Curcumin inhibits Th1 cytokine profile in CD4+ T cells by suppressing interleukin-12 production in macrophages

Immunomodulatory effects of curcumin on macrophage polarization in rheumatoid arthritis

Rheumatoid arthritis (RA) is a systemic autoimmune disease characterized by synovial inflammation, cartilage destruction, pannus formation and bone erosion. Various immune cells, including macrophages, are involved in RA pathogenesis. The heterogeneity and plasticity of macrophages render them pivotal regulators of both the induction and resolution of the inflammatory response. Predominantly, two different phenotypes of macrophages have been identified: classically activated M1 macrophages exacerbate inflammation via the production of cytokines, chemokines and other inflammatory mediators, while alternatively activated M2 macrophages inhibit inflammation and facilitate tissue repair. An imbalance in the M1/M2 macrophage ratio is critical during the initiation and progression of RA. Macrophage polarization is modulated by various transcription factors, epigenetic elements and metabolic reprogramming. Curcumin, an active component of turmeric, exhibits potent immunomodulatory effects and is administered in the treatment of multiple autoimmune diseases, including RA. The regulation of macrophage polarization and subsequent cytokine production as well as macrophage migration is involved in the mechanisms underlying the therapeutic effect of curcumin on RA. In this review, we summarize the underlying mechanisms by which curcumin modulates macrophage function and polarization in the context of RA to provide evidence for the clinical application of curcumin in RA treatment.

A Review of Medicinal Plants and Phytochemicals for the Management of Gout

Gout, characterized by elevated uric acid levels, is a common inflammatory joint disease associated with pain, joint swelling, and bone erosion. Existing treatments for gout often result in undesirable side effects, highlighting the need for new, safe, and cost-effective anti-gout drugs. Natural products, including medicinal plants and phytochemicals, have gained attention as potential sources of anti-gout compounds. In this review, we examined articles from 2000 to 2020 using PubMed and Google Scholar, focusing on the effectiveness of medicinal plants and phyto-chemicals in managing gout. Our findings identified 14 plants and nine phytochemicals with anti-gout properties. Notably, Teucrium polium, Prunus avium, Smilax riparia, Rhus coriaria, Foenic-ulum vulgare, Allium cepa, Camellia japonica, and Helianthus annuus exhibited the highest xa-thine oxidase inhibitory activity, attributed to their unique natural bioactive compounds such as phenolics, tannins, coumarins, terpenoids, and alkaloids. Herbal plants and their phytochemicals have demonstrated promising effects in reducing serum urate and inhibiting xanthine. This review aims to report recent studies on plants/phytochemicals derived from herbs beneficial in gout and their different mechanisms.

The Expression of Selected Cytokine Genes in the Livers of Young Castrated Bucks after Supplementation with a Mixture of Dry Curcuma longa and Rosmarinus officinalis Extracts

The study aims to determine the effect of supplementation with a mixture of Curcuma longa and Rosmarinus officinalis extracts (896:19 ratio) on the expression of 15 cytokine genes in the livers of 20 castrated goat bucks. Two equal groups were created: treated and control groups. The treated group was provided a mixture (1.6 g/day/buck) for 124 days. Liver tissue samples were collected after slaughter. The gene expression was analyzed using RT-qPCR with two reference genes. Variance analysis was conducted using a model with the group fixed effect. IL-2 and IL-8 expression was below the detection level. No differences were found for IL-1α, IL-1β, IL-4, IL-6, IL-10, IL-16, IFN-α, IFN-β, TNF-α, and CCL4 expressions, suggesting that supplementation does not activate cytokine production in the healthy hepatocytes. The treated group demonstrated lower IL-12 expression (p < 0.05) and a tendency for higher IL-18 and INF-γ (0.05 < p < 0.10) expressions, which may indicate a hypersensitivity resulting from excessive supplement dose. The increased IFN-γ expression could be caused by the increased IL-18 expression. If a small dose of extract can induce an allergic reaction in young goat bucks, it is also possible that humans may be susceptible to an overdose of curcumin and/or turmeric extracts.

Interleukin-12 induces IFN-γ secretion and STAT signaling implying its potential regulation of Th1 cell response in Nile tilapia

As a pleiotropic cytokine consisting of IL-12p35 and IL-12p40, Interleukin-12 (IL-12) features in inflammation regulation and anti-bacterial immunity. While IL-12 homologs have been identified in non-mammalian species, the precise mechanisms by which IL-12 contributes to early adaptive immune responses in vertebrates remain incompletely understood. Herein, an evolutionary conserved Oreochromis niloticus IL-12 (defined as OnIL-12) was identified by synteny characterization, structural comparisons and phylogenetic pattern of IL-12p35b and IL-12p40a. IL-12p35b and IL-12p40a exhibited widespread expression in lymphoid-related tissues of tilapia, while their mRNA expression in head-kidney demonstrated a significant increase after Edwardsiella piscicida infection. Compared with other lymphocytes, recombinant OnIL-12 (rOnIL-12) displayed stronger affinity binding to T cells. Although stimulation of lymphocytes with the p35b or p40a subunit resulted in a significant induction of IFN-γ expression, rOnIL-12 showed stronger potential to promote IFN-γ expression than these subunits. rOnIL-12 not only elevated the mRNA expression level Th1 cell-associated transcription factor T-bet in lymphocytes, but also increased the proportion of CD4-1+IFN-γ+ lymphocytes. Moreover, the mRNA and phosphorylation levels of STAT1, STAT3, STAT4 and STAT5 were enhanced by rOnIL-12. These findings will offer previous evidence for further exploration into the regulatory mechanisms of Th1 cellular immunity in early vertebrates.

Evaluating the effects of curcumin nanomicelles on clinical outcome and cellular immune responses in critically ill sepsis patients: A randomized, double-blind, and placebo-controlled trial

Introduction

In sepsis, the immune system is overreacting to infection, leading to organ dysfunction and death. The purpose of this study was to investigate the impacts of curcumin nanomicelles on clinical outcomes and cellular immune responses in critically ill sepsis patients.

Method

For 10 days, 40 patients in the intensive care units (ICU) were randomized between the nano curcumin (NC) and placebo groups in a randomized study. We evaluated serum levels of biochemical factors, inflammatory biomarkers, the mRNA expression levels of FOXP3, NLRP-3, IFN-γ, and NF-κp genes in the PBMCs, and clinical outcomes before the beginning of the supplementation and on days 5 and 10.

Results

NLR family pyrin domain containing 3 (NLRP3), interferon gamma (IFN-γ), and nuclear factor kappa-light-chain-enhancer of activated B cells (NF-κB) mRNA expression levels significantly P = 0.014, P = 0.014, and P = 0.019, respectively) decreased, but forkhead box P3 (FOXP3) mRNA expression levels increased significantly (P = 0.008) in the NC group compared to the placebo group after 10 days. NC supplementation decreased serum levels of IL-22, IL-17, and high mobility group box 1 (HMGB1) (P < 0.05). Nevertheless, biochemical factors and nutritional status did not differ significantly (P > 0.05). NC supplementation resulted in decreased sequential organ failure assessment and multiple organ dysfunction syndromes scores, while it did not have significant impacts on length of stay in the ICU, systolic blood pressure, diastolic blood pressure, a saturation of oxygen (%), and respiratory rate (breaths/min) PaO2/FiO2 (p > 0.05).

Conclusion

For critically ill patients with sepsis, NC supplementation may be an effective therapeutic strategy. More randomized clinical trials involving longer follow-up periods and different doses are needed to achieve the best results.

