Inhibition of nitric oxide (NO.) production in murine macrophages by flavones

Antioxidant peptides, the guardian of life from oxidative stress

Reactive oxygen species (ROS) are produced during oxidative metabolism in aerobic organisms. Under normal conditions, ROS production and elimination are in a relatively balanced state. However, under internal or external environmental stress, such as high glucose levels or UV radiation, ROS production can increase significantly, leading to oxidative stress. Excess ROS production not only damages biomolecules but is also closely associated with the pathogenesis of many diseases, such as skin photoaging, diabetes, and cancer. Antioxidant peptides (AOPs) are naturally occurring or artificially designed peptides that can reduce the levels of ROS and other pro-oxidants, thus showing great potential in the treatment of oxidative stress-related diseases. In this review, we discussed ROS production and its role in inducing oxidative stress-related diseases in humans. Additionally, we discussed the sources, mechanism of action, and evaluation methods of AOPs and provided directions for future studies on AOPs.

Antioxidants and antioxidant methods: an updated overview

Antioxidants had a growing interest owing to their protective roles in food and pharmaceutical products against oxidative deterioration and in the body and against oxidative stress-mediated pathological processes. Screening of antioxidant properties of plants and plant-derived compounds requires appropriate methods, which address the mechanism of antioxidant activity and focus on the kinetics of the reactions including the antioxidants. Many studies evaluating the antioxidant activity of various samples of research interest using different methods in food and human health have been conducted. These methods are classified, described, and discussed in this review. Methods based on inhibited autoxidation are the most suited for termination-enhancing antioxidants and for chain-breaking antioxidants, while different specific studies are needed for preventive antioxidants. For this purpose, the most common methods used in vitro determination of antioxidant capacity of food constituents were examined. Also, a selection of chemical testing methods was critically reviewed and highlighted. In addition, their advantages, disadvantages, limitations and usefulness were discussed and investigated for pure molecules and raw extracts. The effect and influence of the reaction medium on the performance of antioxidants are also addressed. Hence, this overview provides a basis and rationale for developing standardized antioxidant methods for the food, nutraceuticals, and dietary supplement industries. In addition, the most important advantages and shortcomings of each method were detected and highlighted. The chemical principles of these methods are outlined and critically discussed. The chemical principles of methods of 2,2'-azinobis-(3-ethylbenzothiazoline-6-sulphonate) radical (ABTS^·+) scavenging, 1,1-diphenyl-2-picrylhydrazyl (DPPH·) radical scavenging, Fe³⁺-Fe²⁺ transformation assay, ferric reducing antioxidant power (FRAP) assay, cupric ions (Cu²⁺) reducing power assay (Cuprac), Folin-Ciocalteu reducing capacity (FCR assay), peroxyl radical (ROO·), superoxide radical anion (O₂^·-), hydrogen peroxide (H₂O₂) scavenging assay, hydroxyl radical (OH·) scavenging assay, singlet oxygen (¹O₂) quenching assay, nitric oxide radical (NO·) scavenging assay and chemiluminescence assay are outlined and critically discussed. Also, the general antioxidant aspects of main food components were discussed by a number of methods, which are currently used for the detection of antioxidant properties of food components. This review consists of two main sections. The first section is devoted to the main components in the food and pharmaceutical applications. The second general section comprises some definitions of the main antioxidant methods commonly used for the determination of the antioxidant activity of components. In addition, some chemical, mechanistic and kinetic basis, and technical details of the used methods are given.

Medicinal plants with anti-inflammatory activities from selected countries and regions of Africa

Various nonsteroidal anti-inflammatory drugs have been shown to reduce pain and inflammation by blocking the metabolism of arachidonic acid by isoform of cyclooxygenase enzyme, thereby reducing the production of prostaglandin. Sadly, there are many side effects associated with the administration of nonsteroidal anti-inflammatory drugs. However, there are medicinal plants with anti-inflammatory therapeutic effects with low or no side effects. The Afri-can continent is richly endowed with diverse medicinal plants with anti-inflammatory activities that have been shown to be effective in the treatment of inflammatory conditions in traditional medicine. Interestingly, scientists have examined some of these African medicinal plants and documented their biological and therapeutic activities. Unfortunately, medicinal plants from different countries in Africa with anti-inflammatory properties have not been documented in a single review paper. It is important to document the ethnobotanical knowledge and applications of anti-inflammatory medicinal plants from selected countries representing different regions of the African continent. This paper therefore documents anti-inflammatory activities of various medicinal plants from different geographical regions of Africa with the aim of presenting the diversity of medicinal plants that are of traditional or therapeutic use in Africa.

The inhibitory effect of flavonoids on interleukin-8 release by human gastric adenocarcinoma (AGS) cells infected with cag PAI (+) Helicobacter pylori

Introduction

It is well known that the presence of Helicobacter pylori in the stomach induces gastritis and causes an immune response. Exposure of gastric epithelial cell lines to this germ induces the secretion of interleukin-8 (IL-8), which is a potent PMN-activating chemotactic cytokine. Interleukin-8 is usually elevated in gastric biopsy samples of patients with H. pylori-associated gastritis and significantly increases in the supernatant of in vitro cultivated biopsy samples of gastric mucosa with active H. pylori gastritis. Interleukin-8 is an activating factor for leucocytes and other pro-inflammatory factors, free radicals, and proteolytic enzymes. That is why natural compounds potentially useful in therapy are still investigated – among them flavonoids. They reveal anti-oxidative and anti-inflammatory activities and significantly inhibit the gastric mucosa damage.

The aim of the study

Was the estimation of the anti-inflammatory effects of flavonoids on H. pylori-induced activation of human gastric adenocarcinoma cells (AGS). After infection of AGS cells by cag PAI (+) H. pylori in vitro, secretion of IL-8, effects of flavonoids on viability of AGS cells, and effects of flavonoids on increase of H. pylori were determined. Such flavones as chrysin, quercetin, kaemferide, flavanone, galangin, and kaempferol were examined.

Results

This study has shown an inhibitory effect of flavonoids on the release of IL-8 through infected AGS cells (except chrysin), and no toxic effects to AGS cells were observed. Galangin revealed antibacterial effects against H. pylori. Flavonoids limit the inflammatory process through the inhibition of IL-8 release in infected AGS cells with H. pylori. The strongest inhibitor of IL-8 was galangin.

