihydroxyflavothione (chrysinthione), 7-dodecyloxy-5-hydroxyflavothione, 7-butyloxy-5-hydroxyflavothione, 2',3,4',7-tetramethoxy-5-hydroxyflavothione, 3,3',4',7-tetramethoxy-5-hydroxyflavothione, 7-butyloxy-4',5-dihydroxyflavothione and 7-butyloxy-4',5-hydroxyflavanonethione have been synthesized from the corresponding hydroxyflavones in two steps, alkylation of the non-hydrogen-bonded hydroxyl groups by bromoalkanes or dimethyl sulfate followed by conversion of the carbonyl group to a thione using Lawesson's Reagent under microwave irradiation and solvent-free conditions. Part of the alkylated flavanone, 7-butyloxy-4',5-dihydroxyflavanone, was oxidized during the treatment with Lawesson's reagent to yield a second product 7-butyloxy-4',5-dihydroxyflavothione in addition to the target product butyloxy-4',5-hydroxyflavanonethione. Deuterium isotope effects on 13C chemical shifts have been measured in hydroxyflavones, isoflavones, flavanones and the thio analogs. Formal four-bond deuterium isotope effects on 13C chemical shifts, nDeltaC=S(OD) are very sensitive to variations in structures and substitution patterns. Density functional theory (DFT) calculations are carried out to obtain geometries. Correlations relating distances around the hydrogen bond system to the deuterium isotope effects on 13C chemical shifts are discussed. 13C chemical shifts are calculated by DFT methods. Effects of thiocarbonyl anisotropies are suggested.

Peanut skin color: a biomarker for total polyphenolic content and antioxidative capacities of peanut cultivars

Attempts to establish a relationship between peanut skin color (PSC) and total flavonoid (TF) content have produced inconclusive results. This study investigated the potential of PSC as a biomarker for polyphenol content and antioxidant capacity. Peanut cultivars were objectively evaluated for their skin color, total phenolic (TP), flavonoid (TF), proanthocyanidin (TPC) contents and antioxidant capacities (AC). Their relationship was determined by Pearson’s correlation analyses. TP had stronger correlations with CIE a*, hue angle and AC (r² = 0.77, 0.82 and 0.80, respectively) compared to TF. Therefore, hue angle of peanut skin may be used as a biomarker for TP content rather than TF.

Regioselective hydroxylation of isoflavones by Streptomyces avermitilis MA-4680

Screening of bacterial whole cells was performed for regioselective hydroxylation of daidzein and genistein. Among the strains examined, Streptomyces avermitilis MA-4680 showed high ortho-dihydroxylation activity to produce 3',4',7-trihydroxyisoflavone and 3',4',5,7-tetrahydroxyisoflavone from daidzein (4',7-dihydroxyisoflavone) and genistein (4',5,7-trihydroxyisoflavone), respectively. Using 100 mg cells (wet wt.) and 1% (v/v) Triton X100 in 1 ml of total reaction volume, where 100 microl of the substrate solution (0.5 mM in 10% (v/v) mixed solvent of DMSO:MeOH = 3:7) was added to 900 microl of potassium phosphate buffer (100 mM, pH 7.2), a 16% molar conversion yield of 3',4',7-trihydroxyisoflavone was obtained from 0.5 mM daidzein after 24 h of reaction time at 28 degrees C and 200 rpm. Ketoconazole significantly (ca. 90%) inhibited the ortho-hydroxylation activity of daidzein, suggesting that cytochrome P450 enzymes putatively play roles in regiospecific daidzein hydroxylation. The analysis of the reaction products was determined by gas chromatography/mass spectrometry (GC/MS) and (1)H NMR.