Relationship Between the In Vitro Efficacy, Pharmacokinetics and In Vivo Efficacy of Curcumin

Considerable interest continues to be focused on the development of curcumin either as an effective stand-alone therapeutic or as an adjunct therapy to established therapies. Curcumin (1, 7-bis (4-hydroxy-3-methoxyphenyl)-1, 6-heptadiene-3, 5- dione; also called diferuloylmethane) is a polyphenolic phytochemical extracted from the root of curcuma longa, commonly called turmeric. Despite evidence from in vitro (cell culture) and preclinical studies in animals, clinical studies have not provided strong evidence for a therapeutic effect of curcumin. The relevance of curcumin as a drug has been questioned based on its classification as a compound with pan assay interference and invalid metabolic panaceas properties bringing into question the relevance of the therapeutic targets identified for curcumin. To some extent this is due to the lack of a complete understanding of the link between the in vitro (cell culture activity), pharmacokinetics and in vivo activity of curcumin. In this review and using NF-κB as a cellular target for curcumin, we have investigated the relationship between the potency of curcumin as an inhibitor of NF-κB in cell culture, the pharmacokinetics of curcumin and curcumin's anticancer and anti-inflammatory effects in preclinical models of cancer and inflammation. Plausible explanations and rationale are provided to link these activities together and suggest that both curcumin and its more soluble Phase II metabolite curcumin glucuronide may play a key role in the treatment effects of curcumin in vivo mediated at NF-κB.

Nano-curcumin supplementation in critically ill patients with sepsis: a randomized clinical trial investigating the inflammatory biomarkers, oxidative stress indices, endothelial function, clinical outcomes and nutritional status

Sepsis is a severe reaction and excessive immune response to infection, which can lead to organ dysfunction, and death. This study aimed to investigate the protective effect of nano-curcumin (NC) on inflammatory biomarkers, endothelial function, oxidative stress indices, biochemical factors, nutritional status, and clinical outcomes in patients with sepsis. In the present double-blind placebo-controlled randomized clinical trial, 40 ICU-admitted patients were randomly allocated into either NC or placebo group for 10 days. Both nano-curcumin (160 mg) and placebo were administered via a nasogastric tube twice a day. The mRNA expression of nuclear-related factor 2 (Nrf-2), BCL2 associated X (BAX), B-cell lymphoma 2 (BCL-2), and toll-like receptor 4 (TLR-4) genes in the peripheral blood mononuclear cells (PBMCs), and the serum levels of primary, secondary, tertiary, and exploratory outcomes were assessed before the baseline and on days 5 and 10. There were significant improvements in the primary outcomes, including inflammatory markers (IL-6, IL-18, IL-1β, IL-10, TLR-4, BCL-2 and BAX), markers of endothelial function (ICAM-1 and VCAM-1), and oxidative stress indices (malondialdehyde (MDA), nuclear-related factor 2 (Nrf-2), catalase, superoxide dismutase (SOD), and TAC) (p < 0.005) in the NC group compared to the placebo group after 10 days, while no significant increase was observed in the glutathione peroxidase (GPx) level between the two groups. However, no significant decrease was observed in the levels of secondary outcomes, including biochemical factors (creatinine, fasting blood sugar (FBS), alanine aminotransferase (ALT), aspartate aminotransferase (AST), alkaline phosphatase (ALP), gamma-glutamyl transferase (GGT), total bilirubin, triglycerides (TG) and total cholesterol (TC)) (P > 0.05). Our results showed that in the tertiary outcome (nutritional status), there was no significant increase (P > 0.05) except for TLC (P = 0.003). NC supplementation also resulted in a significant decrease in the exploratory outcomes including the SOFA score and the duration of mechanical ventilation (P < 0.05). Supplementation with NC may be a promising treatment strategy for critically ill patients with sepsis. However, further experiments are suggested to investigate the effects of nano-curcumin on biochemical pathways involved in sepsis.

Anti-Inflammatory Effect of Curcumin on the Mouse Model of Myocardial Infarction through Regulating Macrophage Polarization

Inflammation causes tissue damage and promotes ventricular remodeling after myocardial infarction (MI), and the infiltration and polarization of macrophages play an important role in regulating inflammation post-MI. Here, we investigated the anti-inflammatory function of curcumin after MI and studied its relationship with macrophage polarization. In vivo, curcumin not only attenuated ventricular remodeling 3 months after MI but also suppressed inflammation during the first 7 days post-MI. Importantly, the results of qPCR and immunochemistry showed that curcumin decreased M1 (iNOS, CCL2, and CD86) but increased M2 macrophage (Arg1, CD163, and CD206) marker expression in the myocardium of MI mice during the first 7 days post-MI. And flow cytometry analysis indicated that curcumin suppressed M1 (CD45+Gr-1-CD11b+iNOS+ cells) but enhanced M2 macrophage (CD45+Gr-1-CD11b+Arg+ cells) expansion in the myocardium of MI mice during the first 7 days post-MI. In vitro, curcumin decreased LPS/IFNγ-elevated M1 macrophage marker (iNOS and CD86) expression and the proportion of M1 macrophages (iNOS+F4/80+ cells) but increased LPS/IFNγ-suppressed M2 macrophage marker (Arg1 and CD206) expression and the proportion of M2 macrophages (Arg1+F4/80+ cells). In addition, curcumin modulates M1/M2 macrophage polarization partly via AMPK. In conclusion, curcumin suppressed the MI-induced inflammation by modulating macrophage polarization partly via the AMPK pathway.

Complementary and alternative medicine (CAM) supplements in cancer outpatients: analyses of usage and of interaction risks with cancer treatment

Purpose

The aim of our study was to analyze the use of complementary and alternative medicine (CAM) supplements, identify possible predictors, and analyze and compile potential interactions of CAM supplements with conventional cancer therapy.

Methods

We included outpatient cancer patients treated at a German university hospital in March or April 2020. Information was obtained from questionnaires and patient records. CAM–drug interactions were identified based on literature research for each active ingredient of the supplements consumed by the patients.

Results

37.4% of a total of 115 patients consumed CAM supplements. Potential interactions with conventional cancer treatment were identified in 51.2% of these patients. All types of CAM supplements were revealed to be a potential source for interactions: vitamins, minerals, food and plant extracts, and other processed CAM substances. Younger age (< 62 years) (p = 0.020, φc = 0.229) and duration of individual cancer history of more than 1 year (p = 0.006, φc = 0.264) were associated with increased likelihood of CAM supplement use. A wide range of different CAM supplement interactions were reviewed: effects of antioxidants, cytochrome (CYP) interactions, and specific agonistic or antagonistic effects with cancer treatment.

Conclusion

The interaction risks of conventional cancer therapy with over-the-counter CAM supplements seem to be underestimated. Supplements without medical indication, as well as overdoses, should be avoided, especially in cancer patients. To increase patient safety, physicians should address the risks of interactions in physician–patient communication, document the use of CAM supplements in patient records, and check for interactions.

Immunomodulatory Effects of Curcumin in Rheumatoid Arthritis: Evidence from Molecular Mechanisms to Clinical Outcomes

Rheumatoid arthritis (RA) is a chronic immune-mediated inflammatory disorder characterized by the destruction of the joint and bone resorption. The production of pro-inflammatory cytokines and chemokines, dysregulated functions of three important subtypes of T helper (T_H) cells including T_H1, T_H17, and regulator T (Treg) cells are major causes of the initiation and development of RA. Moreover, B cells as a source of the production of several autoantibodies play key roles in the pathogenesis of RA. The last decades have seen increasingly rapid advances in the field of immunopharmacology using natural origin compounds for the management of various inflammatory diseases. Curcumin, a main active polyphenol compound isolated from turmeric, curcuma longa, possesses a wide range of pharmacologic properties for the treatment of several diseases. This review comprehensively will assess beneficial immunomodulatory effects of curcumin on the production of pro-inflammatory cytokines and also dysregulated functions of immune cells including T_H1, T_H17, Treg, and B cells in RA. We also seek the clinical efficacy of curcumin for the treatment of RA in several recent clinical trials. In conclusion, curcumin has been found to ameliorate RA complications through modulating inflammatory and autoreactive responses in immune cells and synovial fibroblast cells via inhibiting the expression or function of pro-inflammatory mediators, such as nuclear factor-κB (NF-κB), activated protein-1 (AP-1), and mitogen-activated protein kinases (MAPKs). Of note, curcumin treatment without any adverse effects can attenuate the clinical symptoms of RA patients and, therefore, has therapeutic potential for the treatment of the diseases.

