Plant polyphenols as inhibitors of NF-κB induced cytokine production-a potential anti-inflammatory treatment for Alzheimer's disease?

Active Cousinia thomsonii Extracts Modulate Expression of Crucial Proinflammatory Mediators/Cytokines and NFκB Cascade in Lipopolysaccharide-Induced Albino Wistar Rat Model

INTRODUCTION

Chronic inflammation is implicated in a multitude of diseases, including arthritis, neurodegeneration, autoimmune myositis, type 2 diabetes, rheumatic disorders, spondylitis, and cancer. Therefore, strategies to explore potent anti-inflammatory regimens are pivotal from a human-health perspective. Medicinal plants represent a vast unexplored treasure trove of therapeutically active constituents with diverse pharmacological activities, including anti-inflammatory properties. Herein, we evaluated Cousinia thomsonii, an edible medicinal herb, for its anti-inflammatory/immunomodulatory properties.

METHODS

Soxhlet extraction was used to obtain different solvent extracts (hexane, ethyl acetate, ethanol, methanol, and aqueous extract) in increasing order of polarity. In vitro anti-inflammatory assays were performed to investigate the effects of extracts on protein denaturation, proteinase activity, nitric oxide surge, and erythrocyte-membrane stabilization. The most effective extracts, ie, ethyl acetate (CTEA) and ethanol (CTE) extracts (150-200 g) were selected for further in vivo analysis using albino Wistar rats. Wistar rats received varying concentrations of CTEA and CTE (25, 50, and 100 mg/kg) for 3 weeks, followed by a single subplantar injection of lipopolysaccharide. Dexamethasone served as positive control. Blood was obtained from the retro-orbital plexus and serum separated for estimation of proinflammatory cytokines (IL6, IL1β, IFNγ and TNFα). Western blotting was performed to study expression patterns of crucial proteins implicated in the NFκB pathway, ie, NFκB p65, NFκB1 p50, and NFκB2 p52. Histopathological examination was done and gas chromatography-mass spectrometry (GC-MS) carried out to reveal the identity of compounds responsible for ameliorating effects of C. thomsonii.

RESULTS

Among five tested extracts, CTEA and CTE showed marked inhibition of protein denaturation, proteinase activity, nitric oxide surge and erythrocyte-membrane hemolysis at 600 μg/mL (P<0.001). Both these extracts showed no toxic effects up to a dose of 2,500 mg/kg. Extracts exhibited concentration-dependent reductions in expression of IL6, IL1β, IFNγ, TNFα, NFκB-p65, NFκB1, and NFκB2 (P<0.05). Healing effects of extracts were evident from histopathological investigation. GC-MS analysis revealed the presence of important anti-inflammatory compounds, notably stigmast-5-en-3-ol, oleate, dotriacontane, ascorbic acid, n-hexadecanoic acid, and α-tocopherol, in C. thomsonii.

CONCLUSION

C. thomsonii possesses significant anti-inflammatory/immunomodulatory potential by virtue of modifying levels of proinflammatory cytokines/markers and NFκB proteins.

In vitro differential responses of rat and human aryl hydrocarbon receptor to two distinct ligands and to different polyphenols

TCDD (2,3,7,8-tetrachlorodibenzo-p-dioxin) and several other environment/food-borne toxic compounds induce their toxicity via the aryl hydrocarbon receptor (AhR). AhR is also modulated by various endogenous ligands e.g. highly potent tryptophan (Trp)-derivative FICZ (6-formylindolo[3,2-b]carbazole) and natural ligands abundant in the human diet e.g. polyphenols. Therefore, evaluating AhR species-specific responses is crucial for understanding AhR physiological functions, establishing risk assessments, and exploring the applicability of AhR mediators in drug and food industry towards human-based usages. We studied AhR transactivation of FICZ/TCDD in vitro in a time-dependent and species-specific manner using dioxin responsive luciferase reporter gene assays derived from rat (DR-H4IIE) and human (DR-HepG2) hepatoma cells. We observed for the first time that FICZ potency was similar in both cell lines and was 40 times higher than TCDD in DR-HepG2 cells. Depleting Trp-derivative endogenously produced ligands by using culture medium without Trp, resulted in 3-fold higher AhR activation upon adding FICZ in DR-H4IIE cells, in contrast to DR-HepG2 cells which revealed a fast degradation of FICZ induction from 10 h post-exposure to complete disappearance after 24 h. Seven polyphenols and a mixture thereof, chosen based on commercially recommended doses and adjusted to human realistic exposure, caused rat and human species-specific AhR responses. Two isoflavones (daidzein and genistein) induced rat AhR synergistic effects with FICZ and/or TCDD, while quercetin, chrysin, curcumin, resveratrol, and the mixture exerted a strong inhibitory effect on the human AhR. Strikingly, resveratrol and quercetin at their realistic nanomolar concentrations acted additively in the mixture to abolish human AhR activation induced by various TCDD concentrations. Taken together, these results illustrate the species-specific complexity of AhR transcriptional activities modulated by various ligands and highlight the need for studies of human-based approaches.

Curcumin (a constituent of turmeric): New treatment option against COVID-19

In late December 2019, the outbreak of respiratory illness emerged in Wuhan, China, and spreads worldwide. World Health Organization (WHO) named this disease severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) caused by a new member of beta coronaviruses. Several medications are prescribed to patients, and some clinical trials are underway. Scientists are trying to find a specific drug against this virus. In this review, we summarize the pathogenesis, clinical features, and current treatments of coronavirus disease 2019 (COVID-19). Then, we describe the possible therapeutic effects of curcumin and its molecular mechanism against coronavirus-19. Curcumin, as an active constituent of Curcuma longa (turmeric), has been studied in several experimental and clinical trial studies. Curcumin has some useful clinical effects such as antiviral, antinociceptive, anti-inflammatory, antipyretic, and antifatigue effects that could be effective to manage the symptoms of the infected patient with COVID-19. It has several molecular mechanisms including antioxidant, antiapoptotic, and antifibrotic properties with inhibitory effects on Toll-like receptors, NF-κB, inflammatory cytokines and chemokines, and bradykinin. Scientific evidence suggests that curcumin could have a potential role to treat COVID-19. Thus, the use of curcumin in the clinical trial, as a new treatment option, should be considered.

The Role of Dietary Phenolic Compounds in Epigenetic Modulation Involved in Inflammatory Processes

A better understanding of the interactions between dietary phenolic compounds and the epigenetics of inflammation may impact pathological conditions and their treatment. Phenolic compounds are well-known for their antioxidant, anti-inflammatory, anti-angiogenic, and anti-cancer properties, with potential benefits in the treatment of various human diseases. Emerging studies bring evidence that nutrition may play an essential role in immune system modulation also by altering gene expression. This review discusses epigenetic mechanisms such as DNA methylation, post-translational histone modification, and non-coding microRNA activity that regulate the gene expression of molecules involved in inflammatory processes. Special attention is paid to the molecular basis of NF-κB modulation by dietary phenolic compounds. The regulation of histone acetyltransferase and histone deacetylase activity, which all influence NF-κB signaling, seems to be a crucial mechanism of the epigenetic control of inflammation by phenolic compounds. Moreover, chronic inflammatory processes are reported to be closely connected to the major stages of carcinogenesis and other non-communicable diseases. Therefore, dietary phenolic compounds-targeted epigenetics is becoming an attractive approach for disease prevention and intervention.

