Curcumin: Getting Back to the Roots

The Protective Effects of Curcumin on Obesity-Related Glomerulopathy Are Associated with Inhibition of Wnt/β-Catenin Signaling Activation in Podocytes

The present study investigated the effects of curcumin, one of the most important active ingredients of turmeric, on podocyte injury in vitro and obesity-related glomerulopathy (ORG) in vivo. Cellular experiments in vitro showed that curcumin significantly antagonized leptin-induced downregulation of the mRNA and protein expression of podocyte-associated molecules including nephrin, podocin, podoplanin, and podocalyxin. Animal experiments in vivo showed that curcumin significantly reduced the body weight, Lee's index, abdominal fat index, urinary protein excretion, and average glomerular diameter and significantly upregulated the mRNA and protein expressions of the above podocyte-associated molecules in ORG mice. Furthermore, the experiments in vitro and in vivo both displayed that curcumin could downregulate the mRNA and protein expressions of Wnt1, Wnt2b, Wnt6, and β-catenin and upregulate the phosphorylation level of β-catenin protein in podocytes and renal tissue. In conclusion, curcumin is able to alleviate the harmful reaction of leptin on podocytes and reduce the severity of ORG. The above protective effects are associated with the inhibition of Wnt/β-catenin signaling activation in podocytes.

Curcumin induces brown fat-like phenotype in 3T3-L1 and primary white adipocytes

Recent advances have been made in the understanding of pharmacological and dietary agents that contribute to browning of white adipose tissue in order to combat obesity by promoting energy expenditure. Here, we show that curcumin induces browning of 3T3-L1 and primary white adipocytes via enhanced expression of brown fat-specific genes. Curcumin-induced browning in white adipocytes was investigated by determining expression levels of brown adipocyte-specific genes/proteins by real-time reverse transcriptase polymerase chain reaction, immunoblot analysis and immunocytochemical staining. Curcumin increased mitochondrial biogenesis, as evidenced by transmission electronic microscopic detection and enhanced expression of proteins involved in fat oxidation. Cucurmin also increased protein levels of hormone-sensitive lipase and p-acyl-CoA carboxylase, suggesting its possible role in augmentation of lipolysis and suppression of lipogenesis. Increased expression of UCP1 and other brown adipocyte-specific markers was possibly mediated by curcumin-induced activation of AMP-activated protein kinase (AMPK) based on the fact that inhibition of AMPK by dorsomorphin abolished expression of PRDM16, UCP1 and peroxisome proliferator-activated receptor gamma co-activator 1-alpha while the activator 5-Aminoimidazole-4-carboxamide ribonucleotide elevated expression of these brown marker proteins. Our findings suggest that curcumin plays a dual modulatory role in inhibition of adipogenesis as well as induction of the brown fat-like phenotype and thus may have potential therapeutic implications for treatment of obesity.

Role of phytochemicals in colorectal cancer prevention

Although the incidence of colorectal cancer (CRC) has been declining in recent decades, it remains a major public health issue as a leading cause of cancer mortality and morbidity worldwide. Prevention is one milestone for this disease. Extensive study has demonstrated that a diet containing fruits, vegetables, and spices has the potential to prevent CRC. The specific constituents in the dietary foods which are responsible for preventing CRC and the possible mechanisms have also been investigated extensively. Various phytochemicals have been identified in fruits, vegetables, and spices which exhibit chemopreventive potential. In this review article, chemopreventive effects of phytochemicals including curcumin, polysaccharides (apple polysaccharides and mushroom glucans), saponins (Paris saponins, ginsenosides and soy saponins), resveratrol, and quercetin on CRC and the mechanisms are discussed. This review proposes the need for more clinical evidence for the effects of phytochemicals against CRC in large trials. The conclusion of the review is that these phytochemicals might be therapeutic candidates in the campaign against CRC.

Codelivery of SH-aspirin and curcumin by mPEG-PLGA nanoparticles enhanced antitumor activity by inducing mitochondrial apoptosis

Natural product curcumin (Cur) and H₂S-releasing prodrug SH-aspirin (SH-ASA) are potential anticancer agents with diverse mechanisms, but their clinical application prospects are restricted by hydrophobicity and limited efficiency. In this work, we coencapsulated SH-ASA and Cur into methoxy poly(ethylene glycol)-poly (lactide-coglycolide) (mPEG-PLGA) nanoparticles through a modified oil-in-water single-emulsion solvent evaporation process. The prepared SH-ASA/Cur-coloaded mPEG-PLGA nanoparticles had a mean particle size of 122.3±6.8 nm and were monodispersed (polydispersity index =0.179±0.016) in water, with high drug-loading capacity and stability. Intriguingly, by treating with SH-ASA/Cur-coloaded mPEG-PLGA nanoparticles, obvious synergistic anticancer effects on ES-2 and SKOV3 human ovarian carcinoma cells were observed in vitro, and activation of the mitochondrial apoptosis pathway was indicated. Our results demonstrated that SH-ASA/Cur-coloaded mPEG-PLGA nanoparticles could have potential clinical advantages for the treatment of ovarian cancer.

Dietary phytochemicals alter epigenetic events and signaling pathways for inhibition of metastasis cascade: phytoblockers of metastasis cascade

Cancer metastasis is a multistep process in which a cancer cell spreads from the site of the primary lesion, passes through the circulatory system, and establishes a secondary tumor at a new nonadjacent organ or part. Inhibition of cancer progression by dietary phytochemicals (DPs) offers significant promise for reducing the incidence and mortality of cancer. Consumption of DPs in the diet has been linked to a decrease in the rate of metastatic cancer in a number of preclinical animal models and human epidemiological studies. DPs have been reported to modulate the numerous biological events including epigenetic events (noncoding micro-RNAs, histone modification, and DNA methylation) and multiple signaling transduction pathways (Wnt/β-catenin, Notch, Sonic hedgehog, COX-2, EGFR, MAPK-ERK, JAK-STAT, Akt/PI3K/mTOR, NF-κB, AP-1, etc.), which can play a key role in regulation of metastasis cascade. Extensive studies have also been performed to determine the molecular mechanisms underlying antimetastatic activity of DPs, with results indicating that these DPs have significant inhibitory activity at nearly every step of the metastatic cascade. DPs have anticancer effects by inducing apoptosis and by inhibiting cell growth, migration, invasion, and angiogenesis. Growing evidence has also shown that these natural agents potentiate the efficacy of chemotherapy and radiotherapy through the regulation of multiple signaling pathways. In this review, we discuss the variety of molecular mechanisms by which DPs regulate metastatic cascade and highlight the potentials of these DPs as promising therapeutic inhibitors of cancer.

