Pharmacological basis for the role of curcumin in chronic diseases: an age-old spice with modern targets. Trends Pharmacol Sci. 2009;30:85-94. [PMID: 19110321 DOI: 10.1016/j.tips.2008.11.002]

Advances in understanding mechanisms underlying the antitumor activity of curcumin analogue EF24

Curcumin, a natural polyphenol which was first extracted by Vogel and Pelletier from rhizomes of the plant Curcuma longa L, has potent anticarcinogenic activity and low toxic side effects in a wide variety of tumor cells. It has been listed as a third-generation chemoprophylactic drug by the US National Cancer Institute. However, the therapeutic benefit is hampered by its low absorption after transdermal or oral application. Ames et al. have developed a series of novel synthetic curcumin analogs that are more potent and have better water solubility than curcumin. One of these leading compounds, EF24, exhibits about 10-fold greater cytotoxic activity against various cancer cell lines in relation to curcumin. This article will review the recent advances in understanding mechanisms underlying the antitumor activity of EF24.

Curcumin induces differentiation of embryonic stem cells through possible modulation of nitric oxide-cyclic GMP pathway

Curcumin, an active ingredient of dietary spice used in curry, has been shown to exhibit anti-oxidant, anti-inflammatory and anti-proliferative properties. Using EB directed differentiation protocol of H-9 human embryonic stem (ES) cells; we evaluated the effect of curcumin (0-20 μmol/L) in enhancing such differentiation. Our results using real time PCR, western blotting and immunostaining demonstrated that curcumin significantly increased the gene expression and protein levels of cardiac specific transcription factor NKx2.5, cardiac troponin I, myosin heavy chain, and endothelial nitric oxide synthase during ES cell differentiation. Furthermore, an NO donor enhanced the curcumin-mediated induction of NKx2.5 and other cardiac specific proteins. Incubation of cells with curcumin led to a dose dependent increase in intracellular nitrite to the same extent as giving an authentic NO donor. Functional assay for second messenger(s) cyclic AMP (cAMP) and cyclic GMP (cGMP) revealed that continuous presence of curcumin in differentiated cells induced a decrease in the baseline levels of cAMP but it significantly elevated baseline contents of cGMP. Curcumin addition to a cell free assay significantly suppressed cAMP and cGMP degradation in the extracts while long term treatment of intact cells with curcumin increased the rates of cAMP and cGMP degradation suggesting that this might be due to direct suppression of some cyclic nucleotide-degrading enzyme (phosphodiesterase) by curcumin. These studies demonstrate that polyphenol curcumin may be involved in differentiation of ES cells partly due to manipulation of nitric oxide signaling.

Effects of a water-soluble curcumin protein conjugate vs. pure curcumin in a diabetic model of erectile dysfunction

INTRODUCTION

Curcumin is involved in erectile signaling via elevation of cyclic guanosine monophosphate (cGMP).

AIM

Assessment of the effects of water-soluble curcumin in erectile dysfunction (ED).

METHODS

One hundred twenty male white albino rats were divided into: 1st and 2nd control groups with or without administration of Zinc protoporphyrin (ZnPP), 3rd and 4th diabetic groups with or without ZnPP, 5th diabetic group on single oral dose of pure curcumin, 6th diabetic group on pure curcumin administered daily for 12 weeks, 7th and 8th diabetic groups on single dose of water-soluble curcumin administered with or without ZnPP, 9th and 10th diabetic groups on water-soluble curcumin administered daily for 12 weeks with or without ZnPP. All curcumin dosage schedules were administered after induction of diabetes.

MAIN OUTCOME MEASURES

Quantitative gene expression of endothelial nitric oxide synthase (eNOS), neuronal NOS (nNOS), inducible NOS (iNOS), heme oxygenase-1 (HO-1), nuclear transcription factor-erythroid2 (Nrf2), NF-Кβ, and p38. Cavernous tissue levels of HO and NOS enzyme activities, cGMP and intracavernosal pressure (ICP).

RESULTS

Twelve weeks after induction of diabetes, ED was confirmed by the significant decrease in ICP. There was a significant decrease in cGMP, NOS, HO enzymes, a significant decrease in eNOS, nNOS, HO-1 genes and a significant elevation of NF-Кβ, p38, iNOS genes. Administration of pure curcumin or its water-soluble conjugate led to a significant elevation in ICP, cGMP levels, a significant increase in HO-1 and NOS enzymes, a significant increase in eNOS, nNOS, HO-1, and Nrf2 genes, and a significant decrease in NF-Кβ, p38, and iNOS genes. Water-soluble curcumin showed significant superiority and more prolonged duration of action. Repeated doses regimens were superior to single dose regimen. Administration of ZnPP significantly reduced HO enzyme, cGMP, ICP/ mean arterial pressure (MAP), HO-1 genes in diabetic groups.

CONCLUSION

Water-soluble curcumin could enhance erectile function with more effectiveness and with more prolonged duration of action.

Synthesis and characterization of poly(antioxidant β-amino esters) for controlled release of polyphenolic antioxidants

Attenuation of cellular oxidative stress, which plays a central role in biomaterial-induced inflammation, provides an exciting opportunity to control the host tissue response to biomaterials. In the case of biodegradable polymers, biomaterial-induced inflammation is often a result of local accumulation of polymer degradation products, hence there is a need for new biomaterials that can inhibit this response. Antioxidant polymers, which have antioxidants incorporated into the polymer backbone, are a class of biomaterials that, upon degradation, release active antioxidants, which can scavenge free radicals and attenuate oxidative stress, resulting in improved material biocompatibility. In this work, we have synthesized poly(antioxidant β-amino ester) (PAβAE) biodegradable hydrogels of two polyphenolic antioxidants, quercetin and curcumin. The degradation characteristics of PAβAE hydrogels and the antioxidant activity of PAβAE degradation products were studied. Treatment of endothelial cells with PAβAE degradation products protected cells from hydrogen-peroxide-induced oxidative stress.