Immunomodulatory and Anti-Inflammatory Potential of Curcumin for the Treatment of Allergic Asthma: Effects on Expression Levels of Pro-inflammatory Cytokines and Aquaporins

Curcumin is well known for possessing anti-inflammatory properties and for its beneficial effects in the treatment of asthma. Current study investigates the immunomodulatory and anti-inflammatory effects of curcumin using mouse model of ovalbumin-induced allergic asthma. BALB/c mice were immunized with ovalbumin on day 0 and 14 to induce allergic asthma. Animals were treated with two different doses of curcumin (20 mg/kg and 100 mg/kg) and methylprednisolone from day 21 to 28. Mice were also daily challenged intranasally with ovalbumin during treatment period, and all groups were sacrificed at day 28. Histopathological examination showed amelioration of allergic asthma in treated groups as evident by the attenuation of infiltration of inflammatory cells, goblet cell hyperplasia, alveolar thickening, and edema and vascular congestion. Curcumin significantly reduced total and differential leukocyte counts in both bronchoalveolar lavage fluid and blood. Reverse transcription polymerase chain reaction analysis showed significantly suppressed mRNA expression levels of IL-4 and IL-5 (pro-inflammatory cytokines), TNF-α, TGF-β (pro-fibrotic cytokines), eotaxin (chemokine), and heat shock protein 70 (marker of airway obstruction) in treated groups. Attenuation of these pro-inflammatory markers might have led to the suppression of airway inflammation. The expression levels of aquaporin-1 (AQP) and AQP-5 were found significantly elevated in experimental groups which might be responsible for reduction of pulmonary edema. In conclusion, curcumin significantly ameliorated allergic asthma. The anti-asthmatic effect might be attributed to the suppression of pro-inflammatory cytokines, and elevation of aquaporin expression levels, suggesting further studies and clinical trials to establish its candidature in the treatment of allergic asthma.

Curcumin mediates attenuation of pro-inflammatory interferon γ and interleukin 17 cytokine responses in psoriatic disease, strengthening its role as a dietary immunosuppressant

Curcumin exhibits anti-inflammatory properties and has been used for centuries in traditional medicine and as dietary supplement. Data from clinical trials has strengthened the notion that curcumin may exert an anti-inflammatory and immunosuppressive role in patients with psoriatic disease, but its mode of action has remained elusive. We hypothesized that curcumin could inhibit interferon (IFN)-γ and interleukin (IL)-17 production in peripheral blood mononuclear cells from patients with psoriasis and psoriatic arthritis (PsA). To this end, we assessed the in vitro effect of curcumin on IFN-γ production by cluster differentiation (CD)4(+), CD8(+) T cells, natural killer (NK) and NKT cells and on IL-17 production by CD4(+) T cells from 34 patients with psoriatic disease (22 with psoriasis and 12 with PsA); 15 normal subjects were included as healthy controls. We also assessed the effect of curcumin on signal transducer and activator of transcription (STAT)3 activation. Curcumin significantly decreased, in a dose dependent manner, IFNγ-production by CD4(+) and CD8(+) T cells, and NK and NKT cells in patients with psoriatic disease and healthy controls. It also decreased IL-17 production by CD4(+) T cells (Th17). At the molecular level, curcumin increased STAT3 serine 727 phosphorylation intensity and p-STAT3(+) CD4(+) T cells in patients with PsA and psoriasis. In conclusion, curcumin in vitro inhibits pro-inflammatory IFN-γ and IL-17 production in psoriatic disease, and this may strengthen its role as a dietary immunosuppressant in patients with this disease.

Therapeutic effects of curcumin on sepsis and mechanisms of action: A systematic review of preclinical studies

Sepsis is a complex disease that begins with an infectious disorder and causes excessive immune responses. Curcumin is considered as an active component of turmeric that can improve the condition in sepsis due to its anti-inflammatory and antioxidant properties. PubMed, Embase, Google Scholar, Web of Science, and Scopus databases were searched. Searching was not limited to a specific publication period. Only English-language original articles, which had examined the effect of curcumin on sepsis, were included. At first, 1,098 articles were totally found, and 209 articles were selected after excluding duplicated data; 46 articles were remained due to the curcumin effects on sepsis. These included 23 in vitro studies and 23 animal studies. Our results showed that curcumin and various analogs of curcumin can have an inhibitory effect on sepsis-induced complications. Curcumin has the ability to inhibit the inflammatory, oxidative coagulation factors, and regulation of immune responses in sepsis. Despite the promising evidence of the therapeutic effects of curcumin on the sepsis complication, further studies seem necessary to investigate its effect and possible mechanisms of action in human studies.

Targeting the balance of T helper cell responses by curcumin in inflammatory and autoimmune states

CD4⁺ T helper (Th) cells are a crucial player in host defense but under certain conditions can contribute to the pathogenesis of inflammatory and autoimmune diseases. Beside the Th1/Th2 subset, several additional Th subsets have been identified, each with a distinctive transcription factor, functional properties, signature cytokine profile, and possible role in the pathophysiology of diseases. These newer Th subsets include Th17, regulatory Th cells (Tregs), and more recently, Th9, Th22, and follicular T helper cells. Interestingly, imbalance of Th subsets contributes to the immunopathology of several disease states. Therefore, targeting the imbalance of Th subsets and their signature cytokine profiles by a safe, effective and inexpensive nutraceutical agent such as curcumin could be helpful to treat autoimmune and inflammatory diseases. In this study different Th subsets and how the imbalance of these subsets could promote pathology of several diseases has been reviewed. Furthermore, the role of curcumin in this process will be discussed and the impact of targeting Th subsets by curcumin.

Some Biological Properties of Curcumin: A Review

Curcumin (diferuloyl methane), a small-molecular weight compound isolated from the roots of Curcuma longa L. (family Zingiberaceae), has been used traditionally for centuries in Asia for medicinal, culinary and other purposes. A large number of in vitro and in vivo studies in both animals and man have indicated that curcumin has strong antioxidant, anti-carcinogenic, anti-inflammatory, anti-angiogenic, antispasmodic, antimicrobial, anti-parasitic and other activities. The mechanisms of some of these actions have recently been intensively investigated. Curcumin inhibits the promotion/ progression stage of carcinogenesis by induction of apoptosis and the arrest of cancer cells in the S, G2/M cell cycle phase. The compound inhibits the activity of growth factor receptors. The anti-inflammatory properties of curcumin are mediated through their effects on cytokines, lipid mediators, eicosanoids and proteolytic enzymes. Curcumin scavenges the superoxide radical, hydrogen peroxide and nitric oxide, and inhibits lipid peroxidation. These actions may be the basis for many of its pharmacological and therapeutic properties.

Curcumin is a nutraceutical of low toxicity, which has been used successfully in a number of medical conditions that include cataracts, cystic fibrosis, and prostate and colon cancers.

The effects of curcumin on the prevention of atrial and ventricular arrhythmias and heart failure in patients with unstable angina: A randomized clinical trial

OBJECTIVE

Inflammation along with oxidative stress has an important role in the pathophysiology of unstable angina which leads to acute myocardial infarction, arrhythmias and eventually heart failure. Curcumin has anti-inflammatory and anti-oxidant effects and thereby, it may reduce cardiovascular complications. This randomized controlled trial aimed to investigate the effects of curcumin on the prevention of atrial and ventricular arrhythmias and heart failure in patients with unstable angina.

