Comparative absorption of a standardized curcuminoid mixture and its lecithin formulation

Oral Curcumin (Meriva) Is Effective as an Adjuvant Treatment and Is Able to Reduce IL-22 Serum Levels in Patients with Psoriasis Vulgaris

Curcumin is a complementary therapy that may be helpful for the treatment of psoriasis due to its anti-inflammatory, antiangiogenic, antioxidant, and antiproliferative effects. In the present study we performed a randomized, double-blind, placebo-controlled clinical trial to assess the effectiveness of a bioavailable oral curcumin in the treatment of psoriasis. Sixty-three patients with mild-to-moderate psoriasis vulgaris (PASI < 10) were randomly divided into two groups treated with topical steroids and Meriva, a commercially available lecithin based delivery system of curcumin, at 2 g per day (arm 1), or with topical steroids alone (arm 2), both for 12 weeks. At the beginning (T0) and at the end of the therapy (T12), clinical assessment and immunoenzymatic analysis of the serum levels of IL-17 and IL-22 were performed. At T12, both groups achieved a significant reduction of PASI values that, however, was higher in patients treated with both topical steroids and oral curcumin than in patients treated only with topical steroids. Moreover, IL-22 serum levels were significantly reduced in patients treated with oral curcumin. In conclusion, curcumin was demonstrated to be effective as an adjuvant therapy for the treatment of psoriasis vulgaris and to significantly reduce serum levels of IL-22.

Beyond Yellow Curry: Assessing Commercial Curcumin Absorption Technologies

BACKGROUND: Few natural products have demonstrated the range of protective and therapeutic promise as have turmeric and its principal bioactive components: curcumin, demethoxycurcumin, and bisdemethoxycurcumin. Success in translating this potential into tangible benefits has been limited by inherently poor intestinal absorption, rapid metabolism, and limited systemic bioavailability. Seeking to overcome these limitations, food ingredient formulators have begun to employ a variety of approaches to enhance absorption and bioactivity. Many of these strategies improve upon the age-old practice of consuming turmeric in fat-based sauces, such as in a fat-rich yellow curry. However, there exists uncertainty as to how the various commercially available offerings compare to each other in terms of either uptake or efficacy, and this uncertainty leaves physicians and nutritionists with a dearth of data for making recommendations to interested patients and consumers. Further complicating the issue are recent data suggesting that formulation strategies may not equally enhance the absorption of individual curcuminoids, a significant issue in that these curcuminoids exhibit somewhat different physiologic properties.

OBJECTIVE: This review introduces needed order to the curcumin marketplace by examining bioavailability studies on a number of commercial curcumin ingredients and evaluating them on a level playing field.

METHODS: The comparative analysis includes standard pharmacokinetic parameters and a new metric, relative mass efficiency (E). Relative mass efficiency allows for the comparison of different formulations even in cases in which the weight percentage of curcuminoids is vastly different.

RESULTS: A hydrophilic carrier dispersed curcuminoid formula exhibits 45.9 times the bioavailability of the standard purified 95 percent curcuminoid preparation and, based on relative mass efficiency, 1.5 times the bioavailability of the next best commercial ingredient, a cyclodextrin complex.

CONCLUSIONS: Delivery strategies can significantly improve the bioavailability of curcuminoids. Total formula mass is important for making practical formulation decisions about dosing, cost and space.

Curcumin as a putative antidepressant

Due to inadequate efficacy of antidepressants, various new chemical entities and agents of natural origin have been tested for therapeutic efficacy both alone and to augment existing antidepressants, producing varied clinical results. This article summarizes the basic properties of curcumin and its mechanisms of action, with specific emphasis on the etiopathogenesis of depression, preclinical and current clinical evidence, and future research directions, to better understand the possible role of curcumin in treating depression. Curcumin may have antidepressant activities with diverse mechanisms of action involving primarily neurotransmitters, transcription pathways, neurogenesis, the hypothalamic-pituitary-adrenal axis and inflammatory and immune pathways, as demonstrated in various animal and human studies. Current published randomized clinical trials suggest a small, non-significant benefit of curcumin for major depression. More adequately-powered and methodologically improved studies are mandatory.

The effect of turmeric (Curcumin) supplementation on cytokine and inflammatory marker responses following 2 hours of endurance cycling

BACKGROUND

Endurance exercise induces IL-6 production from myocytes that is thought to impair intracellular defence mechanisms. Curcumin inhibits NF-κB and activator protein 1, responsible for cytokine transcription, in cell lines. The aim of this study was to investigate the effect of curcumin supplementation on the cytokine and stress responses following 2 h of cycling.