Curcuminoid binding to embryonal carcinoma cells: reductive metabolism, induction of apoptosis, senescence, and inhibition of cell proliferation

Curcumin preparations typically contain a mixture of polyphenols, collectively referred to as curcuminoids. In addition to the primary component curcumin, they also contain smaller amounts of the co-extracted derivatives demethoxycurcumin and bisdemethoxycurcumin. Curcuminoids can be differentially solubilized in serum, which allows for the systematic analysis of concentration-dependent cellular binding, biological effects, and metabolism. Technical grade curcumin was solubilized in fetal calf serum by two alternative methods yielding saturated preparations containing either predominantly curcumin (60%) or bisdemethoxycurcumin (55%). Continual exposure of NT2/D1 cells for 4–6 days to either preparation in cell culture media reduced cell division (1–5 µM), induced senescence (6–7 µM) or comprehensive cell death (8–10 µM) in a concentration-dependent manner. Some of these effects could also be elicited in cells transiently exposed to higher concentrations of curcuminoids (47 µM) for 0.5–4 h. Curcuminoids induced apoptosis by generalized activation of caspases but without nucleosomal fragmentation. The equilibrium binding of serum-solubilized curcuminoids to NT2/D1 cells incubated with increasing amounts of curcuminoid-saturated serum occurred with apparent overall dissociation constants in the 6–10 µM range. However, the presence of excess free serum decreased cellular binding in a hyperbolic manner. Cellular binding was overwhelmingly associated with membrane fractions and bound curcuminoids were metabolized in NT2/D1 cells via a previously unidentified reduction pathway. Both the binding affinities for curcuminoids and their reductive metabolic pathways varied in other cell lines. These results suggest that curcuminoids interact with cellular binding sites, thereby activating signal transduction pathways that initiate a variety of biological responses. The dose-dependent effects of these responses further imply that distinct cellular pathways are sequentially activated and that this activation is dependent on the affinity of curcuminoids for the respective binding sites. Defined serum-solubilized curcuminoids used in cell culture media are thus suitable for further investigating the differential activation of signal transduction pathways.

Improving the oral bioavailability of curcumin using novel organogel-based nanoemulsions

Curcumin is a natural bioactive compound with many health-promoting benefits. Its low oral bioavailability limits its application in functional foods. In the present study, novel organogel-based nanoemulsions have been developed for oral delivery of curcumin and improvement of its bioavailability. Recently developed curcumin organogel was used as the oil phase in the curcumin nanoemulsion formulation. Tween 20 was selected as the emulsifier on the basis of maximum in vitro bioaccessibility of curcumin in the nanoemulsion. In vitro lipolysis profile revealed that the digestion of nanoemulsion was significantly faster and more complete than the organogel. Permeation experiments on Caco-2 cell monolayers suggested that digestion-diffusion was the major absorption mechanism for curcumin in the nanoemulsion. Furthermore, in vivo pharmacokinetics analysis on mice confirmed that the oral bioavailability of curcumin in the nanoemulsion was increased by 9-fold compared with unformulated curcumin. This novel formulation approach may also be used for oral delivery of other poorly soluble nutraceuticals with high loading capacity, which has significant impact in functional foods, dietary supplements and pharmaceutical industries.

Pilot study of oral administration of a curcumin-phospholipid formulation for treatment of central serous chorioretinopathy

Background

The purpose of this open-label study was to investigate the effect of a curcumin-phospholipid (lecithin, Meriva^®) formulation (Norflo^® tablet) on visual acuity and retinal thickness in patients with acute or chronic central serous chorioretinopathy.

Methods

Visual acuity was assessed by ophthalmologic evaluation, and optical coherence tomography was used to measure retinal thickness. Norflo tablets were administered twice a day to patients affected by central serous chorioretinopathy. The study included 18 eyes from 12 patients who completed a 6-month follow-up period. Visual acuity before and after Norflo treatment was the primary endpoint. The secondary endpoints were neuroretinal or pigment epithelial detachment, as measured by optical coherence tomography.

Results

After 6 months of therapy, 0% of eyes showed reduction in visual acuity, 39% showed stabilization, and 61% showed improvement. The improvement was statistically significant (P = 0.08). After 6 months of therapy, 78% of eyes showed reduction of neuroretinal or retinal pigment epithelium detachment, 11% showed stabilization, and 11% showed an increase.

Conclusion

Our results, albeit preliminary, show that curcumin administered as Norflo tablets is efficacious for the management of central serous chorioretinopathy, a relapsing eye disease, and suggest that bioavailable curcumin is worth considering as a therapeutic agent for the management of inflammatory and degenerative eye conditions, including those that activate the retinal microglia.

Effects of cyclohexanone analogues of curcumin on growth, apoptosis and NF-κB activity in PC-3 human prostate cancer cells

Curcumin is a non-nutritive yellow pigment found in the spice turmeric, which is derived from the rhizome of the plant Curcuma longa Linn. Six cyclohexanone analogues of curcumin (A(1)-A(6)) were investigated for their effects on growth and apoptosis in PC-3 human prostate cancer cells. The ability of these compounds to inhibit NF-κB activity in PC-3 cells was also determined. Five out of the six curcumin analogues (A(2)-A(6)) had stronger inhibitory effects compared to curcumin on the growth of cultured PC-3 cells. Compounds A(2)-A(6) also had stronger stimulatory effects on apoptosis in PC-3 cells than curcumin, and these curcumin analogues more potently inhibited NF-κB activity than curcumin. The inhibitory effects of these compounds on NF-κB activity correlated with their effects on growth inhibition and apoptosis stimulation in PC-3 cells. The results of the present study provide a rationale for in vivo studies with A(2)-A(6) using suitable animal models of prostate cancer.

Curcumin--from molecule to biological function

Turmeric is traditionally used as a spice and coloring in foods. It is an important ingredient in curry and gives curry powder its characteristic yellow color. As a consequence of its intense yellow color, turmeric, or curcumin (food additive E100), is used as a food coloring (e.g. mustard). Turmeric contains the curcuminoids curcumin, demethoxycurcumin, and bisdemethoxycurcumin. Recently, the health properties (neuroprotection, chemo-, and cancer prevention) of curcuminoids have gained increasing attention. Curcuminoids induce endogenous antioxidant defense mechanisms in the organism and have anti-inflammatory activity. Curcuminoids influence gene expression as well as epigenetic mechanisms. Synthetic curcumin analogues also exhibit biological activity. This Review describes the development of curcumin from a "traditional" spice and food coloring to a "modern" biological regulator.

The release rate of curcumin from calcium alginate beads regulated by food emulsifiers

Curcumin-loaded alginate beads, which contain different food emulsifiers, have been prepared using CaCl₂ as the cross-linking agent. The controlled release of the curcumin from the beads was investigated at room temperature. For calcium alginate/Span-80/Tween-80 (A/S/T) formulations, almost all of the curcumin loaded in the beads was released into the medium within about 20 h, and the release rates could be regulated by changing the concentration of both Tween-80 and Span-80. However, for the systems of calcium alginate/Q-12A/F-18A (A/Q/F), about 60% of the curcumin loaded in the beads was released at the end of experiments. The studies of scanning electron microscopy indicated that the microstructure of the walls of beads could significantly vary with the concentration or type of emulsifiers. The Fourier transform infrared spectral measurements confirmed that the interactions between calcium alginate and polyglycerol fatty acid esters were stronger than that between calcium alginate and Tween-80/Span-80. The results of swelling studies demonstrated that the initial rates of water uptake for A/Q/F beads were higher than that for A/S/T beads. Moreover, the data of release rates were fitted by an empirical equation, which showed that the release mechanism of curcumin from the alginate gels varied with the composition of emulsifiers for the A/S/T systems. This work provides an important insight into the effect of food emulsifiers on the release rates of the curcumin from calcium alginate beads and will be helpful for the application of the systems in controlled release of other hydrophobic drug.

