Analgesic Efficacy and Safety of Curcuminoids in Clinical Practice: A Systematic Review and Meta-Analysis of Randomized Controlled Trials

Targeting mTOR with curcumin: therapeutic implications for complex diseases

The mammalian target of rapamycin (mTOR) is a crucial enzyme in regulating multiple signaling pathways in the body, including autophagy, proliferation and apoptosis. Disruption of these mTOR signaling pathways can lead to an array of abnormalities and trigger disease processes, examples being neurodegenerative conditions, cancer, obesity and diabetes. Under conditions of oxidative stress, mTOR can regulate apoptosis and autophagy, with tissue repair being favored under such circumstances. Moreover, the correlation between mTOR and other signaling pathways could play a pivotal role in the pathophysiology of numerous disorders. mTOR has a tight connection with NF-κB, Akt, PI3K, MAPK, GSK-3β, Nrf2/HO-1, JAK/STAT, CREB/BDNF, and ERK1/2 pathways, which together could play significant roles in the regulation of inflammation, apoptosis, cell survival, and oxidative stress in different body organs. Research suggests that inhibiting mTOR could be beneficial in treating metabolic, neurological and cardiovascular conditions, as well as potentially extending life expectancy. Therefore, identifying new chemicals and agents that can modulate the mTOR signaling pathway holds promise for treating and preventing these disorders. Curcumin is one such agent that has demonstrated regulatory effects on the mTOR pathway, making it an exciting alternative for reducing complications associated with complex diseases by targeting mTOR. This review aims to examine the potential of curcumin in modulating the mTOR signaling pathway and its therapeutic implications.

Management of Fibromyalgia: Novel Nutraceutical Therapies Beyond Traditional Pharmaceuticals

The pathophysiology of fibromyalgia, a condition that causes chronic pain throughout the body, involves abnormal pain signaling, genetic predispositions, and abnormal neuroendocrine function, significantly impairing quality of life. Fibromyalgia is commonly characterized by musculoskeletal pain, chronic fatigue, and severe sleep alterations. Changes in the central processing of sensory input and defects in endogenous pain inhibition could be the basis of enhanced and persistent pain sensitivity in individuals with fibromyalgia. The term central sensitivity syndrome was chosen as an umbrella term for fibromyalgia and related illnesses, including myalgic encephalomyelitis/chronic fatigue syndrome, migraine, and irritable bowel syndrome. Given the substantial impact of fibromyalgia on health, there is a need for new prevention and treatment strategies, particularly those involving bioavailable nutraceuticals and/or phytochemicals. This approach is particularly important considering the adverse effects of current fibromyalgia pharmaceutical treatments, such as antidepressants and anticonvulsants, which can lead to physical dependence and tolerance. Natural products have recently been considered for the design of innovative analgesics and antinociceptive agents to manage fibromyalgia pain. Polyphenols show promise in the management of neuropathic pain and fibromyalgia, especially considering how anti-inflammatory treatments, including corticosteroids and nonsteroidal medical drugs, are effective only when inflammatory processes coexist and are not recommended as the primary treatment for fibromyalgia.

Evaluating the efficacy of curcumin in the management of oral potentially malignant disorders: a systematic review and meta-analysis

Background

Oral potentially malignant disorders (OPMDs) not only harbour the risk of malignant transformation but can also affect patients' quality of life owing to severe symptoms. Therefore, there is an urgent need for therapeutic strategies to improve patients' quality of life. The objective of this meta-analysis was to comprehensively assess the efficacy of curcumin in the management of OPMDs.

Methods

PubMed, Embase, the Cochrane Library, and Web of Science were searched for clinical trials evaluating the efficacy of curcumin in the treatment of OPMDs from inception until March 2024. RevMan 5.4 software was used to perform statistical and subgroup analyses.

Results

Sixteen randomised controlled trials (1,089 patients) were selected. Curcumin exhibited comparable efficacy to conventional controls in alleviating pain (I2 = 98%, P = 0.49) and improving tongue protrusion (I2 = 94%, P = 0.51) in oral submucous fibrosis (OSF). Additionally, topical use of curcumin had an efficacy equivalent to that of conventional therapy in reducing pain (I2 = 83%, P = 0.31) and facilitating clinical remission (I2 = 67%, P = 0.38) of oral lichen planus (OLP).

Conclusion

The topical use of curcumin may palliate pain and promote clinical healing in OLP patients. Systemic curcumin can ameliorate the degree of pain and tongue protrusion in OSF. Therefore, our study suggests that curcumin could serve as an alternative treatment for managing OPMDs with lower medical toxicity than steroids, especially when steroids are not suitable. Further studies with larger sample sizes and adequate follow-up periods are required to validate our results.