Metabolic engineering of Escherichia coli for the biological synthesis of 7-O-xylosyl naringenin

Flavonoids are a group of polyphenolic compounds that have been recognized as important due to their physiological and pharmacological roles and their health benefits. Glycosylation of flavonoids has a wide range of effects on flavonoid solubility, stability, and bioavailability. We previously generated the E. coli BL21 (DE3) Deltapgi host by deleting the glucose-phosphate isomerase (Pgi) gene in E. coli BL21 (DE3). This host was further engineered for whole-cell biotransformation by integration of galU from E. coli K12, and expression of calS8 (UDP-glucose dehydrogenase) and calS9 (UDP-glucuronic acid decarboxylase) from Micromonospora echinospora spp. calichensis and arGt-4 (7-O-glycosyltransferase) from Arabidopsis thaliana to form E. coli (US89Gt-4), which is expected to produce glycosylated flavonoids. To test the designed system, the engineered host was fed with naringenin as a substrate, and naringenin 7-O-xyloside, a glycosylated naringenin product, was detected. Product was verified by HPLCLC/MS and ESI-MS/MS analyses. The reconstructed host can be applied for the production of various classes of glycosylated flavonoids.

Synthesis and antioxidant properties of dendritic polyphenols

Three dendritic polyphenols (generation 1) were synthesized: a syringaldehyde-based dendrimer (1), a vanillin-based dendrimer (2), and an iodinated vanillin-based dendrimer (3). They all showed strong antioxidant activity according to the 1,1-diphenyl-2-picrylhydrazyl (DPPH) radical assay. The syringaldehyde dendrimer was twice and 10 times stronger than quercetin and Trolox, respectively. The vanillin-based dendrimer and its more hydrophobic iodinated derivative were also more potent antioxidants than quercetin and Trolox. The DPPH order of potency was 1>2, 3>quercetin>Trolox. All three dendrimers also protected human LDL from free radical attack in a dose-dependent manner. Their order of free radical scavenging was 1>3>2>quercetin>Trolox. The increased hydrophobic nature of the iodinated derivative may have contributed to its better LDL protection than 2. Protection of linoleic acid oxidation was studied by the beta-carotene-linoleate assay. Dendrimer 1 was clearly superior to the other antioxidants in protecting the fatty acid. In case of DNA protection against free radical damage, the order of activity was 1>quercetin>2>3, Trolox. Pro-oxidant effect on copper-induced DNA oxidation showed the following order: quercetin, Trolox>1>2>3. Results of the study show that dendritic antioxidants, even at the generation 1 level, provide promising antioxidant properties for their potential use as drug candidates for diseases associated with oxidative stress.

Preventative effect of a flavonoid, enzymatically modified isoquercitrin on ocular symptoms of Japanese cedar pollinosis

BACKGROUND

Flavonoids are nutrients that exert anti-allergic effects. We investigated the preventative effect of enzymatically modified isoquercitrin (EMIQ), a flavonoid, to relieve the symptoms of Japanese cedar pollinosis.

METHODS

In a parallel-group, double-blind placebo-controlled study design, 24 subjects with Japanese cedar pollinosis took 100mg EMIQ or a placebo for 8 weeks, starting 4 weeks prior to the onset of pollen release. Subjective symptoms, ADL scores and the usage of drugs were recorded daily, and the QOL score was obtained every 4 weeks. Blood sampling was performed before and after the study to measure serum levels of IgE and flavonoids.

RESULTS

During the entire study period, ocular symptom + medication score for the EMIQ group was significantly lower (p < 0.05) than that of the placebo group. When limited to the period, ocular symptom scores (p < 0.05, weeks 5-6), and ocular congestion scores (p < 0.05, weeks 5-6) for the EMIQ group was significantly lower than that for the placebo group while other scores for the EMIQ group, such as ocular itching scores (p = 0.09, weeks 4-5), lacrimation scores (p = 0.07, weeks 5-6), and ocular congestion scores (p = 0.06, weeks 4-5), all tended to be lower. However no significant differences were found in nasal symptoms between the two groups. Serum concentrations of IgE were not significantly downregulated but the serum concentrations of quercetin and its derivatives were elevated significantly by the intake of EMIQ.

CONCLUSIONS

Intake of the quercetin glycoside EMIQ proved to be effective for the relief of ocular symptoms caused by Japanese cedar pollinosis.