Age-associated chronic diseases require age-old medicine: role of chronic inflammation

Most chronic diseases--such as cancer, cardiovascular disease (CVD), Alzheimer disease, Parkinson disease, arthritis, diabetes and obesity--are becoming leading causes of disability and death all over the world. Some of the most common causes of these age-associated chronic diseases are lack of physical activity, poor nutrition, tobacco use, and excessive alcohol consumption. All the risk factors linked to these chronic diseases have been shown to up-regulate inflammation. Therefore, downregulation of inflammation-associated risk factors could prevent or delay these age-associated diseases. Although modern science has developed several drugs for treating chronic diseases, most of these drugs are enormously expensive and are associated with serious side effects and morbidity. In this review, we present evidence on how chronic inflammation leads to age-associated chronic disease. Furthermore, we discuss diet and lifestyle as solutions for age-associated chronic disease.

Curcumin loaded NLC induces histone hypoacetylation in the CNS after intraperitoneal administration in mice

The natural p300-specific histone acetyltransferase (HAT) inhibitor, curcumin (CUR), has been widely investigated for its potential therapeutic effect as an anticancer and anti-inflammatory agent. Notwithstanding this interesting pharmacological profile, CUR shows some drawbacks, such as poor absorption and a very fast metabolism and elimination, that limit its clinical use. Aim of the present study was to formulate CUR loaded nanostructured lipid carriers (NLC-CUR) in order to improve the bioavailability and stability of this compound after systemic administration with increased effects in the central nervous system (CNS). NLC-CUR were prepared and characterized on their physicochemical properties by PCS and DSC analyses. Thus, NLC-CUR were systemically injected and the effects in the CNS were compared with a CUR control formulation containing 0.05% DMSO (DMSO-CUR). Our results demonstrate that CUR is able to decrease histone acetylation in the CNS when included in NLCs. Western blot analysis shows that intraperitoneal injection of NLC-CUR (100mg/kg) in mice induces a marked hypoacetylation of histone 4 (H4) at lysine 12 (K12) in the spinal cord compared with control group. Notably, DMSO-CUR (100mg/kg) did not change the H4K12 acetylation level in the CNS. Our study suggests a novel approach to ameliorate the pharmacokinetics of CUR that allows a better permeation in the CNS.

Curcumin has neuroprotection effect on homocysteine rat model of Parkinson

Parkinson's disease (PD) is a progressive neurological disorder which is emanated by dopaminergic death cell and depletion. Curcumin as a nontoxic matter has antioxidant, anti-inflammatory, and antiproliferative activities, and it involves antioxidant property same to vitamins C and E. In this study, we investigated the neuroprotective properties of the natural polyphenolic antioxidant compound, curcumin, against homocysteine (Hcy) neurotoxicity. Curcumin (50 mg/kg) was injected intraperitoneally (i.p.) once daily for a period of 10 days beginning 5 days prior to Hcy (2 μmol/μl) intracerebroventricular (i.c.v.) injection in rats. The studies included immunohistological and locomotor activity tests. These results suggest that homocysteine intracerebroventricular administration (2 μmol/μl i.c.v.) may induce changes in rat brain, and subsequently, polyphenol treatment curcumin 50 mg/kg (i.p.) was capable in improving locomotor function in insulted animal by protecting the nervous system against homocysteine toxicity.

The pharmacology of curcumin: is it the degradation products?

The natural product curcumin has gained considerable attention in recent years for its multiple pharmacological activities, but more efforts are needed to understand how curcumin can have these pharmacological effects considering its low bioavailability. In addition, it is unclear how curcumin exerts inhibitory effects against numerous enzymes, especially those that cannot accommodate curcumin within recognized binding pockets. By analyzing the similarities between the biological activities of curcumin and its degradation products against diseases such as Alzheimer's disease and cancer, as well as the preferential inhibition of some enzymes by degradation products, it appears that the bioactive degradation products may contribute to the pharmacological effects of curcumin. This possibility should be given full attention when elucidating the pharmacology of this promising natural product for various diseases.

Curcumin affects cell survival and cell volume regulation in human renal and intestinal cells

Curcumin (1,7-bis(4-hydroxy-3-methoxyphenyl)-1E,6E-heptadiene-3,5-dione or diferuloyl methane) is a polyphenol derived from the Curcuma longa plant, commonly known as turmeric. This substance has been used extensively in Ayurvedic medicine for centuries for its anti-oxidant, analgesic, anti-inflammatory and antiseptic activity. More recently curcumin has been found to possess anti-cancer properties linked to its pro-apoptotic and anti-proliferative actions. The underlying mechanisms of these diverse effects are complex, not fully elucidated and subject of intense scientific debate. Despite increasing evidence indicating that different cation channels can be a molecular target for curcumin, very little is known about the effect of curcumin on chloride channels. Since, (i) the molecular structure of curcumin indicates that the substance could potentially interact with chloride channels, (ii) chloride channels play a role during the apoptotic process and regulation of the cell volume, and (iii) apoptosis is a well known effect of curcumin, we set out to investigate whether or not curcumin could (i) exert a modulatory effect (direct or indirect) on the swelling activated chloride current ICl(swell) in a human cell system, therefore (ii) affect cell volume regulation and (iii) ultimately modulate cell survival. The ICl(swell) channels, which are essential for regulating the cell volume after swelling, are also known to be activated under isotonic conditions as an early event in the apoptotic process. Here we show that long-term exposure of a human kidney cell line to extracellular 0.1-10 μM curcumin modulates ICl(swell) in a dose-dependent manner (0.1 μM curcumin is ineffective, 0.5-5.0 μM curcumin increase, while 10 μM curcumin decrease the current), and short-term exposure to micromolar concentrations of curcumin does not affect ICl(swell) neither if applied from the extracellular nor from the intracellular side - therefore, a direct effect of curcumin on ICl(swell) can be ruled out. Furthermore, we show that curcumin exposure induces apoptosis in human kidney cells, and at a concentration of 5.0-10 μM induces the appearance of a sub-population of cells with a dramatically increased volume. In these cells the regulation of the cell volume seems to be impaired, most likely as a consequence of the ICl(swell) blockade. Similarly, 50 μM curcumin induced apoptosis, caused cell cycle arrest in G1-phase and increased the volume of human colorectal adenocarcinoma HT-29 cells. The cell cycle arrest in G1 phase may be the mechanism underlying the volume increase observed in this cell line after exposure to curcumin.