Healthy brain, healthy life: a review of diet and exercise interventions to promote brain health and reduce Alzheimer's disease risk

With the world's population aging at a rapid rate, the prevalence of Alzheimer's disease (AD) has significantly increased. These statistics are alarming given recent evidence that a third of dementia cases may be preventable. The role of lifestyle factors, such as diet and exercise, can directly alter the risk of disease development. However, an understanding of the effectiveness of dietary patterns and exercise strategies to reduce AD risk or improve brain function is not fully understood. The aim of this review is to discuss the effects of diet and exercise on AD risk. Key components of the Western and Mediterranean diets are discussed in relation to AD progression, as well as how physical activity promotes brain health. Components of the Western diet (saturated fatty acids and simple carbohydrates) are detrimental to the brain, impair cognition, and increase AD pathologies. While components of the Mediterranean diet (polyunsaturated fatty acids, polyphenols, and antioxidants) are considered to be neuroprotective. Exercise can significantly reduce the risk of AD; however, specific exercise recommendations for older adults are limited and optimal intensity, duration, and type remains unknown. This review highlights important modifiable risk factors for AD and points out potential avenues for future research. Novelty Diet and exercise are modifiable factors that can improve brain health and reduce the risk of AD. Polyunsaturated fatty acids, polyphenols, and antioxidants are neuroprotective. Exercise reduces neuroinflammation, improves brain insulin sensitivity, and increases brain derived neurotrophic factor.

Small Molecule NF-κB Pathway Inhibitors in Clinic

Nuclear factor kappa B (NF-κB) signaling is implicated in all major human chronic diseases, with its role in transcription of hundreds of gene well established in the literature. This has propelled research into targeting the NF-κB pathways for modulating expression of those genes and the diseases mediated by them. In-spite of the critical, but often promiscuous role played by this pathway and the inhibition causing adverse drug reaction, currently many biologics, macromolecules, and small molecules that modulate this pathway are in the market or in clinical trials. Furthermore, many marketed drugs that were later found to also have NF-κB targeting activity were repurposed for new therapeutic interventions. Despite the rising importance of biologics in drug discovery, small molecules got around 76% of US-FDA (Food and Drug Administration-US) approval in the last decade. This encouraged us to review information regarding clinically relevant small molecule inhibitors of the NF-κB pathway from cell surface receptor stimulation to nuclear signaling. We have also highlighted the underexplored targets in this pathway that have potential to succeed in clinic.

The effects of green cardamom supplementation on blood pressure and endothelium function in type 2 diabetic patients: A study protocol for a randomized controlled clinical trial

INTRODUCTION

Cardamom possesses antioxidant, anti-inflammation, and blood pressure lowering properties, which might improve endothelial function in type 2 diabetic patients. However, no study has examined the effect of cardamom on diabetic patients. The present study aimed to examine the effects of 10-week green cardamom intake on blood pressure, concentrations of inflammatory and endothelial function biomarkers in type 2 diabetes mellitus patients, and its potential mechanisms.

METHODS AND ANALYSIS DESIGN

Eighty overweight or obese patients with type 2 diabetes mellitus (aged 30-60 years) will be recruited into the trial and will assign to receive either cardamom (3 g/day, 6 capsules) or placebo (rusk powder, 6 capsules) for a period of 10 weeks. Systolic blood pressure and diastolic blood pressure, asymmetric dimethylarginine, and nitric oxide will be measured. Serum inflammatory markers namely interleukin 6, tumor necrosis factor-α, high-sensitivity C-reactive protein, and factors related to endothelial function including intercellular adhesion molecule-1, vascular cell adhesion molecule 1, CD62 antigen-like family member E, and cluster of differentiation 163 will be measured at baseline and at the end of the trial. Sociodemographic, International Physical Activity Questionnaire, and three 24-hour dietary recall questionnaires will be collected for each participant.

ETHICS AND DISSEMINATION

The study has been approved by The Ethics Committee of Tehran University of Medical Sciences (IR.TUMS.REC.1395.2700). Each participant will sign a written informed consent at the beginning of the study. At the end of the study, results will be published timely manner.

TRIAL REGISTRATION NUMBER

(http://www.irct.ir, identifier: IRCT-2016042717254N5) Date of registration: 2016-11-23.

In vitro neuroprotective effects of farnesene sesquiterpene on alzheimer's disease model of differentiated neuroblastoma cell line

OBJECTIVE

To investigate neuroprotective properties of the farnesene sesquiterpene on the experimental Alzheimer's disease model in vitro.

METHODS

Human neuroblastoma cell line (SHSY-5Y) was differentiated into neuron-like cells by using retinoic acid to constitute the in vitro Alzheimer's Disease model. β-amyloid 1-42 protein was applied to the transformed cells for 24 and 48 hours in a wide dose ranges (3.125-200 μM) to establish AD cytotoxicity. Then, farnesene was applied to cell cultures in a wide spectrum dose interval (1.625-100 μg/ml) to investigate neuroprotective effect against β-amyloid for 24 and 48 hours. 3-(4,5-dimethyl-thiazol-2-yl) 2,5-diphenyltetrazolium bromide (MTT) and lactate dehydrogenase (LDH) release tests were executed to determine cytotoxicity in the Alzheimer model. Nuclear DNA integrity of cells was examined under the fluorescent microscope using the Hoechst 33258 staining method. Furthermore, acetylcholinesterase (AChE) activity, total antioxidant capacity (TAC) and total oxidative status (TOS) levels were analyzed to understand the protection mechanism of the farnesene application on the cell culture model. Finally, flow cytometry analysis was used to find out the cell death mechanism after beta-amyloid and farnesene application to the cell culture.

RESULTS

Cell viability tests revealed significant neuroprotection against β-amyloid toxicity in both 24 and 48 hours and the Hoechst 33258 fluorescence staining method showed a significant decrease in necrotic deaths after farnesene application in the cell cultures. Finally, flow cytometry analysis put forth that farnesene could decrease necrotic cell death up to 3-fold resulted from beta-amyloid exposure.

CONCLUSION

According to the investigations, farnesene can potentially be a safe, anti-necrotic and neuroprotective agents against Alzheimer's disease.

Curcumin's Nanomedicine Formulations for Therapeutic Application in Neurological Diseases

The brain is the body's control center, so when a disease affects it, the outcomes are devastating. Alzheimer's and Parkinson's disease, and multiple sclerosis are brain diseases that cause a large number of human deaths worldwide. Curcumin has demonstrated beneficial effects on brain health through several mechanisms such as antioxidant, amyloid β-binding, anti-inflammatory, tau inhibition, metal chelation, neurogenesis activity, and synaptogenesis promotion. The therapeutic limitation of curcumin is its bioavailability, and to address this problem, new nanoformulations are being developed. The present review aims to summarize the general bioactivity of curcumin in neurological disorders, how functional molecules are extracted, and the different types of nanoformulations available.

The role of myricetin from Rhodomyrtus tomentosa (Aiton) Hassk fruits on downregulation of FcɛRI-mediated mast cell activation

Rhodomyrtus tomentosa was reported to contain various bioactive metabolites, especially phenolic compounds. In the present study, the suppressive activity of phenolic compound from R. tomentosa fruits on mast cell activation was investigated in vitro. The result showed that myricetin was isolated from R. tomentosa fruits and its characterization was identified by nuclear magnetic resonance spectroscopy. Notably, myricetin was found to be effective in inhibition of mast cell degranulation by attenuating the release of β-hexosaminidase and the elevation of intracellular calcium. Moreover, myricetin exhibited inhibitory effect on the production of IL-4 and Tumor necrosis factor alpha (TNF-α) in a concentration-dependent manner. Furthermore, high antioxidant activity of myricetin due to scavenging 1,1-diphenyl-2-picryl-hydrazyl (DPPH) and ABTS⁺ radicals was also evidenced. Notably, the activation of FcɛRI-mediated signaling molecules including Syk, PLCγ, and NF-κB was also suppressed by myricetin treatment. Accordingly, myricetin from R. tomentosa fruits could be suggested as a functional food for the amelioration of allergic diseases. PRACTICAL APPLICATIONS: Polyphenol have been shown to exert various biological activities and health beneficial effects. Results from the present study revealed that myricetin from R. tomentosa fruits possesses the inhibitory effect on allergic response in mast cells. Therefore, myricetin from R. tomentosa fruits could be developed as a functional ingredient for the amelioration of allergic diseases.

