Curcumin enhances the immunosuppressive activity of cyclosporine in rat cardiac allografts and in mixed lymphocyte reactions

Neuroprotective and anti-inflammatory effects of curcumin in Alzheimer's disease: Targeting neuroinflammation strategies

Alzheimer's disease (AD) is a progressive neurodegenerative disorder characterized by the accumulation of amyloid-beta plaques and neurofibrillary tangles, leading to neuronal loss. Curcumin, a polyphenolic compound derived from Curcuma longa, has shown potential neuroprotective effects due to its anti-inflammatory and antioxidant properties. This review aims to synthesize current preclinical data on the anti-neuroinflammatory mechanisms of curcumin in the context of AD, addressing its pharmacokinetics, bioavailability, and potential as a therapeutic adjunct. An exhaustive literature search was conducted, focusing on recent studies within the last 10 years related to curcumin's impact on neuroinflammation and its neuroprotective role in AD. The review methodology included sourcing articles from specialized databases using specific medical subject headings terms to ensure precision and relevance. Curcumin demonstrates significant neuroprotective properties by modulating neuroinflammatory pathways, scavenging reactive oxygen species, and inhibiting the production of pro-inflammatory cytokines. Despite its potential, challenges remain regarding its limited bioavailability and the scarcity of comprehensive human clinical trials. Curcumin emerges as a promising therapeutic adjunct in AD due to its multimodal neuroprotective benefits. However, further research is required to overcome challenges related to bioavailability and to establish effective dosing regimens in human subjects. Developing novel delivery systems and formulations may enhance curcumin's therapeutic potential in AD treatment.

Self Nano-Emulsifying Curcumin (SNEC30) attenuates arsenic-induced cell death in mice

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Sodium arsenite disrupts the histoarchitecture and cell morphology causing cell death in thymus and spleen of Swiss albino mice.

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Activation of apoptotic cell death occurred due to high level of ROS generation and increased promotion of autophagy upon arsenic insult.

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SNEC30 restored cellular architecture, reduced ROS generation and ameliorated autophagy-mediated cell death in the immune organs.

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This study clearly demonstrated anti-oxidative and anti-apoptotic properties of SNEC30 against NaAsO₂-induced in vivo immunotoxicity.

Several precedents have confirmed numerous infirmities caused by arsenic poisoning, including immune suppression and cancer. Exposure to arsenic leads to alterations of the cellular machinery and eventually cell death, depending on the dose and duration of exposure. Oxidative stress induced by arsenic is the major mechanism by which it inflicts cellular toxicity, challenging the survival-support - autophagy and culminating in apoptosis in the thymus and spleen of mice. Curcumin, a potent dietary anti-oxidant with known anti-apoptotic and anti-inflammatory properties, was assessed for therapeutic benefits. However, the major caveat of this polyphenol is its low water solubility and limited bioavailability. Therefore, Self Nano-Emulsifying Curcumin (SNEC30) was used to treat mice exposed to arsenic. When administered, SNEC30 effectively ameliorated the adverse effects of arsenic in mice, by restoring structural alterations and reducing ROS-mediated cell death, thereby endorsing the importance of nutraceuticals in counteracting heavy metal-induced cellular toxicity.

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.

Cellular and molecular mechanisms of curcumin in prevention and treatment of disease

Curcumin is a naturally occurring polyphenolic compound present in rhizome of Curcuma longa belonging to the family zingiberaceae. Growing experimental evidence revealed that curcumin exhibit multitarget biological implications signifying its crucial role in health and disease. The current review highlights the recent progress and mechanisms underlying the wide range of pharmacological effects of curcumin against numerous diseases like neuronal, cardiovascular, metabolic, kidney, endocrine, skin, respiratory, infectious, gastrointestinal diseases and cancer. The ability of curcumin to modulate the functions of multiple signal transductions are linked with attenuation of acute and chronic diseases. Numerous preclinical and clinical studies have revealed that curcumin modulates several molecules in cell signal transduction pathway including PI3K, Akt, mTOR, ERK5, AP-1, TGF-β, Wnt, β-catenin, Shh, PAK1, Rac1, STAT3, PPARγ, EBPα, NLRP3 inflammasome, p38MAPK, Nrf2, Notch-1, AMPK, TLR-4 and MyD-88. Curcumin has a potential to prevent and/or manage various diseases due to its anti-inflammatory, anti-oxidant and anti-apoptotic properties with an excellent safety profile. In contrast, the anti-cancer effects of curcumin are reflected due to induction of growth arrest and apoptosis in various premalignant and malignant cells. This review also carefully emphasized the pharmacokinetics of curcumin and its interaction with other drugs. Clinical studies have shown that curcumin is safe at the doses of 12 g/day but exhibits poor systemic bioavailability. The use of adjuvant like piperine, liposomal curcumin, curcumin nanoparticles and curcumin phospholipid complex has shown enhanced bioavailability and therapeutic potential. Further studies are warranted to prove the potential of curcumin against various ailments.