MATERIALS AND METHODS

Forty patients with unstable angina who met the trial inclusion and exclusion criteria, participated in this double-blind randomized clinical trial. The patients were randomized into two groups: curcumin (80 mg/day for 5days) and placebo (80 mg/day for 5days). Cardiac function was evaluated by two-dimensional echocardiography devices at baseline (immediately after hospitalization) and 5 days after the onset of the trial. Atrial and ventricular arrhythmias were recorded by Holter monitors in cardiology ward, Ghaem academic hospital, Mashhad, Iran. Progression to heart failure, myocardial infarction, and pulmonary and cardiopulmonary resuscitation events as well as mortality were recorded daily throughout the study.

RESULTS

There were no significant differences between the two groups in atrial and ventricular arrhythmias (p=0.2), and other echocardiographic parameters (Ejection fraction, E, A, E/A ratio, Em, and pulmonary artery pressure) at baseline and five days after the start of the trial.

CONCLUSION

Nanocurcumin administered at the dose of 80 mg/day for five days had no effect in the incidence of cardiovascular complications in patients with unstable angina.

Macrophage plasticity, polarization and function in response to curcumin, a diet-derived polyphenol, as an immunomodulatory agent

Monocytes and macrophages are important cells of the innate immune system that have diverse functions, including defense against invading pathogens, removal of dead cells by phagocytosis, antigen presentation in the context of MHC class I and class II molecules, and production of various pro-inflammatory cytokines and chemokines such as IL-1β, IL-6, TNF-α and MCP-1. In addition, pro-inflammatory (M1) and anti-inflammatory (M2) macrophages clearly play important roles in the progression of several inflammatory diseases. Therefore, therapies that target macrophage polarization and function by either blocking their trafficking to sites of inflammation, or skewing M1 to M2 phenotype polarization may hold clinical promise in several inflammatory diseases. Dietary-derived polyphenols have potent natural anti-oxidative properties. Within this group of polyphenols, curcumin has been shown to suppress macrophage inflammatory responses. Curcumin significantly reduces co-stimulatory molecules and also inhibits MAPK activation and the translocation of NF-κB p65. Curcumin can also polarize/repolarize macrophages toward the M2 phenotype. Curcumin-treated macrophages have been shown to be highly efficient at antigen capture and endocytosis via the mannose receptor. These novel findings provide new perspectives for the understanding of the immunopharmacological role of curcumin, as well as its therapeutic potential for impacting macrophage polarization and function in the context of inflammation-related disease. However, the precise effects of curcumin on the migration, differentiation, polarization and immunostimulatory functions of macrophages remain unknown. Therefore, in this review, we summarized whether curcumin can influence macrophage polarization, surface molecule expression, cytokine and chemokine production and their underlying pathways in the prevention of inflammatory diseases.

Effects of curcumin on NF-κB, AP-1, and Wnt/β-catenin signaling pathway in hepatitis B virus infection

Curcumin is a yellow-orange powder derived from the Curcuma longa plant. Curcumin has been used extensively in traditional medicine for centuries. This component is non-toxic and shown different therapeutic properties such as anti-inflammatory, anti-cancer, antiviral, anti-bacterial, anti-fungal, anti-parasites, and anti-oxidant. Hepatitis B virus (HBV) is a small DNA member of the genus Orthohepadnavirus (Hepadnaviridae family) which is a highly contagious blood-borne viral pathogen. HBV infection is a major public health problem with 2 billion people infected throughout the world and 350 million suffering from chronic HBV infection. Increasing evidence indicated that curcumin as a natural product could be employed in the treatment of HBV patients. It has been showed that curcumin exerts its therapeutic effects on HBV patients via targeting a variety of cellular and molecular pathways such as Wnt/β-catenin, Ap1, STAT3, MAPK, and NF-κB signaling. Here, we summarized the therapeutic effects of curcumin on patients who infected with HBV. Moreover, we highlighted main signaling pathways (eg, NF-κB, AP1, and Wnt/β-catenin signaling) which affected by curcumin in HBV infections.

Role of Vital Trace Elements in Nanocurcumin-Centered Formulation: A Novel Approach to Resuscitate the Immune System

The present paper described the immunomodulatory potential of novel nanocurcumin-based formulation enriched with trace elements and vitamins on cyclophosphamide-induced immunosuppression in rat model. Major immune-related assays were monitored such as hemagglutination assay, delayed-type hypersensitivity (DTH) reaction, cellular immune response, IgG, IgE, IgM, cerebrospinal fluid biomarkers, hematological study, antioxidant profile, and lipid biomarkers. Chemical characterization of novel formulation showed retention time (R _t ) 18.98 of curcumin, while LC-MS data revealed the presence of the curcumin mass at m/z 369.01 [M + H]⁺ (calculated for C₂₁H₂₁O₆⁺, 369.13). This novel formulation exhibited significantly (p ≤ 0.001) increased primary and secondary antibody titer by 72.41% and 33.25%, respectively, while DTH response being improved by 87.50% (p ≤ 0.01). However, CD4⁺, CD8⁺, and CD28⁺ counts were significantly (p ≤ 0.05) increased by 76.46%, 68.21%, and 19.29%, respectively, while the concentrations of IgE, IgM, and IgG were significantly (p ≤ 0.05) increased by 40%, 28.43%, and 38.75%, respectively. CSF biomarkers analysis showed a decreased level of corticosterone, dopamine, serotonin, and tau protein by 29.38%, 51.73%, 29.93%, and 4.87%, respectively. Antioxidant enzymes such as CAT, GPx, and SOD were increased by 43.74%, 49.00%, and 40.84%, respectively, and non-enzymatic component, GSH, was increased by 55.52%. Similarly, free radical LPO was significantly (p ≤ 0.05) decreased by 40.37%, and acute inflammatory marker, MPO concentration, was reduced by 31.14%, compared with the disease control group. In addition, supportive hematology and lipid profile analysis showed promising results with improved overall animal profile. Thus, trace elements in novel formulation can be used in the various pharmacological activities and as dietary supplement due to its wide properties.

Curcumin: A natural modulator of immune cells in systemic lupus erythematosus

Curcumin is a polyphenol natural product isolated from turmeric, interacting with different cellular and molecular targets and, consequently, showing a wide range of pharmacological effects. Recent preclinical and clinical trials have revealed immunomodulatory properties of curcumin that arise from its effects on immune cells and mediators involved in the immune response, such as various T-lymphocyte subsets and dendritic cells, as well as different inflammatory cytokines. Systemic lupus erythematosus (SLE) is an inflammatory, chronic autoimmune-mediated disease characterized by the presence of autoantibodies, deposition of immune complexes in various organs, recruitment of autoreactive and inflammatory T cells, and excessive levels of plasma proinflammatory cytokines. The function and numbers of dendritic cells and T cell subsets, such as T helper 1 (Th1), Th17, and regulatory T cells have been found to be significantly altered in SLE. In the present report, we reviewed the results of in vitro, experimental (pre-clinical), and clinical studies pertaining to the modulatory effects that curcumin produces on the function and numbers of dendritic cells and T cell subsets, as well as relevant cytokines that participate in SLE.