Adhesion and anti-inflammatory potential of Lactobacillus rhamnosus GG in a sea buckthorn based beverage matrix

A seabuckthorn based beverage matrix retains the functionality of L. rhamnosus GG and exhibits enhanced anti-inflammatory effects against LPS-induced inflammation in zebrafish.

Role of Nuclear Factor Kappa B (NF-κB) Signalling in Neurodegenerative Diseases: An Mechanistic Approach

A transcriptional regulatory nuclear factor kappa B (NF-κB) protein is a modulator of cellular biological activity via binding to a promoter region in the nucleus and transcribing various protein genes. The recent research implicated the intensive role of nuclear factor kappa B (NF-κB) in diseases like autoimmune disorder, inflammatory, cardiovascular and neurodegenerative diseases. Therefore, targeting the nuclear factor kappa B (NF-κB) protein offers a new opportunity as a therapeutic approach. Activation of IκB kinase/NF-κB signaling pathway leads to the development of various pathological conditions in human beings, such as neurodegenerative, inflammatory disorders, autoimmune diseases, and cancer. Therefore, the transcriptional activity of IκB kinase/NF- κB is strongly regulated at various cascade pathways. The nuclear factor NF-kB pathway plays a major role in the expression of pro-inflammatory genes, including cytokines, chemokines, and adhesion molecules. In response to the diverse stimuli, the cytosolic sequestered NF-κB in an inactivated form by binding with an inhibitor molecule protein (IkB) gets phosphorylated and translocated into the nucleus further transcribing various genes necessary for modifying various cellular functions. The various researches confirmed the role of different family member proteins of NF-κB implicated in expressing various genes products and mediating various cellular cascades. MicroRNAs, as regulators of NF- κB microRNAs play important roles in the regulation of the inflammatory process. Therefore, the inhibitor of NF-κB and its family members plays a novel therapeutic target in preventing various diseases. Regulation of NF- κB signaling pathway may be a safe and effective treatment strategy for various disorders.

Natural polyphenols for the prevention of irritable bowel syndrome: molecular mechanisms and targets; a comprehensive review

Irritable bowel syndrome (IBS) is a well diagnosed disease, thoroughly attributed to series of symptoms criteria that embrace a broad range of abdominal complainers. Such criteria help to diagnosis the disease and can guide controlled clinical trials to seek new therapeutic agents. Accordingly, a verity of mechanisms and pathophysiological conditions including inflammation, oxidative stress, lipid peroxidation and different life styles are involved in IBS. Predictably, diverse therapeutic approaches are available and prescribed by clinicians due to major manifestations (i.e., diarrhea-predominance, constipation-predominance, abdominal pain and visceral hypersensitivity), psychological disturbances, and patient preferences between herbal treatments versus pharmacological therapies, dietary or microbiological approaches. Herein, we gathered the latest scientific data between 1973 and 2019 from databases such as PubMed, Google Scholar, Scopus and Cochrane library on relevant studies concerning beneficial effects of herbal treatments for IBS, in particular polyphenols. This is concluded that polyphenols might be applicable for preventing IBS and improving the IBS symptoms, mainly through suppressing the inflammatory signaling pathways, which nowadays are known as novel platform for the IBS management. Graphical abstract.

Commiphora myrrha inhibits itch-associated histamine and IL-31 production in stimulated mast cells

Commiphora myrrha (Myrrh) is widely recognized for its anti-inflammatory and antimicrobial properties, which are utilized for the treatment of oral ulcers, gingivitis, sinusitis, glomerulonephritis, brucellosis and a variety of skin disorders. The current study aimed to assess whether myrrh modulates itch-associated interleukin (IL)-31 cytokine production and histamine release in stimulated human mast cells (HMC-1). To realize this, molecular biology techniques including real-time quantitiative PCR, western blotting and ELISA were employed. The results indicated that Myrrh successfully suppressed phorbol myristate acetate and calcium ionophore-stimulated mRNA expression, and reduced the production of IL-31 in HMC-1 cells. In addition, myrrh served as a suppressor of extracellular signal-regulated kinase and NF-κB activation, indicating its mechanism in the prevention of HMC-1 cell IL-31 production. Myrrh also prevented the release of histamine in HMC-1 cells. Whilst the present study awaits in vivo support, the pharmacological actions of myrrh provide new indications as to its potential applicability for itch treatment, which cannot be treated with histamine receptor blockers alone.

Protective Effects of Foods Containing Flavonoids on Age-Related Cognitive Decline

PURPOSE OF REVIEW

Evidence suggests that flavonoids, polyphenolic compounds found in many plant-derived foods, such as berries, may allay cognitive impairment. We review recent research exploring the protective effects of flavonoids on age-related cognitive decline and neurodegenerative disorders in humans and animals. We also address the mechanisms by which flavonoids may exert their effects and promising avenues of future research.

RECENT FINDINGS

Flavonoids have been found to decrease neuroinflammation, reduce oxidative stress, and mediate neuroplasticity in animal models of neurodegeneration and aging. Injecting flavonoids encased in metal nanoparticles may further enhance the efficacy of flavonoids. Animal studies also demonstrate that flavonoid supplementation may alleviate neurodegenerative cognitive and memory impairments. Limited human studies, however, demonstrate the need for further clinical research investigating flavonoids. Flavonoid supplementation, as well as dietary modification to include whole foods high in flavonoids, may provide therapeutic potential for aging individuals experiencing cognitive deficits resulting from neurodegeneration.

Ambrosin, a potent NF-κβ inhibitor, ameliorates lipopolysaccharide induced memory impairment, comparison to curcumin

Despite its poor bioavailability, curcumin is a promising natural polyphenol targeting NF-κβ. NF-κβ is a target for new therapeutics because it plays a pivotal role in the pathophysiology of Alzheimer disease (AD). In contrast, ambrsoin, a sesquiterpene lactone which is a potent NF-κβ inhibitor, is scarcely studied in AD models. The current work aims to assess the efficacy of ambrosin as a possible remedy for AD. In silico studies showed that bioavailability and BBB permeability could be favorable for ambrosin over curcumin. Memory impairment was induced in mice by single intraperitoneal injection of LPS (0.4 mg/kg). Treated groups received curcumin (100 mg/kg) or ambrosin at doses (5 or 10 mg/kg) for 7 days. Mice in treated groups showed a significant improvement in memory functions during Morris water maze and object recognition tests. Curcumin and ambrosin (10 mg/kg) inhibited the upsurge of NF-κβp65 transcript and protein levels. Consequently, downstream pro-inflammatory and nitrosative mediators were inhibited, namely, TNF-α, IL-1β, COX-2 and iNOS. BACE1 was inhibited, thereby reducing amyloid plaques (Aβ) deposition and eventually reducing inflammation and apoptosis of neurons as revealed by immunohistopathological examination. In conclusion, ambrosin can be repurposed as AD remedy after further pharmacokinetic/pharamacodynamic assessments. It could serve as an additional lead drug for AD therapeutics.