METHODS

Eleven male recreational athletes (35.5 ± 5.7 years; Wmax 275 ± 6 W; 87.2 ± 10.3 kg) consuming a low carbohydrate diet of 2.3 ± 0.2 g/kg/day underwent three double blind trials with curcumin supplementation, placebo supplementation, and no supplementation (control) to observe the response of serum interleukins (IL-6, IL1-RA, IL-10), cortisol, c-reactive protein (CRP), and subjective assessment of training stress. Exercise was set at 95% lactate threshold (54 ± 7% Wmax) to ensure that all athletes completed the trial protocol.

RESULTS

The trial protocol elicted a rise in IL-6 and IL1-RA, but not IL-10. The supplementation regimen failed to produce statistically significant results when compared to placebo and control. IL-6 serum concentrations one hour following exercise were (Median (IQR): 2.0 (1.8-3.6) Curcumin; 4.8 (2.1-7.3) Placebo; 3.5 (1.9-7.7) Control). Differences between supplementation and placebo failed to reach statistical significance (p = 0.18) with the median test. Repeated measures ANOVA time-trial interaction was at p = 0.06 between curcumin supplementation and placebo. A positive correlation (p = 0.02) between absolute exercise intensity and 1 h post-exercise for IL-6 concentration was observed. Participants reported "better than usual" scores in the subjective assessment of psychological stress when supplementing with curcumin, indicating that they felt less stressed during training days (p = 0.04) compared to placebo even though there was no difference in RPE during any of the training days or trials.

CONCLUSION

The limitations of the current regimen and trial involved a number of factors including sample size, mode of exercise, intensity of exercise, and dose of curcumin. Nevertheless these results provide insight for future studies with larger samples, and multiple curcumin dosages to investigate if different curcumin regimens can lead to statistically different interleukin levels when compared to a control and placebo.

Recent advances in pharmacotherapy for hypertriglyceridemia

Elevated plasma triglyceride (TG) concentrations are associated with an increased risk of atherosclerotic cardiovascular disease (CVD), hepatic steatosis and pancreatitis. Existing pharmacotherapies, such as fibrates, n-3 polyunsaturated fatty acids (PUFAs) and niacin, are partially efficacious in correcting elevated plasma TG. However, several new TG-lowering agents are in development that can regulate the transport of triglyceride-rich lipoproteins (TRLs) by modulating key enzymes, receptors or ligands involved in their metabolism. Balanced dual peroxisome proliferator-activated receptor (PPAR) α/γ agonists, inhibitors of microsomal triglyceride transfer protein (MTTP) and acyl-CoA:diacylglycerol acyltransferase-1 (DGAT-1), incretin mimetics, and apolipoprotein (apo) B-targeted antisense oligonucleotides (ASOs) can all decrease the production and secretion of TRLs; inhibitors of cholesteryl ester transfer protein (CETP) and angiopoietin-like proteins (ANGPTLs) 3 and 4, monoclonal antibodies (Mabs) against proprotein convertase subtilisin/kexin type 9 (PCSK9), apoC-III-targeted ASOs, selective peroxisome proliferator-activated receptor modulators (SPPARMs), and lipoprotein lipase (LPL) gene replacement therapy (alipogene tiparvovec) enhance the catabolism and clearance of TRLs; dual PPAR-α/δ agonists and n-3 polyunsaturated fatty acids can lower plasma TG by regulating both TRL secretion and catabolism. Varying degrees of TG reduction have been reported with the use of these therapies, and for some agents such as CETP inhibitors and PCSK9 Mabs findings have not been consistent. Whether they reduce CVD events has not been established. Trials investigating the effect of CETP inhibitors (anacetrapib and evacetrapib) and PCSK9 Mabs (AMG-145 and REGN727/SAR236553) on CVD outcomes are currently in progress, although these agents also regulate LDL metabolism and, in the case of CETP inhibitors, HDL metabolism. Further to CVD risk reduction, these new treatments might also have a potential role in the management of diabetes and non-alcoholic fatty liver disease owing to their insulin-sensitizing action (PPAR-α/γ agonists) and potential capacity to decrease hepatic TG accumulation (PPAR-α/δ agonists and DGAT-1 inhibitors), but this needs to be tested in future trials. We summarize the clinical trial findings regarding the efficacy and safety of these novel therapies for hypertriglyceridemia.

Reduction of delayed onset muscle soreness by a novel curcumin delivery system (Meriva®): a randomised, placebo-controlled trial

BACKGROUND

Delayed onset muscle soreness (DOMS) due to eccentric muscle activity is associated with inflammatory responses and production of reactive oxygen species (ROS) that sustain both inflammation and oxidative stress. Curcumin, a powerful promoter of anti-oxidant response, is one of the best-investigated natural products, and is now commercially available as a lecithin delivery system (Meriva®, Indena SpA, Milan) with improved bio-availability. The aim of this study was to test whether curcumin could attenuate damage from oxidative stress and inflammation related to acute muscle injury induced by eccentric continuous exercise.