Pharmacological Activities of Ruthenium Complexes Related to Their NO Scavenging Properties

Angiogenesis is considered responsible for the growth of primary tumours and of their metastases. With the present study, the effects of three ruthenium compounds, potassiumchlorido (ethylendiamminotetraacetate)rutenate(III) (RuEDTA), sodium (bis-indazole)tetrachloro-ruthenate(III), Na[trans-RuCl₄Ind₂] (KP1339) and trans-imidazoledimethylsulphoxidetetrachloro-ruthenate (NAMI-A), are studied in vitro in models mimicking the angiogenic process. The ruthenium compounds reduced the production and the release of nitrosyls from either healthy macrophages and immortalized EA.hy926 endothelial cells. The effects of NAMI-A are qualitatively similar and sometimes quantitatively superior to those of RuEDTA and KP1339. NAMI-A reduces the production and release of nitric oxide (NO) by the EA.hy926 endothelial cells and correspondingly inhibits their invasive ability; it also strongly inhibits the angiogenesis in matrigel sponges implanted subcutaneously in healthy mice. Taken together, these data support the anti-angiogenic activity of the tested ruthenium compounds and they contribute to explain the selective activity of NAMI-A against solid tumour metastases, the tumour compartment on which angiogenesis is strongly involved. This anti-angiogenic effect may also contribute to the inhibition of the release of metastatic cells from the primary tumour. Investigations on the anti-angiogenic effects of NAMI-A at this level will increase knowledge of its pharmacological properties and it will give a further impulse to the development of this class of innovative metal-based drugs.

Antioxidant Activities of 4-Methylumbelliferone Derivatives

The synthesis of derivatives of 4-Methylumbelliferone (4-MUs), which are structurally interesting antioxidants, was performed in this study. The modification of 4-Methylumbelliferone (4-MU) by different reaction steps was performed to yield the target compounds, the 4-MUs. The 4-MUs were characterized by different spectroscopic techniques (Fourier transform infrared; FT-IR and Nuclear magnetic resonance; NMR) and micro-elemental analysis (CHNS). The in vitro antioxidant activity of the 4-MUs was evaluated in terms of their free radical scavenging activities against 2,2-diphenyl-1-picrylhydrazyl (DPPH), Nitric oxide radical scavenging activity assay, chelating activity and their (FRAP) ferric-reducing antioxidant power, which were compared with a standard antioxidant. Our results reveal that the 4-MUs exhibit excellent radical scavenging activities. The antioxidant mechanisms of the 4-MUs were also studied. Density Function Theory (DFT)-based quantum chemical studies were performed with the basis set at 3-21G. Molecular models of the synthesized compounds were studied to understand the antioxidant activity. The electron levels, namely HOMO (highest occupied molecular orbital) and LUMO (lowest unoccupied molecular orbital), for these synthesized antioxidants were also studied.

Tartary buckwheat on nitric oxide-induced inflammation in RAW264.7 macrophage cells

We investigated the effects of tartary buckwheat (TB, Fagopyrum tataricum) on the production of pro-inflammatory mediators in lipopolysaccharide (LPS)- and interferon (IFN)-γ-stimulated RAW264.7 cells.

The antioxidant effects of the flavonoids rutin and quercetin inhibit oxaliplatin-induced chronic painful peripheral neuropathy

BACKGROUND

Oxaliplatin, the third-generation platinum compound, has evolved as one of the most important therapeutic agents in colorectal cancer chemotherapy. The main limiting factor in oxaliplatin treatment is painful neuropathy that is difficult to treat. This side effect has been studied for several years, but its full mechanism is still inconclusive, and effective treatment does not exist. Data suggest that oxaliplatin's initial neurotoxic effect is peripheral and oxidative stress-dependent. A spinal target is also suggested in its mechanism of action. The flavonoids rutin and quercetin have been described as cell-protecting agents because of their antioxidant, antinociceptive, and anti-inflammatory actions. We proposed a preventive effect of these agents on oxaliplatin-induced painful peripheral neuropathy based on their antioxidant properties.

METHODS

Oxaliplatin (1 mg/kg, i.v.) was injected in male Swiss mice, twice a week (total of nine injections). The development of sensory alterations, such as thermal and mechanical allodynia, was evaluated using the tail immersion test in cold water (10°C) and the von Frey test. Rutin and quercetin (25-100 mg/kg, i.p.) were injected 30 min before each oxaliplatin injection. The animals' spinal cords were removed for histopathological and immunohistochemical evaluation and malondialdehyde assay.

RESULTS

Oxaliplatin significantly increased thermal and mechanical nociceptive response, effects prevented by quercetin and rutin at all doses. Fos immunostaining in the dorsal horn of the spinal cord confirmed these results. The oxidative stress assays mainly showed that oxaliplatin induced peroxidation in the spinal cord and that rutin and quercetin decreased this effect. The flavonoids also decreased inducible nitric oxide synthase and nitrotyrosine immunostaining in the dorsal horn of the spinal cord. These results suggest that nitric oxide and peroxynitrite are also involved in the neurotoxic effect of oxaliplatin and that rutin and quercetin can inhibit their effect in the spinal cord. We also observed the preservation of dorsal horn structure using histopathological analyses.

CONCLUSIONS

Oxaliplatin induced painful peripheral neuropathy in mice, an effect that was prevented by rutin and quercetin. The mechanism of action of oxaliplatin appears to be, at least, partially oxidative stress-induced damage in dorsal horn neurons, with the involvement of lipid peroxidation and protein nitrosylation.

Anti-Inflammatory Effects of Hyptis albida Chloroform Extract on Lipopolysaccharide-Stimulated Peritoneal Macrophages

We examined the effects of a chloroform extract of Hyptis albida (CHA) on inflammatory responses in mouse lipopolysaccharide (LPS) induced peritoneal macrophages. Our findings indicate that CHA inhibits LPS-induced production of tumor necrosis factor (TNF- α ) and interleukin-6 (IL-6). During the process, levels of cyclooxygenase-2 (COX-2), nitric oxide synthase (iNOS), and nitric oxide (NO) increased in the mouse peritoneal macrophages; however, the extract suppressed them significantly. These results provide novel insights into the anti-inflammatory actions of CHA and support its potential use in the treatment of inflammatory diseases.