Advanced Molecular Knowledge of Therapeutic Drugs and Natural Products Focusing on Inflammatory Cytokines in Asthma

Asthma is a common respiratory disease worldwide. Cytokines play a crucial role in the immune system and the inflammatory response to asthma. Abnormal cytokine expression may lead to the development of asthma, which may contribute to pathologies of this disease. As cytokines exhibit pleiotropy and redundancy characteristics, we summarized them according to their biologic activity in asthma development. We classified cytokines in three stages as follows: Group 1 cytokines for the epithelial environment stage, Group 2 cytokines for the Th2 polarization stage, and Group 3 cytokines for the tissue damage stage. The recent cytokine-targeting therapy for clinical use (anti-cytokine antibody/anti-cytokine receptor antibody) and traditional medicinal herbs (pure compounds, single herb, or natural formula) have been discussed in this review. Studies of the Group 2 anti-cytokine/anti-cytokine receptor therapies are more prominent than the studies of the other two groups. Anti-cytokine antibodies/anti-cytokine receptor antibodies for clinical use can be applied for patients who did not respond to standard treatments. For traditional medicinal herbs, anti-asthmatic bioactive compounds derived from medicinal herbs can be divided into five classes: alkaloids, flavonoids, glycosides, polyphenols, and terpenoids. However, the exact pathways targeted by these natural compounds need to be clarified. Using relevant knowledge to develop more comprehensive strategies may provide appropriate treatment for patients with asthma in the future.

Plant-Derived Tandem Drug/Mesoporous Silicon Microcarrier Structures for Anti-Inflammatory Therapy

The properties of nanostructured plant-derived porous silicon (pSi) microparticles as potential candidates to increase the bioavailability of plant extracts possessing anti-inflammatory activity are described in this work. pSi drug carriers were fabricated using an eco-friendly route from the silicon accumulator plant bamboo (tabasheer) powder by magnesiothermic reduction of plant-derived silica and loaded with ethanolic extracts of Equisetum arvense, another silicon accumulator plant rich in polyphenolic compounds. The anti-inflammatory properties of the active therapeutics present in this extract were measured by sensitive luciferase reporter assays; this active extract was subsequently loaded and released from the pSi matrix, with a clear inhibition of the activity of the inflammatory signaling protein NF-κB over a period of hours in a sustained manner. Our results showed that after loading the extracts of E. arvense into pSi microparticles derived from tabasheer, enhanced anti-inflammatory activity was observed owing to enhanced solubility of the extract.

The mechanism(s) of action of antioxidants: From scavenging reactive oxygen/nitrogen species to redox signaling and the generation of bioactive secondary metabolites

Small molecule, dietary antioxidants exert a remarkably broad range of bioactivities, and many of these can be explained by the influence of antioxidants on the redox homeostasis. Such compounds help to modulate the levels of harmful reactive oxygen/nitrogen species, and therefore participate in the regulation of various redox signaling pathways. However, upon ingestion, antioxidants usually undergo extensive metabolism that can generate a wide range of bioactive metabolites. This makes it difficult, but otherwise a need, to identify the ones responsible for the different activities of antioxidants. By better understanding their ways of action, the use of antioxidants in therapy can be improved. This review provides a summary on the role of the in vivo metabolic changes and the oxidized metabolites on the mechanisms behind the bioactivity of antioxidants. A special attention is given to metabolites described as products of biomimetic oxidative chemical reactions, which can be considered as models of free radical scavenging. During such reactions a wide variety of metabolites are formed, and they can exert completely different specific bioactivities as compared to their parent antioxidants. This implies that exploring the free radical scavenging-related metabolite fingerprint of each antioxidant molecule, collectively defined here as the scavengome, will lead to a deeper understanding of the bioactivity of these compounds. Furthermore, this paper aims to be a working tool for systematic studies on oxidized metabolic fingerprints of antioxidants, which will certainly reveal an often-neglected segment of chemical space that is a treasury of bioactive compounds.

Nuclear factor-kappa β as a therapeutic target for Alzheimer's disease

Alzheimer's disease (AD) is a typical progressive, chronic neurodegenerative disorder with worldwide prevalence. Its clinical manifestation involves the presence of extracellular plaques and intracellular neurofibrillary tangles (NFTs). NFTs occur in brain tissues as a result of both Aβ agglomeration and Tau phosphorylation. Although there is no known cure for AD, research into possible cures and treatment options continues using cell-cultures and model animals/organisms. The nuclear factor-kappa β (NF-κβ) plays an active role in the progression of AD. Impairment to this signaling module triggers undesirable phenotypic changes such as neuroinflammation, activation of microglia, oxidative stress related complications, and apoptotic cell death. These imbalances further lead to homeostatic abnormalities in the brain or in initial stages of AD essentially pushing normal neurons toward the degeneration process. Interestingly, the role of NF-κβ signaling associated receptor-interacting protein kinase is currently observed in apoptotic and necrotic cell death, and has been reported in brains. Conversely, the NF-κβ signaling pathway has also been reported to be involved in normal brain functioning. This pathway plays a crucial role in maintaining synaptic plasticity and balancing between learning and memory. Since any impairment in the pathways associated with NF-κβ signaling causes altered neuronal dynamics, neurotherapeutics using compounds including, antioxidants, bioflavonoids, and non-steroidal anti-inflammatory drugs against such abnormalities offer possibilities to rectify aberrant excitatory neuronal activity in AD. In this review, we have provided an extensive overview of the crucial role of NF-κβ signaling in normal brain homeostasis. We have also thoroughly outlined several established pathomechanisms associated with NF-κβ pathways in AD, along with their respective therapeutic approaches.

Essential element Cu and non-essential element Hg exposures have different toxicological effects in the liver of large yellow croaker

The objective was to compare the different effects of essential element Cu and non-essential element Hg on antioxidant and inflammatory responses in the liver of large yellow croaker Larimichthys crocea. Fish were exposed to Cu stresses (72 and 288 μg L^-1) and Hg stresses (14 and 56 μg L^-1) for 96 h. High-dose Cu increased metallothioneins (MTs) levels and immune defenses in response to elevated reactive oxygen species (ROS), but low-dose Cu had no effect on ROS. High-dose Hg reduced antioxidant and inflammatory responses, which contributed to the increment of ROS. MTs may be a suitable biomarker to assess Cu contamination, but no relationship was observed between MTs levels and Hg content. Furthermore, NFE2-related nuclear factor 2 (Nrf2) and nuclear transcription factor κB (NF-κB) were positively related to their respective target genes in the Cu-exposed groups. In conclusion, Cu and Hg induced some differences in antioxidant and inflammatory responses, which providing some novel insights into toxicological effects of Cu and Hg stresses.

Wine-Derived Phenolic Metabolites in the Digestive and Brain Function

Wine, and specifically red wine, is a beverage with a great chemical complexity comprising a particular combination of phenolic compounds which are directly associated with its health-promoting properties. Wine polyphenols could induce changes in the composition of intestinal microbiota that would affect the production of physiologically active phenolic metabolites modifying the content and phenolic profile at the systemic level. In addition, in the human population, it seems that different “metabotypes”, or patterns of metabolizing wine polyphenols, exist, which would be reflected in the different biological fluids (i.e., plasma, urine and feces) and tissues of the human body. Moreover, wine polyphenols might change the composition of oral microbiota by an antimicrobial action and/or by inhibition of the adhesion of pathogens to oral cells, thus contributing to the maintenance of oral health. In turn, polyphenols and/or its metabolites could have a direct action on brain function, by positively affecting signaling routes involved in stress-induced neuronal response, as well as by preventing neuroticism-like disorders (i.e., anxiety and depression) through anti-inflammatory and epigenetic mechanisms. All of this would condition the positive effects on health derived from moderate wine consumption. This paper reviews all these topics, which are directly related with the effects of wine polyphenols at both digestive and brain level. Further progresses expected in the coming years in these fields are also discussed.