Oral administration of curcumin (Curcuma longa) can attenuate the neutrophil inflammatory response in zymosan-induced arthritis in rats

PURPOSE

To evaluate the effect of curcumin in the acute phase of zymosan-induced arthritis.

METHODS

Twenty-eight male rats were subjected to intra-articular infiltration of zymosan of both knees and, in four the infiltration was made with saline. The animals were divided into five groups second received every six hours by gavage: corn oil by (positive and negative control); curcumin (100 mg/kg); prednisone 1 mg/kg/day; prednisone 8 mg/kg. All animals were sacrificed after six, 12, 24 and 48 hours of the infiltration. The knees were removed for evaluation of neutrophil infiltration. The number of neutrophils was counted by computer-assisted analysis of the images. The neutrophil infiltrate was stratified into four grades: 0 = normal; + = mild; ++/+++ = moderate; > ++++ = severe. The results were compared using the Mann-Whitney test and the variance by Kruskal-Wallis test adopting a significance level of 5% (p<0.05).

RESULTS

Curcumin reduces inflammatory activity in the first six hours after zymosan-induced arthritis when compared to saline (p<0.01). This was also observed in animals subjected to administration of prednisone (1 mg/kg) and those treated with prednisone (8 mg/kg). Curcumin was more effective than lower doses of prednisone in the first six hours after induction of the arthritis. After 12, 24 and 48 hours, curcumin does not have the same anti-inflammatory effects when compared to prednisone. After 48 hours, prednisone is more effective than curcumin in reducing the inflammatory infiltrate regardless of the dose of prednisone used.

CONCLUSION

Oral administration of curcumin reduces inflammation in the first six hours after experimentally zymosan-induced arthritis.

Inhibition of PI3K signaling triggered apoptotic potential of curcumin which is hindered by Bcl-2 through activation of autophagy in MCF-7 cells

Curcumin is a natural anti-cancer agent derived from turmeric (Curcuma longa). Curcumin triggers intrinsic apoptotic cell death by activating mitochondrial permeabilization due to the altered expression of pro- and anti-apoptotic Bcl-2 family members. Phosphoinositol-3-kinase (PI3K) and Akt, key molecular players in the survival mechanism, have been shown to be associated with the Bcl-2 signaling cascade; therefore, evaluating the therapeutic efficiency of drugs that target both survival and the apoptosis mechanism has gained importance in cancer therapy. We found that Bcl-2 overexpression is a limiting factor for curcumin-induced apoptosis in highly metastatic MCF-7 breast cancer cells. Forced overexpression of Bcl-2 also blocked curcumin-induced autophagy in MCF-7 cells, through its inhibitory interactions with Beclin-1. Pre-treatment of PI3K inhibitor LY294002 enhanced curcumin-induced cell death, apoptosis, and autophagy via modulating the expression of Bcl-2 family members and autophagosome formation in MCF-7 breast cancer cells. Atg7 silencing further increased apoptotic potential of curcumin in the presence or absence of LY294002 in wt and Bcl-2+ MCF-7 cells. The findings of this study support the hypothesis that blocking the PI3K/Akt pathway may further increased curcumin-induced apoptosis and overcome forced Bcl-2 expression level mediated autophagic responses against curcumin treatment in MCF-7 cells.

Efficacy of Turmeric as Adjuvant Therapy in Type 2 Diabetic Patients

It is known that there is a significant interplay of insulin resistance, oxidative stress, dyslipidemia, and inflammation in type 2 diabetes mellitus (T2DM). The study was undertaken to investigate the effect of turmeric as an adjuvant to anti-diabetic therapy. Sixty diabetic subjects on metformin therapy were recruited and randomized into two groups (30 each). Group I received standard metformin treatment while group II was on standard metformin therapy with turmeric (2 g) supplements for 4 weeks. The biochemical parameters were assessed at the time of recruitment for study and after 4 weeks of treatment. Turmeric supplementation in metformin treated type 2 diabetic patient significantly decreased fasting glucose (95 ± 11.4 mg/dl, P < 0.001) and HbA1c levels (7.4 ± 0.9 %, P < 0.05). Turmeric administered group showed reduction in lipid peroxidation, MDA (0.51 ± 0.11 µmol/l, P < 0.05) and enhanced total antioxidant status (511 ± 70 µmol/l, P < 0.05). Turmeric also exhibited beneficial effects on dyslipidemia LDL cholesterol (113.2 ± 15.3 mg/dl, P < 0.01), non HDL cholesterol (138.3 ± 12.1 mg/dl, P < 0.05) and LDL/HDL ratio (3.01 ± 0.61, P < 0.01) and reduced inflammatory marker, hsCRP (3.4 ± 2.0 mg/dl, P < 0.05). Turmeric supplementation as an adjuvant to T2DM on metformin treatment had a beneficial effect on blood glucose, oxidative stress and inflammation.