METHODS

This was a randomised, placebo-controlled, single-blind pilot trial. Twenty male healthy, moderately active volunteers were randomised to curcumin given as the Phytosome® delivery system 1 g twice daily (200 mg curcumin b.i.d.) or matching placebo. Supplementation was initiated 48 hours prior to a downhill running test and was continued for 24 hours after the test (4 days in total). Muscle damage was quantified by magnetic resonance imaging, laboratory tests and histological analyses on muscle samples obtained 48 hours after the test. Patient-reported pain intensity was also recorded.

RESULTS

Subjects in the curcumin group reported less pain in the lower limb as compared with subjects in the placebo group, although significant differences were observed only for the right and left anterior thighs. Significantly fewer subjects in the curcumin group had MRI evidence of muscle injury in the posterior or medial compartment of both thighs. Increases in markers of muscle damage and inflammation tended to be lower in the curcumin group, but significant differences were only observed for interleukin-8 at 2 h after exercise. No differences in markers of oxidative stress and muscle histology were observed.

CONCLUSIONS

Curcumin has the potential for preventing DOMS, as suggested by its effects on pain intensity and muscle injury. Larger studies are needed to confirm these results and further clarify the mechanism of action of curcumin.

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.

Targeting cancer stem cells by curcumin and clinical applications

Curcumin is a well-known dietary polyphenol derived from the rhizomes of turmeric, an Indian spice. The anticancer effect of curcumin has been demonstrated in many cell and animal studies, and recent research has shown that curcumin can target cancer stem cells (CSCs). CSCs are proposed to be responsible for initiating and maintaining cancer, and contribute to recurrence and drug resistance. A number of studies have suggested that curcumin has the potential to target CSCs through regulation of CSC self-renewal pathways (Wnt/β-catenin, Notch, sonic hedgehog) and specific microRNAs involved in acquisition of epithelial-mesenchymal transition (EMT). The potential impact of curcumin, alone or in combination with other anticancer agents, on CSCs was evaluated as well. Furthermore, the safety and tolerability of curcumin have been well-established by numerous clinical studies. Importantly, the low bioavailability of curcumin has been dramatically improved through the use of structural analogues or special formulations. More clinical trials are underway to investigate the efficacy of this promising agent in cancer chemoprevention and therapy. In this article, we review the effects of curcumin on CSC self-renewal pathways and specific microRNAs, as well as its safety and efficacy in recent human studies. In conclusion, curcumin could be a very promising adjunct to traditional cancer treatments.

Curcumin-enhanced chemosensitivity of FDA-approved platinum (II)-based anti-cancer drugs involves downregulation of nuclear endonuclease G and NF-κB as well as induction of apoptosis and G2/M arrest

Curcumin, an active natural compound in turmeric and curry, has been reported to exhibit anti-cancer effect. Cisplatin, carboplatin and oxaliplatin are used to treat various types of cancers. However, acquired resistance and toxicities are observed. Here, the addition of curcumin significantly increased cytotoxicity of the anti-cancer drugs on human colorectal cancer HT-29 cells, producing synergistic (cisplatin and carboplatin) and additivity (oxaliplatin) effects. Treatments in combination with curcumin resulted in a significantly increased induction of apoptosis and occurrence of G2/M arrest. Nuclear apoptosis-inducing factor (AIF), EndoG and NF-κB were elevated by anti-cancer drugs, suggesting the involvement of AIF and EndoG. The addition of curcumin suppressed nuclear AIF and EndoG and reversed anti-cancer drugs-induced NF-κB expression, suggesting the association of EndoG and NF-κB in curcumin-enhanced chemosensitivity. Therefore, the intake of foods rich in curcumin or curcumin-containing supplements should be taken into consideration for patients receiving chemotherapy to optimize the outcome of treatments.

Clinical usefulness of oral supplementation with alpha-lipoic Acid, curcumin phytosome, and B-group vitamins in patients with carpal tunnel syndrome undergoing surgical treatment

We investigated the clinical usefulness of oral supplementation with a combination product containing alpha-lipoic acid, curcumin phytosome, and B-group vitamins in 180 patients with carpal tunnel syndrome (CTS), scheduled to undergo surgical decompression of the median nerve. Patients in Group A (n = 60) served as controls and did not receive any treatment either before or after surgery. Patients in Group B (n = 60) received oral supplementation twice a day for 3 months both before and after surgery (totaling 6 months of supplementation). Patients in Group C (n = 60) received oral supplementation twice a day for 3 months before surgery only. Patients in Group B showed significantly lower nocturnal symptoms scores compared with Group A subjects at both 40 days and 3 months after surgery (both P values <0.05). Moreover, patients in Group B had a significantly lower number of positive Phalen's tests at 3 months compared with the other study groups (P < 0.05). We conclude that oral supplementation with alpha-lipoic acid, curcumin phytosome, and B-group vitamins twice a day both before and after surgery is safe and effective in CTS patients scheduled to undergo surgical decompression of the median nerve.