Parkia speciosa empty pod extract exerts anti-inflammatory properties by modulating NFκB and MAPK pathways in cardiomyocytes exposed to tumor necrosis factor-α

Parkia speciosa Hassk is a plant found abundantly in the Southeast Asia region. Its seeds, with or without pods, have been used in traditional medicine locally to treat cardiovascular problems. The pathogenesis of cardiovascular diseases involves inflammation and oxidative stress. Based on this information, we sought to investigate the potential protective effects of Parkia speciosa empty pod extract (PSE) on inflammation in cardiomyocytes exposed to tumor necrosis factor-α (TNF-α). H9c2 cardiomyocytes were divided into four groups; negative control, TNF-α, PSE + TNF-α and quercetin + TNF-α. Groups 3 and 4 were pretreated with PSE ethyl acetate fraction of ethanol extract (500 µg/mL) or quercetin (1000 µM, positive control) for 1 h before inflammatory induction with TNF-α (12 ng/mL) for 24 h. TNF-α increased protein expression of nuclear factor kappa B cell (NFκB) p65, p38 mitogen-activated protein kinase (p38 MAPK), inducible nitric oxide synthase, cyclooxygenase-2 and vascular cell adhesion molecule-1 when compared to the negative control (p < 0.05). It also elevated iNOS activity, nitric oxide and reactive oxygen species levels. These increases were significantly reduced with PSE and quercetin pretreatments. The effects of PSE were comparable to that of quercetin. PSE exhibited anti-inflammatory properties against TNF-α-induced inflammation in H9c2 cardiomyocytes by modulating the NFκB and p38 MAPK pathways.

Mitochondria-Centric Review of Polyphenol Bioactivity in Cancer Models

SIGNIFICANCE

Humans are exposed daily to polyphenols in milligram-to-gram amounts through dietary consumption of fruits and vegetables. Polyphenols are also available as components of dietary supplements for improving general health. Although polyphenols are often advertised as antioxidants to explain health benefits, experimental evidence shows that their beneficial cancer preventing and controlling properties are more likely due to stimulation of pro-oxidant and proapoptotic pathways. Recent Advances: The understanding of the biological differences between cancer and normal cell, and especially the role that mitochondria play in carcinogenesis, has greatly advanced in recent years. These advances have resulted in a wealth of new information on polyphenol bioactivity in cell culture and animal models of cancer. Polyphenols appear to target oxidative phosphorylation and regulation of the mitochondrial membrane potential (MMP), glycolysis, pro-oxidant pathways, and antioxidant (adaptive) stress responses with greater selectivity in tumorigenic cells.

CRITICAL ISSUES

The ability of polyphenols to dissipate the MMP (Δψm) by a protonophore mechanism has been known for more than 50 years. However, researchers focus primarily on the downstream molecular effects of Δψm dissipation and mitochondrial uncoupling. We argue that the physicochemical properties of polyphenols are responsible for their anticancer properties by virtue of their protonophoric and pro-oxidant properties rather than their specific effects on downstream molecular targets.

FUTURE DIRECTIONS

Polyphenol-induced dissipation of Δψm is a physicochemical process that cancer cells cannot develop resistance against by gene mutation. Therefore, polyphenols should receive more attention as agents for cotherapy with cancer drugs to gain synergistic activity. Antioxid. Redox Signal.

A Combination of Resveratrol and Curcumin is Effective Against Aluminum Chloride-Induced Neuroinflammation in Rats

BACKGROUND

Experimental studies have demonstrated that aluminum is an environmental toxin that induces neuroinflammation and the development of Alzheimer's disease.

OBJECTIVE

In this report, we investigated the beneficial effect of a combination of resveratrol and curcumin to reduce aluminum-induced neuroinflammation.

METHOD

We employed both an in vivo model of aluminum-induced neuroinflammation and an in vitro aluminum stimulated cultured PC-12 cells. Neuroinflammation in rats was assessed by measuring the expression of β-secretase, amyloid-β protein precursor, and γ-subunits (PS-1 and PS-2), along with the inflammatory COX-2, Il-1β, Il-1α, and TNF-α. Furthermore, we measured the expression profiles of neuro-protective Apurinic/apyrimidinic endonuclease 1 (APE1) protein and let-7c microRNA. In parallel, PC-12 cells were treated with 0.5 mM aluminum to induce a neuroinflammation-like state. In addition, curcumin effect, as a selective COX-2 expression inhibitor, was detected in a time course manner.

RESULTS

An overall significant attenuation of the inflammatory markers, as well as a decrease in the amyloidogenic mediators, was observed in resveratrol-curcumin treated rats. The therapeutic effect was also confirmed by transmission electron microscopic analysis of the brain cortexes. APE1 was significantly induced by resveratrol-curcumin combination. Both in vivo and in vitro studies indicated that Let-7c expression is significantly reduced after aluminum stimulation, an effect that was partially suppressed by co-addition of either resveratrol or curcumin and totally restored to the normal level by their combination.

CONCLUSIONS

The present study clearly indicates the synergistic and therapeutic effect of a  resveratrol-curcumin combination. We also show that both compounds exert beneficial effect either cooperatively or through differential molecular mechanisms in counteracting aluminum-induced neuroinflammation.

RKIP-Mediated NF-κB Signaling is involved in ELF-MF-mediated improvement in AD rat

In a previous study, we reported the positive effects of extremely low frequency electromagnetic field (ELF-MF) exposure on Alzheimer's disease (AD) rats; however, the underlying mechanism remains unclear. In addition, we found that Raf-1 kinase inhibitor protein (RKIP) was downregulated by microwave exposure in the rat hippocampus. Our hypothesis was that RKIP-mediated NF-κB pathway signaling is involved in the effect of ELF-MF on the AD rat. In this study, D-galactose intraperitoneal (50 mg/kg/d for 42 d) and Aβ_25-35 hippocampal (5 μL/unilateral, bilateral, single-dose) injection were implemented to establish an AD rat model. Animals were exposed to 50 Hz and 400 µT ELF-MF for 60 continuous days. The spatial memory ability of the rat was then tested using the Morris water maze. Protein expression and interaction were detected by western blotting and co-immunoprecipitation for RKIP-mediated NF-κB pathway factors. The results showed that ELF-MF exposure partially improved the cognitive disorder, upregulated the levels of RKIP, TAK1, and the RKIP/TAK1 interaction, but downregulated p-IKK levels in AD rats. These results indicated that RKIP-mediated NF-κB pathway signaling plays an important role in the ELF-MF exposure-mediated improvements in the AD rat. Our study suggested that ELF-MF exposure might have a potential therapeutic value for AD. Further in depth studies are required in the future.

Proteasome and Organs Ischemia-Reperfusion Injury

The treatment of organ failure on patients requires the transplantation of functional organs, from donors. Over time, the methodology of transplantation was improved by the development of organ preservation solutions. The storage of organs in preservation solutions is followed by the ischemia of the organ, resulting in a shortage of oxygen and nutrients, which damage the tissues. When the organ is ready for the transplantation, the reperfusion of the organ induces an increase of the oxidative stress, endoplasmic reticulum stress, and inflammation which causes tissue damage, resulting in a decrease of the transplantation success. However, the addition of proteasome inhibitor in the preservation solution alleviated the injuries due to the ischemia-reperfusion process. The proteasome is a protein structure involved in the regulation the inflammation and the clearance of damaged proteins. The goal of this review is to summarize the role of the proteasome and pharmacological compounds that regulate the proteasome in protecting the organs from the ischemia-reperfusion injury.