Anti-proliferative effect and induction of apoptosis in androgen-independent human prostate cancer cells by 1,5-bis(2-hydroxyphenyl)-1,4-pentadiene-3-one

Curcumin has poor in vivo absorption and bioavailability, highlighting a need for new curcumin analogues with better characteristics in these aspects. The aim of this study is to determine the anti-cancer properties of four selected curcumin analogues, on the cytotoxicity, proliferative and apoptotic effects on androgen-independent human prostate cancer cells (PC-3 and DU 145). Initial cytotoxicity screening showed MS17 has the highest cell inhibitory effect, with EC50 values of 4.4 ± 0.3 and 4.1 ± 0.8 µM, followed by MS13 (7.5 ± 0.1 and 7.4 ± 2.6 µM), MS49 (14.5 ± 1.2 and 12.3 ± 2.3 µM) and MS40E (28.0 ± 7.8 and 30.3 ± 1.9 µM) for PC-3 and DU 145 cells, respectively. Time-dependent analysis also revealed that MS13 and MS17 displayed a greater anti-proliferative effect than the other compounds. MS17 was chosen based on the high selectivity index value for further analysis on the morphological and biochemical hallmarks of apoptosis. Fluorescence microscopy analysis revealed apoptotic changes in both treated prostate cancer cells. Relative caspase-3 activity increased significantly at 48 h in PC-3 and 12 h in DU 145 cells. Highest enrichment of free nucleosomes was noted at 48 h after treatment with MS17. In conclusion, MS17 demonstrated anti-proliferative effect and induces apoptosis in a time and dose-dependent manner suggesting its potential for development as an anti-cancer agent for androgen-independent prostate cancer.

Curcumin entrapped folic acid conjugated PLGA–PEG nanoparticles exhibit enhanced anticancer activity by site specific delivery

Herein we report curcumin entrapped nanoparticles of PLGA–PEG copolymer which were conjugated with folic acid (PPF copolymer) for site specific targeting since many cancer cells exhibit external folic acid binding receptors.

Synergistic Effect of Curcumin in Combination with Anticancer Agents in Human Retinoblastoma Cancer Cell Lines

PURPOSE

Curcumin (diferuloylmethane), a phenolic compound obtained from the rhizome of the herb Curcuma longa, is known to have anti-proliferative and anti-tumor properties. In this study, we evaluated the cytotoxic effect of curcumin alone and in combination with individual drugs like carboplatin, etoposide, or vincristine in a human retinoblastoma (RB) cancer cell line.

MATERIALS AND METHODS

A drug-drug interaction was analyzed using the median effect/isobologram method and combination index values were used to characterize the interaction as synergistic or additive. We also performed the apoptosis and cell-cycle kinetics study with single drugs in combination with curcumin in a human RB cell lines (Y79 and Weri-Rb1).

RESULTS

Curcumin caused concentration-dependent decrease in cell proliferation, cell kinetics, and also induced apoptosis in both the RB cell lines. When combination of curcumin with individual drugs like carboplatin or etoposide or vincristine was treated on to RB cells, both cell viability and cell cycling were reduced and increased apoptosis was noted, in comparison with single drug treatment. These effects were significant in both the cell lines, indicating the ability of curcumin to increase the sensitivity of RB cells to chemotherapy drugs.

CONCLUSION

Our in vitro findings showed that the combination of curcumin with single drug treatment showed marked synergistic inhibitory effect against RB cell lines. These results suggest that curcumin can be used as a modulator which may have a potential therapeutic value for the treatment of RB cancer patients.

Anti-Inflammatory Effects of Novel Standardized Solid Lipid Curcumin Formulations

Inflammation and the presence of pro-inflammatory cytokines are associated with numerous chronic diseases such as type-2 diabetes mellitus, cardiovascular disease, Alzheimer's disease, and cancer. An overwhelming amount of data indicates that curcumin, a polyphenol obtained from the Indian spice turmeric, Curcuma longa, is a potential chemopreventive agent for treating certain cancers and other chronic inflammatory diseases. However, the low bioavailability of curcumin, partly due to its low solubility and stability in the digestive tract, limits its therapeutic applications. Recent studies have demonstrated increased bioavailability and health-promoting effects of a novel solid lipid particle formulation of curcumin (Curcumin SLCP, Longvida(®)). The goal of this study was to evaluate the aqueous solubility and in vitro anti-inflammatory effects of solid lipid curcumin particle (SLCP) formulations using lipopolysaccharide (LPS)-stimulated RAW 264.7 cultured murine macrophages. SLCPs treatment significantly decreased nitric oxide (NO) and prostaglandin-E2 (PGE2) levels at concentrations ranging from 10 to 50 μg/mL, and reduced interleukin-6 (IL-6) levels in a concentration-dependent manner. Transient transfection experiments using a nuclear factor-kappa B (NF-κB) reporter construct indicate that SLCPs significantly inhibit the transcriptional activity of NF-κB in macrophages. Taken together, these results show that in RAW 264.7 murine macrophages, SLCPs have improved solubility over unformulated curcumin, and significantly decrease the LPS-induced pro-inflammatory mediators NO, PGE2, and IL-6 by inhibiting the activation of NF-κB.

NDS27 combines the effect of curcumin lysinate and hydroxypropyl-β-cyclodextrin to inhibit equine PKCδ and NADPH oxidase involved in the oxidative burst of neutrophils

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The antioxidant effects of curcumin lysinate complexed with two cyclodextrins were compared.

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NDS27 is complexed with hydroxypropyl-β- and NDS28 with γ-cyclodextrin.

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NDS27 but not NDS28 inhibits translocation and activity of PKCδ and NADPH oxidase.

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NDS27 but not NDS28 improved the release of curcumin lysinate and its exchange with membrane lipids.

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NDS27 is a good candidate molecule to inhibit ROS production by neutrophils.

Polymorphonuclear neutrophils (PMNs) are involved in host defence against infections by the production of reactive oxygen species (ROS), but excessive PMN stimulation is associated with the development of inflammatory diseases. After appropriate stimuli, protein kinase C (PKC) triggers the assembly of NADPH oxidase (Nox2) which produces superoxide anion (O₂^•−), from which ROS derive. The therapeutic use of polyphenols is proposed to lower ROS production by limiting Nox2 and PKC activities. The purpose of this study was to compare the antioxidant effect of NDS27 and NDS28, two water-soluble forms of curcumin lysinate respectively complexed with hydroxypropyl-β-cyclodextrin (HPβCD) and γ-cyclodextrin (γ-CD), on the activity of Nox2 and PKCδ, involved in the Nox2 activation pathway. Our results, showed that NDS27 is the best inhibitor for Nox2 and PKCδ. This was illustrated by the combined effect of HPβCD and curcumin lysinate: HPβCD, but not γ-CD, improved the release of curcumin lysinate and its exchange against lipid or cholesterol as demonstrated by the lipid colouration with Oil Red O, the extraction of radical lipophilic probes recorded by ESR and the HPLC measurements of curcumin. HPβCD not only solubilised and transported curcumin, but also indirectly enhanced its action on both PKC and Nox2 activities. The modulatory effect of NDS27 on the Nox2 activation pathway of neutrophils may open therapeutic perspectives for the control of pathologies with excessive inflammatory reactions.