Protectivity of blue honeysuckle extract against oxidative human endothelial cells and rat hepatocyte damage

The effect of Lonicera caerulea L. (blue honeysuckle) phenolic fraction (18.5% anthocyanins) on cell viability and against oxidative damage in low density lipoproteins (oxLDL), in rat microsomes and in primary cultures of rat hepatocytes and human umbilical vein endothelial cells (HUVEC), was tested. The phenolic fraction was nontoxic to rat hepatocytes and HUVEC at tested concentrations (1-1000 microg/mL) and time intervals up to 24 h inclusive. Phenolic fraction inhibited rat liver microsome peroxidation, induced by tert-butyl hydroperoxide (tBH), with IC(50) values of 160 +/- 20 microg/mL. The fraction at 0.5, 1.0, and 2.0 microg/mL delayed LDL oxidation, induced by Cu(2+), by 130 +/- 20%, 200 +/- 30%, and 400 +/- 10%, respectively. The treatment of HUVEC with oxidatively modified LDL induced an increase in lactate dehydrogenase (LDH) leakage and thiobarbituric acid reactive substances (TBARS) formation, and resulted in lower formazan formation from 3-(4,5-dimethyl-2-thiazolyl)-2,5-diphenyl-2H-tetrazolium bromide (MTT) uptake, most pronounced for 200 microg/mL (24 h oxidation) after 2 h of incubation. The protective effect of the phenolic fraction against cell damage caused by oxLDL was noted at 0.1 microg/mL for HUVEC and against tBH at 1000 microg/mL for both HUVEC and hepatocytes. The observed protective effects were probably due to the antioxidant properties of L. caerulea constituents, mainly anthocyanins. Microsome peroxidation and LDL oxidation inhibition results provide promising perspectives into the prevention of some oxidative stress-associated diseases. Other data are important in in vitro systems but seem to be accidental in vivo.

Hesperetin: A Potent Antioxidant Against Peroxynitrite

Peroxynitrite (ONOO-) is a reactive oxidant formed from superoxide (*O2(-)) and nitric oxide (*NO), that can oxidize several cellular components, including essential protein, non-protein thiols, DNA, low-density lipoproteins (LDL), and membrane phospholipids. ONOO- has contributed to the pathogenesis of diseases such as stroke, heart disease, Alzheimer's disease, and atherosclerosis. Because of the lack of endogenous enzymes to thwart ONOO- activation, developing a specific ONOO- scavenger is remarkably important. In this study, the ability of hesperetin (3',5,7-trihydroxy-4-methoxyflavanone) to scavenge ONOO- and to protect cells against ONOO- and ROS was investigated. The data gained show that hesperetin can efficiently scavenge authentic ONOO- . In spectrophotometric analysis, the data revealed that hesperetin led to declined ONOO- -mediated nitration of tyrosine through electron donation. Hesperetin exhibited significant inhibition on the nitration of bovine serum albumin (BSA) by ONOO- in a dose-dependent manner. Hesperetin also manifested cytoprotection from cell damage induced by ONOO- and ROS. The present study suggests that hesperetin is a powerful ONOO- scavenger and promotes cellular defense activity in the protection against ONOO- involved diseases.

Synergistic effects of flavonoids and ascorbate on enhancement in DNA degradation induced by a bleomycin–Fe complex