Nuclear Factor-Kappa B and Alzheimer Disease, Unifying Genetic and Environmental Risk Factors from Cell to Humans

Alzheimer's disease (AD) is the most common form of dementia, an eversible, progressive disease that causes problems with memory, thinking, language, planning, and behavior. There are a number of risk factors associated with developing AD but the exact cause remains unknown. The predominant theory is that excessive build-up of amyloid protein leads to cell death, brain atrophy, and cognitive and functional decline. However, the amyloid hypothesis has not led to a single successful treatment. The recent failure of Solanezumab, a monoclonal antibody to amyloid, in a large phase III trial was emblematic of the repeated failure of anti-amyloid therapeutics. New disease targets are urgently needed. The innate immune system is increasingly being implicated in the pathology of number of chronic diseases. This focused review will summarize the role of transcription factor nuclear factor-kappa B (NF-κB), a key regulator of innate immunity, in the major genetic and environmental risk factors in cellular, invertebrate and vertebrate models of AD. The paper will also explore the relationship between NF-κB and emerging environmental risk factors in an attempt to assess the potential for this transcription factor to be targeted for disease prevention.

Plant Polyphenols and Exendin-4 Prevent Hyperactivity and TNF-α Release in LPS-Treated In vitro Neuron/Astrocyte/Microglial Networks

Increasing evidence supports a decisive role for neuroinflammation in the neurodegenerative process of several central nervous system (CNS) disorders. Microglia are essential mediators of neuroinflammation and can regulate a broad spectrum of cellular responses by releasing reactive oxygen intermediates, nitric oxide, proteases, excitatory amino acids, and cytokines. We have recently shown that also in ex-vivo cortical networks of neurons, astrocytes and microglia, an increased level of tumor necrosis factor-alpha (TNF-α) was detected a few hours after exposure to the bacterial endotoxin lipopolysaccharide (LPS). Simultaneously, an atypical “seizure-like” neuronal network activity was recorded by multi-electrode array (MEA) electrophysiology. These effects were prevented by minocycline, an established anti-inflammatory antibiotic. We show here that the same inhibitory effect against LPS-induced neuroinflammation is exerted also by natural plant compounds, polyphenols, such as curcumin (CU, curcuma longa), crocin (CR, saffron), and resveratrol (RE, grape), as well as by the glucagon like peptide-1 receptor (GLP-1R) agonist exendin-4 (EX-4). The drugs tested also caused per-se early transient (variable) changes of network activity. Since it has been reported that LPS-induced neuroinflammation causes rearrangements of glutamate transporters in astrocytes and microglia, we suggest that neural activity could be putatively increased by an imbalance of glial glutamate transporter activity, leading to prolonged synaptic glutamatergic dysregulation.

Rosuvastatin Attenuates High-Salt and Cholesterol Diet Induced Neuroinflammation and Cognitive Impairment via Preventing Nuclear Factor KappaB Pathway

Recent attention is focused on the impact of diet on health and mental well-being. High-salt and cholesterol diet (HSCD) is known to be associated with neuroinflammation which is the predominant factor for neurodegenerative disease like Alzheimer disease (AD). In the present study, we examined the neuroprotective potential of rosuvastatin, an HMG-CoA reductase inhibitor against HSCD induced neuroinflammation and cognitive impairment. Our results demonstrated that HSCD-induced cognitive impairment as determined by Morris water maze (MWM) task. HSCD also activated nuclear factor kappaB (NF-kB) signaling pathway. The cytokine response was measured using a cytometric bead-based assay quantified by flow cytometry. Treatment with rosuvastatin decreased the production of nitric oxide (NO), tumor necrosis factor alpha (TNF-α) and increased interleukin-10 (IL-10) in a dose-dependent manner. Our results also demonstrated that the rosuvastatin modulates neuronal cell death by inhibiting the overexpression of NF-kB in the CA1 region of hippocampus. In addition, molecular docking study of rosuvastatin indicated high affinity and tighter binding capacity for the active site of the NF-kB. These results suggest that HSCD-triggered inflammatory response and cognitive impairment may be associated with NF-κB signaling pathway. Therefore, treatment with rosuvastatin could be a potential new therapeutic strategy for sporadic dementia of AD.

Pulmonary delivery systems for polyphenols

This review reports on the beneficial pharmacological properties of naturally occurring polyphenols for the treatment of inflammatory pulmonary diseases. In addition, it presents an overview of the different types of inhalable formulations which have been developed in order to achieve efficient delivery of polyphenols to the respiratory tract. The main biological activities of polyphenols (anti-oxidant and anti-inflammatory) are covered, with particular emphasis on the studies describing their therapeutic effects on different factors and conditions characteristic of lung pathologies. Special focus is on the technological aspects which influence the pulmonary delivery of drugs. The various polyphenol-based inhalable formulations reported in the literature are examined with specific attention to the preparation methodologies, aerosol performance, lung deposition and in vitro and in vivo polyphenol uptake by the pulmonary epithelial cells.

Quercetin Has Antimetastatic Effects on Gastric Cancer Cells via the Interruption of uPA/uPAR Function by Modulating NF-κb, PKC-δ, ERK1/2, and AMPKα

Gastric cancer (GC) is a malignancy with few effective treatment options after metastasis occurs. Quercetin (Qu) intake has been associated with reduced incidence and slow development of GC, probably due to its anti-proliferative and apoptotic effects, but it is unclear whether Qu can inhibit the metastatic activity. The urokinase plasminogen activator (uPA)/uPA receptor (uPAR) system plays an important role in cancer metastasis. In this study, we measured both uPA activity and uPAR expression in GC and pericarcinous tissues, and we investigated the correlation between uPAR expression and the migratory and invasive activities of various GC cell lines. GC BGC823 and AGS cells were subjected to treatment with 10 μM Qu for 72 hours and uPAR knockdown, alone or in combination, before evaluating cell metastasis. The results showed that uPA activity and uPAR expression were higher in GC tissues than in pericarcinous tissues. Migratory and invasive activities of GC cell lines positively correlated with uPAR expression. Qu treatment decreased BGC823 and AGS cell migration and invasion, accompanied by reduced uPA and uPAR protein expression. Both Qu treatment and uPAR knockdown decreased matrix metalloproteinase-2 and -9 activity and blocked Pak1-Limk1-cofilin signaling. Qu treatment was associated with inhibition of NF-κb, PKC-δ, and ERK1/2, and with AMPKα activation. Specific inhibitors of NF-κb, PKC, and ERK1/2, and an AMPKα activator suppressed uPA and uPAR expression in GC cells. Collectively, Qu showed an antimetastatic effect on GC cells via the interruption of uPA/uPAR function and modulation of NF-κb, PKC-δ, ERK1/2, and AMPKα. This suggests that Qu is a promising agent against GC metastasis.

Analysis of different innovative formulations of curcumin for improved relative oral bioavailability in human subjects

PURPOSE

The optimal health benefits of curcumin are limited by its low solubility in water and corresponding poor intestinal absorption. Cyclodextrins (CD) can form inclusion complexes on a molecular basis with lipophilic compounds, thereby improving aqueous solubility, dispersibility, and absorption. In this study, we investigated the bioavailability of a new γ-cyclodextrin curcumin formulation (CW8). This formulation was compared to a standardized unformulated curcumin extract (StdC) and two commercially available formulations with purported increased bioavailability: a curcumin phytosome formulation (CSL) and a formulation of curcumin with essential oils of turmeric extracted from the rhizome (CEO).