The oral bioavailability of curcumin from micronized powder and liquid micelles is significantly increased in healthy humans and differs between sexes

SCOPE

Curcumin revealed various health-beneficial properties in numerous studies. However its bioavailability is low due to its limited intestinal uptake and rapid metabolism. The aim of our project was to develop novel curcumin formulations with improved oral bioavailability and to study their safety as well as potential sex-differences.

METHODS AND RESULTS

In this crossover study, healthy subjects (13 women, 10 men) took, in random order, a single oral dose of 500 mg curcuminoids as native powder, micronized powder, or liquid micelles. Blood and urine samples were collected for 24 h and total curcuminoids and safety parameters were quantified. Based on the area under the plasma concentration-time curve (AUC), the micronized curcumin was 14-, 5-, and 9-fold and micellar curcumin 277-, 114-, and 185-fold better bioavailable than native curcumin in women, men, and all subjects, respectively. Thus, women absorbed curcumin more efficiently than men. All safety parameters remained within the reference ranges following the consumption of all formulations.

CONCLUSION

Both, the micronized powder and in particular the liquid micellar formulation of curcumin significantly improved its oral bioavailability without altering safety parameters and may thus be ideally suited to deliver curcumin in human intervention trials. The observed sex differences in curcumin absorption warrant further investigation.

Therapeutic potential of curcumin in digestive diseases

Curcumin is a low-molecular-weight hydrophobic polyphenol that is extracted from turmeric, which possesses a wide range of biological properties including anti-inflammatory, anti-oxidant, anti-proliferative and anti-microbial activities. Despite its diverse targets and substantial safety, clinical applications of this molecule for digestive disorders have been largely limited to case series or small clinical trials. The poor bioavailability of curcumin is likely the major hurdle for its more widespread use in humans. However, complexation of curcumin into phytosomes has recently helped to bypass this problem, as it has been demonstrated that this new lecithin formulation enables increased absorption to a level 29-fold higher than that of traditional curcuminoid products. This allows us to achieve much greater tissue substance delivery using significantly lower doses of curcumin than have been used in past clinical studies. As curcumin has already been shown to provide good therapeutic results in some small studies of both inflammatory and neoplastic bowel disorders, it is reasonable to anticipate an even greater efficacy with the advent of this new technology, which remarkably improves its bioavailability. These features are very promising and may represent a novel and effective therapeutic approach to both functional and organic digestive diseases.

The molecular basis for the pharmacokinetics and pharmacodynamics of curcumin and its metabolites in relation to cancer

This review addresses the oncopharmacological properties of curcumin at the molecular level. First, the interactions between curcumin and its molecular targets are addressed on the basis of curcumin's distinct chemical properties, which include H-bond donating and accepting capacity of the β-dicarbonyl moiety and the phenylic hydroxyl groups, H-bond accepting capacity of the methoxy ethers, multivalent metal and nonmetal cation binding properties, high partition coefficient, rotamerization around multiple C-C bonds, and the ability to act as a Michael acceptor. Next, the in vitro chemical stability of curcumin is elaborated in the context of its susceptibility to photochemical and chemical modification and degradation (e.g., alkaline hydrolysis). Specific modification and degradatory pathways are provided, which mainly entail radical-based intermediates, and the in vitro catabolites are identified. The implications of curcumin's (photo)chemical instability are addressed in light of pharmaceutical curcumin preparations, the use of curcumin analogues, and implementation of nanoparticulate drug delivery systems. Furthermore, the pharmacokinetics of curcumin and its most important degradation products are detailed in light of curcumin's poor bioavailability. Particular emphasis is placed on xenobiotic phase I and II metabolism as well as excretion of curcumin in the intestines (first pass), the liver (second pass), and other organs in addition to the pharmacokinetics of curcumin metabolites and their systemic clearance. Lastly, a summary is provided of the clinical pharmacodynamics of curcumin followed by a detailed account of curcumin's direct molecular targets, whereby the phenotypical/biological changes induced in cancer cells upon completion of the curcumin-triggered signaling cascade(s) are addressed in the framework of the hallmarks of cancer. The direct molecular targets include the ErbB family of receptors, protein kinase C, enzymes involved in prostaglandin synthesis, vitamin D receptor, and DNA.

Curcuma longa L. as a therapeutic agent in intestinal motility disorders. 2: Safety profile in mouse

BACKGROUND

Curcuma extract exerts a myorelaxant effect on the mouse intestine. In view of a possible use of curcuma extract in motor functional disorders of the gastrointestinal tract, a safety profile study has been carried out in the mouse.