Carotenoids: biochemistry, pharmacology and treatment

Carotenoids and retinoids have several similar biological activities such as antioxidant properties, the inhibition of malignant tumour growth and the induction of apoptosis. Supplementation with carotenoids can affect cell growth and modulate gene expression and immune responses. Epidemiological studies have shown a correlation between a high carotenoid intake in the diet with a reduced risk of breast, cervical, ovarian, colorectal cancers, and cardiovascular and eye diseases. Cancer chemoprevention by dietary carotenoids involves several mechanisms, including effects on gap junctional intercellular communication, growth factor signalling, cell cycle progression, differentiation-related proteins, retinoid-like receptors, antioxidant response element, nuclear receptors, AP-1 transcriptional complex, the Wnt/β-catenin pathway and inflammatory cytokines. Moreover, carotenoids can stimulate the proliferation of B- and T-lymphocytes, the activity of macrophages and cytotoxic T-cells, effector T-cell function and the production of cytokines. Recently, the beneficial effects of carotenoid-rich vegetables and fruits in health and in decreasing the risk of certain diseases has been attributed to the major carotenoids, β-carotene, lycopene, lutein, zeaxanthin, crocin (/crocetin) and curcumin, due to their antioxidant effects. It is thought that carotenoids act in a time- and dose-dependent manner. In this review, we briefly describe the biological and immunological activities of the main carotenoids used for the treatment of various diseases and their possible mechanisms of action.

LINKED ARTICLES

This article is part of a themed section on Principles of Pharmacological Research of Nutraceuticals. To view the other articles in this section visit http://onlinelibrary.wiley.com/doi/10.1111/bph.v174.11/issuetoc.

An overview of structure-activity relationship studies of curcumin analogs as antioxidant and anti-inflammatory agents

Curcumin, extracted mainly from Curcuma longa rhizomes, has been reported to possess potent anti-inflammatory and anti-oxidant activities. Although safe at higher doses and exhibiting multiple biological activities, curcumin still has the problem of poor bioavailability which has been an attractive area of research over the last few years. A number of efforts have been made by modifying structural features of curcumin. This review highlights the structurally modified and more stable newly synthesized curcumin analogs that have been screened against antioxidant and anti-inflammatory activities. Also the structure-activity relationship to gain insight into future guidelines for scheming new compounds has been discussed, and further these analogs being more stable may serve as promising agents for use in different pathological conditions.

Degranulation Inhibitors from Medicinal Plants in Antigen-Stimulated Rat Basophilic Leukemia (RBL-2H3) Cells

Mast cells and basophils play important roles in both immediate- and late-phase reactions of type 1 allergy. Histamine, which is released from mast cells and basophils stimulated by an antigen or degranulation inducers, is usually determined as a degranulation marker in experiments on immediate allergic reactions in vitro. β-Hexosaminidase is also stored in secretory granules of the cells and is released concomitantly with histamine when the cells are immunologically activated, and recently this enzyme activity in the medium has been used as a marker of the degranulation. In this paper, we review our studies on the search for degranulation inhibitors, such as flavonoids, stilbenes, and curcuminoids, from medicinal plants using rat basophilic leukemia (RBL-2H3) cells.

Can curcumin modulate allergic rhinitis in rats?

OBJECTIVES

This study aimed to explore the effects of curcumin on experimental allergic rhinitis in rats.

METHODS

Twenty-eight male Wistar albino rats were randomly divided into four groups: a control group; a group in which allergic rhinitis was induced and no treatment given; a group in which allergic rhinitis was induced followed by treatment with azelastine hydrochloride on days 21-28; and a group in which allergic rhinitis was induced followed by treatment with curcumin on days 21-28. Allergy symptoms and histopathological features of the nasal mucosa were examined.

RESULTS

The sneezing and nasal congestion scores were higher in the azelastine and curcumin treatment groups than in the control group. Histopathological examination showed focal goblet cell metaplasia on the epithelial surface in the azelastine group. In the curcumin group, there was a decrease in goblet cell metaplasia in the epithelium, decreased inflammatory cell infiltration and vascular proliferation in the lamina propria.

CONCLUSION

Curcumin is an effective treatment for experimentally induced allergic rhinitis in rats.

The Impact of Turmeric Cream on Healing of Caesarean Scar

OBJECTIVE

The aim of this study was to assess the impact of turmeric cream on the healing of Caesarean wound.

METHODS

This study was done as a randomized double blind trial in three groups on women who had a Caesarean operation. The redness, oedema, ecchymosis, drainage, approximation (REEDA) scale was used to evaluate the wound healing process. The χ², analysis of variance (ANOVA) and Tukey tests were used for statistical analysis.

RESULTS

Seven days after the surgery, the averages of REEDA score in the intervention, placebo and control groups were respectively, 0.46, 0.88, and 1.17 (p < 0.001), while on day 14, it was 0.03, 0.22 and 0.36 (p < 0.001), showing a significant statistical difference. Similarly, there was a difference between the intervention and placebo groups in the amount of oedema on the 7th and 14th days after the surgery (respectively, p = 0.066 and p < 0.001). The observed difference between the intervention and control groups in the amount of oedema was statistically significant on the 7th and 14th days after the surgery (p < 0.001).

CONCLUSION

Turmeric was effective in faster healing of wounds of Caesarean operation. The use of turmeric is suggested to reduce the complications of the wounds from Caesarean section.

Curcumin differs from tetrahydrocurcumin for molecular targets, signaling pathways and cellular responses

Curcumin (diferuloylmethane), a golden pigment from turmeric, has been linked with antioxidant, anti-inflammatory, anticancer, antiviral, antibacterial, and antidiabetic properties. Most of the these activities have been assigned to methoxy, hydroxyl, α,β-unsaturated carbonyl moiety or to diketone groups present in curcumin. One of the major metabolites of curcumin is tetrahydrocurcumin (THC), which lacks α,β-unsaturated carbonyl moiety and is white in color. Whether THC is superior to curcumin on a molecular level is unclear and thus is the focus of this review. Various studies suggest that curcumin is a more potent antioxidant than THC; curcumin (but not THC) can bind and inhibit numerous targets including DNA (cytosine-5)-methyltransferase-1, heme oxygenase-1, Nrf2, β-catenin, cyclooxygenase-2, NF-kappaB, inducible nitric oxide synthase, nitric oxide, amyloid plaques, reactive oxygen species, vascular endothelial growth factor, cyclin D1, glutathione, P300/CBP, 5-lipoxygenase, cytosolic phospholipase A2, prostaglandin E2, inhibitor of NF-kappaB kinase-1, -2, P38MAPK, p-Tau, tumor necrosis factor-α, forkhead box O3a, CRAC; curcumin can inhibit tumor cell growth and suppress cellular entry of viruses such as influenza A virus and hepatitis C virus much more effectively than THC; curcumin affects membrane mobility; and curcumin is also more effective than THC in suppressing phorbol-ester-induced tumor promotion. Other studies, however, suggest that THC is superior to curcumin for induction of GSH peroxidase, glutathione-S-transferase, NADPH: quinone reductase, and quenching of free radicals. Most studies have indicated that THC exhibits higher antioxidant activity, but curcumin exhibits both pro-oxidant and antioxidant properties.

Potent trypanocidal curcumin analogs bearing a monoenone linker motif act on trypanosoma brucei by forming an adduct with trypanothione

We have previously reported that curcumin analogs with a C7 linker bearing a C4-C5 olefinic linker with a single keto group at C3 (enone linker) display midnanomolar activity against the bloodstream form of Trypanosoma brucei. However, no clear indication of their mechanism of action or superior antiparasitic activity relative to analogs with the original di-ketone curcumin linker was apparent. To further investigate their utility as antiparasitic agents, we compare the cellular effects of curcumin and the enone linker lead compound 1,7-bis(4-hydroxy-3-methoxyphenyl)hept-4-en-3-one (AS-HK014) here. An AS-HK014-resitant line, trypanosomes adapted to AS-HK014 (TA014), was developed by in vitro exposure to the drug. Metabolomic analysis revealed that exposure to AS-HK014, but not curcumin, rapidly depleted glutathione and trypanothione in the wild-type line, although almost all other metabolites were unchanged relative to control. In TA014 cells, thiol levels were similar to untreated wild-type cells and not significantly depleted by AS-HK014. Adducts of AS-HK014 with both glutathione and trypanothione were identified in AS-HK014-exposed wild-type cells and reproduced by chemical reaction. However, adduct accumulation in sensitive cells was much lower than in resistant cells. TA014 cells did not exhibit any changes in sequence or protein levels of glutathione synthetase and γ-glutamylcysteine synthetase relative to wild-type cells. We conclude that monoenone curcuminoids have a different mode of action than curcumin, rapidly and specifically depleting thiol levels in trypanosomes by forming an adduct. This adduct may ultimately be responsible for the highly potent trypanocidal and antiparasitic activity of the monoenone curcuminoids.