Chemical Composition and Anti-Inflammatory Effect of Ethanolic Extract of Brazilian Green Propolis on Activated J774A.1 Macrophages

The aim of this study was to investigate the chemical composition and anti-inflammatory effect of ethanolic extract of Brazilian green propolis (EEP-B) on LPS + IFN-γ or PMA stimulated J774A.1 macrophages. The identification and quantification of phenolic compounds in green propolis extract were performed using HPLC-DAD and UPLC-Q-TOF-MS methods. The cell viability was evaluated by MTT and LDH assays. The radical scavenging ability was determined using DPPH^• and ABTS^•+. ROS and RNS generation was analyzed by chemiluminescence. NO concentration was detected by the Griess reaction. The release of various cytokines by activated J774A.1 cells was measured in the culture supernatants using a multiplex bead array system based on xMAP technology. Artepillin C, kaempferide, and their derivatives were the main phenolics found in green propolis. At the tested concentrations, the EEP-B did not decrease the cell viability and did not cause the cytotoxicity. EEP-B exerted strong antioxidant activity and significantly inhibited the production of ROS, RNS, NO, cytokine IL-1α, IL-1β, IL-4, IL-6, IL-12p40, IL-13, TNF-α, G-CSF, GM-CSF, MCP-1, MIP-1α, MIP-1β, and RANTES in stimulated J774A.1 macrophages. Our findings provide new insights for understanding the anti-inflammatory mechanism of action of Brazilian green propolis extract and support its application in complementary and alternative medicine.

Protection by polyphenols of postprandial human plasma and low-density lipoprotein modification: the stomach as a bioreactor

Recent studies dramatically showed that the removal of circulating modified low-density lipoprotein (LDL) results in complete prevention of atherosclerosis. The gastrointestinal tract is constantly exposed to food, some of it containing oxidized compounds. Lipid oxidation in the stomach was demonstrated by ingesting heated red meat in rats. Red wine polyphenols added to the rats' meat diet prevented lipid peroxidation in the stomach and absorption of malondialdehyde (MDA) in rat plasma. In humans, postprandial plasma MDA levels rose by 3-fold after a meal of red meat cutlets. MDA derived from meat consumption caused postprandial plasma LDL modification in human. The levels of plasma MDA showed a 75% reduction by consumption of red wine polyphenols during the meat meal. Locating the main biological site of action of polyphenols in the stomach led to a revision in the understanding of how antioxidants work in vivo and may help to elucidate the mechanism involved in the protective effects of polyphenols in human health.

Anti-inflammatory Effect of Perilla frutescens (L.) Britton var. frutescens Extract in LPS-stimulated RAW 264.7 Macrophages

This study was designed to investigate the inhibitory effects of Perilla frutescens (L.) Britton var. frutescens extract on the production of inflammation-related mediators (NO, ROS, NF-κB, iNOS and COX-2) and pro-inflammatory cytokines (TNF-α, IL-1β, IL-6) in lipopolysaccharide-stimulated RAW 264.7 macrophages. Perilla frutescents (L.) Britton var. frutescens was air-dried and extracted with ethanol. The extract dose-dependently decreased the generation of intracellular reactive oxygen species and dose-dependently increased antioxidant enzyme activities, such as superoxide dismutase, catalase and glutathione peroxidase in lipopolysaccharide stimulated RAW 264.7 macrophages. Also, Perilla frutescens (L.) Britton var. frutescens extract suppressed NO production in lipopolysaccharide-stimulated RAW 264.7 cells. The expressions of pro-inflammatory cytokines (TNF-α, IL-1β and IL-6), NF-κB, iNOS and COX-2 were inhibited by the treatment with the extract. Thus, this study shows the Perilla frutescens (L.) Britton var. frutescens extract could be useful for inhibition of the inflammatory process.

Inhibition of inflammatory mediators by neobavaisoflavone in activated RAW264.7 macrophages

Flavonoids and coumarins are the major bioactive constituents identified in Psoralea corylifolia. The active fraction isolated from fruits, seeds and roots possesses antibacterial, antioxidative and immunomodulatory properties. Neobavaisoflavone is one of the flavonoids found in Psoralea corylifolia. In the present study we investigated in vitro the anti-inflammatory activity of neobavaisoflavone. Macrophages play an important role in inflammation through the release of inflammatory mediators involved in the immune response. Inappropriate and prolonged macrophage activation is largely responsible for the pathology of acute and chronic inflammatory conditions. Neobavaisoflavone significantly inhibited the production of reactive oxygen species (ROS), reactive nitrogen species (RNS) and cytokines: IL-1β, IL-6, IL-12p40, IL-12p70, TNF-α in LPS+IFN-γ– or PMA– stimulated RAW264.7 macrophages.

Inhibitors of microglial neurotoxicity: focus on natural products

Microglial cells play a dual role in the central nervous system as they have both neurotoxic and neuroprotective effects. Uncontrolled and excessive activation of microglia often contributes to inflammation-mediated neurodegeneration. Recently, much attention has been paid to therapeutic strategies aimed at inhibiting neurotoxic microglial activation. Pharmacological inhibitors of microglial activation are emerging as a result of such endeavors. In this review, natural products-based inhibitors of microglial activation will be reviewed. Potential neuroprotective activity of these compounds will also be discussed. Future works should focus on the discovery of novel drug targets that specifically mediate microglial neurotoxicity rather than neuroprotection. Development of new drugs based on these targets may require a better understanding of microglial biology and neuroinflammation at the molecular, cellular, and systems levels.

Anti-inflammatory mechanism of Kaempferia parviflora in murine macrophage cells (RAW 264.7) and in experimental animals

ETHNOPHARMACOLOGICAL RELEVANCE

The rhizomes of Kaempferia parviflora Wall. ex Baker have been used in Thailand for treatment of gout, apthous ulcer, peptic ulcer and abscesses.

AIM OF THE STUDY

In our previous study, the crude ethanol extract of Kaempferia parviflora and its compound (5, 5-hydroxy-3,7,3',4'-tetramethoxyflavone), was reported to show nitric oxide (NO) inhibition in RAW 264.7 cells. The present study is thus investigated the anti-inflammatory mechanism of Kaempferia parviflora extract and compound 5 against inducible nitric oxide synthase (iNOS) and cyclooxygenase-2 (COX-2) mRNA expressions.