Flavonoids were examined for synergistic effects with ascorbate on enhancement of DNA degradation induced by a bleomycin(BLM)-Fe complex. The synergistic effects of flavonoids and ascorbate on DNA degradation induced by the BLM-Fe complex were observed to be greater with flavonoids such as isorhamnetin, kaempferol and morin, which accelerated oxidation more markedly in the presence, than in the absence of BLM. Conversely, myricetin and fisetin, which showed oxidation barely accelerated by the addition of BLM, inhibited DNA degradation promoted by ascorbate. Consequently, there was a good correlation between oxidation of flavonoids accelerated by BLM and the extent of DNA degradation promoted synergistically with ascorbate. Our previous studies indicated that oxidation of flavonoids accelerated by BLM and DNA degradation promoted by flavonoids were not correlated with Fe(III)-reducing activity of flavonoids. Those results suggest that Fe(III)-reducing activity of flavonoids is not the only factor determining DNA degradation-promoting activity induced by the BLM-Fe complex. On the other hand, in a Fenton reaction, degradation of 2-deoxy-d-ribose promoted by flavonoids was correlated to the Fe(III)-reducing activity of flavonoids. However, there was not a synergistic interaction between flavonoids and ascorbate in the degradation of 2-deoxy-d-ribose. Therefore, it is suggested that the synergistic DNA degradation caused by flavonoids and ascorbate in the BLM-Fe redox cycle arose from the difference in the reductive processes in which flavonoids and ascorbate mainly act.

Simultaneous determination of the flavonoid aglycones diosmetin and hesperetin in human plasma and urine by a validated GC/MS method: in vivo metabolic reduction of diosmetin to hesperetin

Diosmetin and hesperetin are the aglycones of the flavonoid glycosides diosmin and hesperidin which occur naturally in citrus fruit. A GC/MS method for the simultaneous determination of diosmetin and hesperetin in human plasma and urine has been developed and validated. The method was linear in the 2-300 ng/mL concentration range for both diosmetin and hesperetin in plasma and urine (r > 0.999). The precision of the method was better than 6.01 and 7.16% for diosmetin and hesperetin, respectively, and the accuracy was 96.76-100.40% and 95.00-105.50% for diosmetin and hesperetin, respectively. The lower limit of quantitation was found to be 2 ng/mL for both analytes in plasma and urine. Recovery of diosmetin, hesperetin and internal standard naringenin was greater than 82.5%. The method has been applied for the determination of diosmetin and hesperetin in plasma and urine samples obtained from a healthy male subject following a single oral 1000 mg dose of the flavonoid glycoside diosmin. The presence of hesperetin in plasma and urine samples indicates the metabolic reduction of diosmetin to its flavanone analogue hesperetin through reduction of the 2,3 double bond of the C-ring by the enzymes of bacteria of the intestinal microflora.

Vitamin C and the Role of Citrus Juices as Functional Food

The literature on the content and stability of vitamin C (ascorbic acid, AA) in citrus juices in relation to industrial practices is reviewed. The role of vitamin C from citrus juices in human diet is also reviewed. Citrus fruits and juices are rich in several types of bioactive compounds. Their antioxidant activity and related benefits derive not only from vitamin C but also from other phytochemicals, mainly flavonoids. During juice processing, temperature and oxygen are the main factors responsible for vitamin C losses. Nonthermal processed juices retain higher levels of vitamin C, but economic factors apparently delay the use of such methods in the citrus industry. Regarding packing material, vitamin C in fruit juice is quite stable when stored in metal or glass containers, whereas juice stored in plastic bottles has a much shorter shelf-life.

The limiting step for vitamin C absorption in humans is transcellular active transport across the intestinal wall where AA may be oxidized to dehydroascorbic acid (DHAA), which is easily transported across the cell membrane and immediately reduced back to AA by two major pathways. AA bioavailability in the presence of flavonoids has yielded controversial results. Whereas flavonoids seem to inhibit intestinal absorption of AA, some studies have shown that AA in citrus extract was more available than synthetic ascorbic acid alone. DHAA is reported to possess equivalent biological activity to AA, so recent studies often consider the vitamin C activity in the diet as the sum of AA plus DHAA. However, this claimed equivalence should be carefully reexamined.

Humans are one of the few species lacking the enzyme (L-gulonolactone oxidase, GLO) to convert glucose to vitamin C. It has been suggested that this is due to a mutation that provided a survival advantage to early primates, since GLO produces toxic H2O2. Furthermore, the high concentration of AA (and DHAA) in neural tissues could have been the key factor that caused primates (vertebrates with relative big brain) to lose the capacity to synthesize vitamin C.