Drug-Herb Interactions in the Elderly Patient with IBD: a Growing Concern

OPINION STATEMENT

Inflammatory bowel disease (IBD), which includes conditions such as Crohn's disease and ulcerative colitis, is becoming more prevalent with the elderly being the fastest growing group. Parallel to this, there is an increasing interest in the use of complementary and alternative medicine (CAM). Nearly half of patients with IBD have used CAM at one time. The elderly patients, however, are burdened by comorbid conditions, polypharmacy, and altered functional status. With increasing use of complementary and alternative medicine in our elderly patients with IBD, it is vital for the provider to provide counsel on drug-herb potential interactions. CAM includes herbal products, diet, dietary supplements, acupuncture, and prayer. In this paper, we will review common CAM, specifically herbs, that are used in patients with IBD including the herb background, suggested use, evidence in IBD, and most importantly, potential interactions with IBD medications used in elderly patients. Most important evidence-based adverse events and drug-herb interactions are summarized. The herbs discussed include Triticum aestivum (wheat grass), Andrographis paniculata (chiretta), Boswellia serrata, tormentil, bilberry, curcumin (turmeric), Plantago ovata (blond psyllium), Oenothera biennis (evening primrose oil), germinated barley foodstuff, an herbal preparation of myrrh, chamomile and coffee extract, chios mastic gum, wormwood (absinthe, thujone), Cannabis sativa (marijuana, THC), tripterygium wilfordii (thunder god vine), Ulmus rubra (slippery elm bark), trigonella foenugraecum (fenugreek), Dioscorea mexicana (wild yam), Harpagophytum procumbens (devil's claw), ginger, cinnamon, licorice, and peppermint.

Curcumin as a potential protective compound against cardiac diseases

Curcumin, which was first used 3000 years ago as an anti-inflammatory agent, is a well-known bioactive compound derived from the active ingredient of turmeric (Curcuma longa). Previous research has demonstrated that curcumin has immense therapeutic potential in a variety of diseases via anti-oxidative, anti-apoptotic, and anti-inflammatory pathways. Cardiac diseases are the leading cause of mortality worldwide and cause considerable harm to human beings. Numerous studies have suggested that curcumin exerts a protective role in the human body whereas its actions in cardiac diseases remain elusive and poorly understood. On the basis of the current evidence, we first give a brief introduction of cardiac diseases and curcumin, especially regarding the effects of curcumin in embryonic heart development. Secondly, we analyze the basic roles of curcumin in pathways that are dysregulated in cardiac diseases, including oxidative stress, apoptosis, and inflammation. Thirdly, actions of curcumin in different cardiac diseases will be discussed, as will relevant clinical trials. Eventually, we would like to discuss the existing controversial opinions and provide a detailed analysis followed by the remaining obstacles, advancement, and further prospects of the clinical application of curcumin. The information compiled here may serve as a comprehensive reference of the protective effects of curcumin in the heart, which is significant to the further research and design of curcumin analogs as therapeutic options for cardiac diseases.

Enhanced colon cancer chemoprevention of curcumin by nanoencapsulation with whey protein