Curcumin regulates peroxisome proliferator-activated receptor-γ coactivator-1α expression by AMPK pathway in hepatic stellate cells in vitro

Curcumin exerts an inhibitory effect on hepatic stellate cell (HSC) activation, a key step for liver fibrogenesis, and on liver fibrosis by up-regulation of peroxisome proliferator-activated receptor-γ (PPARγ) expression. PPARγ plays a crucial role in suppression of HSC activation. Peroxisome proliferator-activated receptor-γ coactivator-1α (PGC-1α) functions as a co-activator for PPARγ. Therefore, researches on the effect of curcumin on PGC-1α might contribute to understanding of the mechanisms underlying curcumin inhibition of HSC activation and liver fibrosis through PPARγ. The present study aimed to investigate the effect of curcumin on PGC-1α expression in HSCs in vitro and examine the underlying molecular mechanisms by western blot, reat-time PCR, and transfection. Our results showed that curcumin stimulation increased PGC-1α expression and the effects of curcumin on PGC-1α expression were correlated with the activation of adenosine monophosphate-activated protein kinase (AMPK). Curcumin increased superoxide dimutase-2 (SOD2) transcription and activity by AMPK/PGC-1α axis. Moreover, PGC-1α was demonstrated to inhibit α1(I) collagen (a marker for liver fibrosis) transcription in cultured HSCs. These results demonstrated the promotion effect of curcumin on PGC-1α expression through AMPK pathway, which led to the increases in PPARγ activity and in SOD-2 transcription and activity. These data might suggest a possible new explanation for the inhibitory effect of curcumin on HSC activation and on liver fibrogenesis.

Phytotherapy and psoriasis: Complementary and alternative medications

Psoriasis comprises severe skin problems affects on quality of patient’s life. It affects 2% of the general population with age before 35 years old. Most potent and cheap psoriatic drugs are still largely unavailable. Recently, as aresult of the apparent side effects of chemical drugs, treatments of herbal origin gains the popularity among patients with skin disorders especially those for psoriasis. In this review, the uses of complementary and alternative medications of various topical herbal formulae with different potency against psoriasis was greatly assessed. Modified Psoriasis scoring systems were performed as evident of improvement when various topical herbal formula including traditional chinese medicine ingredients such as Camptotheca acuminate, Oleum horwathiensis, Capsaicin, furocoumarins, Curcumin, and Tars were used against psoriasis. Also, plant extracts of Aleo Vera, and green tea were reported in topical form for the treatment of psoriasis. Most studies indicated a variety of biological activities of used herbs depending on their chemical constituents. This versatile range of biological activities explaining, the apparent benefits of these herbs in monitoring of psoriasis.

Curcumin improves the recovery of motor function and reduces spinal cord edema in a rat acute spinal cord injury model by inhibiting the JAK/STAT signaling pathway

Curcumin, a yellow pigment extracted from Carcuma longa, has been demonstrated to have extensive pharmacological activity in various studies, and it exhibits protective effects on injuries involving a number of human organs. The present study was designed to evaluate the potential effect and underlying mechanism of curcumin on the motor function and spinal cord edema in a rat acute spinal cord injury (SCI) model. The SCI model was induced by a heavy object falling. At 30min after the SCI was successfully induced, the animals were intraperitoneally given 40mg/kg curcumin. The Basso, Beattie and Bresnahan scores showed that curcumin moderately improved the recovery of the motor function in the injured rats, and hematoxylin-eosin staining demonstrated the role of this compound in reducing the hemorrhage, edema and neutrophil infiltration of the traumatic spinal cord. Furthermore, curcumin also inhibited the SCI-associated aquaporin - 4 (AQP4) overexpression and glial fibrillary acidic protein (GFAP) and repressed the unusual activation of the JAK/STAT signaling pathway. In conclusion, our data demonstrate that curcumin exhibits a moderately protective effect on spinal cord injury, and this effect might be related to the inhibition of overexpressed AQP4 and GFAP and the activated JAK/STAT signaling pathway. Curcumin may have potential for use as a therapeutic option for spinal cord injuries.

Anti-hyperglycemic and insulin sensitizer effects of turmeric and its principle constituent curcumin

CONTEXT

Turmeric is obtained from the plant Curcuma longa L; its major constituent, curcumin, is a polyphenol with multiple effects which can modulate some signaling pathways.

EVIDENCE ACQUISITION

Insulin resistance is a major risk factor for chronic diseases such as type 2 diabetes, atherosclerotic, metabolic syndrome and cardiovascular disease. In addition, Insulin resistance in peripheral tissue is one of the most important reasons of hyperglycemia which can cause global or systemic effects. The present study reviewed studies published in PubMed from 1998 to 2013, indicating the role of curcumin in attenuation of many pathophysiological processes involved in development and progression of hyperglycemia and insulin resistance.

RESULTS

Curcumin can reduce blood glucose level by reducing the hepatic glucose production, suppression of hyperglycemia-induced inflammatory state, stimulation of glucose uptake by up-regulation of GLUT4, GLUT2 and GLUT3 genes expressions, activation of AMP kinase, promoting the PPAR ligand-binding activity, stimulation of insulin secretion from pancreatic tissues, improvement in pancreatic cell function, and reduction of insulin resistance.

CONCLUSIONS

Curcumin has antihyperglycemic and insulin sensitizer effects. Thereby, more studies evaluating the effects of curcumin on hyperglycemic state and insulin resistance in related disorders such as diabetes are recommended.