Oxidative damage has many pathological implications in human health, and AA may play a central role in maintaining the metabolic antioxidant response. The abundance of citrus juices in the Mediterranean diet may provide the main dietary source for natural vitamin C.

Effects on lipid peroxidation and antioxidative enzymes of Euonymus alatus in cultured rat hepatocytes

The Euonymus alatus (Thunb.) Sieb. has long been used as a crude drug. In this paper, we investigate the effects of E. alatus on cultured hepatocyte cell system and lipid peroxidation in hydrogen peroxide (H(2)O(2)) treatment conditions. The study covers the physiological activity (the antioxidative activity and the nitrite-scavenging effect) of E. alatus. H(2)O(2) that can produce intracellular free radical was used for inducer of the peroxidation of cellular lipids. Treatment of E. alatus attenuated in cell killing enhanced by increasing concentrations of H(2)O(2). The increased malondialdehyde level induced by H(2)O(2) treatment was reduced by pre-treatment of E. alatus. Furthermore, addition of E. alatus in cell culture medium significantly reduced cell killing and content of intracellular antioxidants. Changes in nitrite-scavenging effect of E. alatus at various concentrations (5-25 mg/ml) and various pH levels (pH 1.2, 4.2 and 6.0) were also observed. The present study was also done to investigate the effects of E. alatus on cultured hepatocyte cell system, H(2)O(2)-induced cytotoxicity and antioxidative enzyme activities, including catalase, superoxide dismutase, glutathione peroxidase and glutathione S-transferase in H(2)O(2 )treatment conditions. E. alatus treatment had significant protective or elevating activities on these antioxidative enzyme activities compared to a normal group. The results indicate that E. alatus provides a strong antioxidant protection of cells against H(2)O(2)-induced oxidative stress.

Quercetin-induced ubiquitination and down-regulation of Her-2/neu

Her-2/neu (ErbB2) is a transmembrane tyrosine kinase and acts as a co-receptor for the other EGFR family members. It is well known that high expression of Her-2/neu is associated with a poor prognosis in breast cancer. Quercetin, a flavonoid present in many vegetables and fruits, has been studied extensively as a chemoprevention agent in several cancer models. In this study, we observed that quercetin decreased the level of Her-2/neu protein in time- and dose-dependent manners and also inhibited the downstream survival PI3K-Akt signaling pathway in Her-2/neu-overexpressing breast cancer SK-Br3 cells. We also observed that quercetin induced polyubiquitination of Her-2/neu. When the proteasome pathway was blocked by MG-132 during quercetin treatment, accumulation of the NP-40 insoluble form of Her-2/neu occurred. Interestingly, data from immunocomplex studies revealed that quercetin promoted interaction between Her-2/neu and Hsp90 which is a molecular chaperone involved in stabilization of Her-2/neu. In this condition, inhibition of Hsp90 activity by a specific inhibitor, geldanamycin (GA), or intracellular ATP depletion caused dissociation of Hsp90 from Her-2/neu and promoted ubiquitination and down-regulation of Her-2/neu protein. In addition, the carboxyl terminus of Hsc70-interacting protein (CHIP), a chaperone-dependent E3 ubiquitin ligase, played a crucial role in the quercetin-induced ubiquitination of Her-2/neu. Inhibition of tyrosine kinase activity of Her-2/neu by quercetin could indicate an lateration in the Her-2/neu structure which promotes CHIP recruitments and down-regulation of Her-2/neu. We believe that by using quercetin, new therapeutic strategies can be developed to treat Her-2/neu overexpressing cancers.