METHODS

Twelve healthy human volunteers participated in a double-blinded, cross-over study. The plasma concentrations of the individual curcuminoids that are present in turmeric (namely curcumin, demethoxycurcumin, and bisdemethoxycurcumin) were determined at baseline and at various intervals after oral administration over a 12-h period.

RESULTS

CW8 showed the highest plasma concentrations of curcumin, demethoxycurcumin, and total curcuminoids, whereas CSL administration resulted in the highest levels of bisdemethoxycurcumin. CW8 (39-fold) showed significantly increased relative bioavailability of total curcuminoids (AUC_0-12) in comparison with the unformulated StdC.

CONCLUSION

The data presented suggest that γ-cyclodextrin curcumin formulation (CW8) significantly improves the absorption of curcuminoids in healthy humans.

Piperlongumine attenuates experimental autoimmune encephalomyelitis through inhibition of NF-kappaB activity

Multiple sclerosis (MS) is a chronic, autoimmune and neurodegenerative disease in which demyelination sporadically and repeatedly occurs in the central nervous system (CNS). The activity of nuclear factor kappa B (NF-κB), a family of transcription factors, was increased in the cerebrospinal fluid (CSF) and/or the serum and brain and/or spinal cord of MS patients than in a healthy donors. In our study, we investigated whether piperlongumine (PL), which is known to have inhibitory effect on activity of NF-κB, can alleviate an experimental autoimmune encephalomyelitis (EAE). The mice were immunized with myelin oligodendrocyte glycoprotein 35-55 (MOG35-55), and then we injected PL (1.5mg/kg/day or 3.0mg/kg/day) into the mice intraperitoneally on every second day from days 2 to 28. For in vitro study, we treated PL (0.5, 1 and 2.5μM) to RAW 264.7 and Jurkat cells with each stimulator. We observed that the paralytic severity and neuropathology of EAE in PL-treated group were decreased compared with the EAE group. PL showed a suppressed effect on demyelination, immune cells infiltration, astrocytes/microglials activation, level of inflammatory cytokines and proteins as well as NF-κB activity. Production of inflammatory cytokines and proteins as well as translocation of NF-κB into nucleus by treatment stimulators in RAW 264.7 and Jurkat cells were reduced by PL. Moreover, treatment of NF-κB inhibitor further inhibited production of inflammatory cytokines and proteins. These results suggest that PL can mitigate MOG-induced EAE symptoms and activation of macrophages and T cells by inhibiting NF-κB signaling. Therefore, PL could be useful for the treatment for MS.

The in vivo hepato-recovery effects of the polyphenol-rich fermented food Xeniji™ on ethanol-induced liver damage

Xeniji that rich in caffeoylquinic acid and sakuranetin promoted recovery of the ethanol induced liver damage.

Medicinal Plants of the Australian Aboriginal Dharawal People Exhibiting Anti-Inflammatory Activity

Chronic inflammation contributes to multiple ageing-related musculoskeletal and neurodegenerative diseases, cardiovascular diseases, asthma, rheumatoid arthritis, and inflammatory bowel disease. More recently, chronic neuroinflammation has been attributed to Parkinson's and Alzheimer's disease and autism-spectrum and obsessive-compulsive disorders. To date, pharmacotherapy of inflammatory conditions is based mainly on nonsteroidal anti-inflammatory drugs which in contrast to cytokine-suppressive anti-inflammatory drugs do not influence the production of cytokines such as tumour necrosis factor-α or nitric oxide. However, their prolonged use can cause gastrointestinal toxicity and promote adverse events such as high blood pressure, congestive heart failure, and thrombosis. Hence, there is a critical need to develop novel and safer nonsteroidal anti-inflammatory drugs possessing alternate mechanism of action. In this study, plants used by the Dharawal Aboriginal people in Australia for the treatment of inflammatory conditions, for example, asthma, arthritis, rheumatism, fever, oedema, eye inflammation, and inflammation of bladder and related inflammatory diseases, were evaluated for their anti-inflammatory activity in vitro. Ethanolic extracts from 17 Eucalyptus spp. (Myrtaceae) were assessed for their capacity to inhibit nitric oxide and tumor necrosis factor-α production in RAW 264.7 macrophages. Eucalyptus benthamii showed the most potent nitric oxide inhibitory effect (IC₅₀  5.57 ± 1.4 µg/mL), whilst E. bosistoana, E. botryoides, E. saligna, E. smithii, E. umbra, and E. viminalis exhibited nitric oxide inhibition values between 7.58 and 19.77 µg/mL.

Curcumin Attenuates Colistin-Induced Neurotoxicity in N2a Cells via Anti-inflammatory Activity, Suppression of Oxidative Stress, and Apoptosis

Neurotoxicity is an unwanted side-effect seen in patients receiving therapy with the "last-line" polymyxin antibiotics. This is the first study to show that colistin-induced neurotoxicity in neuroblastoma-2a (N2a) cells gives rise to an inflammatory response involving the IL-1β/p-IκB-α/NF-κB pathway. Pretreatment with curcumin at 5, 10, and 20 μM for 2 h prior to colistin (200 μM) exposure for 24 h, produced an anti-inflammatory effect by significantly down-regulating the expression of the pro-inflammatory mediators cyclooxygenase-2 (COX-2), phosphorylation of the inhibitor of nuclear factor-kappa B (NF-κB) (p-IκB)-α, and concomitantly NF-κB levels. Moreover, curcumin significantly decreased intracellular reactive oxygen species (ROS) production and increased the activities of the anti-ROS enzymes superoxide dismutase, catalase, and the intracellular levels of glutathione. Curcumin pretreatment also protected the cells from colistin-induced mitochondrial dysfunction, caspase activation, and subsequent apoptosis. Overall, our findings demonstrate for the first time, a potential role for curcumin for treating polymyxin-induced neurotoxicity through the modulation of NF-κB signaling and its potent anti-oxidative and anti-apoptotic effects.

Aqueous extract from Ipomoea asarifolia (Convolvulaceae) leaves and its phenolic compounds have anti-inflammatory activity in murine models of edema, peritonitis and air-pouch inflammation

ETHNOPHARMACOLOGICAL RELEVANCE

Ipomoea asarifolia (Desr.) Roem. and Schult.(Convolvulaceae), popularly known as salsa or salsa-brava, is a plant of which the decoction of leaves is used in folk medicine to treat various inflammatory disorders such of dermatitis, scabies, symptoms of syphilis, skin ulcers and external wounds. However, little is known about possible compounds and mechanisms of action of the plant to support the activities reported by popular use.

AIM OF THE STUDY

The study aimed to identify bioactive molecules present in the crude extract of I. asarifolia leaves and investigate the anti-inflammatory potential of this extract in different experimental in vivo models to improve the understanding on that activity.

MATERIAL AND METHODS

Aqueous extract of I. asarifolia leaves was prepared by decoction (1:10 m/v) and its chromatographic profile was obtained by high performance liquid chromatography coupled with diode array detector (HPLC-DAD) and liquid chromatography diode array detector coupled with mass spectrometry (LC-DAD-MS). The potential anti-inflammatory activity of the extract was assessed using the following in vivo models: xylene-induced ear edema (20, 30 and 40mg/kg), evaluating the degree of edema formation; carrageenan-induced peritonitis (10, 20 and 30mg/kg), evaluating leukocyte migration and cytokine levels (IL-1β, IL-6, IL-12 and TNF-α) at 4h; zymosan-induced air pouch inflammation (20, 30 and 40mg/kg), evaluating the kinetics of leukocyte migration by total and differential counts at 6, 24 and 48h. The same tests were conducted using pure compounds identified in the aqueous extract from I. asarifolia leaves in different doses for each experimental model.