Phytochemicals perturb membranes and promiscuously alter protein function

A wide variety of phytochemicals are consumed for their perceived health benefits. Many of these phytochemicals have been found to alter numerous cell functions, but the mechanisms underlying their biological activity tend to be poorly understood. Phenolic phytochemicals are particularly promiscuous modifiers of membrane protein function, suggesting that some of their actions may be due to a common, membrane bilayer-mediated mechanism. To test whether bilayer perturbation may underlie this diversity of actions, we examined five bioactive phenols reported to have medicinal value: capsaicin from chili peppers, curcumin from turmeric, EGCG from green tea, genistein from soybeans, and resveratrol from grapes. We find that each of these widely consumed phytochemicals alters lipid bilayer properties and the function of diverse membrane proteins. Molecular dynamics simulations show that these phytochemicals modify bilayer properties by localizing to the bilayer/solution interface. Bilayer-modifying propensity was verified using a gramicidin-based assay, and indiscriminate modulation of membrane protein function was demonstrated using four proteins: membrane-anchored metalloproteases, mechanosensitive ion channels, and voltage-dependent potassium and sodium channels. Each protein exhibited similar responses to multiple phytochemicals, consistent with a common, bilayer-mediated mechanism. Our results suggest that many effects of amphiphilic phytochemicals are due to cell membrane perturbations, rather than specific protein binding.

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.

Novel insights of dietary polyphenols and obesity

The prevalence of obesity has steadily increased over the past three decades both in the United States and worldwide. Recent studies have shown the role of dietary polyphenols in the prevention of obesity and obesity-related chronic diseases. Here, we evaluated the impact of commonly consumed polyphenols, including green tea catechins, especially epigallocatechin gallates, resveratrol and curcumin, on obesity and obesity-related inflammation. Cellular studies demonstrated that these dietary polyphenols reduce viability of adipocytes and proliferation of preadipocytes, suppress adipocyte differentiation and triglyceride accumulation, stimulate lipolysis and fatty acid β-oxidation, and reduce inflammation. Concomitantly, the polyphenols modulate signaling pathways including the adenosine-monophosphate-activated protein kinase, peroxisome proliferator activated receptor γ, CCAAT/enhancer binding protein α, peroxisome proliferator activator receptor gamma activator 1-alpha, sirtuin 1, sterol regulatory element binding protein-1c, uncoupling proteins 1 and 2, and nuclear factor-κB that regulate adipogenesis, antioxidant and anti-inflammatory responses. Animal studies strongly suggest that commonly consumed polyphenols described in this review have a pronounced effect on obesity as shown by lower body weight, fat mass and triglycerides through enhancing energy expenditure and fat utilization, and modulating glucose hemostasis. Limited human studies have been conducted in this area and are inconsistent about the antiobesity impact of dietary polyphenols probably due to the various study designs and lengths, variation among subjects (age, gender, ethnicity), chemical forms of the dietary polyphenols used and confounding factors such as other weight-reducing agents. Future randomized controlled trials are warranted to reconcile the discrepancies between preclinical efficacies and inconclusive clinic outcomes of these polyphenols.

Improving the anticancer activity of curcumin using nanocurcumin dispersion in water

Curcumin is a highly potent, nontoxic bioactive agent found in turmeric and is known to have significant anticancer properties against different types of cancer cells. The major disadvantage associated with the use of curcumin, however, is its low systemic bioavailability due to its poor aqueous solubility. The focus of the present study was to generate nanoparticles of curcumin with improved aqueous phase solubility, and to investigate their efficacy in treating cancer cells. Curcumin nanoparticles having particle size in the range 2-40 nm and aqueous solubility of up to a maximum of 3 mg/mL were prepared. Evaluation of anticancer properties of curcumin nanodispersion was carried out in 3 different cancer cell lines: lung (A549), liver (HepG2), and skin (A431). The results demonstrated that under aqueous conditions curcumin nanoparticles exhibited similar or a much stronger antiproliferative effect on the cancer cells compared to normal curcumin in DMSO. Our results lead way toward unharnessed potential of curcumin in the form of its nanoparticles as an adjuvant therapy for clinical application in treating various cancers.

Curcumin: a pleiotropic phytonutrient in diabetic complications

Curcumin is the major polyphenolic constituent of an indigenous herb, Curcuma longa, found to have a wide range of applications right from its kitchen use as a spicy ingredient to therapeutic and medicinal applications in various diseases. Curcumin has been identified to have a plethora of biologic and pharmacologic properties owing to its antioxidant and anti-inflammatory activities. This pleiotropic regulation of redox balance of cell and inflammation might be the basis of curcumin's beneficial activities in various pathologic conditions including diabetic complications. This review summarizes various in vitro, in vivo studies done on curcumin and its therapeutic utility in diabetic micro-vascular complications. This review also emphasizes the importance of curcumin in addition to the existing therapeutic modalities in diabetic complications.

Evaluation of the effect of curcumin capsules on glyburide therapy in patients with type-2 diabetes mellitus

This study aimed to assess the possible beneficial effects of curcumin capsules as lipid-lowering effects and as a permeability glycoprotein (P-gp) inhibitor on the pharmacokinetics and pharmacodynamics of glyburide and as a P-gp substrate with glyburide in patients with type-2 diabetes mellitus. Open-label, randomized control trial was carried out for 11 days on eight type-2 diabetic patients on glyburide therapy. On the first day of the study, following the administration of 5 mg of glyburide, blood samples were collected from the patients at various time intervals ranging from 0.5 to 24 h. Blood sampling was repeated on the 11th day of the study, after treating the patients with curcumin for ten consecutive days. Glyburide concentrations changed at the second hour, Cmax was unchanged, the glucose levels were decreased, Area Under first Movement Curre (AUMC) was increased, and no patient has experienced the hypoglycaemia. The low-density lipoprotein, very-low-density lipoprotein and triglycerides were decreased significantly, and the high-density lipoprotein content increased. The co-administration of curcumin capsules with glyburide may be beneficial to the patients in better glycaemic control. The lipid lowering and antidiabetic properties of the curcumin show as a potential future drug molecule.