Constituents and antimicrobial properties of blue honeysuckle: a novel source for phenolic antioxidants

The fruit of Lonicera caerulea L. (blue honeysuckle; Caprifoliaceae) and its phenolic fraction were analyzed for nutrients and micronutrients. The phenolic fraction was prepared from berries percolated with 0.1% H3PO4 and SPE using Sepabeads SP207. The sugar and lipid content was analyzed by HPLC and GC-MS. The total content of anthocyanins was determined using the pH differential absorbance method and aliphatic acids by capillary electrophoresis. MicroLC-MS/MS was used for determination of cyanidin-3-glucoside (the predominant anthocyanin), 3,5-diglucoside, and 3-rutinoside, paeonidin-3-glucoside, 3,5-diglucoside, and 3-rutinoside, delphinidin-3-glucoside and 3-rutinoside, pelargonidin-3-glucoside, 3,5-diglucoside, and 3-rutinoside, quercetin, its 3-glucoside, and 3-rutinoside, epicatechin, protocatechuic, gentisic, ellagic, ferulic, caffeic, chlorogenic, and coumaric acids. The phenolic fraction displayed Folin-Ciocalteu reagent reducing (335 +/- 15 microg of gallic acid equivalent/mg) and DPPH and superoxide scavenging activity (IC50 12.1 +/- 0.1 and 115.5 +/- 6.4 microg/mL) and inhibited rat liver microsome peroxidation (IC50 160 +/- 20 microg/mL). The freeze-dried fruit and its phenolic fraction reduced the biofilm formation and adhesion to the artificial surface of Candida parapsilosis, Staphylococcus epidermidis, Escherichia coli, Enterococcus faecalis, and Streptococcus mutans.

Antiviral and immunomodulatory effect of a lyophilized extract of Capparis spinosa L. buds

Herpes simplex virus type 1 (HSV-1) and herpes simplex virus type 2 (HSV-2) are common human pathogens that in particular cases can also cause severe problems especially in immunodeficient patients. The present paper reports the antiviral and immunomodulatory properties of a methanolic extract of C. spinosa buds (CAP), rich in flavonoids, including several quercetin and kaempferol glycosides. In particular we have investigated whether the in vitro exposure of human peripheral blood mononuclear cells (PBMCs) to CAP might inhibit the replication of HSV-2 and modulate the induction kinetics of IL-12, TNF-alpha IFN-gamma. Our findings have shown that CAP treatment interferes with HSV-2 replication in PBMCs inhibiting the extracellular virus release upregulating their production of IL-12, IFN-gamma and TNF-alpha. One could speculate that CAP may contribute in improving immune surveillance of PBMCs toward virus infection by up-regulating expression of peculiar proinflammatory cytokines; it should thus be successfully employed for treatment of HSV-2 infections in immunocompromised hosts.

Strong activation of cyclooxygenase I and II catalytic activity by dietary bioflavonoids

Cyclooxygenases (COXs) catalyze the conversion of arachidonic acid to prostaglandins (PGs), thromboxanes, and hydroxyeicosatetraenoic acids. In the present study, we investigated several dietary bioflavonoids for their ability to modulate the catalytic activity of COX I and II in vitro and also in cultured cells. We found that some of them are the most powerful direct stimulators of the catalytic activity of COX I and II known to date, increasing the formation of prostaglandin products in vitro by up to 11-fold over the controls. This stimulatory effect of bioflavonoids is enzyme specific because none of them stimulates the catalytic activity of a number of lipooxygenases tested. Compared with phenol, a prototypical COX stimulator commonly used in vitro, the naturally occurring bioflavonoids are up to 29 times more efficacious in stimulating the COX activity. Additional studies using intact cells in culture showed that some of the dietary compounds that were active in the biochemical assays also activated the formation of PGE(2) (a representative PG) when they were present at 0.01 to 1 muM concentrations. The stimulatory effect of dietary compounds on COX-mediated PG formation is far more potent in intact cells than in the in vitro assays. Mechanistically, bioflavonoids mainly acted to slow down the suicidal inactivation of the COX enzymes, but they did not appear to reactivate the inactivated enzymes. The finding of this study suggests that some of the bioflavonoids likely will serve as the naturally occurring cofactors for the COX enzymes in humans.