Analgesic Potential Comparison Between Piperine-Combined Curcumin Patch and Non-Piperine Curcumin Patch: A Pragmatic Trial on Post-Cleft Lip/Palate Surgery Pediatric Patients

Purpose

Despite its well-acknowledged analgesic potential, curcumin's low bioavailability has been recognized. Piperine, a substance naturally contained in pepper, has been known for its effect on increasing curcumin bioavailability. To investigate the analgesic potential of curcumin and piperine addition to curcumin patch used as adjuvant therapy in the management of acute postoperative orofacial pain.

Patients and Methods

This pragmatic trial recruited 75 patients that underwent oromaxillofacial surgery at Unpad Dental Hospital, Bandung, Indonesia. Research participants were randomly assigned to three different groups: the first group that did not receive any intervention other than the post-operative standard treatment (POST), the second group that received POST and non-piperine curcumin patch, and the third group that received POST and piperine-combined curcumin patch. Participants' pain intensity was evaluated by using the face, leg, activity, cry, and consolability (FLACC) pain scale and salivary prostaglandin-E2 (PGE2) level for two-time points, which were eight hours apart. All data were gathered and analyzed to compare the within and between-group differences.

Results

Within groups comparison of the FLACC scores for two evaluation points showed significant differences for all groups (p < 0.01). For salivary PGE2 analysis, a comparison of the non-piperine group to the piperine group also showed significant results. Yet, when all three groups were compared, regardless of the differences, the results were not statistically significant.

Conclusion

Despite of the proven efficacy of curcumin patch, the addition of piperine to the curcumin patch in the current study did not provide any significant effects. Further investigation is of importance.

Effects of Functional and Nutraceutical Foods in the Context of the Mediterranean Diet in Patients Diagnosed with Breast Cancer

Several studies report that breast cancer survivors (BCS) tend to have a poor diet, as fruit, vegetable, and legume consumption is often reduced, resulting in a decreased intake of nutraceuticals. Moreover, weight gain has been commonly described among BCS during treatment, increasing recurrence rate and mortality. Improving lifestyle and nutrition after the diagnosis of BC may have important benefits on patients' general health and on specific clinical outcomes. The Mediterranean diet (MD), known for its multiple beneficial effects on health, can be considered a nutritional pool comprising several nutraceuticals: bioactive compounds and foods with anti-inflammatory and antioxidant effects. Recent scientific advances have led to the identification of nutraceuticals that could amplify the benefits of the MD and favorably influence gene expression in these patients. Nutraceuticals could have beneficial effects in the postdiagnostic phase of BC, including helping to mitigate the adverse effects of chemotherapy and radiotherapy. Moreover, the MD could be a valid and easy-to-follow option for managing excess weight. The aim of this narrative review is to evaluate the recent scientific literature on the possible beneficial effects of consuming functional and nutraceutical foods in the framework of MD in BCS.

Curcuma as an anti-inflammatory component in treating osteoarthritis

Osteoarthritis (OA) is nowadays the most common musculoskeletal progressive condition. In recent decades, incidence and prevalence of OA have increased significantly. It is estimated that the prevalence of OA among adults older than 60 is 12%, affecting about 240 million people globally. The cause has not been fully elucidated, and therefore, there is no cure at the moment. It is a multifactorial degenerative disease with an inflammatory component mediated by numerous proinflammatory and anti-inflammatory cytokines, chemokines, and growth factors. OA is not yet fully understood; therefore, therapeutic interventions are aimed primarily at reducing symptoms and slowing the progression of joint destruction. Of the therapeutic options available, the most often prescribed are nonsteroidal antirheumatic drugs, which have numerous side effects. Therefore, a need for a safe, effective substance is differentiated, which will be used in adjuvant treatment, but also in disease prevention, and which will comparatively have no or fewer side effects. One such substance is curcumin, a hydrophobic polyphenol that forms the active component of the rhizome of the Curcuma longa plant. Several studies have shown its potent antioxidant and anti-inflammatory effect, non-toxicity, and safety at high daily doses. In addition to blocking chondrocyte apoptosis, curcumin also blocks the expression of cyclooxygenase, prostaglandin E-2 and proinflammatory cytokines in chondrocytes, potentially alleviating symptomatic diseases. Although there are significant variations in quality, methodology, and research results conducted on curcumin efficiency in OA treatment, curcumin is primarily recommended as systematic short-term and medium-term adjuvant therapy that reduces inflammatory biochemical factors. Reducing inflammation leads to better pain regulation and improved joint function, significantly reducing standard prescribed doses of drugs. The most researched daily doses of curcumin intake are 1000-2000 mg/day, which would also be the doses that most of the authors recommend. Further research is needed to determine the preventive role of curcumin in the pathogenesis of OA, the effects of long-term usage of curcumin in preventive purposes and treatment of osteoarthritis, as well as to determine optimal therapeutic dosages.