MATERIALS AND METHODS

The extract of Kaempferia parviflora and its compound were tested against NO and prostaglandin E(2) (PGE(2)) releases using RAW264.7 cells as well as studied on anti-inflammatory activity in carrageenan-induced rat paw edema and acute toxicity in mice.

RESULTS

The results revealed that the ethanol extract of Kaempferia parviflora markedly inhibited PGE(2) release with an IC(50) value of 9.2 microg/ml. This plant extract and compound 5 also suppressed mRNA expression of iNOS in dose-dependent manners, whereas COX-2 mRNA expression was partly affected. According to the in vivo study, chloroform and hexane fractions greater decreased rat paw edema than ethanol, ethyl acetate and water fractions.

CONCLUSION

The mechanisms for anti-inflammatory activity of Kaempferia parviflora and compound 5 are mainly due to the inhibition of iNOS mRNA expression but partly through that of COX-2 mRNA.

Anti-inflammatory effect of Streblus asper leaf extract in rats and its modulation on inflammation-associated genes expression in RAW 264.7 macrophage cells

AIM OF THIS STUDY

Streblus asper is a medicinal plant from Thailand used in folk medicine for the treatment of several inflammatory diseases. In this study, we investigated the anti-inflammatory effect of Streblus asper leaf ethanolic extract (SAE).

MATERIALS AND METHODS

The experimental carrageenan-induced paw edema in rats was performed in which the SAE at doses of 125, 250, 500 mg/kg body weight was intraperitoneally administered to the rats. Then, reverse transcriptive polymerase chain reaction (RT-PCR) technique was also performed to determine the effect of SAE on the expression of inflammation-associated genes in RAW 264.7 macrophage cells stimulated with lipopolysaccharide (LPS).

RESULTS

The SAE at all given doses caused a significant dose-dependent inhibition of edema (p<0.05). Moreover, the significant and dose-dependent LPS-induced cyclooxygenase (COX)-2 and inducible nitric oxide synthase (iNOS) mRNA expressions were demonstrated in RAW 264.7 cells treated with SAE. The inhibition is selective, since COX-1 mRNA expression did not change in the presence of SAE.

CONCLUSION

The results of this study are the first scientific evidence on the molecular effects of Streblus asper as a potential anti-inflammatory agent, which supports the fact that the plant is employed in traditional remedies.

The Inhibitory Effect of Luteolin-7-O-glucoside on the Formation of Pentyl and 7-Carboxyheptyl Radicals from 13-Hydroperoxy-9,11-octadecadienoic Acid in the Presence of Iron(II) Ions

A flavone glucoside, luteolin-7-O-glucoside (luteolin-7-G) inhibited the formation of pentyl and 7-carboxyheptyl radicals in the reaction of 13-hydroperoxy-9,11-octadecadienoic (13-HPODE) acid with iron(II) ions. The inhibitory effect of luteolin-7-G was diminished in the presence of EDTA. These results indicated that the inhibitory effects of luteolin-7-G occur partly through the chelation of iron ions. Measurement of visible spectra also showed that luteolin-7-G chelates iron ions. On the other hand, luteolin-7-G did not inhibit the reaction under anaerobic conditions, suggesting that oxygen molecules participate in the inhibition. Oxygen consumption measurements showed that the luteolin-7-G/iron ion complexes react with oxygen molecules in competition with 13-HPODE acid, and free iron ions exclusively react with 13-HPODE acid. The reaction of luteolin-7-G/iron ion complexes with oxygen molecules possibly diminishes the formation of pentyl and 7-carboxyheptyl radicals.

The value of phytoestrogens as a possible therapeutic option in postmenopausal women with coronary heart disease

Large epidemiological studies have proved that the risk of coronary heart disease in postmenopausal women can be decreased by oestrogen replacement therapy. The effect is triggered by metabolic processes in the liver (decrease of LDL-cholesterol, increase of HDL-cholesterol) as well as by direct impact on the arterial wall (anti-oxidation, relaxation, anti-proliferation). The therapeutical usage of oestrogens is limited by an increased incidence of breast and endometrial cancer. Cyclic application of progestogens virtually eliminates the risk. Unfortunately, progestogens may antagonise the atheroprotective effect of oestrogens. Structurally modified oestrogens as well as selective oestrogen receptor modulators were investigated in clinical trials. They might provide the desired atheroprotective effects of oestrogen without negative side effects on the mammary gland or the endometrium. In this respect isoflavones also known as phytoestrogens, were analysed. They are widespread and occur naturally in many plants, especially in soy products. Cell culture and animal experiments as well as clinical studies revealed that phytoestrogens such as genistein and daidzein act atheroprotectively in the same way as oestrogen. Effects on the mammary gland or the endometrium could not be detected, but positive side effects on the bone metabolism and the decrease of certain types of cancer could be observed. In total, the therapeutical application of phytoestrogens in postmenopausal women seems to be of real and great benefit. We conclude that in women the risk of death from coronary heart disease increases after the onset of menopause. Recently discovered properties of phyto-oestrogens seem to be of great benefit as they do not seem to have any side effects on the mammary gland and the endometrium which are limiting factors for oestrogen replacement therapy.

Nanonized black soybean enhances immune response in senescence-accelerated mice

Soy isoflavones may have applications in cancer prevention and anti-inflammation, therefore this study was conducted to investigate the effect of dietary supplementation with black soybean on the immune response in the senescence-accelerated-prone mice (SAMP8) and -resistant mice (SAMPR1, as controls). The mechanism of isoflavones was also investigated. Six-month-old male SAMP8 and SAMR1 mice were divided into the control groups and experimental groups supplemented with nanonized (Nano-soy) or microparticled (Micro-soy) black soybeans (n = 8/group), respectively for 12 weeks. Human peripheral blood mononuclear cells (PBMC) and murine splenocytes were stimulated with mitogens and cytokines were determined by reverse transcriptase-polymerase chain reaction and/or ELISA. The results showed that body weight, food intake, and relative weights of organs did not differ among the SAMP8 control and experimental groups. Isoflavone (daidzin and genistin) intake was higher in the Nano-soy group than the Micro-soy group. The lymphoproliferation and production of interleukin-2 (IL-2) and interferon-gamma (IFN-gamma) in the Nano-soy group had a significantly higher (P < 0.05) than those in the control and Micro-soy groups. The Nano-soy supplemented mice reached these cytokine levels similar to SAMR1 mice. This result was consistent with the in vitro data that daidzein (a metabolite of daidzin), at a concentration of 10 muM, increased IL-2, IL-4, and IFN-gamma production from phytohemagglutinin-stimulated PBMC (P < 0.05). However at higher concentrations (> 50 microM), daidzein only reduced IL-10 and IFN-gamma levels, whereas genistein reduced levels of the IL-2, IL-4, IL-10, IFN-gamma mRNA and protein and these results suggest that the Nano-soy supplementation improved immune response in SAMP8 mice which may be attributable to higher daidzin content in the black soybean preparation.