Curcumin protects against ovariectomy-induced bone loss and decreases osteoclastogenesis

Curcumin has anti-oxidative activity. In view of the increasing evidence for a biochemical link between increased oxidative stress and reduced bone density we hypothesized that curcumin might increase bone density by elevating antioxidant activity in some target cell type. We measured bone density by Micro-CT, enzyme expression levels by quantitative PCR or enzyme activity, and osteoclast (OC) formation by tartrate-resistant acid phosphatase staining. The bone mineral density of the femurs of curcumin-administered mice was significantly higher than that of vehicle-treated mice after ovariectomy (OVX) and this was accompanied by reduced amounts of serum collagen-type I fragments, which are markers of bone resorption. Curcumin suppressed OC formation by increasing receptor activator of nuclear factor-κB ligand (RANKL)-induced glutathione peroxidase-1, and reversed the stimulatory effect of homocysteine, a known H(2) O(2) generator, on OC formation by restoring Gpx activity. Curcumin generated an aberrant RANKL signal characterized by reduced expression of nuclear factor of activated T cells 2 (NFAT2) and attenuated activation of mitogen-activated protein kinases (ERK, JNK, and p38). Curcumin thus inhibited OVX-induced bone loss, at least in part by reducing osteoclastogenesis as a result of increased antioxidant activity and impaired RANKL signaling. These findings suggest that bone loss associated with estrogen deficiency could be attenuated by curcumin administration.

Recovery from spinal cord injury using naturally occurring antiinflammatory compound curcumin: laboratory investigation

OBJECT

Spinal cord injury (SCI) is a debilitating disease. Primary SCI results from direct injury to the spinal cord, whereas secondary injury is a side effect from subsequent edema and ischemia followed by activation of proinflammatory cytokines. These cytokines activate the prosurvival molecule nuclear factor-κB and generate obstacles in spinal cord reinnervation due to gliosis. Curcumin longa is an active compound found in turmeric, which acts as an antiinflammatory agent primarily by inhibiting nuclear factor-κB. Here, the authors study the effect of curcumin on SCI recovery.

METHODS

Fourteen female Sprague-Dawley rats underwent T9-10 laminectomy and spinal cord contusion using a weight-drop apparatus. Within 30 minutes after contusion and weekly thereafter, curcumin (60 mg/kg/ml body weight in dimethyl sulfoxide) or dimethyl sulfoxide (1 ml/kg body weight) was administered via percutaneous epidural injection at the injury site. Spinal cord injury recovery was assessed weekly by scoring hindlimb motor function. Animals were killed 6 weeks postcontusion for histopathological analysis of spinal cords and soleus muscle weight evaluation.

RESULTS

Curcumin-treated rats had improved motor function compared with controls starting from Week 1. Body weight gain significantly improved, correlating with improved Basso-Beattie-Bresnahan scores. Soleus muscle weight was greater in curcumin-treated rats than controls. Histopathological analysis validated these results with increased neural element mass with less gliosis at the contusion site in curcumin-treated rats than controls.

CONCLUSIONS

Epidural administration of curcumin resulted in improved recovery from SCI. This occurred with no adverse effects noted in experimental animals. Therefore, curcumin treatment may translate into a novel therapy for humans with SCI.

Purely aqueous PLGA nanoparticulate formulations of curcumin exhibit enhanced anticancer activity with dependence on the combination of the carrier

Curcumin, a yellow pigment present in turmeric, possess potential anti-proliferative and anti-inflammatory activities but poor aqueous solubility limits its applications. In this study we report a novel comparative study of the formulation and characterization of curcumin nanoparticles (nanocurcumin) using two poly (lactide-co-glycolide) (PLGA) combinations, 50:50 and 75:25 having different lactide to glycolide ratios. Nanocurcumin 50:50 showed smaller size with higher encapsulation efficiency. Thermal evaluation suggested the presence of curcumin in molecular dispersion form which supported its sustained release up to a week where nanocurcumin 50:50 showed faster release. Cellular uptake studies in human epithelial cervical cancer cells (HeLa) exhibited enhanced intracellular fluorescence with nanocurcumin when compared to free curcumin, when both given in purely aqueous media. Antiproliferative studies using MTT (3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide) assay, Annexin V/propidium iodide staining, poly (ADP-ribose) polymerase (PARP) cleavage and downregulation of clonogenic potential of HeLa cells proved the better antitumor activity of nanocurcumin 50:50 administered in aqueous media. Superior efficacy of nanocurcumin 50:50 in comparison to free curcumin was further demonstrated by electrophoretic mobility shift assay and immunocytochemical analysis. In conclusion, the enhanced aqueous solubility and higher anticancer efficacy of nanocurcumin administered in aqueous media clearly demonstrates its potential against cancer chemotherapy, with dependence on the combination of PLGA.

American Cancer Society Guidelines on nutrition and physical activity for cancer prevention: reducing the risk of cancer with healthy food choices and physical activity

The American Cancer Society (ACS) publishes Nutrition and Physical Activity Guidelines to serve as a foundation for its communication, policy, and community strategies and, ultimately, to affect dietary and physical activity patterns among Americans. These Guidelines, published approximately every 5 years, are developed by a national panel of experts in cancer research, prevention, epidemiology, public health, and policy, and they reflect the most current scientific evidence related to dietary and activity patterns and cancer risk. The ACS Guidelines focus on recommendations for individual choices regarding diet and physical activity patterns, but those choices occur within a community context that either facilitates or creates barriers to healthy behaviors. Therefore, this committee presents recommendations for community action to accompany the 4 recommendations for individual choices to reduce cancer risk. These recommendations for community action recognize that a supportive social and physical environment is indispensable if individuals at all levels of society are to have genuine opportunities to choose healthy behaviors. The ACS Guidelines are consistent with guidelines from the American Heart Association and the American Diabetes Association for the prevention of coronary heart disease and diabetes, as well as for general health promotion, as defined by the 2010 Dietary Guidelines for Americans and the 2008 Physical Activity Guidelines for Americans.

Inhibition of ecto-ATPase activity by curcumin in hepatocellular carcinoma HepG2 cells

Effects of curcumin, a major constituent of turmeric, on ecto-nucleotidases have not been clarified. Here, we investigated whether curcumin affects ecto-nucleotidase activities in human hepatocellular carcinoma HepG2 cells. In the cells, high levels of Mg(2+)-dependent activity of ecto-nucleotidases were observed in the presence of 1 mM adenosine triphosphate (ATP). The activity was inhibited by ecto-ATPase inhibitors such as suramin, ZnCl(2) and 4,4'-diisothiocyanatostilbene-2,2'-disulfonic acid. On the other hand, the activity was significantly decreased at alkaline pH (pH 9) and was not inhibited by levamisole, an inhibitor of alkaline phosphatase. In the presence of ATP, curcumin inhibited the activity in a concentration-dependent manner (IC(50) = 6.2 μM). In contrast, curcumin had no effects on ecto-nucleotidase activity in the presence of ADP (1 mM) or AMP (1 mM). The K (m) value for ATP hydrolysis of curcumin-sensitive ecto-ATPase was similar to the value of NTPDase2, an isoform of ecto-nucleoside triphosphate diphosphohydrolase. These results suggest that curcumin is a potent inhibitor of ecto-ATPase and may affect extracellular ATP-dependent responses.