Curcumin and inflammatory bowel disease: potential and limits of innovative treatments

Curcumin belongs to the family of natural compounds collectively called curcuminoids and it possesses remarkable beneficial anti-oxidant, anti-inflammatory, anti-cancer, and neuroprotective properties. Moreover it is commonly assumed that curcumin has also been suggested as a remedy for digestive diseases such as inflammatory bowel diseases (IBD), a chronic immune disorder affecting the gastrointestinal tract and that can be divided in two major subgroups: Crohn’s disease (CD) and Ulcerative Colitis (UC), depending mainly on the intestine tract affected by the inflammatory events. The chronic and intermittent nature of IBD imposes, where applicable, long-term treatments conducted in most of the cases combining different types of drugs. In more severe cases and where there has been no good response to the drugs, a surgery therapy is carried out. Currently, IBD-pharmacological treatments are generally not curative and often present serious side effects; for this reason, being known the relationship between nutrition and IBD, it is worthy of interesting the study and the development of new dietary strategy. The curcumin principal mechanism is the suppression of IBD inflammatory compounds (NF-κB) modulating immune response. This review summarizes literature data of curcumin as anti-inflammatory and anti-oxidant in IBD, trying to understand the different effects in CD e UC.

Evaluation of Efficacy of Curcumin as an Add-on therapy in Patients of Bronchial Asthma

BACKGROUND

Bronchial asthma being a chronic inflammatory disease of airways has numerous treatment options none of which have disease modifying properties. Curcumin, a yellow dietary pigment has varied pharmacological activities, prominent among which is an anti-inflammatory activity which may be crucial in bronchial asthma as has been proved by various in vitro and in vivo animal studies.

AIMS

To determine the efficacy and safety of curcumin as an 'add-on' therapy in patients of bronchial asthma.

SETTINGS AND DESIGN

This study was conducted on 77 patients of mild to moderate Bronchial asthma who had a documented positive bronchodilator reversibility test with ≥15% improvement in forced expiratory volume one second (FEV1).

MATERIALS AND METHODS

Seventy seven patients were recruited for the study and randomized into either of the two groups, but 17 patients were lost to follow up. Thus Group A - Receiving standard therapy for bronchial asthma for 30d (n=30) and Group B - Receiving standard therapy for bronchial asthma + Cap Curcumin 500mg BD daily for 30d (n=30). The predefined primary endpoints were clinical assessments of dyspnoea, wheezing, cough, chest tightness and nocturnal symptoms, change in the pre-bronchodilator FEV1 during the treatment and hematological improvement. The secondary end points were assessed by the change in the post-bronchodilator FEV1, C-reactive protein (CRP) concentration and incidence of adverse events.

STATISTICAL ANALYSIS USED

The data was analysed by SPSS 17.0 software using one-way ANOVA or Paired t-test.

RESULTS AND CONCLUSION

The results showed that curcumin capsules help in improving the airway obstruction which was evident by significant improvement in the mean FEV1 values. There was also significant improvement in the hematological parameters and absence of any clinically significant adverse events indicates dependable safety profile of curcumin capsules, though there was no apparent clinical efficacy. Therefore, it is concluded that curcumin is effective and safe as an add-on therapy for the treatment of bronchial asthma.

Curcumin ameliorates autoimmune diabetes. Evidence in accelerated murine models of type 1 diabetes

Type 1 diabetes (T1DM) is a T cell-mediated autoimmune disease that selectively destroys pancreatic β cells. The only possible cure for T1DM is to control autoimmunity against β cell-specific antigens. We explored whether the natural compound curcumin, with anti-oxidant and anti-inflammatory activities, might down-regulate the T cell response that destroys pancreatic β cells to improve disease outcome in autoimmune diabetes. We employed two accelerated autoimmune diabetes models: (i) cyclophosphamide (CYP) administration to non-obese diabetic (NOD) mice and (ii) adoptive transfer of diabetogenic splenocytes into NODscid mice. Curcumin treatment led to significant delay of disease onset, and in some instances prevented autoimmune diabetes by inhibiting pancreatic leucocyte infiltration and preserving insulin-expressing cells. To investigate the mechanisms of protection we studied the effect of curcumin on key immune cell populations involved in the pathogenesis of the disease. Curcumin modulates the T lymphocyte response impairing proliferation and interferon (IFN)-γ production through modulation of T-box expressed in T cells (T-bet), a key transcription factor for proinflammatory T helper type 1 (Th1) lymphocyte differentiation, both at the transcriptional and translational levels. Also, curcumin reduces nuclear factor (NF)-κB activation in T cell receptor (TCR)-stimulated NOD lymphocytes. In addition, curcumin impairs the T cell stimulatory function of dendritic cells with reduced secretion of proinflammatory cytokines and nitric oxide (NO) and low surface expression of co-stimulatory molecules, leading to an overall diminished antigen-presenting cell activity. These in-vitro effects correlated with ex-vivo analysis of cells obtained from curcumin-treated mice during the course of autoimmune diabetes. These findings reveal an effective therapeutic effect of curcumin in autoimmune diabetes by its actions on key immune cells responsible for β cell death.

Curcumin attenuates acute graft-versus-host disease severity via in vivo regulations on Th1, Th17 and regulatory T cells

BACKGROUND

In this study we examined the in vivo and in vitro effects and mechanisms of action of curcumin on the development of acute graft-versus-host disease (GVHD) using a murine model.

METHODOLOGY/PRINCIPAL FINDINGS

Mixed lymphocyte reactions were used to determine the in vitro effects of curcumin. Treatment with curcumin attenuated alloreactive T cell proliferation and inhibited the production of interferon (IFN)-γ and interleukin (IL)-17. In a murine acute GVHD model, transplantation of curcumin-treated allogeneic splenocytes into irradiated recipient mice significantly reduced the clinical severity scores of acute GVHD manifested in the liver, skin, colon and lung as compared with animals receiving vehicle-treated splenocytes. c-Fos and c-Jun expression levels in the skin and intestine, which are major target organs, were analyzed using immunohistochemical staining. Expression of both proteins was reduced in epithelial tissues of skin and intestine from curcumin-treated GVHD animals. The IFN-γ-expressing CD4(+) splenocytes and IFN-γ-expressing lymph node cells were dramatically decreased in curcumin-treated mice. In contrast, CD4(+)Foxp3(+) splenocytes were increased in the curcumin-treated acute GVHD animals. Flow cytometric analysis revealed that animals transplanted with curcumin-treated allogeneic splenocytes showed increased populations of CD4(+) regulatory T cells (Tregs) as well as CD8(+) Treg cells, compared to animals administered vehicle-treated splenocytes. Curcumin-treated acute GVHD animals could have a change in B cell subpopulations.

CONCLUSION/SIGNIFICANCE

In the present study, we investigated the efficacy and mechanism of action of curcumin treatment against acute GVHD. The acute GVHD mice administered with curcumin-treated splenocytes showed significantly reduced severity of acute GVHD. Curcumin exerted in vivo preventive effects on acute GVHD by reciprocal regulation of T helper 1 (Th1) and Treg (both CD4(+) and CD8(+) Treg) cell lineages as well as B cell homeostasis.