Curcumin and chemokines: mechanism of action and therapeutic potential in inflammatory diseases

Chemokines belong to the family of cytokines with chemoattractant properties that regulate chemotaxis and leukocyte migration, as well as the induction of angiogenesis and maintenance of hemostasis. Curcumin, the major component of the Curcuma longa rhizome, has various pharmacological actions, including anti-inflammatory, immune-regulatory, anti-oxidative, and lipid-modifying properties. Chemokines and chemokine receptors are influenced/modulated by curcumin. Thus, the current review focuses on the molecular mechanisms associated with curcumin's effects on chemoattractant cytokines, as well as putting into context the many studies that have reported curcumin-mediated regulatory effects on inflammatory conditions in the organs/systems of the body (e.g., the central nervous system, liver, and cardiovascular system). Curcumin's effects on viral and bacterial infections, cancer, and adverse pregnancy outcomes are also reviewed.

Role of curcumin and its nanoformulations in the treatment of neurological diseases through the effects on stem cells

Curcumin from turmeric is a natural phenolic compound with a promising potential to regulate fundamental processes involved in neurological diseases, including inflammation, oxidative stress, protein aggregation, and apoptosis at the molecular level. In this regard, employing nanoformulation can improve curcumin efficiency by reducing its limitations, such as low bioavailability. Besides curcumin, growing data suggest that stem cells are a noteworthy candidate for neurodegenerative disorders therapy due to their anti-inflammatory, anti-oxidative, and neuronal-differentiation properties, which result in neuroprotection. Curcumin and stem cells have similar neurogenic features and can be co-administered in a cell-drug delivery system to achieve better combination therapeutic outcomes for neurological diseases. Based on the evidence, curcumin can induce the neuroprotective activity of stem cells by modulating their related signalling pathways. The present review is about the role of curcumin and its nanoformulations in the improvement of neurological diseases alone and through the effect on different categories of stem cells by discussing the underlying mechanisms to provide a roadmap for future investigations.

The effects of phytochemicals on serum triglycerides in subjects with hypertriglyceridemia: A systematic review of randomized controlled trials

This systematic review aimed to evaluate the efficacy of phytochemicals on lipid parameters in patients with hypertriglyceridemia (HTG). A comprehensive search was performed in PubMed/Medline, Scopus, ISI Web of Science, and Google Scholar from inception up to October 2021 to recognize randomized controlled trials (RCTs) assessing the effects of phytochemicals on lipid profiles in patients with HTG. Forty-eight RCTs including 53 arms and comprising 3,478 HTG patients met the eligibility criteria. Phytochemicals significantly reduced the serum levels of triglycerides in 32 out 53 arms, total cholesterol in 22 out of 51, low-density lipoprotein cholesterol in 21 out of 48, very low-density lipoprotein cholesterol in 1 out of 5, apolipoprotein B in 2 out of 4, and lipoprotein(a) levels in 2 out of 4 arms. Furthermore, phytochemicals supplementation increased the levels of high-density lipoprotein cholesterol in 15 out of 48 arms. In brief, phytochemicals supplementation might have beneficial effects on HTG. In most of the studies, phytochemicals had a favorable effect on at least one of the lipid parameters.

A review on curcumin colon-targeted oral drug delivery systems for the treatment of inflammatory bowel disease

Synthetic drugs and monoclonal antibodies are the typical treatments to combat inflammatory bowel disease (IBD). However, side effects are present when these treatments are used, and their continued application could be restricted by the high relapse rate of the disease. One potential alternative to these treatments is the use of plant-derived products. The use curcumin is one such treatment option that has seen an increase in usage in treating IBD. Curcumin is derived from a rhizome of turmeric (Curcuma longa), and the results of studies on the use of curcumin to treat IBD are promising. These studies suggest that curcumin interacts with cellular targets such as NF-κB, JAKs/STATs, MAPKs, TNF-α, IL-6, PPAR, and TRPV1 and may reduce the progression of IBD. Potentially, curcumin can be used as a therapeutic agent for patients with IBD when it reduces the incidence of clinical relapse. This review discusses the strategies utilized in designing and developing an oral colonic delivery dosage form of curcumin.