METHODS

Thirty mice were used to study the in vitro effect of curcuma on gallbladder, bladder, aorta and trachea smooth muscular layers and hearth inotropic and chronotropic activity. The myorelaxant effect on the intestine was also thoroughly investigated. Moreover, curcuma extract (200 mg/Kg/day) was orally administered to twenty mice over 28 days and serum liver and lipids parameters were evaluated. Serum, bile and liver bile acids qualitative and quantitative composition was were also studied.

RESULTS

In the intestine, curcuma extract appeared as a not competitive inhibitor through cholinergic, histaminergic and serotoninergic receptors and showed spasmolytic effect on K(+) induced contraction at the level of L type calcium channels. No side effect was observed on bladder, aorta, trachea and heart when we used a dose that is effective on the intestine. An increase in gallbladder tone and contraction was observed. Serum liver and lipids parameters were normal, while a slight increase in serum and liver bile acids concentration and a decrease in bile were observed.

CONCLUSIONS

Although these data are consistent with the safety of curcuma extract as far as its effect on the smooth muscular layers of different organs and on the heart, the mild cholestatic effect observed in absence of alteration of liver function tests must be further evaluated and the effective dose with minimal side effects considered.

Improving permeability and oral absorption of mangiferin by phospholipid complexation

Mangiferin is an active ingredient of medicinal plant with poor hydrophilicity and lipophilicity. Many reports focused on improving aqueous solubility, but oral bioavailability of mangiferin was still limited. In this study, we intended to increase not only solubility, but also membrane permeability of mangiferin by a phospholipid complexation technique. The new complex's physicochemical properties were characterized in terms of scanning electron microscopy (SEM), differential scanning calorimetry (DSC), infrared absorption spectroscopy (IR), aqueous solubility, oil-water partition coefficient and in vitro dissolution. The intestinal absorption of the complex was studied by the rat in situ intestinal perfusion model. After oral administration of mangiferin-phospholipid complex and crude mangiferin in rats, the concentrations of mangiferin were determined by a validated RP-HPLC method. Results showed that the solubility of the complex in water and in n-octanol was enhanced and the oil-water partition coefficient was improved by 6.2 times and the intestinal permeability in rats was enhanced significantly. Peak plasma concentration and AUC of mangiferin from the complex (Cmax: 377.66 μg/L, AUC: 1039.94 μg/L*h) were higher than crude mangiferin (Cmax: 180 μg/L, AUC: 2355.63 μg/L*h). In view of improved solubility and enhanced permeability, phospholipid complexation technique can increase bioavailability of mangiferin by 2.3 times in comparison to the crude mangiferin.

Dissecting the pharmacophore of curcumin. Which structural element is critical for which action?

The dietary phenolic curcumin (1a) is the archetypal network pharmacological agent, but is characterized by an ill-defined pharmacophore. Nevertheless, structure-activity studies of 1a have mainly focused on a single biological end-point and on a single structural element, the aliphatic bis-enoyl moiety. The comparative investigation of more than one end-point of curcumin and the modification of its aromatic region have been largely overlooked. To address these issues, we have investigated the effect of aromatic C-prenylation in the three archetypal structural types of curcuminoids, namely, curcumin itself (1a), its truncated analogue 2a (C5-curcumin), and (as the reduced isoamyl version) the tetrahydro derivative 3a, comparatively evaluating reactivity with thiols and activity in biochemical (inhibition of NF-κB, HIV-1-Tat transactivation, Nrf2 activation) and phenotypic (anti-HIV action) assays sensitive, to a various extent, to thia-Michael addition. Prenylation, a validated maneuver for bioactivity modulation in plant phenolics, had no effect on Michael reactivity, but was detrimental for all biological end-points investigated, dissecting thiol trapping from activity, while hydrogenation attenuated, but did not completely abrogate, the activity of 1a. The C5-curcuminoid 2a outperformed the natural product in all end-points investigated and was identified as a novel high-potency anti-HIV lead in a cellular model of HIV infection. Taken together, these observations show that Michael reactivity is a critical element of the curcumin pharmacophore, but also reveal a surprising sensitivity of bioactivity to C-prenylation of the vanillyl moiety.

Oral administration of a curcumin-phospholipid delivery system for the treatment of central serous chorioretinopathy: a 12-month follow-up study

BACKGROUND

The therapeutic effects of Meriva®, a curcumin-phospholipid (lecithin) delivery system (formulated as Norflo® tablets), on visual acuity and retinal thickness in patients with acute and chronic central serous chorioretinopathy was previously investigated in a six-month open-label study.