Curcumin inhibits CD4(+) T cell activation, but augments CD69 expression and TGF-β1-mediated generation of regulatory T cells at late phase

BACKGROUND

Curcumin is a promising candidate for a natural medicinal agent to treat chronic inflammatory diseases. Although CD4(+) T cells have been implicated in the pathogenesis of chronic inflammation, whether curcumin directly regulates CD4(+) T cells has not been definitively established. Here, we showed curcumin-mediated regulation of CD2/CD3/CD28-initiated CD4(+) T cell activation in vitro.

METHODOLOGY/PRINCIPAL FINDINGS

Primary human CD4(+) T cells were stimulated with anti-CD2/CD3/CD28 antibody-coated beads as an in vitro surrogate system for antigen presenting cell-T cell interaction and treated with curcumin. We found that curcumin suppresses CD2/CD3/CD28-initiated CD4(+) T cell activation by inhibiting cell proliferation, differentiation and cytokine production. On the other hand, curcumin attenuated the spontaneous decline of CD69 expression and indirectly increased expression of CCR7, L-selectin and Transforming growth factor-β1 (TGF-β1) at the late phase of CD2/CD3/CD28-initiated T cell activation. Curcumin-mediated up-regulation of CD69 at late phase was associated with ERK1/2 signaling. Furthermore, TGF-β1 was involved in curcumin-mediated regulation of T cell activation and late-phase generation of regulatory T cells.

CONCLUSIONS/SIGNIFICANCE

Curcumin not merely blocks, but regulates CD2/CD3/CD28-initiated CD4(+) T cell activation by augmenting CD69, CCR7, L-selectin and TGF-β1 expression followed by regulatory T cell generation. These results suggest that curcumin could directly reduce T cell-dependent inflammatory stress by modulating CD4(+) T cell activation at multiple levels.

Curcumin induces apoptotic cell death of activated human CD4+ T cells via increasing endoplasmic reticulum stress and mitochondrial dysfunction

Curcumin, a natural polyphenolic antioxidant compound, exerts well-known anti-inflammatory and immunomodulatory effects, the latter which can influence the activation of immune cells including T cells. Furthermore, curcumin can inhibit the expression of pro-inflammatory cytokines and chemokines, through suppression of the NF-κB signaling pathway. The beneficial effects of curcumin in diseases such as arthritis, allergy, asthma, atherosclerosis, diabetes and cancer may be due to its immunomodulatory properties. We studied the potential of curcumin to modulate CD4+ T cells-mediated autoimmune disease, by examining the effects of this compound on human CD4+ lymphocyte activation. Stimulation of human T cells with PHA or CD3/CD28 induced IL-2 mRNA expression and activated the endoplasmic reticulum (ER) stress response. The treatment of T cells with curcumin induced the unfolded protein response (UPR) signaling pathway, initiated by the phosphorylation of PERK and IRE1. Furthermore, curcumin increased the expression of the ER stress associated transcriptional factors XBP-1, cleaved p50ATF6α and C/EBP homologous protein (CHOP) in human CD4+ and Jurkat T cells. In PHA-activated T cells, curcumin further enhanced PHA-induced CHOP expression and reduced the expression of the anti-apoptotic protein Bcl-2. Finally, curcumin treatment induced apoptotic cell death in activated T cells via eliciting an excessive ER stress response, which was reversed by the ER-stress inhibitor 4-phenylbutyric acid or transfection with CHOP-specific siRNA. These results suggest that curcumin can impact both ER stress and mitochondria functional pathways, and thereby could be used as a promising therapy in the context of Th1-mediated autoimmune diseases.

Optimized turmeric extract reduces β-Amyloid and phosphorylated Tau protein burden in Alzheimer's transgenic mice

In a previous in vitro study, the standardized turmeric extract, HSS-888, showed strong inhibition of Aβ aggregation and secretion in vitro, indicating that HSS-888 might be therapeutically important. Therefore, in the present study, HSS-888 was evaluated in vivo using transgenic ‘Alzheimer’ mice (Tg2576) over-expressing Aβ protein. Following a six-month prevention period where mice received extract HSS-888 (5mg/mouse/day), tetrahydrocurcumin (THC) or a control through ingestion of customized animal feed pellets (0.1% w/w treatment), HSS-888 significantly reduced brain levels of soluble (~40%) and insoluble (~20%) Aβ as well as phosphorylated Tau protein (~80%). In addition, primary cultures of microglia from these mice showed increased expression of the cytokines IL-4 and IL-2. In contrast, THC treatment only weakly reduced phosphorylated Tau protein and failed to significantly alter plaque burden and cytokine expression. The findings reveal that the optimized turmeric extract HSS-888 represents an important step in botanical based therapies for Alzheimer’s disease by inhibiting or improving plaque burden, Tau phosphorylation, and microglial inflammation leading to neuronal toxicity.

Differential modulation of intracellular survival of cytosolic and vacuolar pathogens by curcumin

Curcumin, a principal component of turmeric, acts as an immunomodulator regulating the host defenses in response to a diseased condition. The role of curcumin in controlling certain infectious diseases is highly controversial. It is known to alleviate symptoms of Helicobacter pylori infection and exacerbate that of Leishmania infection. We have evaluated the role of curcumin in modulating the fate of various intracellular bacterial pathogens. We show that pretreatment of macrophages with curcumin attenuates the infections caused by Shigella flexneri (clinical isolates) and Listeria monocytogenes and aggravates those caused by Salmonella enterica serovar Typhi CT18 (a clinical isolate), Salmonella enterica serovar Typhimurium, Staphylococcus aureus, and Yersinia enterocolitica. Thus, the antimicrobial nature of curcumin is not a general phenomenon. It modulated the intracellular survival of cytosolic (S. flexneri and L. monocytogenes) and vacuolar (Salmonella spp., Y. enterocolitica, and S. aureus) bacteria in distinct ways. Through colocalization experiments, we demonstrated that curcumin prevented the active phagosomal escape of cytosolic pathogens and enhanced the active inhibition of lysosomal fusion by vacuolar pathogens. A chloroquine resistance assay confirmed that curcumin retarded the escape of the cytosolic pathogens, thus reducing their inter- and intracellular spread. We have demonstrated that the membrane-stabilizing activity of curcumin is crucial for its differential effect on the virulence of the bacteria.

Safrole-modulated immune response is mediated through enhancing the CD11b surface marker and stimulating the phagocytosis by macrophages in BALB/c mice

Safrole, a component of piper betle inflorescence, is a documented rodent hepatocarcinogen and inhibits bactericidal activity and the release of superoxide anion (O(2-)) by polymorphonuclear leukocytes (PMNs). In the present study, we investigated the effects of safrole on immune responses, including natural killer (NK) cell cytotoxicity, phagocytic activity and population distribution of leukocytes from normal BALB/c mice. The cells population (cell surface markers) and phagocytosis by macrophages and monocytes from the peripheral blood mononuclear cells (PBMCs) were determined, and NK cell cytotoxicity from splenocytes of mice after oral treatment with safrole was performed using flow cytometric assay. Results indicated that safrole did not affect the weights of body, spleen and liver when compared with the normal mice group. Safrole also promoted the levels of CD11b (monocytes) and Mac-3 (macrophages) that might be the reason for promoting the activity of phagocytosis. However, safrole reduced the cell population such as CD3 (T cells) and CD19 (B cells) of safrole-treated normal mice by oral administration. Furthermore, safrole elevated the uptake of Escherichia coli-labelled fluorescein isothiocyanate (FITC) by macrophages from blood and significantly stimulated the NK cell cytotoxicity in normal mice in vivo. In conclusions, alterations of the cell population (the increase in monocytes and macrophages, respectively) in safrole-treated normal BALB/c mice might indirectly influence the immune responses in vivo.