Folic acid conjugated cross-linked acrylic polymer (FA-CLAP) hydrogel for site specific delivery of hydrophobic drugs to cancer cells

Background

The hydrogel based system is found to be rarely reported for the delivery of hydrophobic drug due to the incompatibility of hydrophilicity of the polymer network and the hydrophobicity of drug. This problem can be solved by preparing semi-interpenetrating network of cross-linked polymer for tuning the hydrophilicity so as to entrap the hydrophobic drugs. The current study is to develop a folic acid conjugated cross-linked pH sensitive, biocompatible polymeric hydrogel to achieve a site specific drug delivery. For that, we have synthesized a folic acid conjugated PEG cross-linked acrylic polymer (FA-CLAP) hydrogel and investigated its loading and release of curcumin. The formed polymer hydrogel was then conjugated with folic acid for the site specific delivery of curcumin to cancer cells and then further characterized and conducted the cell uptake and cytotoxicity studies on human cervical cancer cell lines (HeLa).

Results

In this study, we synthesized folic acid conjugated cross-linked acrylic hydrogel for the delivery of hydrophobic drugs to the cancer site. Poly (ethyleneglycol) (PEG) diacrylate cross-linked acrylic polymer (PAA) was prepared via inverse emulsion polymerization technique and later conjugated it with folic acid (FA-CLAP). Hydrophobic drug curcumin is entrapped into it and investigated the entrapment efficiency. Characterization of synthesized hydogel was done by using Fourier Transform-Infrared spectroscopy (FT-IR), Transmission Electron Microscopy (TEM), Differential Scanning Calorimetry (DSC). Polymerization and folate conjugation was confirmed by FT-IR spectroscopy. The release kinetics of drug from the entrapped form was studied which showed initial burst release followed by sustained release due to swelling and increased cross-linking. In vitro cytotoxicity and cell uptake studies were conducted in human cervical cancer (HeLa) cell lines.

Conclusions

Results showed that curcumin entrapped folate conjugated cross-linked acrylic polymer (FA-CLAP) hydrogel showed higher cellular uptake than the non folate conjugated form. So this can be suggested as a better delivery system for site specific release of hydrophobic cancer drugs.

The Attenuation of Pain Behavior and Serum COX-2 Concentration by Curcumin in a Rat Model of Neuropathic Pain

Background

Neuropathic pain is generally defined as a chronic pain state resulting from peripheral and/or central nerve injury. There is a lack of effective treatment for neuropathic pain, which may possibly be related to poor understanding of pathological mechanisms at the molecular level. Curcumin, a therapeutic herbal extract, has shown to be effectively capable of reducing chronic pain induced by peripheral administration of inflammatory agents such as formalin. In this study, we aimed to show the effect of curcumin on pain behavior and serum COX-2 level in a Chronic Constriction Injury (CCI) model of neuropathic pain.

Methods

Wistar male rats (150-200 g, n = 8) were divided into three groups: CCI vehicle-treated, sham-operated, and CCI drug-treated group. Curcumin (12.5, 25, 50 mg/kg, IP) was injected 24 h before surgery and continued daily for 7 days post-surgery. Behavioral tests were performed once before and following the days 1, 3, 5, 7 after surgery. The serum COX-2 level was measured on day 7 after the surgery.

Results

Curcumin (50 mg/kg) decreased mechanical and cold allodynia (P < 0.001) and produced a decline in serum COX-2 level (P < 0.001).

Conclusions

A considerable decline in pain behavior and serum COX-2 levels was seen in rat following administration of curcumin in CCI model of neuropathic pain. High concentration of Curcumin was able to reduce the chronic neuropathic pain induced by CCI model and the serum level of COX-2.

Comparative evaluation of the efficacy of two controlled release devices: Chlorhexidine chips and indigenous curcumin based collagen as local drug delivery systems

Aim:

To comparatively evaluate the therapeutic efficacy of chlorhexidine (CHX) chips (Periocol-CG) and indigenous curcumin (CU) based collagen as adjuncts to scaling and root planning in the nonsurgical management of chronic periodontitis.

Materials and Methods:

A total of 120 sites from 60 patients presenting with chronic periodontitis (age group 25-55 years) of both sexes, with pocket depth of ≥5 mm with radiographic evidence of bilateral bone loss were earmarked for the study. A split mouth design was employed, and all the clinical parameters-plaque index, gingival index, probing pocket depth (PPD) and clinical attachment levels (CAL) were recorded at baseline, 1 month, 3 months, and 6 months. However, the microbiological parameters, i.e., N-benzoyl-DL-arginine-β-naphthylamide (BANA) test and microbial colony count were recorded at baseline, 3 months and 6 months postoperatively.

Results:

Significant reduction in plaque and gingival index scores were observed in both groups at the end of the study period, i.e., 6 months. The microbiological parameters (BANA test, microbial colony count), PPD and CAL levels also showed significant improvement in both groups. However, at the end of the study period CHX group showed greater improvement in all of these parameters compared to CU collagen group.

Conclusion:

Future directions of this study should include targeting the beneficial effects of these local drug delivery systems at varied concentrations so that they could be utilized to achieve the maximum beneficial therapeutic effects in the nonsurgical treatment of periodontal disease.

Unraveling the mechanism of neuroprotection of curcumin in arsenic induced cholinergic dysfunctions in rats

Earlier, we found that arsenic induced cholinergic deficits in rat brain could be protected by curcumin. In continuation to this, the present study is focused to unravel the molecular mechanisms associated with the protective efficacy of curcumin in arsenic induced cholinergic deficits. Exposure to arsenic (20mg/kg body weight, p.o) for 28 days in rats resulted to decrease the expression of CHRM2 receptor gene associated with mitochondrial dysfunctions as evident by decrease in the mitochondrial membrane potential, activity of mitochondrial complexes and enhanced apoptosis both in the frontal cortex and hippocampus in comparison to controls. The ultrastructural images of arsenic exposed rats, assessed by transmission electron microscope, exhibited loss of myelin sheath and distorted cristae in the mitochondria both in the frontal cortex and hippocampus as compared to controls. Simultaneous treatment with arsenic (20mg/kg body weight, p.o) and curcumin (100mg/kg body weight, p.o) for 28 days in rats was found to protect arsenic induced changes in the mitochondrial membrane potential and activity of mitochondrial complexes both in frontal cortex and hippocampus. Alterations in the expression of pro- and anti-apoptotic proteins and ultrastructural damage in the frontal cortex and hippocampus following arsenic exposure were also protected in rats simultaneously treated with arsenic and curcumin. The data of the present study reveal that curcumin could protect arsenic induced cholinergic deficits by modulating the expression of pro- and anti-apoptotic proteins in the brain. More interestingly, arsenic induced functional and ultrastructural changes in the brain mitochondria were also protected by curcumin.