To improve bioavailability and enhance colon cancer prevention ability of curcumin, whey protein was used to nanoencapsulate at three different ratios such as 70:30, 50:50 and 35:65 for the first time. The drug loading, entrapment efficiency and structural changes of curcumin was confirmed by quantitative NMR spectroscopy. The nanoparticles prepared using the three ratios had an average diameters of 236.5±8.8, 212±3.4, and 187±11.4nm, as well as zeta (ζ) potentials of -13.1,-9.26, and -4.63mV, respectively, at pH 7.0. The cytotoxicity assay was performed for human colon and prostate cancer (SW480 and LNCap) by MTT assay and results showed significantly higher cytotoxicity of nanoencapsulated curcumin (NEC) (equivalent to 30.91, 20.70 and 16.86µM of NEC-1, 2 and 3 respectively), as compared to plain curcumin at 50µM after 72h of treatment. Cytotoxicity was also confirmed by microscopy of treated cells stained with acridine orange and propidium iodide. The cells treated with 50µM of curcumin, 30.91µM (NEC-1), 20.70µM (NEC-2) and 16.86µM (NEC-3) showed enhanced activation of p53 and elevated bax/Bcl2 expression (NEC-3), increased cytochrome-c in cytosol (NEC-2) confirming the enhanced cytotoxicity. To confirm the increased bioavailability, the intracellular curcumin was measured using fluorescence intensity. The fluorescent signal for intracellular curcumin was increased by 12, 30, and 21% for NEC-1, NEC-2, and NEC-3 respectively as compared to plain curcumin at 4h. Based on these results, we conclude that nanoencapsulated curcumin with whey protein will have potential to be considered for clinical applications for future studies.

Preparation and enhancement of oral bioavailability of curcumin using microemulsions vehicle

A new microemulsions system of curcumin (CUR-MEs) was successfully developed to improve the solubility and bioavailability of curcumin. Several formulations of the microemulsions system were prepared and evaluated using different ratios of oils, surfactants, and co-surfactants (S&CoS). The optimal formulation, which consists of Capryol 90 (oil), Cremophor RH40 (surfactant), and Transcutol P aqueous solution (co-surfactant), could enhance the solubility of curcumin up to 32.5 mg/mL. The pharmacokinetic study of microemulsions was performed in rats compared to the corresponding suspension. The stability of microemulsions after dilution was excellence. Microemulsions have significantly increased the C(max) and area under the curve (AUC) in comparison to that in suspension (p < 0.05). The relative bioavailability of curcumin in microemulsions was 22.6-fold higher than that in suspension. The results indicated that the CUR-MEs could be used as an effective formulation for enhancing the oral bioavailability of curcumin.

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.

An in vitro study of liposomal curcumin: stability, toxicity and biological activity in human lymphocytes and Epstein-Barr virus-transformed human B-cells

Curcumin is a multi-functional and pharmacologically safe natural agent. Used as a food additive for centuries, it also has anti-inflammatory, anti-virus and anti-tumor properties. We previously found that it is a potent inhibitor of cyclosporin A (CsA)-resistant T-cell co-stimulation pathway. It inhibits mitogen-stimulated lymphocyte proliferation, NFkappaB activation and IL-2 signaling. In spite of its safety and efficacy, the in vivo bioavailability of curcumin is poor, and this may be a major obstacle to its utility as a therapeutic agent. Liposomes are known to be excellent carriers for drug delivery. In this in vitro study, we report the effects of different liposome formulations on curcumin stability in phosphate buffered saline (PBS), human blood, plasma and culture medium RPMI-1640+10% FBS (pH 7.4, 37 degrees C). Liposomal curcumin had higher stability than free curcumin in PBS. Liposomal and free curcumin had similar stability in human blood, plasma and RPMI-1640+10% FBS. We looked at the toxicity of non-drug-containing liposomes on (3)H-thymidine incorporation by concanavalin A (Con A)-stimulated human lymphocytes, splenocytes and Epstein-Barr virus (EBV)-transformed human B-cell lymphoblastoid cell line (LCL). We found that dimyristoylphosphatidylcholine (DMPC) and dimyristoylphosphatidylglycerol (DMPG) were toxic to the tested cells. However, addition of cholesterol to the lipids at DMPC:DMPG:cholesterol=7:1:8 (molar ratio) almost completely eliminated the lipid toxicity to these cells. Liposomal curcumin had similar or even stronger inhibitory effects on Con A-stimulated human lymphocyte, splenocyte and LCL proliferation. We conclude that liposomal curcumin may be useful for intravenous administration to improve the bioavailability and efficacy, facilitating in vivo studies that could ultimately lead to clinical application of curcumin.