Spicy SDS-PAGE gels: curcumin/turmeric as an environment-friendly protein stain

Gel proteins are commonly stained with calorimetric/fluorescent dyes. Here, we demonstrate that heat-solubilized curcumin can serve as a nontoxic and environment-friendly fluorescent/colorimetric reversible protein stain. Curcumin, the yellow pigment found in the rhizomes of the perennial herb Curcuma longa (turmeric), is insoluble in aqueous solvents. However, heat (100°C) solubilization in water renders 1.5% of curcumin soluble. Curcumin solubilized by ethanol or alkali is ineffective in staining proteins. Heat solubilized curry spice turmeric stains proteins similarly. Staining is achieved in 30 min, with a sensitivity almost equaling that of Coomassie Brilliant Blue (CBB). Destaining is not required, and excess curcumin/turmeric can be discarded into the sink. Binding of proteins by silver inhibits curcumin binding, suggesting similarity of protein binding by silver and curcumin. It costs $1.5-2.0 to stain a mini-gel with curcumin, while turmeric costs less than 0.005 cent. CBB staining/destaining costs about 2 cents. However, CBB is toxic and its use necessitates specialized disposal efforts. Curcumin/turmeric, thus, can serve as an ideal nontoxic protein stain.

Controlled systemic delivery by polymeric implants enhances tissue and plasma curcumin levels compared with oral administration

Curcumin possesses potent anti-inflammatory and anti-proliferative activities but with poor biopharmaceutical attributes. To overcome these limitations, curcumin implants were developed and tissue (plasma, brain and liver) curcumin concentrations were measured in female ACI rats for 3 months. Biological efficacy of tissue levels achieved was analyzed by modulation of hepatic cytochromes. Curcumin implants exhibited diffusion-mediated biphasic release pattern with ∼2-fold higher in vivo release as compared to in vitro. Plasma curcumin concentration from implants was ∼3.3 ng/ml on day 1, which dropped to ∼0.2 ng/ml after 3 months, whereas only 0.2-0.3 ng/ml concentration was observed from 4-12 days with diet and was undetected subsequently. Almost 10-fold higher curcumin levels were observed in brain on day 1 from implants compared with diet (30.1 ± 7.3 vs 2.7 ± 0.8 ng/g) and were still significant even after 90 days (7.7 ± 3.8 vs 2.2 ± 0.8 ng/g). Although curcumin levels were similar in liver from both the routes (∼25-30 ng/g from day 1-4 and ∼10-15 ng/g at 90 days), implants were more efficacious in altering hepatic CYP1A1 levels and CYP3A4 activity at ∼28-fold lower doses at 90 days. Curcumin implants provided much higher plasma and tissue concentrations and are a viable alternative for delivery of curcumin to various organs like brain.

Curcumin protects against sepsis-induced acute lung injury in rats

The present study aimed to investigate the effect of curcumin on sepsis-induced acute lung injury (ALI) in rats, and explore its possible mechanisms. Male Sprague-Dawley rats were randomly divided into the following five experimental groups (n = 20 per group): animals undergoing a sham cecal ligature puncture (CLP) (sham group); animals undergoing CLP (control group); or animals undergoing CLP and treated with vehicle (vehicle group), curcumin at 50 mg/kg (low-dose curcumin [L-Cur] group), or curcumin at 200 mg/kg (high-dose curcumin [H-Cur] group).At 6, 12, 24 h after CLP, blood, bronchoalveolar lavage fluid (BALF) and lung tissue were collected. The lung wet/dry weight (W/D) ratio, protein level, and the number of inflammatory cells in the BALF were determined. Optical microscopy was performed to examine the pathologic changes in lungs. Myeloperoxidase (MPO) activity, malondialdehyde (MDA) content, as well as superoxidase dismutase (SOD) activity were measured in lung tissues. The expression of inflammatory cytokines, tumor necrosis factor-alpha (TNF-α), interluekin-8 (IL-8), and macrophage migration inhibitory factor (MIF) were determined in the BALF. Survival rates were recorded at 72 h in the five groups in another experiment. Treatment with curcumin significantly attenuated the CLP-induced pulmonary edema and inflammation, as it significantly decreased lung W/D ratio, protein concentration, and the accumulation of the inflammatory cells in the BALF, as well as pulmonary MPO activity. This was supported by the histopathologic examination, which revealed marked attenuation of CLP-induced ALI in curcumin treated rats. In addition, curcumin significantly increased SOD activity with significant decrease in MDA content in the lung. Also, curcumin caused down-regulation of the inflammatory cytokines TNF-α, IL-8, and MIF levels in the lung. Importantly, curcumin improved the survival rate of rats by 40%-50% with CLP-induced ALI. Taken together, these results demonstrate the protective effects of curcumin against the CLP-induced ALI. This effect can be attributed to curcumin ability to counteract the inflammatory cells infiltration and, hence, ROS generation and regulate cytokine effects.

Inhibition of the NF-κB signaling pathway by the curcumin analog, 3,5-Bis(2-pyridinylmethylidene)-4-piperidone (EF31): anti-inflammatory and anti-cancer properties

Nuclear factor kappa B (NF-κB) is a key signaling molecule in the elaboration of the inflammatory response. Data indicate that curcumin, a natural ingredient of the curry spice turmeric, acts as a NF-κB inhibitor and exhibits both anti-inflammatory and anti-cancer properties. Curcumin analogs with enhanced activity on NF-κB and other inflammatory signaling pathways have been developed including the synthetic monoketone compound 3,5-Bis(2-fluorobenzylidene)-4-piperidone (EF24). 3,5-Bis(2-pyridinylmethylidene)-4-piperidone (EF31) is a structurally-related curcumin analog whose potency for NF-κB inhibition has yet to be determined. To examine the activity of EF31 compared to EF24 and curcumin, mouse RAW264.7 macrophages were treated with EF31, EF24, curcumin (1-100 μM) or vehicle (DMSO 1%) for 1h. NF-κB pathway activity was assessed following treatment with lipopolysaccharide (LPS) (1 μg/mL). EF31 (IC(50)~5 μM) exhibited significantly more potent inhibition of LPS-induced NF-κB DNA binding compared to both EF24 (IC(50)~35 μM) and curcumin (IC(50) >50 μM). In addition, EF31 exhibited greater inhibition of NF-κB nuclear translocation as well as the induction of downstream inflammatory mediators including pro-inflammatory cytokine mRNA and protein (tumor necrosis factor-α, interleukin-1β, and interleukin-6). Regarding the mechanism of these effects on NF-κB, EF31 (IC(50)~1.92 μM) exhibited significantly greater inhibition of IκB kinase β compared to EF24 (IC(50)~131 μM). Finally, EF31 demonstrated potent toxicity in NF-κB-dependent cancer cell lines while having minimal and reversible toxicity in RAW264.7 macrophages. These data indicate that EF31 is a more potent inhibitor of NF-κB activity than either EF24 or curcumin while exhibiting both anti-inflammatory and anticancer activities. Thus, EF31 represents a promising curcumin analog for further therapeutic development.