Sopungyangjae-tang inhibits development of dermatitis in nc/nga mice

Sopungyangjae-Tang (SYT) is a traditional Korean decoction used for the treatment of dermatitis. The aim of this study was to confirm whether or not SYT has a preventive effect on the development of atopic dermatitis in dinitrochlorobenzene-applied Nc/Nga mice. SYT was administered orally to Nc/Nga mice, which led to the remarkable suppression of the development of dermatitis, as determined by a histological examination and the serum IgE levels. Moreover, SYT inhibited the production of thymus- and activation-regulated chemokine (TARC) and its mRNA expression in a keratinocyte cell line, HaCaT, which had been stimulated with tumor necrosis factor-alpha (TNF-alpha) and interferon-gamma (IFN-gamma). Activation of the nuclear factor-kappaB (NF-kappaB) or activator protein-1 (AP-1) is one of the key steps in the signaling pathways mediating induction of TARC. In this study, SYT selectively suppressed NF-kappaB activation, which may be essential for TARC expression in TNF-alpha/IFN-gamma treated keratinocytes. The inhibitory effect of SYT on NF-kappaB activation and TARC production might be associated with the anti-dermatitic effects of SYT.

Effects of spray-dried porcine plasma and plant extracts on intestinal morphology and on leukocyte cell subsets of weaned pigs

We evaluated the effects of a 6% spray-dried porcine plasma (SDPP) and a plant extracts mixture (XT; 5% carvacrol, 3% cinnamaldehyde, and 2% capsicum oleoresin) on the productive performance, intestinal morphology, and leukocyte cell subsets of early-weaned pigs compared with a control group. Morphometry of the jejunum, ileum, and colon, and immune cell analysis of blood, ileocolic lymph node (LN), and ileal Peyer's patches were done in 24 weaned pigs (20 +/- 2 d) at 19 or 21 d postweaning. Although SDPP and XT treatments did not increase ADG or ADFI, SDPP improved the G:F ratio (P = 0.024) compared with the control group. Dietary SDPP reduced the percentages of blood monocytes (P = 0.006) and macrophages in ileal Peyer's patches and LN (P = 0.04), of B lymphocytes (P = 0.04) and gammadelta+ T cells in LN (P = 0.009), and of intraepithelial lymphocytes (P = 0.026) as well as the density of lamina propria cells in the colon (P < 0.01). Dietary XT reduced intraepithelial lymphocyte numbers in jejunum (P = 0.034) and the percentages of blood cytotoxic cells (P = 0.07) and B lymphocytes in LN (P = 0.03); however, XT increased blood monocytes (P = 0.038) and the density of lamina propria lymphocytes in the colon (P = 0.003). These results indicate that dietary SDPP and plant extracts can affect intestinal morphology and immune cell subsets of gut tissues and blood in weaned pigs. Furthermore, the effects of SDPP suggest lower activation of the immune system of the piglets.

Repression of calcitonin gene-related peptide expression in trigeminal neurons by a Theobroma cacao extract

ETHNOPHARMACOLOGICAL RELEVANCE

Cocoa bean preparations were first used by the ancient Maya and Aztec civilizations of South America to treat a variety of medical ailments involving the cardiovascular, gastrointestinal, and nervous systems. Diets rich in foods containing abundant polyphenols, as found in cocoa, underlie the protective effects reported in chronic inflammatory diseases. Release of calcitonin gene-related peptide (CGRP) from trigeminal nerves promotes inflammation in peripheral tissues and nociception.

AIM OF THE STUDY

To determine whether a methanol extract of Theobroma cacao L. (Sterculiaceae) beans enriched for polyphenols could inhibit CGRP expression, both an in vitro and an in vivo approach was taken.

RESULTS

Treatment of rat trigeminal ganglia cultures with depolarizing stimuli caused a significant increase in CGRP release that was repressed by pretreatment with Theobroma cacao extract. Pretreatment with Theobroma cacao was also shown to block the KCl- and capsaicin-stimulated increases in intracellular calcium. Next, the effects of Theobroma cacao on CGRP levels were determined using an in vivo model of temporomandibular joint (TMJ) inflammation. Capsaicin injection into the TMJ capsule caused an ipsilateral decrease in CGRP levels. Theobroma cacao extract injected into the TMJ capsule 24h prior to capsaicin treatment repressed the stimulatory effects of capsaicin.