METHODS

In this follow-up study, visual acuity was again assessed by ophthalmologic evaluation and retinal thickness by optical coherence tomography (OCT). Norflo tablets were administered twice daily to patients with central serous chorioretinopathy. The study group consisted of 12 patients (total 18 eyes) who completed 12 months of follow-up. The primary endpoint was change in visual acuity before and after treatment with Norflo, and change in neuroretinal or retinal pigment epithelium detachment on OCT was the secondary endpoint.

RESULTS

After 12 months of therapy, no eyes showed further reduction in visual acuity, 39% showed stabilization, and 61% showed statistically significant improvement (P = 0.0001 by Student's t-test and P = 0.0005 by Wilcoxon signed rank test). Ninety-five percent of eyes showed a reduction in neuroretinal or retinal pigment epithelium detachment and 5% showed stabilization. The difference in retinal thickness after 12 months was statistically significant (P = 0.0001 by Student's t-test and P = 0.0004 by Wilcoxon signed rank test).

CONCLUSION

These results, albeit preliminary, confirm our previous finding that this curcumin delivery system is effective in the management of central serous chorioretinopathy. When administered in a bioavailable formulation, curcumin is worth considering as a therapeutic agent for the management of inflammatory and degenerative eye conditions involving activation of retinal microglial cells.

Comparative evaluation of the pain-relieving properties of a lecithinized formulation of curcumin (Meriva(®)), nimesulide, and acetaminophen

In addition to its anti-inflammatory activity, Meriva^®, a proprietary lecithin formulation of curcumin, has been anecdotally reported to decrease acute pain in patients with various chronic diseases. Given that curcumin can desensitize transient receptor potential A1, a nociceptor seemingly also mediating the analgesic effect of acetaminophen, as well as inhibiting and downregulating the expression of cyclo-oxygenase 2, the selective target of nimesulide, a nonsteroidal anti-inflammatory agent, we carried out a pilot comparative study of the acute pain-relieving properties of these three agents. At a dose of 2 g (corresponding to 400 mg of curcumin), Meriva showed clear analgesic activity, comparable with that of a standard dose (1 g) of acetaminophen, but lower than that of a therapeutic (100 mg) dose of nimesulide. The analgesic activity of lower (1.5 g) doses of Meriva was less satisfactory, and the onset of activity was longer than that of nimesulide for both doses. On the other hand, gastric tolerability was significantly better than that of nimesulide and comparable with that of acetaminophen. Taken together, our results show that the preclinical analgesic properties of curcumin have clinical relevance, at least at a dose of 2 g as the Meriva formulation. While this dose is significantly higher than that used to relieve chronic inflammatory conditions (1–1.2 g/day), its pain-relieving activity could benefit from the general downregulation of the inflammatory response induced by curcumin, considering that the transient receptor potential channel-mediated mechanisms of analgesia are magnified by attenuation of inflammation. In patients on treatment with Meriva, this would also translate into better control of acute pain, providing a rationale for the analgesic properties associated with this curcumin formulation.

Curcumin, a component of turmeric: from farm to pharmacy

Curcumin, an active polyphenol of the golden spice turmeric, is a highly pleiotropic molecule with the potential to modulate the biological activity of a number of signaling molecules. Traditionally, this polyphenol has been used in Asian countries to treat such human ailments as acne, psoriasis, dermatitis, and rash. Recent studies have indicated that curcumin can target newly identified signaling pathways including those associated with microRNA, cancer stem cells, and autophagy. Extensive research from preclinical and clinical studies has delineated the molecular basis for the pharmaceutical uses of this polyphenol against cancer, pulmonary diseases, neurological diseases, liver diseases, metabolic diseases, autoimmune diseases, cardiovascular diseases, and numerous other chronic diseases. Multiple studies have indicated the safety and efficacy of curcumin in numerous animals including rodents, monkeys, horses, rabbits, and cats and have provided a solid basis for evaluating its safety and efficacy in humans. To date, more than 65 human clinical trials of curcumin, which included more than 1000 patients, have been completed, and as many as 35 clinical trials are underway. Curcumin is now used as a supplement in several countries including the United States, India, Japan, Korea, Thailand, China, Turkey, South Africa, Nepal, and Pakistan. In this review, we provide evidence for the pharmaceutical uses of curcumin for various diseases.