Antioxidant and Anti-Inflammatory Activities of the PlantAndrographis PaniculataNees

In this study, we explored the antioxidant and anti-inflammatory properties of the medicinal herb Andrographis paniculata using in vitro as well as in vivo systems. Methanolic extract of Andrographis paniculata was found to inhibit formation of oxygen derived free radicals such as superoxide (32%) hydroxyl radicals (80%) lipid peroxidation (80%) and nitric oxide (42.8%) in in vitro system. In vivo studies using BALB/c mice models also showed significant inhibition in PMA induced superoxide (32.4%) and nitric oxide (65.3%) formation. Interestingly we also found that, administration of Andrographis paniculata extract produced complete inhibition of carageenan induced inflammation compared with control models.

Inhibition of inducible nitric oxide synthase expression by an acetonic extract from Feijoa sellowiana Berg. fruits

Feijoa sellowiana Berg. fruits and especially the acetonic extract have been shown to possess biological activities, although the responsible compounds have never been identified. The present study was designed to evaluate the anti-inflammatory activity of an acetonic extract from F. sellowiana Berg. fruits on the nitric oxide (NO) pathway, which plays an important role in inflammation. To this aim the J774 cell line, which expresses inducible nitric oxide synthase (iNOS) following stimulation with lipopolysaccharide (LPS), has been utilized, and the effects of this extract and its fractions on NO production, iNOS protein expression, and signal pathways involved in its regulation have been evaluated. This study demonstrates that at least some part of the anti-inflammatory activity of the acetonic extract is due to the suppression of NO production by flavone and stearic acid. The mechanism of this inhibition seems to be related to an action on the expression of the enzyme iNOS through the attenuation of nuclear factor kappaB (NF-kappaB) and/or mitogen-activated protein kinase (MAPK) activation.

Isolation and structure elucidation of phenolic antioxidants from Tamarind (Tamarindus indica L.) seeds and pericarp

Although it is already known that Tamarind (Tamarindus indica L.) seeds contain phenolic substances, the individual components of the seeds have not been fully identified and quantitated, and in the case of Tamarind pericarp not reported. Therefore, major polyphenolic compounds were extracted using organic solvents and the metabolites were isolated by semi-preparative high performance liquid chromatography. Their structures were elucidated by liquid chromatography-electrospray-ionisation-mass spectrometry (LC-ESI-MS), nano-electrospray-ionisation mass spectrometry (ESI-MS), and where possible by gas chromatography-mass spectrometry (GC-MS) and 1H and 13C NMR. Quantitative analysis of polyphenolic compounds in Tamarind seeds and pericarp was conducted by analytical high performance liquid chromatography (HPLC), calculated against standard curves of authentic compounds. The yields of total phenolic compounds after Soxhlet extraction with methanol were 6.54 and 2.82 g/kg (dry weight) in the seeds and pericarp respectively. The profile (%) of polyphenolics in Tamarind pericarp was dominated by proanthcyanidins (73.4) in various forms (+)-catechin (2.0), procyanidin B2 (8.2), (-)-epicatechin (9.4), procyanidin trimer (11.3), procyanidin tetramer (22.2), procyanidin pentamer (11.6), procyanidin hexamer (12.8) along with taxifolin (7.4), apigenin (2.0), eriodictyol (6.9), luteolin (5.0) and naringenin (1.4) of total phenols, respectively. The content of Tamarind seeds comprised only procyanidins, represented (%) mainly by oligomeric procyanidin tetramer (30.2), procyanidin hexamer (23.8), procyanidin trimer (18.1), procyanidin pentamer (17.6) with lower amounts of procyanidin B2 (5.5) and (-)-epicatechin (4.8). Extraction of Tamarind pericarp and seeds using acetone:methanol:acetic acid gave only procyanidin oligomers, but in much higher yield and variety. The antioxidant capacities of the Soxhlet methanolic extracts were determined, and indicates that Tamarind may be an important source of cancer chemopreventive natural products in tropical regions.

Suppression of cyclooxygenase-2 expression of skin fibroblasts by wogonin, a plant flavone from Scutellaria radix

Previously, wogonin (5,7-dihydroxy-8-methoxyflavone) was found to suppress proinflammatory enzyme expression including cyclooxygenase-2 (COX-2), contributing to in vivo anti-inflammatory activity against skin inflammation. However, the detailed effect on each skin cell type has not been understood. Therefore, present investigation was carried out to find the effect of wogonin on inflammation associated gene expression from skin fibroblasts in culture using reverse transcriptase-polymerase chain reaction. As a result, it was found that wogonin (10-100 microM) clearly down-regulated COX-2 expression from NIH/3T3 cells treated with 12-O-tetradecanoylphorbol 13-acetate, interleukin-1beta or tumor necrosis factor-alpha. But, the expression levels of COX-1, interleukin-1beta and fibronectin were not significantly affected. This finding was well correlated with significant reduction of prostaglandin E2 (PGE2) production by wogonin. As a comparison, NS-398 (selective cyclooxygenase 2 inhibitor) did not suppress COX-2 expression and other gene levels, while PGE2 production was potently reduced at 0.1-10 microM. All these results suggest that COX-2 down-regulation of skin fibroblasts may be, at least in part, one of anti-inflammatory mechanisms of wogonin against skin inflammation.