CONCLUSIONS

Our results demonstrate that Theobroma cacao extract can repress stimulated CGRP release by a mechanism that likely involves blockage of calcium channel activity. Furthermore, our findings suggest that the beneficial effects of diets rich in cocoa may include suppression of sensory trigeminal nerve activation.

Demethylnobiletin inhibits delayed-type hypersensitivity reactions, human lymphocyte proliferation and cytokine production

BACKGROUND AND PURPOSE

Our aim was to examine the effect of demethylnobiletin on various experimental models of delayed-type hypersensitivity (DTH) reactions and to determine its influence on the mediators and enzymes involved in these reactions.

EXPERIMENTAL APPROACH

DTH was induced in mice by oxazolone, dinitrofluorobenzene (DNFB) and sheep red blood cells (SRBC). The effect of demethylnobiletin on the ensuing DTH was studied, especially in relation to oedema formation, cell infiltration and tissue damage. Its activity on different mediators implicated in DTH reactions was also determined and its effect on nitric oxide synthase (NOS)-2 analysed. Finally, its influence on T lymphocyte proliferation, apoptosis and caspase 3 activity was tested.

KEY RESULTS

DTH reactions were all reduced by demethylnobiletin. The experimental results suggest that the compound may act by reducing cell infiltration and by suppressing mediators such as interleukin-2 (IC50=1.63 microM), interleukin-4 (IC50=2.76 microM), tumour necrosis factor-alpha (IC50=0.66 microM), interferon-gamma (IC50=1.35 microM), and interleukin-1 beta (46% at 2.5 microM) and by concomitantly increasing the production of the anti-inflammatory cytokine, interleukin-10. In addition, while demethylnobiletin affected nitric oxide production, it did not modify NOS-2 expression. Finally, demethylnobiletin inhibited proliferation of T cells and induced their apoptosis.

CONCLUSIONS AND IMPLICATIONS

Demethylnobiletin decreased DTH reactions induced by various agents. This finding, along with the fact that the compound has a low toxicity and exhibits several other interesting properties, could pave the way for other structurally related citroflavonoids to be used as pharmacological agents in complementary therapies.

An extract of Apium graveolens var. dulce leaves: structure of the major constituent, apiin, and its anti-inflammatory properties

Flavonoids, natural compounds widely distributed in the plant kingdom, are reported to affect the inflammatory process and to possess anti-inflammatory as well as immunomodulatory activity in-vitro and in-vivo. Since nitric oxide (NO) produced by inducible nitric oxide synthase (iNOS) is one of the inflammatory mediators, the effects of the ethanol/water (1:1) extract of the leaves of Apium graveolens var. dulce (celery) on iNOS expression and NO production in the J774.A1 macrophage cell line stimulated for 24 h with Escherichia coli lipopolysaccharide (LPS) were evaluated. The extract of A. graveolens var. dulce contained apiin as the major constituent (1.12%, w/w, of the extract). The extract and apiin showed significant inhibitory activity on nitrite (NO) production in-vitro (IC50 0.073 and 0.08 mg mL(-1) for the extract and apiin, respectively) and iNOS expression (IC50 0.095 and 0.049 mg mL(-1) for the extract and apiin, respectively) in LPS-activated J774.A1 cells. The croton-oil ear test on mice showed that the extract exerted anti-inflammatory activity in-vivo (ID50 730 microg cm(-2)), with a potency seven-times lower than that of indometacin (ID50 93 microg cm(-2)), the non-steroidal anti-inflammatory drug used as reference. Our results clearly indicated the inhibitory activity of the extract and apiin in-vitro on iNOS expression and nitrite production when added before LPS stimulation in the medium of J774.A1 cells. The anti-inflammatory properties of the extract demonstrated in-vivo might have been due to reduction of iNOS enzyme expression.