Curcumin in various cancers

Curcumin (diferuloylmethane), an active constituent of turmeric, is a well-described phytochemical, which has been used since ancient times for the treatment of various diseases. The dysregulation of cell signaling pathways by the gradual alteration of regulatory proteins is the root cause of cancers. Curcumin modulates regulatory proteins through various molecular mechanisms. Several research studies have provided in-depth analysis of multiple targets through which curcumin induces protective effects against cancers including gastrointestinal, genitourinary, gynecological, hematological, pulmonary, thymic, brain, breast, and bone. The molecular mechanisms of action of curcumin in treating different types of cancers remain under investigation. The multifaceted role of this dietary agent is mediated through its inhibition of several cell signaling pathways at multiple levels. Curcumin has the ability to inhibit carcinogenicity through the modulation of the cell cycle by binding directly and indirectly to molecular targets including transcription factors (NF-kB, STAT3, β-catenin, and AP-1), growth factors (EGF, PDGF, and VEGF), enzymes (COX-2, iNOS, and MMPs), kinases (cyclin D1, CDKs, Akt, PKC, and AMPK), inflammatory cytokines (TNF, MCP, IL-1, and IL-6), upregulation of proapoptotic (Bax, Bad, and Bak) and downregulation of antiapoptotic proteins (Bcl(2) and Bcl-xL). A variety of animal models and human studies have proven that curcumin is safe and well tolerated even at very high doses. This study elaborates the current understanding of the chemopreventive effects of curcumin through its multiple molecular pathways and highlights its therapeutic value in the treatment and prevention of a wide range of cancers.

Spices: the savory and beneficial science of pungency

Spicy food does not only provide an important hedonic input in daily life, but has also been anedoctically associated to beneficial effects on our health. In this context, the discovery of chemesthetic trigeminal receptors and their spicy ligands has provided the mechanistic basis and the pharmacological means to investigate this enticing possibility. This review discusses in molecular terms the connection between the neurophysiology of pungent spices and the "systemic" effects associated to their trigeminality. It commences with a cultural and historical overview on the Western fascination for spices, and, after analysing in detail the mechanisms underlying the trigeminality of food, the main dietary players from the transient receptor potential (TRP) family of cation channels are introduced, also discussing the "alien" distribution of taste receptors outside the oro-pharingeal cavity. The modulation of TRPV1 and TRPA1 by spices is next described, discussing how spicy sensations can be turned into hedonic pungency, and analyzing the mechanistic bases for the health benefits that have been associated to the consumption of spices. These include, in addition to a beneficial modulation of gastro-intestinal and cardio-vascular function, slimming, the optimization of skeletal muscle performance, the reduction of chronic inflammation, and the prevention of metabolic syndrome and diabetes. We conclude by reviewing the role of electrophilic spice constituents on cancer prevention in the light of their action on pro-inflammatory and pro-cancerogenic nuclear factors like NFκB, and on their interaction with the electrophile sensor protein Keap1 and the ensuing Nrf2-mediated transcriptional activity. Spicy compounds have a complex polypharmacology, and just like any other bioactive agent, show a balance of beneficial and bad actions. However, at least for moderate consumption, the balance seems definitely in favour of the positive side, suggesting that a spicy diet, a caveman-era technology, could be seriously considered in addition to caloric control and exercise as a measurement to prevent and control many chronic diseases associate to malnutrition from a Western diet.

Multiple antidepressant potential modes of action of curcumin: a review of its anti-inflammatory, monoaminergic, antioxidant, immune-modulating and neuroprotective effects

Curcumin is the principal curcuminoid of the popular Indian spice turmeric and has attracted increasing attention for the treatment of a range of conditions. Research into its potential as a treatment for depression is still in its infancy, although several potential antidepressant mechanisms of action have been identified. Research completed to date on the multiple effects of curcumin is reviewed in this paper, with a specific emphasis on the biological systems that are compromised in depression. The antidepressant effects of curcumin in animal models of depression are summarised, and its influence on neurotransmitters such as serotonin and dopamine is detailed. The effects of curcumin in moderating hypothalamus-pituitary-adrenal disturbances, lowering inflammation and protecting against oxidative stress, mitochondrial damage, neuroprogression and intestinal hyperpermeability, all of which are compromised in major depressive disorder, are also summarised. With increasing interest in natural treatments for depression, and efforts to enhance current treatment outcomes, curcumin is presented as a promising novel, adjunctive or stand-alone natural antidepressant.