The effect of the phytoestrogen coumestrol on the NZB/W F1 murine model of systemic lupus

Coumestrol is a naturally occurring plant estrogen. As estrogen influences cellular and humoral immunity, and has known effects on murine models of lupus, we investigated the effect of coumestrol on disease expression in the NZB/W F1 mouse. Female NZB/W F1 mice were fed a "standard" rodent diet including soy proteins, a non-soy diet, or a non-soy diet with 0.01% coumestrol. Outcome measures included survival, autoantibody expression, immunoglobulin levels, proteinuria, renal histology and B cell immunohistochemistry, and renal mRNA expression. At 24 weeks, the treatment group had decreased prevalence of autoantibodies detected by immunofluorescence and less splenomegaly. At 39 weeks, the prevalence of autoantibodies was similar but the treatment group had less proteinuria. Overall, there was little effect of treatment on renal mRNA levels as assessed by gene array analysis, but functional ontology mapping revealed that genes encoding proteins involved in the immune response were most often affected. These results suggest that treatment with coumestrol may ameliorate some aspects of disease progression in this model of systemic autoimmunity.

Anti-inflammatory plant flavonoids and cellular action mechanisms

Plant flavonoids show anti-inflammatory activity in vitro and in vivo. Although not fully understood, several action mechanisms are proposed to explain in vivo anti-inflammatory action. One of the important mechanisms is an inhibition of eicosanoid generating enzymes including phospholipase A2, cyclooxygenases, and lipoxygenases, thereby reducing the concentrations of prostanoids and leukotrienes. Recent studies have also shown that certain flavonoids, especially flavone derivatives, express their anti-inflammatory activity at least in part by modulation of proinflammatory gene expression such as cyclooxygenase-2, inducible nitric oxide synthase, and several pivotal cytokines. Due to these unique action mechanisms and significant in vivo activity, flavonoids are considered to be reasonable candidates for new anti-inflammatory drugs. To clearly establish the therapeutic value in inflammatory disorders, in vivo anti-inflammatory activity, and action mechanism of varieties of flavonoids need to be further elucidated. This review summarizes the effect of flavonoids on eicosanoid and nitric oxide generating enzymes and the effect on expression of proinflammatory genes. In vivo anti-inflammatory activity is also discussed. As natural modulators of proinflammatory gene expression, certain flavonoids have a potential for new anti-inflammatory agents.

Inhibition of nitric oxide production from lipopolysaccharide-treated RAW 264.7 cells by synthetic flavones: Structure-activity relationship and action mechanism

Recent investigations have shown that certain flavonoids, especially flavone derivatives, inhibit nitric oxide (NO) production by inducible NO synthase (iNOS) in macrophages, which contribute their anti-inflammatory action. For the purpose of finding the optimized chemical structures of flavonoids that inhibit NO production, various A- and B-ring substituted flavones were synthesized and evaluated for their inhibitory activity using lipopolysaccharide-treated RAW 264.7 cells. It was found that the optimal chemical structures were A-ring 5,7-dihydroxyflavones having the B-ring 2',3'-dihydroxy or 3',4'-dihydroxy or 3',4'-hydroxy/methoxy (methoxy/hydroxy) groups. These structurally optimized compounds were revealed to be down-regulators of iNOS induction, but not direct iNOS inhibitors. Of these derivatives that were evaluated, 2',3',5,7-tetrahydroxyflavone and 3',4',5,7-tetrahydroxyflavone (luteolin) showed the strongest inhibition. The IC50 values for these compounds were 19.7 and 17.1 microM, respectively. Therefore, these compounds may have a potential as new anti-inflammatory agents.

Suppression of nitric oxide production in mouse macrophages by soybean flavonoids accumulated in response to nitroprusside and fungal elicitation

BACKGROUND

The anti-inflammatory properties of some flavonoids have been attributed to their ability to inhibit the production of NO by activated macrophages. Soybean cotyledons accumulate certain flavonoids following elicitation with an extract of the fungal pathogen Diaporthe phaseolorum f. sp. meridionalis (Dpm). Sodium nitroprusside (SNP), a nitric oxide donor, can substitute for Dpm in inducing flavonoid production. In this study, we investigated the effect of flavonoid-containing diffusates obtained from Dpm- and SNP-elicited soybean cotyledons on NO production by lipopolysaccharide (LPS)- and LPS plus interferon-gamma (IFNgamma)-activated murine macrophages.

RESULTS

Significant inhibition of NO production, measured as nitrite formation, was observed when macrophages were activated in the presence of soybean diffusates from Dpm- or SNP-elicited cotyledons. This inhibition was dependent on the duration of exposure to the elicitor. Daidzein, genistein, luteolin and apigenin, the main flavonoids present in diffusates of elicited cotyledons, suppressed the NO production by LPS + IFNgamma activated macrophages in a concentration-dependent manner, with IC50 values of 81.4 microM, 34.5 microM, 38.6 microM and 10.4 microM respectively. For macrophages activated with LPS alone, the IC50 values were 40.0 microM, 16.6 microM, 10.4 microM and 2.8 microM, respectively. Western blot analysis showed that iNOS expression was not affected by daidzein, was reduced by genistein, and was abolished by apigenin, luteolin and Dpm- and SNP-soybean diffusates at concentrations that significantly inhibited NO production by activated macrophages.

CONCLUSIONS

These results suggest that the suppressive effect of flavonoids on iNOS expression could account for the potent inhibitory effect of Dpm- and SNP-diffusates on NO production by activated macrophages. Since the physiological concentration of flavonoids in plants is normally low, the treatment of soybean tissues with SNP may provide a simple method for substantially increasing the concentration of metabolites that are beneficial for the treatment of chronic inflammatory diseases associated with NO production.

Extract of the seed coat of Tamarindus indica inhibits nitric oxide production by murine macrophages in vitro and in vivo

The seed coat extract of Tamarindus indica, a polyphenolic flavonoid, has been shown to have antioxidant properties. The present studies investigated the inhibitory effect of the seed coat extract of T. indica on nitric oxide production in vitro using a murine macrophage-like cell line, RAW 264.7, and in vitro and in vivo using freshly isolated B6C3F1 mouse peritoneal macrophages. In vitro exposure of RAW 264.7 cells or peritoneal macrophages to 0.2-200 microg/mL of T. indica extract significantly attenuated (as much as 68%) nitric oxide production induced by lipopolysaccharide (LPS) and interferon gamma (IFN-gamma) in a concentration-dependent manner. In vivo administration of T. indica extract (100-500 mg/kg) to B6C3F1 mice dose-dependently suppressed TPA, LPS and/or IFN-gamma induced production of nitric oxide in isolated mouse peritoneal macrophages in the absence of any effect on body weight. Exposure to T. indica extract had no effect on cell viability as assessed by the MTT assay. In B6C3F1 mice, preliminary safety studies demonstrated a decrease in body weight at only the highest dose tested (1000 mg/kg) without alterations in hematology, serum chemistry or selected organ weights or effects on NK cell activity. A significant decrease in body weight was observed in BALB/c mice exposed to concentrations of extract of 250 mg/kg or higher. Oral exposure of BALB/c mice to T. indica extract did not modulate the development of T cell-mediated sensitization to DNFB or HCA as measured by the local lymph node assay, or dermal irritation to nonanoic acid or DNFB. These studies suggest that in mice, T. indica extract at concentrations up to 500 mg/kg may modulate nitric oxide production in the absence of overt acute toxicity.