Curcumin: preventive and therapeutic properties in laboratory studies and clinical trials

Curcumin is a natural polyphenol used in ancient Asian medicine. Since the first article referring to the use of curcumin to treat human disease was published in The Lancet in 1937, >2,600 research studies using curcumin or turmeric have been published in English language journals. The mechanisms implicated in the inhibition of tumorigenesis by curcumin are diverse and appear to involve a combination of antiinflammatory, antioxidant, immunomodulatory, proapoptotic, and antiangiogenic properties via pleiotropic effects on genes and cell-signaling pathways at multiple levels. The potentially adverse sequelae of curcumin's effects on proapoptotic genes, particularly p53, represent a cause for current debate. When curcumin is combined with some cytotoxic drugs or certain other diet-derived polyphenols, synergistic effects have been demonstrated. Although curcumin's low systemic bioavailability after oral dosing may limit access of sufficient concentrations for pharmacologic effects in tissues outside the gastrointestinal tract, chemical analogues and novel delivery methods are in preclinical development to overcome this barrier. This article provides an overview of the extensive published literature on the use of curcumin as a therapy for malignant and inflammatory diseases and its potential use in the treatment of degenerative neurologic diseases, cystic fibrosis, and cardiovascular diseases. Despite the breadth of the coverage, particular emphasis is placed on the prevention and treatment of human cancers.

CURCUMIN: THE INDIAN SOLID GOLD

Turmeric, derived from the plant Curcuma longa, is a gold-colored spice commonly used in the Indian subcontinent, not only for health care but also for the preservation of food and as a yellow dye for textiles. Curcumin, which gives the yellow color to turmeric, was first isolated almost two centuries ago, and its structure as diferuloylmethane was determined in 1910. Since the time of Ayurveda (1900 Bc) numerous therapeutic activities have been assigned to turmeric for a wide variety of diseases and conditions, including those of the skin, pulmonary, and gastrointestinal systems, aches, pains, wounds, sprains, and liver disorders. Extensive research within the last half century has proven that most of these activities, once associated with turmeric, are due to curcumin. Curcumin has been shown to exhibit antioxidant, anti-inflammatory, antiviral, antibacterial, antifungal, and anticancer activities and thus has a potential against various malignant diseases, diabetes, allergies, arthritis, Alzheimer's disease, and other chronic illnesses. These effects are mediated through the regulation of various transcription factors, growth factors, inflammatory cytokines, protein kinases, and other enzymes. Curcumin exhibits activities similar to recently discovered tumor necrosis factor blockers (e.g., HUMIRA, REMICADE, and ENBREL), a vascular endothelial cell growth factor blocker (e.g., AVASTIN), human epidermal growth factor receptor blockers (e.g., ERBITUX, ERLOTINIB, and GEFTINIB), and a HER2 blocker (e.g., HERCEPTIN). Considering the recent scientific bandwagon that multitargeted therapy is better than monotargeted therapy for most diseases, curcumin can be considered an ideal "Spice for Life".

Immunomodulation by curcumin

Turmeric, the bright yellow spice extracted from the tuberous rhizome of the plant Curcuma longa, has been used in traditional Indian and Chinese systems of medicine for centuries to treat a variety of ailments, including jaundice and hepatic disorders, rheumatism, anorexia, diabetic wounds, and menstrual difficulties. Most of the medicinal effects of turmeric have been attributed to curcumin, the principal curcumanoid found in turmeric. Recent evidence that curcumin exhibits strong anti-inflammatory and antioxidant activities and modulates the expression of transcription factors, cell cycle proteins, and signal transducing kinases has prompted the mechanism-based studies on the potential of curcumin to primarily prevent and treat cancer and inflammatory diseases. Little work has been done to study the effect of curcumin on the development of immune responses. This review discusses current knowledge on the immunomodulatory effects of curcumin on various facets of the immune response, including its effect on lymphoid cell populations, antigen presentation, humoral and cell-mediated immunity, and cytokine production.

Studies on curcumin and curcuminoids

A series of curcuminoids, including curcumin, were studied with the main focus on their solubility, phase-distribution, hydrolytic stability and photochemical stability in cyclodextrin (CD) solutions. Their radical scavenging properties were also briefly studied. All the investigated derivatives were more stable towards hydrolytic degradation in CD solutions than curcumin, and the general order of the stabilising effect was HPbetaCD>MbetaCD>>HPgammaCD. In contrast, the photochemical studies showed that curcumin is generally more stable than its derivatives. Solubility and phase-distribution studies showed that curcuminoids with side groups on the phenyl moiety have higher affinity for the HPgammaCD than for the betaCDs and that the relative affinity of the larger HPgammaCD cavity increases with the curcuminoid molecule size. The radical scavenging studies showed that curcumin is more active than the derivatives investigated and that the free phenolic hydroxyl group may be essential for the scavenging properties. This study also indicates that the two halves of the symmetric curcumin molecule act as two separate units and scavenge one radical each.