Therapeutic roles of curcumin: lessons learned from clinical trials

Extensive research over the past half century has shown that curcumin (diferuloylmethane), a component of the golden spice turmeric (Curcuma longa), can modulate multiple cell signaling pathways. Extensive clinical trials over the past quarter century have addressed the pharmacokinetics, safety, and efficacy of this nutraceutical against numerous diseases in humans. Some promising effects have been observed in patients with various pro-inflammatory diseases including cancer, cardiovascular disease, arthritis, uveitis, ulcerative proctitis, Crohn's disease, ulcerative colitis, irritable bowel disease, tropical pancreatitis, peptic ulcer, gastric ulcer, idiopathic orbital inflammatory pseudotumor, oral lichen planus, gastric inflammation, vitiligo, psoriasis, acute coronary syndrome, atherosclerosis, diabetes, diabetic nephropathy, diabetic microangiopathy, lupus nephritis, renal conditions, acquired immunodeficiency syndrome, β-thalassemia, biliary dyskinesia, Dejerine-Sottas disease, cholecystitis, and chronic bacterial prostatitis. Curcumin has also shown protection against hepatic conditions, chronic arsenic exposure, and alcohol intoxication. Dose-escalating studies have indicated the safety of curcumin at doses as high as 12 g/day over 3 months. Curcumin's pleiotropic activities emanate from its ability to modulate numerous signaling molecules such as pro-inflammatory cytokines, apoptotic proteins, NF-κB, cyclooxygenase-2, 5-LOX, STAT3, C-reactive protein, prostaglandin E(2), prostate-specific antigen, adhesion molecules, phosphorylase kinase, transforming growth factor-β, triglyceride, ET-1, creatinine, HO-1, AST, and ALT in human participants. In clinical trials, curcumin has been used either alone or in combination with other agents. Various formulations of curcumin, including nanoparticles, liposomal encapsulation, emulsions, capsules, tablets, and powder, have been examined. In this review, we discuss in detail the various human diseases in which the effect of curcumin has been investigated.

Enhanced absorption of boswellic acids by a lecithin delivery form (Phytosome(®)) of Boswellia extract

The anti-inflammatory potential of Boswellia serrata gum resin extracts has been demonstrated in vitro and in animal studies as well as in pilot clinical trials. However, pharmacokinetic studies have evidenced low systemic absorption of boswellic acids (BAs), especially of KBA and AKBA, in rodents and humans. This observation has provided a rationale to improve the formulation of Boswellia extract. We present here the results of a murine comparative bioavailability study of Casperome™, a soy lecithin formulation of standardized B. serrata gum resin extract (BE), and its corresponding non-formulated extract. The concentration of the six major BAs [11-keto-β-boswellic acid (KBA), acetyl-11-keto-β-boswellic acid (AKBA), β-boswellic acid (βBA), acetyl-β-boswellic acid (AβBA), α-boswellic acid (αBA), and acetyl-α-boswellic acid (AαBA)] was evaluated in the plasma and in a series of tissues (brain, muscle, eye, liver and kidney), providing the first data on tissue distribution of BAs. Weight equivalent and equimolar oral administration of Casperome™ provided significantly higher plasma levels (up to 7-fold for KBA, and 3-fold for βBA quantified as area under the plasma concentration time curve, AUC(last)) compared to the non-formulated extract. This was accompanied by remarkably higher tissue levels. Of particular relevance was the marked increase in brain concentration of KBA and AKBA (35-fold) as well as βBA (3-fold) following Casperome™ administration. Notably, up to 17 times higher BA levels were observed in poorly vascularized organs such as the eye. The increased systemic availability of BAs and the improved tissue distribution, qualify Casperome™ for further clinical development to fully exploit the clinical potential of BE.

Emerging role of nanocarriers to increase the solubility and bioavailability of curcumin

INTRODUCTION

Curcumin is a safe, affordable and natural bioactive molecule of turmeric (Curcuma longa). It has gained considerable attention in recent years for its multiple pharmacological activities. However, its optimum pharmaceutical potential has been limited by its lack of aqueous solubility and poor bioavailability. To mitigate the above limitations, recently various nanostructured water-soluble delivery systems were developed to increase the solubility and bioavailability of curcumin.

AREAS COVERED

Major reasons contributing to the low bioavailability of curcumin appear to be owing to its poor solubility, low absorption, rapid metabolism and rapid systemic elimination. The present review summarizes the strategies using curcumin in various nanocarrier delivery systems to overcome poor solubility and inconsistent bioavailability of curcumin and describes the current status and challenges for the future.

EXPERT OPINION

The development of various drug delivery systems to deliver curcumin will certainly provide a step up towards augmenting the therapeutic activity of curcumin thereby increasing the solubility and bioavailability of curcumin. However, the future of such delivery technology will be highly dependent on the development of safe, non-toxic and non-immunogenic nanocarriers.

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.

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: the potential for efficacy in gastrointestinal diseases

Curcumin is a naturally occurring phytochemical and an extract of turmeric. Extensive in vitro and in vivo data have paved the way for curcumin to become the subject of clinical trials. Curcumin modulates key signalling pathways important in cellular processes. Numerous mechanisms of action have been elucidated. The potential for clinical efficacy is apparent from benign and malignant disease models. Curcumin has potent anti-inflammatory and anti-neoplastic properties used alone and in combination with standard therapies. Early-phase trials have ascertained pharmacological properties and consistently demonstrate it to be safe and well tolerated. However, bioavailability is limited and efficacious doses have not yet been determined. Evidence of efficacy has been derived from animal models or small clinical trials. There is only finite data supporting the use of curcumin in phase III trials with specific diseases (e.g. ulcerative colitis). However, for the vast majority of conditions additional early-phase studies are required to justify larger trials determining efficacy.