Inhibition of contact dermatitis in animal models and suppression of proinflammatory gene expression by topically applied Flavonoid, Wogonin

Wogonin (5,7-dihydroxy-8-methoxyflavone) is a down-regulator of cyclooxygenase-2 and inducible nitric oxide synthase expression, contributing to anti-inflammatory activity in vivo. For further characterization of modulatory activity on proinflammatory gene expression in vivo, the effect of wogonin was examined in this experiment using animal models of skin inflammation. By topical application, wogonin inhibited an edematic response as well as proinflammatory gene expression against contact dermatitis in mice. Wogonin inhibited ear edema (19.4-22.6%) at doses of 50-200 microg/ear and down-regulated interleukin-1beta induction (23.1%) at 200 microg/ear in phenol-induced simple irritation. Wogonin (2x50-2x200 microg/ear) also inhibited edematic response (51.2-43.9%) and down-regulated proinflammatory gene expression of cyclooxygenase-2, interleukin-1beta, interferon-gamma, intercellular adhesion molecule-1 and inducible nitric oxide synthase with some different sensitivity against picryl chloride-induced delayed hypersensitivity reaction. All these results clearly demonstrate that wogonin is a down-regulator of proinflammatory gene expression in animal models of skin inflammation. Therefore, wogonin may have potential for a new anti-inflammatory agent against skin inflammation.

Effects of ethanol extract of propolis (EEP) and its flavones on inducible gene expression in J774A.1 macrophages

Propolis, a bee-hive product, has been used in folk medicine for centuries, and recently in modern medicine as an anti-inflammatory and immunomodulatory agent. These activities would be mainly due to phenolic compounds such as flavonoids, especially flavone derivatives. The present study examined the effect of ethanol extract of propolis (EEP) and selected flavone derivatives (chrysin, galangin, kaempferol and quercetin) on interleukin-1beta (IL-1beta) and inducible nitric oxide synthase (iNOS) gene expression in lipopolysaccharide (LPS)-induced J774A.1 macrophages. Treatment of cells with EEP significantly suppressed both IL-1beta mRNA (P<0.02) and iNOS mRNA (P<0.001) expression. The concentrations of cytokine in cell culture supernatants and cell lysates and nitric oxide (NO) generation were reduced in a dose-dependent manner. The tested phenolic compounds significantly decreased the IL-1beta mRNA level and IL-1beta protein concentration (P<0.05) (excluding galangin), iNOS mRNA level and NO production (P<0.001). The most potent inhibitor of the IL-1beta synthesis and NO generation was chrysin. These results indicate that EEP exerts its inhibitory effect on the IL-1beta and iNOS gene expression in J774A.1 macrophages at the transcriptional level. Tested flavone derivatives contribute to the anti-inflammatory activity of propolis.

Dietary constituents as novel therapies for pain

The use of complementary and alternative medicine has dramatically increased in the United States. The effects of select dietary constituents in animal models and clinical pain states are reviewed. Specifically, the antinociceptive and analgesic properties of soybeans, sucrose, and tart cherries are discussed. The potential actions of dietary constituents as antiinflammatory and antioxidant agents are presented.

Effects of wogonin, a plant flavone from Scutellaria radix, on skin inflammation: in vivo regulation of inflammation-associated gene expression

Flavonoids from plant origin show anti-inflammatory activity in vitro and in vivo. In addition to inhibition of inflammation-associated enzymes, such as cyclooxygenases (COX) and lipoxygenases, they have been found to regulate the expression of inflammation-associated proteins from in vitro experiments. In order to prove in vivo behavior and the potential for beneficial use against inflammatory skin disorders, the effect of wogonin (5,7-dihydroxy-8-methoxyflavone) on in vivo expression of several inflammation-associated genes was examined in the intact as well as in the inflamed mouse skin by reverse transcriptase-polymerase chain reaction analysis. When applied topically on the intact skin, only a high dose treatment of wogonin (1000 microg/ear/3 days) slightly increased COX-1 and fibronectin mRNA. On the other hand, wogonin at the doses of 250-1000 microg/ear/3 days potently lowered mRNA levels of COX-2 and tumor necrosis factor-alpha with less effect on intercellular adhesion molecule-1 and interleukin-1beta in a sub-chronic skin inflammation model of tetradecanoylphorbol-13-acetate-induced ear edema (multiple treatment). The decrease of prostaglandin E(2) concentration (27.3-34.3%) was concomitantly observed in the wogonin-treated groups. A similar effect was also observed in an acute inflammation model of arachidonic acid-induced ear edema. From the present study, wogonin was proved to differentially regulate the expression of inflammation-associated genes in vivo and to become a useful therapeutic agent for skin inflammatory diseases mainly due to its modulation of the expression of proinflammatory molecules.