RESULTS

The compounds identified in the aqueous extract of I. asarifolia leaves by HPLC-DAD and LC-DAD-MS were rutin, chlorogenic acid and caffeic acid. The extract significantly reduced ear edema induced by xylene (81%, 85% and 86% for doses of 20, 30 and 40mg/kg, respectively, p<0.001), as well as cell migration in experimental models of peritonitis (70%, 78% and 83% for doses of 10, 20 and 30mg/kg, respectively, p<0.001) and air pouch inflammation (58%, 67% and 53% for doses of 20, 30 and 40mg/kg, respectively, p<0.001). In addition, the extract demonstrated the ability to significantly inhibit the production of cytokines IL-1β, IL-6, IL-12 and TNF-α (p<0.001). The secondary metabolites tested (rutin, chlorogenic acid and caffeic acid) also showed the ability to significantly (p<0.001) decrease the parameters analyzed above.

CONCLUSION

This is the first study to identify and confirm these phenolic compounds in I. asarifolia leaves extract and to suggest that these compounds contribute to the anti-inflammatory activity in vivo, as reported by ethnomedicinal use of this plant. Through the different experimental models performed, we can conclude that the results obtained with the aqueous extract from I. asarifolia leaves support its popular use for the treatment of inflammatory disorders.

Anti-Inflammatory Activity of Natural Products

This article presents highlights of the published literature regarding the anti-inflammatory activities of natural products. Many review articles were published in this regard, however, most of them have presented this important issue from a regional, limited perspective. This paper summarizes the vast range of review and research articles that have reported on the anti-inflammatory effects of extracts and/or pure compounds derived from natural products. Moreover, this review pinpoints some interesting traditionally used medicinal plants that were not investigated yet.

Curcumin and Resveratrol in the Management of Cognitive Disorders: What is the Clinical Evidence?

A growing body of in vitro and in vivo evidences shows a possible role of polyphenols in counteracting neurodegeneration: curcumin and resveratrol are attractive substances in this regard. In fact, epidemiological studies highlight a neuroprotective effect of turmeric (rhizome of Curcuma longa L.), the main source of curcumin. Moreover, the consumption of red wine, the main source of resveratrol, has been related to a lower risk of developing dementia. In this review, we analyzed the published clinical trials investigating curcumin and resveratrol in the prevention or treatment of cognitive disorders. The ongoing studies were also described, in order to give an overview of the current search on this topic. The results of published trials (five for curcumin, six for resveratrol) are disappointing and do not allow to draw conclusions about the therapeutic or neuroprotective potential of curcumin and resveratrol. These compounds, being capable of interfering with several processes implicated in the early stages of dementia, could be useful in preventing or in slowing down the pathology. To this aim, an early diagnosis using peripheral biomarkers becomes necessary. Furthermore, the potential preventive activity of curcumin and resveratrol should be evaluated in long-term exposure clinical trials, using preparations with high bioavailability and that are well standardized.

Polyphenolic profiles and the in vivo antioxidant effect of nipa vinegar on paracetamol induced liver damage

Nipa vinegar, which is rich in gallic acid and protocatechuic acid, has reverted the paracetamol-induced liver damage in mice by reduction of inflammation and oxidative stress.

The contribution of neuroinflammation to amyloid toxicity in Alzheimer's disease

Alzheimer's disease (AD) is a progressive neurodegenerative disease and the most common cause of dementia. Deposition of amyloid-β (Aβ) remains a hallmark feature of the disease, yet the precise mechanism(s) by which this peptide induces neurotoxicity remain unknown. Neuroinflammation has long been implicated in AD pathology, yet its contribution to disease progression is still not understood. Recent evidence suggests that various Aβ complexes interact with microglial and astrocytic expressed pattern recognition receptors that initiate innate immunity. This process involves secretion of pro-inflammatory cytokines, chemokines and generation of reactive oxygen species that, in excess, drive a dysregulated immune response that contributes to neurodegeneration. The mechanisms by which a neuroinflammatory response can influence Aβ production, aggregation and eventual clearance are now becoming key areas where future therapeutic intervention may slow progression of AD. This review will focus on evidence supporting the combined neuroinflammatory-amyloid hypothesis for pathogenesis of AD, describing the key cell types, pathways and mediators involved. Alzheimer's disease (AD) is a progressive neurodegenerative disorder and the leading cause of dementia worldwide. Deposition of intracellular plaques containing amyloid-beta (Aβ) is a hallmark proteinopathy of the disease yet the precise mechanisms by which this peptide induces neurotoxicity remains unknown. A neuroinflammatory response involving polarized microglial activity, enhanced astrocyte reactivity and elevated pro-inflammatory cytokine and chemokine load has long been implicated in AD and proposed to facilitate neurodegeneration. In this issue we discuss key receptor systems of innate immunity that detect Aβ, drive pro-inflammatory cytokine and chemokine production and influence Aβ aggregation and clearance. Evidence summarized in this review supports the combined neuroinflammatory-amyloid hypothesis for pathogenesis of AD and highlights the potential of immunomodulatory agents as potential future therapies for AD patients.

Novel promising therapeutics against chronic neuroinflammation and neurodegeneration in Alzheimer's disease

Alzheimer's disease (AD) is a progressive neurodegenerative disorder, characterized by deposition of amyloid plaques and neurofibrillary tangles, as well as microglial and astroglial activation, and, finally, leading to neuronal dysfunction and death. Current treatments for AD primarily focus on enhancement of cholinergic transmission. However, these treatments are only symptomatic, and no disease-modifying drug is available for the treatment of AD patients. This review will provide an overview of the antioxidant, anti-inflammatory, anti-amyloidogenic, neuroprotective, and cognition-enhancing effects of a variety of nutraceuticals including curcumin, apigenin, docosahexaenoic acid, epigallocatechin gallate, α-lipoic acid and resveratrol and their potential for AD prevention and treatment. We suggest that therapeutic use of these compounds might lead to a safe strategy to delay the onset of AD or slow down its progression. The continuing investigation of the potential of these substances is necessary as they are promising compounds to yield a possible remedy for this pervasive disease.

Neuroprotection of Neuro2a cells and the cytokine suppressive and anti-inflammatory mode of action of resveratrol in activated RAW264.7 macrophages and C8-B4 microglia

Chronic inflammation is a hallmark of neurodegenerative disease and cytotoxic levels of nitric oxide (NO) and pro-inflammatory cytokines can initiate neuronal death pathways. A range of cellular assays were used to assess the anti-inflammatory and neuroprotective action of resveratrol using murine microglial (C8-B4), macrophage (RAW264.7) and neuronal-like (Neuro2a) cell lines. We examined the release of NO by Griess assay and used a Bioplex array to measure a panel of pro- and anti-inflammatory cytokines and chemokines, in response to the inflammatory stimuli lipopolysaccharide (LPS) and interferon-γ (IFN-γ). Resveratrol was a potent inhibitor of NO and cytokine release in activated macrophages and microglia. The activity of resveratrol increased marginally in potency with longer pre-incubation times in cell culture that was not due to cytotoxicity. Using an NO donor we show that resveratrol can protect Neuro2a cells from cytotoxic concentrations of NO. The protective effect of resveratrol from pro-inflammatory signalling in RAW264.7 cells was confirmed in co-culture experiments leading to increased survival of Neuro2a cells. Together our data are indicative of the potential neuroprotective effect of resveratrol during nitrosative stress and neuroinflammation.