Preventive and therapeutic effects of NF-kappaB inhibitor curcumin in rats colitis induced by trinitrobenzene sulfonic acid

AIM: To ascertain the molecule mechanism of nuclear factor-κB (NF-κB) inhibitor curcumin preventive and therapeutic effects in rats’ colitis induced by trinitrobenzene sulfonic acid (TNBS).

METHODS: Sixty rats with TNBS-induced colitis were treated with 2.0% curcumin in the diet. Thirty positive control rats were treated with 0.5% sulfasalazine (SASP). Thirty negative control rats and thirty model rats were treated with general diet. Changes of body weight together with histological scores were evaluated. Survival rates were also evaluated. Cell nuclear NF-κB activity in colonic mucosa was evaluated by using electrophoretic mobility shift assay. Cytoplasmic IκB protein in colonic mucosa was detected by using Western Blot analysis. Cytokine messenger expression in colonic tissue was assessed by using semiquantitative reverse-transcription polymerase chain reaction.

RESULTS: Treatment with curcumin could prevent and treat both wasting and histopathologic signs of rats with TNBS-induced intestinal inflammation. In accordance with these findings, NF-κB activation in colonic mucosa was suppressed in the curcumin-treated groups. Degradations of cytoplasmic IκB protein in colonic mucosa were blocked by curcumin treatment. Proinflammatory cytokine messenger RNA expression in colonic mucosa was also suppressed.

CONCLUSION: This study shows that NF-κB inhibitor curcumin could prevent and improve experimental colitis in murine model with inflammatory bowel disease (IBD). The findings suggest that NF-κB inhibitor curcumin could be a potential target for the patients with IBD.

Curcumin inhibits mitogen stimulated lymphocyte proliferation, NFκB activation, and IL-2 signaling

BACKGROUND

T cell mediated acute rejection of transplanted organ continues to be a noticeable problem in solid organ transplantation. We showed that Curcumin is a potent inhibitor of Cyclosporin A resistant T cell CD28 co-stimulation pathway. Here we report the inhibitory effects of Curcumin on mitogen-stimulated lymphocyte proliferation, IL-2 synthesis/signaling, and NFkappaB (transcription factor of IL-2 promoter) activation.

MATERIALS AND METHODS

Human lymphocytes were isolated from fresh human spleen (SP-L). Mitogens [final concentrations of 2 microg/ml concanavalin A (Con A), 5 microg/ml phytohemagglutinin (PHA), and 20 ng/ml of phorbol-12-myristate-13-acetate (PMA)] were added to the designated wells in a 96-well plate with 0.2 million SP-L and cultured for 48 h and then assayed for IL-2 synthesis by ELISA and 3H-thymidine uptake. In another parallel experiment we added IL-2 (0.5 nM) to stimulate the cells to check if Curcumin's inhibition of IL-2 synthesis is the sole reason for inhibition of cell proliferation. Electrophoretic mobility shift assay (EMSA) was performed in PMA (20 ng/ml, 1 h) stimulated cells with or without Curcumin to assay NFkappaB activation.

RESULTS

Curcumin at 2.5 microg/ml inhibited Con A, PHA, and PMA stimulated SP-L proliferation at 77, 23, and 48%, respectively, over controls and Curcumin at 5 microg/ml completely (nearly 100%) inhibited the mitogen stimulated proliferation. Curcumin inhibited IL-2 synthesis in Con A, PHA, and PMA stimulated SP-L in a concentration-dependent manner with an ED50 (concentration required for 50% inhibition) measured at 3.5 microg/ml. Exogenous IL-2 stimulated SP-L proliferation was also inhibited by Curcumin in a concentration-dependent manner with an ED50 of 2 microg/ml. EMSA assay indicated that PMA at 20 ng/ml stimulated NFkappaB activation 253% over control, which was inhibited by 24, 38, and 73%, respectively, with Curcumin at final concentrations of 2.5, 5, and 10 microg/ml, respectively.

CONCLUSION

Curcumin has profound immunosuppressive effects mediated via inhibition of IL-2 synthesis, mitogen, and IL-2 induced activation of human lymphocytes. This effect may be mediated via NFkappaB inhibition.