Effect of flavone derivatives on interleukin-1beta (IL-1beta) mRNA expression and IL-1beta protein synthesis in stimulated RAW 264.7 macrophages

It is known that the redox status of cells affects gene expression. Flavones, as natural antioxidants, efficiently modulate this status and may play a role in the regulation of inducible gene expression of inflammatory mediators. This study was designed to investigate the effect of five flavone derivatives variously substituted with hydroxyl groups (chrysin, galangin, kaempferol, quercetin and myricetin) on interleukin-1beta (IL-1beta) gene expression in stimulated RAW 264.7 macrophages. The cells were incubated with tested hydroxyflavones and stimulated with lipopolysaccharide (LPS) and interferon-gamma (IFN-gamma). Then, the following were estimated: the level of IL-1beta mRNA in these cells and the concentration of IL-1beta protein in cell-culture supernatants and cell lysates. Each of the tested compounds significantly decreased IL-1beta mRNA expression. The most potent inhibitor was chrysin (hydroxyflavone with two hydroxyl groups and a weak antioxidant activity). The effects of galangin and kaempferol were similar. Myricetin (hydroxyflavone with a strong antioxidant activity) significantly decreased the level of IL-1beta mRNA, but it had no effect on the IL-1beta protein synthesis. The results indicated that hydroxyflavones could modulate the IL-1beta gene expression in activated RAW 264.7 macrophages via inhibiting gene transcription. This action seems unlikely to be the result of antioxidant properties of tested compounds.

Flavonoids and gene expression in mammalian cells

Flavonoids appear to regulate the expression of many genes. As expected, when multiple flavonoids were compared in one study, structure-specificity was always observed. Unfortunately, little information is available regarding the proportion of contribution of various structural elements. Also, we have very limited information on their molecular mechanisms of action. The affinity of flavonoids for ER could explain the stimulatory effect on genes with ERE but other modes of action apparently also exist and need to be further explored. Physiological relevance is always a concern when investigating the regulation of gene expression by environmental chemicals such as flavonoids. One factor of concern is the in vivo concentration of flavonoids. Besides intestinal cells, liver cells and skin cells, other tissues obtain flavonoids through blood circulation. Thus, plasma concentrations of flavonoids are normally discussed. Steady state plasma concentrations of flavonoids are usually not much higher than 1 microM even in populations that consume large amounts of plant material. This concentration is relatively low compared to the concentrations of flavonoids that were commonly used in cell culture systems to demonstrate their effectiveness. Nevertheless, we have evidence that some flavonoids may accumulate in the cell. The effect of quercetin on metallothionein expression in Caco-2 cells persisted for at least 24 hours after its removal from the culture medium (Kuo et al., 1998). Also, long-term treatment of cultured cells with quercetin at low concentrations led to a similar effect on metallothionein expression as one high concentration treatment (Kuo et al., 2001). If intracellular accumulation of certain flavonoids is a shared characteristic for various cell types, it implies that routine ingestion of flavonoids could lead to biological effects at the concentration lower than predicted from a single treatment. Experiments to address possible cell/tissue accumulation of flavonoids are greatly needed.

Quercetin suppresses proinflammatory cytokines production through MAP kinases andNF-kappaB pathway in lipopolysaccharide-stimulated macrophage

Quercetin is a flavonoid molecule ubiquitous in nature and functions as an anti-oxidant and anti-inflammatory agent with little toxicity in vivo and in vitro. Dose- and time-dependent effect of quercetin has been investigated on proinflammatory cytokine expression and NO production, focusing on its effects on the MAP kinases and the NF-kappaB signal transduction pathways in LPS-stimulated RAW 264.7 cells by using RT-PCR and immunoblotting. Quercetin strongly reduced activation of phosphorylated ERK kinase and p38 MAP kinase but not JNK MAP kinase by LPS treatment. In addition, quercetin treatment inhibited NF-kappaB activation through stabilization of the NF-kappaB/IkappaB complex and IkappaB degradation and proinflammatory cytokines and NO/iNOS expression. Quercetin may exert its anti-inflammatory and immunomodulatory properties in the effect molecules such as proinflammatory cytokines and NO/iNOS by suppressing the activation of ERK and p38 MAP kinase, and NF-kappaB/IkappaB signal transduction pathways.

Identification and in vitro biological activities of hop proanthocyanidins: inhibition of nNOS activity and scavenging of reactive nitrogen species

Oligomeric proanthocyanidins constitute a group of water-soluble polyphenolic tannins that are present in the female inflorescences (up to 5% dry wt) of the hop plant (Humulus lupulus). Humans are exposed to hop proanthocyanidins through consumption of beer. Proanthocyanidins from hops were characterized for their chemical structure and their in vitro biological activities. Chemically, they consist mainly of oligomeric catechins ranging from dimers to octamers, with minor amounts of catechin oligomers containing one or two gallocatechin units. The chemical structures of four procyanidin dimers (B1, B2, B3, and B4) and one trimer, epicatechin-(4beta-->8)-catechin-(4alpha-->8)-catechin (TR), were elucidated using mass spectrometry, NMR spectroscopy, and chemical degradation. When tested as a mixture, the hop oligomeric proanthocyanidins (PC) were found to be potent inhibitors of neuronal nitric oxide synthase (nNOS) activity. Among the oligomers tested, procyanidin B2 was most inhibitory against nNOS activity. Procyanidin B3, catechin, and epicatechin were noninhibitory against nNOS activity. PC and the individual oligomers were all strong inhibitors of 3-morpholinosydnonimine (SIN-1)-induced oxidation of LDL, with procyanidin B3 showing the highest antioxidant activity at 0.1 microg/mL. The catechin trimer (TR) exhibited antioxidant activity more than 1 order of magnitude greater than that of alpha-tocopherol or ascorbic acid on a molar basis.

The "French Paradox" and beyond: neuroprotective effects of polyphenols

Chronic ethanol ingestion is known to cause oxidative damage to a number of organs including the brain. This is partly due to the ability of ethanol to enhance oxygen free radical production and lipid peroxidation. Increase in oxidative stress has been regarded as an important underlying factor for a number of human health problems including cardiovascular diseases, aging, as well as many age-related neurodegenerative diseases. The strikingly low incidences of coronary heart diseases (CHD) in France, despite intake of a high-fat diet, have been attributed to the consumption of red wine containing high levels of polyphenolic compounds. In recent years, understanding the "French Paradox" has stimulated new research interest to investigate whether polyphenolic antioxidants may offer protective effects beyond the cardiovascular system, and whether polyphenols from other botanical sources may similarly offer beneficial effects to human health. Our studies with animal models have provided information clearly indicating the ability of grape polyphenols to ameliorate neuronal damages due to chronic ethanol consumption. Studies with resveratrol, an important component of grape polyphenols, also show protective effects on neuron cell death induced by ethanol and other oxidative agents. These studies demonstrate an urgent need to extend research beyond the "French Paradox" towards better understanding molecular mechanisms of action of polyphenolic compounds and their application to human health.