Chronic curcumin treatment normalizes depression-like behaviors in mice with mononeuropathy: involvement of supraspinal serotonergic system and GABAA receptor

RATIONALE

Comorbid depression is commonly observed in individuals who suffer from neuropathic pain, which necessitates improved treatment. Curcumin, a phenolic compound derived from Curcuma longa, possesses both antinociceptive and antidepressant-like activities in animal studies, suggesting its possible usefulness in treating this comorbidity.

OBJECTIVE

We investigated the effect of curcumin on depressive-like behaviors in mice with mononeuropathy, and explored the mechanism(s).

METHODS

Chronic constriction injury (CCI) was produced by loosely ligating the sciatic nerves in mice. The nociceptive behaviors were examined using Hargreaves test, and the depressive-like behaviors were determined by forced swim test (FST) and tail suspension test (TST).

RESULTS

After CCI injury, the neuropathic mice developed nociceptive and depressive-like behaviors, as shown by thermal hyperalgesia in Hargreaves test and protracted immobility time in FST and TST. Chronic treatment of neuropathic mice with curcumin (45 mg/kg, p.o., twice per day for 3 weeks) corrected their exacerbated nociceptive and depressive-like behaviors, which was abolished by chemical depletion of brain serotonin rather than noradrenaline. The paralleled antinociceptive and antidepressant-like actions of curcumin seem to be pharmacologically segregated, since intrathecal and intracerebroventricular injection of methysergide, a nonselective 5-HT receptor antagonist, separately counteracted the two actions of curcumin. Further, this antidepression was abrogated by repeated co-treatment with 5-HT1A receptor antagonist WAY-100635 and greatly attenuated by acute co-treatment with GABAA receptor antagonist bicuculline.

CONCLUSION

Curcumin can normalize the depressive-like behaviors of neuropathic mice, which may be independent of the concurrent analgesic action and possibly mediated via the supraspinal serotonergic system and downstream GABAA receptor.

Swietenia macrophylla King induces mitochondrial-mediated apoptosis through p53 upregulation in HCT116 colorectal carcinoma cells

ETHNOPHARMACOLOGICAL RELEVANCE

Swietenia macrophylla King is a traditional herb used to treat various diseases including hypertension, diabetes and cancer. Previous study demonstrated its anti-tumor effect but the potential mechanisms have not been clearly defined. The current study was to further investigate the underlying mechanism of ethyl acetate fraction of Swietenia macrophylla (SMEAF)-induced anti-proliferative effect and apoptosis in HCT116 colorectal carcinoma cell.

MATERIALS AND METHODS

Cell viability was evaluated in HCT116 cells by trypan blue exclusion assay. Apoptotic cell death was detected by Hoechst 33342/propidium iodide (PI) staining and intracellular reactive oxygen species (ROS) was analyzed by flow cytometry. The apoptotic gene and protein expression were determined by Real-time quantitative PCR (q-PCR) and immunofluorescence staining using flow cytometry, respectively.

RESULTS

SMEAF significantly inhibited HCT116 cell viability and induced apoptosis in a dose-dependent manner. SMEAF-induced apoptosis was triggered by the activation of p53 and intracellular reactive oxygen species (ROS) production. Moreover, the significant increase in p53 was accompanied by a decrease murine double minute 2 (MDM2) expression. SMEAF significantly increased the expression of the Bax protein resulting in a markedly elevated Bax/Bcl-2 ratio which may have triggered the mitochondrial apoptotic pathway, resulting in caspase-3/7 and caspase-9 activation.

CONCLUSION

These results suggested that SMEAF exerts its antitumor activity in HCT116 cells by activating proapoptotic signaling pathway through intracellular ROS formation triggering the mitochondrial-mediated pathway via p53 activation.

Dietary plant extracts modulate gene expression profiles in ileal mucosa of weaned pigs after an Escherichia coli infection

This study was conducted to characterize the effects of infection with a pathogenic F-18 Escherichia coli and 3 different plant extracts on gene expression of ileal mucosa in weaned pigs. Weaned pigs (total = 64, 6.3 ± 0.2 kg BW, and 21-d old) were housed in individual pens for 15 d, 4 d before and 11 d after the first inoculation (d 0). Treatments were in a 2 × 4 factorial arrangement: with or without an F-18 E. coli challenge and 4 diets (a nursery basal, control diet [CON], 10 ppm of capsicum oleoresin [CAP], garlic botanical [GAR], or turmeric oleoresin [TUR]). Results reported elsewhere showed that the plant extracts reduced diarrhea in challenged pigs. Total RNA (4 pigs/treatment) was extracted from ileal mucosa of pigs at d 5 post inoculation. Double-stranded cDNA was amplified, labeled, and further hybridized to the microarray, and data were analyzed in R. Differential gene expression was tested by fitting a mixed linear model in a 2 × 4 factorial ANOVA. Bioinformatics analysis was conducted by DAVID Bioinformatics Resources 6.7 (DAVID; National Institute of Allergy and Infectious Diseases [NIAID, NIH], http://david.abcc.ncifcrf.gov). The E. coli infection altered (P < 0.05) the expression of 240 genes in pigs fed the CON (148 up- and 92 down-regulated). Compared with the infected CON, feeding CAP, GAR, or TUR altered (P < 0.05) the expression of 52 genes (18 up, 34 down), 117 genes (34 up- and 83 down-regulated), or 84 genes (16 up- and 68 down-regulated), respectively, often counteracting the effects of E. coli. The E. coli infection up-regulated (P < 0.05) the expression of genes related to the activation of immune response and complement and coagulation cascades, but down-regulated (P < 0.05) the expression of genes involved in protein synthesis and accumulation. Compared with the CON, feeding CAP and GAR increased (P < 0.05) the expression of genes related to integrity of membranes in infected pigs, indicating enhanced gut mucosa health. Moreover, feeding all 3 plant extracts reduced (P < 0.05) the expression of genes associated with antigen presentation or other biological processes of immune responses, indicating they attenuated overstimulation of immune responses caused by E. coli. These findings may explain why diarrhea was reduced and clinical immune responses were ameliorated in infected pigs fed plant extracts. In conclusion, plant extracts altered the expression of genes in ileal mucosa of E. coli-infected pigs, perhaps leading to the reduction in diarrhea reported previously.