Protective effect of curcumin against arsenic-induced apoptosis in murine splenocytes in vitro

Arsenic is a potent environmental pollutant and immunotoxic agent. Curcumin is a natural anti-oxidant used to treat a broad variety of diseases. Here, the effects were investigated of curcumin on sodium arsenite-induced apoptosis in murine splenocytes in vitro. Cells were exposed to sodium arsenite (NaAsO₂, 5 µM) with and without curcumin (5 and 10 µg/ml) and incubated at 37°C for 12 h. NaAsO₂ caused a decrease in cell viability and induction of apoptosis. These outcomes were concurrent with increases in the numbers of cells with reactive oxygen species generation, loss of mitochondrial transmembrane potential, an increase in the frequency of cells with sub-G₁ DNA content, and DNA fragmentation. Co-administration of curcumin with the NaAsO₂ caused significant recoveries in cell viability values and mitigation of the induced apoptosis-related molecular changes. A significant protection against apoptosis parameters in murine splenocytes simultaneously treated with NaAsO₂ and curcumin suggested a protective efficacy of curcumin. From the results it is concluded that the immuno-modulation exerted by curcumin might be attributed to its multifaceted effects including its anti-oxidative and anti-apoptotic properties. These findings have implications not only for the under-standing of the toxicity of arsenic to murine splenocytes in vitro but are also potentially important for developing preventive and/or corrective strategies against/during chronic arsenicosis.

Effects of diarylpentanoid analogues of curcumin on chemiluminescence and chemotactic activities of phagocytes

OBJECTIVES

A series of 43 curcumin diarylpentanoid analogues were synthesized and evaluated for their inhibitory effects on the chemiluminescence and chemotactic activity of phagocytes in vitro.

METHODS

The effects of the compounds on the respiratory burst of human whole blood and isolated human polymorphonuclear leukocytes (PMNs) were evaluated using a luminol-based chemiluminescence assay and their effect on chemotactic migration of PMNs was investigated using the Boyden chamber technique.

KEY FINDINGS

Compounds 6, 17, 25 and 30 exhibited significant inhibitory activity on the oxidative burst of PMNs. The presence of methoxy groups at positions 2 and 5, and methoxylation and fluorination at positions 4 and 2 of both phenyl rings, respectively, may contribute significantly to their reactive oxygen species inhibition activity. Compounds 7, 17, 18, 24 and 32 showed strong inhibition of the chemotaxis migration of PMNs. Chlorination at various positions of both phenyl rings of cyclohexanone diarylpentanoid resulted in compounds with potent inhibitory effects on PMN migration.

CONCLUSIONS

The results suggest that some of these diarylpentanoid analogues are able to modulate the innate immune response of phagocytes at different steps, emphasizing their potential as a source of new immunomodulatory agents.

Turmeric (Curcuma longa) inhibits inflammatory nuclear factor (NF)-κB and NF-κB-regulated gene products and induces death receptors leading to suppressed proliferation, induced chemosensitization, and suppressed osteoclastogenesis

SCOPE

The incidence of cancer is significantly lower in regions where turmeric is heavily consumed. Whether lower cancer incidence is due to turmeric was investigated by examining its effects on tumor cell proliferation, on pro-inflammatory transcription factors NF-κB and STAT3, and on associated gene products.

METHODS AND RESULTS

Cell proliferation and cell cytotoxicity were measured by the MTT method, NF-κB activity by EMSA, protein expression by Western blot analysis, ROS generation by FACS analysis, and osteoclastogenesis by TRAP assay. Turmeric inhibited NF-κB activation and down-regulated NF-κB-regulated gene products linked to survival (Bcl-2, cFLIP, XIAP, and cIAP1), proliferation (cyclin D1 and c-Myc), and metastasis (CXCR4) of cancer cells. The spice suppressed the activation of STAT3, and induced the death receptors (DR)4 and DR5. Turmeric enhanced the production of ROS, and suppressed the growth of tumor cell lines. Furthermore, turmeric sensitized the tumor cells to chemotherapeutic agents capecitabine and taxol. Turmeric was found to be more potent than pure curcumin for cell growth inhibition. Turmeric also inhibited NF-κB activation induced by RANKL that correlated with the suppression of osteoclastogenesis.

CONCLUSION

Our results indicate that turmeric can effectively block the proliferation of tumor cells through the suppression of NF-κB and STAT3 pathways.

Dendrosomal curcumin significantly suppresses cancer cell proliferation in vitro and in vivo

Curcumin, the main compound of spice turmeric, is one of the natural products that has been shown to possess effective anti-cancer properties. However, the absorption efficacy of curcumin is too low to make dramatic results in therapy. Therefore, we based the main aim of this study on improving the bioavailability of curcumin taking advantage of dendrosome nanoparticles; and subsequently evaluating in vitro and in vivo anti-tumor properties of dendrosomal curcumin. In vitro studies were carried out utilizing A431 and WEHI-164 cell lines and mouse embryonic normal fibroblasts. Our data revealed that dendrosomal curcumin not only exhibits a much higher bioavailability than void curcumin (P<0.05) but also inhibits the proliferation of cancer cells (P<0.01) in a time- and dose-dependent manner that could be ascribed to the induction of apoptosis. However, dendrosome did not indicate any toxic effect on different types of cell lines. For in vivo studies, BALB/c tumor-bearing mice were treated with dendrosomal curcumin, void curcumin, dendrosome and PBS. The results indicated that dendrosomal curcumin reduces significantly the tumor size in comparison with void curcumin and control samples (P<0.05). Furthermore, in animals treated with dendrosomal curcumin a longer survival was observed (P<0.01). We also found that the mice treated with dendrosomal curcumin, showed a significant increase in splenocyte proliferation and IFN-γ production as well as a significant decrease in IL-4 production. This can be a proof of anti-tumor immunity caused by dendrosomal curcumin. The findings demonstrate that dendrosomal curcumin offers a great potential to be a promising anti-cancer therapeutic agent.