Differential regulation of CD4(+) T helper cell responses by curcumin in experimental autoimmune encephalomyelitis

Nutraceuticals and phytochemicals are important regulators of human health and diseases. Curcumin is a polyphenolic phytochemical isolated from the rhizome of the plant Curcuma longa (turmeric) that has been traditionally used for the treatment of inflammation and wound healing for centuries. Systematic analyses have shown that curcumin exerts its beneficial effects through antioxidant, antiproliferative and anti-inflammatory properties. We and others have shown earlier that curcumin ameliorates experimental autoimmune encephalomyelitis (EAE) model for multiple sclerosis. In this study, we show that C57BL/6 mice induced to develop EAE express elevated levels of interferon (IFN) γ and interleukin (IL)-17 in the central nervous system (CNS) and lymphoid organs that decreased significantly following in vivo treatment with curcumin. The EAE mice also showed elevated expression of IL-12 and IL-23 that decreased after treatment with curcumin. Ex vivo and in vitro treatment with curcumin resulted in a dose-dependent decrease in the secretion of IFNγ, IL-17, IL-12 and IL-23 in culture. The inhibition of EAE by curcumin was also associated with an up-regulation of IL-10, peroxisome proliferator activated receptor γ and CD4(+)CD25(+-)Foxp3(+) Treg cells in the CNS and lymphoid organs. These findings highlight that curcumin differentially regulates CD4(+) T helper cell responses in EAE.

Curcumin suppresses T cell activation by blocking Ca2+ mobilization and nuclear factor of activated T cells (NFAT) activation

Curcumin is the active ingredient of the spice turmeric and has been shown to have a number of pharmacologic and therapeutic activities including antioxidant, anti-microbial, anti-inflammatory, and anti-carcinogenic properties. The anti-inflammatory effects of curcumin have primarily been attributed to its inhibitory effect on NF-κB activity due to redox regulation. In this study, we show that curcumin is an immunosuppressive phytochemical that blocks T cell-activation-induced Ca(2+) mobilization with IC(50) = ∼12.5 μM and thereby prevents NFAT activation and NFAT-regulated cytokine expression. This finding provides a new mechanism for curcumin-mediated anti-inflammatory and immunosuppressive function. We also show that curcumin can synergize with CsA to enhance immunosuppressive activity because of different inhibitory mechanisms. Furthermore, because Ca(2+) is also the secondary messenger crucial for the TCR-induced NF-κB signaling pathway, our finding also provides another mechanism by which curcumin suppresses NF-κB activation.

Protective role of curcumin on colchicine-induced cognitive dysfunction and oxidative stress in rats

Dementia is a syndrome of progressive nature, affects wide range of cognitive abilities like memory, language, calculation and so on, neuropsychiatric and social deficits to impair the routine social functions. The present study was designed to assess the effect of curcumin against colchicine-induced cognitive dysfunction and oxidative stress in rats and compare it with rivastigmine. Colchicine (15 µg/5µl) was administered to male Wistar rats intracerebroventricularly (i.c.v.) by stereotaxic apparatus to induce cognitive dysfunction. Administration of colchicine caused poor retention of memory in elevated plus maze, passive avoidance apparatus and Morris water maze paradigms. Chronic treatment with curcumin (100, 200 and 400 mg/kg, p.o.) twice daily and rivastigmine (2.5 mg/kg, p.o.) daily for a period of 28 days beginning 7 days prior to colchicine injection significantly improved colchicine-induced cognitive impairment. Biochemical assessment revealed that i.c.v. colchicine injection significantly increased lipid peroxidation, depleted reduced glutathione levels and decreased acetyl cholinesterase (AChE) activity in rat brains. Chronic administration of curcumin significantly reduced the elevated lipid peroxidation, restored the reduced glutathione levels and AChE activity; however, rivastigmine failed to prevent oxidative stress. The results of the current study indicate that curcumin (100, 200 and 400 mg/kg, p.o.) twice daily has a protective role against colchicine-induced cognitive impairment and associated oxidative stress.

Modulation of pentylenetetrazole-induced kindling and oxidative stress by curcumin in mice

Epilepsy is a chronic neurological disorder affecting 1% population worldwide. A number of experimental studies have reported anticonvulsant, neuroprotective and antioxidant activity of certain natural products like curcumin, an active ingredient of turmeric. The present study was designed to explore the effect of acute administration of curcumin at doses 50, 100 and 200 mg/kg, orally (p.o.) pentylenetetrazole-induced kindling in mice. Further two oxidative stress markers viz., malondialdehyde (MDA) and glutathione were estimated in brain tissues of rodents. Curcumin (50, 100 and 200 mg/kg, p.o.) dose dependently suppressed the progression of kindling in mice. In addition, the increased levels of MDA and glutathione were also reduced by curcumin in kindled animals. These results suggest that curcumin appears to possess protective activity against kindling in mice.

Protective effect of curcumin on immune system and body weight gain on rats intoxicated with 2,3,7,8-Tetrachlorodibenzo-p-dioxin (TCDD)

BACKGROUND AND AIM

In this study, the negative effects of 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD) on the immune system and body weight gain of rats and the preventive effects of curcumin were examined.

MATERIAL AND METHODS

For this purpose, 128 3-4-month-old Wistar albino rats with 280-310 g body weights were used. The 2 microg/kg dose of 2,3,7,8-TCDD and 100 mg/kg dose of curcumin were dissolved in corn oil and orally given to the rats found in the experimental and control groups. Then, the serum samples were taken from all rats at 15, 30, 45 and 60 days to analyzed for the determination of TNF-alpha, IFN-gamma, IL-12 and IL-13 levels by ELISA method. The data of body weight gain was measured at 15, 30, 45 and 60 days.

RESULTS

The results indicated that 2,3,7,8-TCDD caused a significant increase (p<0.05) in serum TNF-alpha level. However, it caused significant (p<0.05) decreases in the levels of IFN-gamma, IL-12 and IL-13 in rats. On the contrary, curcumin increased IFN-gamma, IL-12 and IL-13 levels, but decreased TNF-alpha level in rats. Additionally, TCDD caused significant (P<0.01) reductions in the body weight gain. However, curcumin reversed this effect of TCDD.

CONCLUSION

2,3,7,8-TCDD significantly suppressed the humoral immunity and body weight gain in rats at doses of 2 microg/kg. However curcumin, which was found in some plants, eliminated the effect of TCDD on immune system and body weight when it was given together with 2,3,7,8-TCDD. It is thought that this effect may have occurred via curcumin and TCDD binding aryl hydrocarbon receptor (AhR) competitively.

Curcumin suppresses p38 mitogen-activated protein kinase activation, reduces IL-1beta and matrix metalloproteinase-3 and enhances IL-10 in the mucosa of children and adults with inflammatory bowel disease

Inflammatory bowel disease (IBD) is a major source of morbidity in children and adults. Its incidence is rising, particularly in young people. IBD carries a lifelong risk of cancer, which is proportional to disease duration. Drug and surgical treatments rarely offer cure and often carry a high side effect burden. Dietary therapy is highly effective in Crohn's disease. For these reasons, there is much interest in developing novel dietary treatments in IBD. Curcumin, a component of the spice turmeric, and an anti-inflammatory and anti-cancer agent, shows preclinical and clinical potential in IBD. Its mechanisms of action are unknown. Our aim was to assess the effect of curcumin on key disease mediators p38 mitogen-activated protein kinase (MAPK), IL-1beta, IL-10 and matrix metalloproteinase-3 (MMP-3) in the gut of children and adults with IBD. Colonic mucosal biopsies and colonic myofibroblasts (CMF) from children and adults with active IBD were cultured ex vivo with curcumin. p38 MAPK, NF-kappaB and MMP-3 were measured by immunoblotting. IL-1beta and IL-10 were measured by ELISA. We show reduced p38 MAPK activation in curcumin-treated mucosal biopsies, enhanced IL-10 and reduced IL-1beta. We demonstrate dose-dependent suppression of MMP-3 in CMF with curcumin. We conclude that curcumin, a naturally occurring food substance with no known human toxicity, holds promise as a novel therapy in IBD.