Structure-Function Elucidation of Antioxidative and Prooxidative Activities of the Polyphenolic Compound Curcumin

Phenolic compounds have been very well known for their antioxidant properties, owing to their unique ability to act as free radical scavengers which, in turn, is an outstanding attribute of their unique biochemical structure. Recent accumulating lines of evidence inculcate sustainable interest and curiosity towards the chemoprotective nature of the natural polyphenolic compound curcumin (diferuloylmethane) against oxidative stress-mediated disorders. Curcumin is naturally found as a constituent of dietary spices called turmeric, extracted from the plant Curcuma longa. However, like every phenolic antioxidant, curcumin possesses a concentration and medium dependent anti- and pro-oxidant behaviour. A detailed study of the structure-function analysis and the understanding of the mode of action of curcumin as well as its chemical analogues is thus essential to understand the selective biochemical consequences of curcumin. Moreover, the presence of transition metal ions, route of administration, and localized tissue are also the vital decisive factors to determine curcumin behaviour. With this viewpoint, this paper sheds lights on the medium dependent prooxidative and antioxidative attributes of curcumin. Further, with respect to emergence of nanocarriers, a brief discussion focusing on the biochemical effect exertion of curcumin chiefly due to targeted and slow release has also been added towards the end.

Chemotherapeutic potential of curcumin-bearing microcells against hepatocellular carcinoma in model animals

Curcumin (diferuloylmethane) is found in large quantities in the roots of Curcuma longa. It possesses strong antioxidant and anti-inflammatory properties, and inhibits chemically-induced carcinogenesis in the skin, forestomach, colon, and liver. Unfortunately, the poor bioavailability and hydrophobicity of curcumin pose a major hurdle to its use as a potent anticancer agent. To circumvent some of these problems, we developed a novel, dual-core microcell formulation of curcumin. The encapsulation of curcumin in microcells increases its solubility and bioavailability, and facilitates slow release kinetics over extended periods. Besides being safe, these formulations do not bear any toxicity constraints, as revealed by in vitro and in vivo studies. Histopathological analysis revealed that curcumin-bearing microcells helped in regression of hepatocellular carcinoma and the maintenance of cellular architecture in liver tissue. Free curcumin had a very mild effect on cancer suppression. Empty (sham) microcells and microparticles failed to inhibit cancer cells. The novel curcumin formulation was found to suppress hepatocellular carcinoma efficiently in Swiss albino mice.

The neuroprotective effect of treatment with curcumin in acute spinal cord injury: laboratory investigation

The purpose of this study was investigating the effects of curcumin on the histological changes and functional recovery following spinal cord injury (SCI) in a rat model. Following either sham operation or SCI, 36 male Sprague–Dawley rats were distributed into three groups: sham group, curcumin-treated group, and vehicle-injected group. Locomotor function was assessed according to the Basso, Beattie, and Bresnahan (BBB) scale in rats who had received daily intraperitoneal injections of 200 mg/kg curcumin or an equivalent volume of vehicle for 7 days following SCI. The injured spinal cord was then examined histologically, including quantification of cavitation. BBB scores were significantly higher in rats receiving curcumin than receiving vehicle (P < 0.05). The cavity volume was significantly reduced in the curcumin group as compared to the control group (P = 0.039). Superoxide dismutase (SOD) activity was significantly elevated in the curcumin group as compared to the vehicle group but was not significantly different from the sham group (P < 0.05, P > 0.05, respectively) at one and two weeks after SCI. Malondialdehyde (MDA) levels were significantly elevated in the vehicle group as compared to the sham group (P < 0.05 at 1 and 2 weeks). MDA activity was significantly reduced in the curcumin group at 2 weeks after SCI when compared to the vehicle group (P = 0.004). The numbers of macrophage were significantly decreased in the curcumin group (P = 0.001). This study demonstrated that curcumin enhances early functional recovery after SCI by diminishing cavitation volume, anti-inflammatory reactions, and antioxidant activity.

Comparative absorption of curcumin formulations

Background

The potential health benefits of curcumin are limited by its poor solubility, low absorption from the gut, rapid metabolism and rapid systemic elimination. The purpose of this study was the comparative measurement of the increases in levels of curcuminoids (curcumin, demethoxycurcumin, bisdemethoxycurcumin) and the metabolite tetrahydrocurcumin after oral administration of three different curcumin formulations in comparison to unformulated standard.

Methods

The relative absorption of a curcumin phytosome formulation (CP), a formulation with volatile oils of turmeric rhizome (CTR) and a formulation of curcumin with a combination of hydrophilic carrier, cellulosic derivatives and natural antioxidants (CHC) in comparison to a standardized curcumin mixture (CS) was investigated in a randomized, double-blind, crossover human study in healthy volunteers. Samples were analyzed by HPLC-MS/MS.

Results

Total curcuminoids appearance in the blood was 1.3-fold higher for CTR and 7.9-fold higher for CP in comparison to unformulated CS. CHC showed a 45.9-fold higher absorption over CS and significantly improved absorption over CP (5.8-fold) and CTR (34.9-fold, all p < 0.001).

Conclusion

A formulation of curcumin with a combination of hydrophilic carrier, cellulosic derivatives and natural antioxidants significantly increases curcuminoid appearance in the blood in comparison to unformulated standard curcumin CS, CTR and CP.