Synthesis, biological evaluation and molecular docking studies of resveratrol derivatives possessing curcumin moiety as potent antitubulin agents

A series of resveratrol derivatives possessing curcumin moiety were synthesized and evaluated for their antiproliferative activity against three cancer cell lines including murine melanoma B16-F10, human hepatoma HepG2 and human lung carcinoma A549. Among them, compound C5 displayed the most potent in vitro antiproliferative activity against B16-F10 with IC(50) value of 0.71 μg/mL. Compound C5 also exhibited good tubulin polymerization inhibitory activity with IC(50) value of 1.45 μg/mL. Furthermore, docking simulation was carried out to position C5 into the tubulin-colchicine binding site to determine the probable binding mode.

Specificity protein, Sp1-mediated increased expression of Prdx6 as a curcumin-induced antioxidant defense in lens epithelial cells against oxidative stress

Peroxiredoxin 6 (Prdx6) is a pleiotropic oxidative stress-response protein that defends cells against reactive oxygen species (ROS)-induced damage. Curcumin, a naturally occurring agent, has diversified beneficial roles including cytoprotection. Using human lens epithelial cells (hLECs) and Prdx6-deficient cells, we show the evidence that curcumin protects cells by upregulating Prdx6 transcription via invoking specificity protein 1 (Sp1) activity against proapoptotic stimuli. Curcumin enhanced Sp1 and Prdx6 mRNA and protein expression in a concentration-dependent manner, as evidenced by western and real-time PCR analyses, and thereby negatively regulated ROS-mediated apoptosis by blunting ROS expression and lipid peroxidation. Bioinformatic analysis and DNA–protein binding assays disclosed three active Sp1 sites (−19/27, −61/69 and −82/89) in Prdx6 promoter. Co-transfection experiments with Sp1 and Prdx6 promoter–chloramphenicol acetyltransferase (CAT) constructs showed that CAT activity was dramatically increased in LECs or Sp1-deficient cells (SL2). Curcumin treatment of LECs enhanced Sp1 binding to its sites, consistent with curcumin-dependent stimulation of Prdx6 promoter with Sp1 sites and cytoprotection. Notably, disruption of Sp1 sites by point mutagenesis abolished curcumin transactivation of Prdx6. Also, curcumin failed to activate Prdx6 expression in the presence of Sp1 inhibitors, demonstrating that curcumin-mediated increased expression of Prdx6 was dependent on Sp1 activity. Collectively, the study may provide a foundation for developing transcription-based inductive therapy to reinforce endogenous antioxidant defense by using dietary supplements.

Evaluation in vitro of synthetic curcumins as agents promoting monocytic gene expression related to β-amyloid clearance

Accumulation of amyloid-beta (Aβ) is one of the hallmarks of Alzheimer's disease (AD), and efficient clearance of Aβ by cells of the innate immune system may be an important mechanism for controlling or preventing disease onset. It was reported that peripheral blood mononuclear cells (PBMCs) of most AD patients are defective in the phagocytosis of soluble Aβ. Natural curcumins were shown to restore Aβ phagocytosis by AD PBMCs and to up-regulate the expression of key genes including MGAT3 and those encoding Toll-like receptors (TLRs). Bisdemethoxycurcumin (BDC), a minor component of natural curcumin, was shown to have the greatest potency for stimulating AD PBMCs. Because natural curcumins have inherent limitations with regard to physicochemical properties, synthetic curcumin analogues were developed that showed improved solubility, stability, and bioavailability. An in vitro system using human monocytic cell lines (U-937, THP-1) was used to evaluate analogues for the potency of innate immune cell stimulation. These cell lines showed responses to curcuminoids and to 1α,25-dihydroxyvitamin D3 (VD3) resembling those seen in human PBMCs. From more than 45 curcuminoids analyzed, the most potent compounds possessing enhanced pharmaceutical properties were identified. The most promising candidates included prodrug versions containing water solubility-enhancing amino acids and stability-increasing modifications near the central diketone. In vivo studies showed compound (5) substantially increased bioavailability by combining several promising structural modifications. Studies examining ex vivo phagocytosis of Aβ and bead particles in mouse microglia showed that BDC and several water-soluble analogues were quite effective compared to curcumin or an unnatural analogue. In vitro studies using monocytic cell lines reported herein complement those using human PBMCs and represent a routinely accessible and uniform cellular resource allowing direct comparisons between compounds.

Beneficial dietary effect of turmeric and sulphur on weight gain, fat deposition and lipid profile of serum and liver in rats

This study was designed to investigate the effects of turmeric powder and processed sulphur on the weight gain, body fat deposition and lipid profile of serum and liver in Wistar rats. Twenty-five rats of 6 weeks old were divided into five groups with 5 rats in each group. Each group was fed different diets as follows I. common diet (CON); II. high fat diet (HFD); III. 10% turmeric powder with HFD (T); IV. 10% turmeric powder and 0.19% processed sulphur with HFD (TS); and V. 0.38% processed sulphur with HFD (S). The experimental feeding was continued for 6 weeks. The body weight gain and feed efficiency ratio (FER) in the T and TS group rats were significantly (p < 0.05) lower than that of the HFD group rats. The retroperitoneal fat weights in the rats belong to T, TS and S groups were lower than that of the HFD group rats and the TS group had significant (p < 0.05) reduction in retroperitoneal fat compared to the HFD group rats. The epididymal fat weights in rats of the T, TS and S groups also showed a lowering tendency compared to that of the HFD group rats. The hepatic total lipid levels in the T and TS group rats were significantly (p < 0.05) lower than that of the HFD group rats. The hepatic triglyceride level in the rats of TS group was significantly (p < 0.05) lower than that of the HFD group rats. The serum total cholesterol, high-density lipoprotein (HDL) and low density lipoprotein (LDL) associated cholesterol contents in rats of the T and TS group were significantly (p < 0.05) higher than that of the HFD group rats, however, there was no significant difference in serum triglyceride. The results suggest that turmeric powder along with sulphur can reduce the weight gain, body fat deposition and improve serum and liver lipid profile in rats fed with a high fat diet.

Multitargeting by curcumin as revealed by molecular interaction studies

Curcumin (diferuloylmethane), the active ingredient in turmeric (Curcuma longa), is a highly pleiotropic molecule with anti-inflammatory, anti-oxidant, chemopreventive, chemosensitization, and radiosensitization activities. The pleiotropic activities attributed to curcumin come from its complex molecular structure and chemistry, as well as its ability to influence multiple signaling molecules. Curcumin has been shown to bind by multiple forces directly to numerous signaling molecules, such as inflammatory molecules, cell survival proteins, protein kinases, protein reductases, histone acetyltransferase, histone deacetylase, glyoxalase I, xanthine oxidase, proteasome, HIV1 integrase, HIV1 protease, sarco (endo) plasmic reticulum Ca(2+) ATPase, DNA methyltransferases 1, FtsZ protofilaments, carrier proteins, and metal ions. Curcumin can also bind directly to DNA and RNA. Owing to its β-diketone moiety, curcumin undergoes keto-enol tautomerism that has been reported as a favorable state for direct binding. The functional groups on curcumin found suitable for interaction with other macromolecules include the α, β-unsaturated β-diketone moiety, carbonyl and enolic groups of the β-diketone moiety, methoxy and phenolic hydroxyl groups, and the phenyl rings. Various biophysical tools have been used to monitor direct interaction of curcumin with other proteins, including absorption, fluorescence, Fourier transform infrared (FTIR) and circular dichroism (CD) spectroscopy, surface plasmon resonance, competitive ligand binding, Forster type fluorescence resonance energy transfer (FRET), radiolabeling, site-directed mutagenesis, matrix-assisted laser desorption/ionization time-of-flight mass spectrometry (MALDI-TOF MS), immunoprecipitation, phage display biopanning, electron microscopy, 1-anilino-8-naphthalene-sulfonate (ANS) displacement, and co-localization. Molecular docking, the most commonly employed computational tool for calculating binding affinities and predicting binding sites, has also been used to further characterize curcumin's binding sites. Furthermore, the ability of curcumin to bind directly to carrier proteins improves its solubility and bioavailability. In this review, we focus on how curcumin directly targets signaling molecules, as well as the different forces that bind the curcumin-protein complex and how this interaction affects the biological properties of proteins. We will also discuss various analogues of curcumin designed to bind selective targets with increased affinity.

Effect of intraperitoneal injection of curcumin on food intake in a goldfish model

Although spice compounds have several pharmacological and biochemical actions such as antioxidant activity, their physiological effects on neuropeptides related to feeding regulation are not well known. The aim of the present study was to identify the pharmacological activities of spice compounds on appetite regulation using a goldfish (Carassius auratus) model with emphasis on the role of neuropeptides. The spice compounds used in this study were curcumin, piperine, and ursolic acid. Goldfish were injected intraperitoneally with test solutions containing each spice or vehicle (including 10% dimethyl sulfoxide in saline), and the changes in food intake were measured every 15 min for 60 min. Among the tested spice compounds, curcumin was found to reduce cumulative food intake and was thus selected for further experiments. Pretreatment with capsaicin, a neurotoxin of afferent nerves, abolished the curcumin-induced decrease of food intake. Curcumin-induced anorexigenic action was also attenuated by intracerebroventricular injection of the corticotropin-releasing hormone (CRH) receptor antagonist α-helical CRH((9-41)). We also examined the expression levels of mRNA for CRH, which is a potent anorexigenic neuropeptide in goldfish, in the diencephalon at 1 h after treatment with curcumin, and found that they were increased. Therefore, the reduction of appetite induced by curcumin treatment in goldfish was suggested to be mediated by the vagal afferent and subsequently through the CRH/CRH receptor pathway.

Curcumin sensitizes chemotherapeutic drugs via modulation of PKC, telomerase, NF-κB and HDAC in breast cancer

Background: Several tumor markers are overexpressed in breast cancer. Chemotherapy in breast cancer fails due to resistance to chemotherapeutic drugs. A phytochemical such as curcumin can be used in a therapeutic modality as it elicits anti-tumor effects. Methods: Action of curcumin on the expression of several tumor markers, such as protein kinase C, telomerase, NF-κB and histone deacetylase in MCF-7 (ER positive), MDA-MB-231 (ER negative), MCF-12F (control) and also in mice mammary tumors were investigated. Results: Curcumin downregulated the expression of tumor markers both in vitro and in vivo and sensitized tumor cells to the chemotherapeutic drugs cyclophosphamide and paclitaxel. Discussion: Curcumin may be of considerable value in synergistic therapy of cancer such that the drug dose level could be minimized reducing the associated toxicity.

Oxidative genome damage and its repair in neurodegenerative diseases: function of transition metals as a double-edged sword

The neurons in the central nervous system (CNS) with high O2 consumption and prolonged life span are chronically exposed to high levels of reactive oxygen species (ROS). Accumulation of ROS-induced genome damage in the form of oxidized bases and single-strand breaks (SSBs) as well as their defective or reduced repair in the brain has been implicated in the etiology of various neurological disorders including Alzheimer's/Parkinson's diseases (AD/PD). Although inactivating mutations in some DNA repair genes have been linked to hereditary neurodegenerative diseases, the underlying mechanisms of repair deficiencies for the sporadic diseases is not understood. The ROS-induced DNA damage is predominantly repaired via the highly conserved and regulated base excision/SSB repair (BER/SSBR) pathway. We recently made an interesting discovery that the transition metals iron and copper, which accumulate excessively in the brains of AD, PD, and other neurodegenerative diseases, act as a 'double-edged sword' by inducing genotoxic ROS and inhibiting DNA damage repair at the same time. These metals inhibit the base excision activity of NEIL family DNA glycosylases by oxidizing them, changing their structure, and inhibiting their binding to downstream repair proteins. Metal chelators and reducing agents partially reverse the inhibition, while curcumin with both chelating and reducing activities reverses the inhibition nearly completely. In this review, we have discussed the possible etiological linkage of BER/SSBR defects to neurodegenerative diseases and the therapeutic potential of metal chelators in restoring DNA repair capacity.

Curcumin provides potential protection against the activation of hypoxia and prolyl 4-hydroxylase inhibitors on prostate-specific antigen expression in human prostate carcinoma cells

SCOPE

Prostate-specific antigen (PSA) is a well-known marker for diagnosing and monitoring prostate cancer. Curcumin, a yellow curry pigment, has been reported to enhance androgen receptor (AR) degradation. We examined the effects of curcumin on increasing PSA expression by hypoxia and prolyl hydroxylase inhibitors, L-mimosine and dimethyloxalylglycine (DMOG), in human prostate carcinoma LNCaP cells.

METHODS AND RESULTS

The 3H-thymidine incorporation assay revealed that either L-mimosine or DMOG treatments attenuated cell proliferation. Immunoblot and enzyme-linked immunosorbent assays (ELISA) indicated that both L-mimosine and DMOG have an effect similar to hypoxia, which stabilized hypoxia-inducible factor-1α (HIF-1α) and induced PSA gene expression. The results of the immunoblot and transient gene expression assays indicated that induction of the PSA expression by hypoxia is both HIF-1α- and AR-dependent. Immunoblot assays revealed that a curcumin treatment (10 μM) decreased the protein abundance of AR but did not significantly affect the protein levels of HIF-1α and vascular endothelial growth factor, which were induced by hypoxia. ELISA and transient gene expression assays indicated that curcumin blocked the activation of L-mimosine or DMOG treatment on PSA expression.

CONCLUSIONS

These results indicate that curcumin blocked the enhanced effect of PSA expression by L-mimosine and DMOG that induce hypoxia condition.