Curcumin-piperine co-supplementation and human health: A comprehensive review of preclinical and clinical studies

Curcumin is extracted from the rhizomes Curcuma longa L. It is known for its anti-inflammatory and anti-oxidant activities. Despite its safety and potential for use against various diseases, curcumin's utility is restricted due to its low oral bioavailability. Co-administration of curcumin along with piperine could potentially improve the bioavailability of curcumin. The present review aimed to provide an overview of the efficacy and safety of curcumin-piperine co-supplementation in human health. The findings of this comprehensive review show the beneficial effects of curcumin-piperine in improving glycemic indices, lipid profile and antioxidant status in diabetes, improving the inflammatory status caused by obesity and metabolic syndrome, reducing oxidative stress and depression in chronic stress and neurological disorders, also improving chronic respiratory diseases, asthma and COVID-19. Further high-quality clinical trial studies are needed to firmly establish the clinical efficacy of the curcumin-piperine supplement.

An update on molecular mechanisms of curcumin effect on diabetes

Owing to its prevalent nature, diabetes mellitus has become one of the most serious endocrine illnesses affecting a patient's quality of life due to the manifestation of side effects such as cardiovascular diseases, retinopathy, neuropathy, and nephropathy. Curcumin ((1E, 6E) 21, 7-bis (4-hydroxy-3-methoxyphenyl)-1,6-heptadiene-3,5-dione), a major compound of turmeric, has been used in conventional medicine because of its safe nature and cost-effectiveness to meliorate diabetes and its comorbidities. These effects have also been observed in rodent models of diabetes resulting in a reduction of glycemia and blood lipids. Both the preventive and therapeutic activities of this compound are due to its antioxidant and anti-inflammatory characteristics. Furthermore, preclinical outcomes and clinical investigation demonstrate that the use of curcumin neutralizes insulin resistance, obesity, and hyperglycemia. Despite the many benefits of curcumin, its two limiting factors, solubility and bioavailability, remain a challenge for researchers; therefore, several methods such as drug formulation, nano-drug delivery, and the use of curcumin analogs have been developed to deliver curcumin and increase its bioavailability. PRACTICAL APPLICATIONS: The rise of people with type 2 diabetes has become a major concern at the global healthcare level. The best diabetes treatments today are anti-diabetic drug administration, lifestyle-related interventions (such as healthy eating and daily physical activity), arterial pressure detection, and fat control. The polyphenol curcumin, found in turmeric, can promote health by acting on a variety of cellular signaling pathways. This review article discusses curcumin and its role in the treatment of diabetes.

Effects of curcumin on low-density lipoprotein oxidation: From experimental studies to clinical practice

Atherosclerosis is the most frequent cause of death globally. Oxidized low-density lipoprotein (ox-LDL) has an essential role in the formation of atherosclerotic plaques and foamy macrophages. Ox-LDL increases the uptake of cholesterol by macrophages and is the major cause of blood flow disruption. Ox-LDL is produced during oxidative stress and treatment with antioxidants could inhibit the production and function of ox-LDL. Curcumin is a potent antioxidant and has a strong track record in the treatment of numerous diseases. Recent studies indicate that Curcumin exerts a lipid-lowering effect, and can modulate the formation of atherosclerotic plaque. The current review focuses upon the role of Curcumin in oxidation of LDL and foam cell formation in atherosclerotic lesions.

Nuclear and Radiological Emergencies: Biological Effects, Countermeasures and Biodosimetry

Atomic and radiological crises can be caused by accidents, military activities, terrorist assaults involving atomic installations, the explosion of nuclear devices, or the utilization of concealed radiation exposure devices. Direct damage is caused when radiation interacts directly with cellular components. Indirect effects are mainly caused by the generation of reactive oxygen species due to radiolysis of water molecules. Acute and persistent oxidative stress associates to radiation-induced biological damages. Biological impacts of atomic radiation exposure can be deterministic (in a period range a posteriori of the event and because of destructive tissue/organ harm) or stochastic (irregular, for example cell mutation related pathologies and heritable infections). Potential countermeasures according to a specific scenario require considering basic issues, e.g., the type of radiation, people directly affected and first responders, range of doses received and whether the exposure or contamination has affected the total body or is partial. This review focuses on available medical countermeasures (radioprotectors, radiomitigators, radionuclide scavengers), biodosimetry (biological and biophysical techniques that can be quantitatively correlated with the magnitude of the radiation dose received), and strategies to implement the response to an accidental radiation exposure. In the case of large-scale atomic or radiological events, the most ideal choice for triage, dose assessment and victim classification, is the utilization of global biodosimetry networks, in combination with the automation of strategies based on modular platforms.

Investigation of the Effect of Curcumin on Protein Targets in NAFLD Using Bioinformatic Analysis

BACKGROUND: Non-alcoholic fatty liver disease (NAFLD) is a prevalent metabolic disorder. Defects in function/expression of genes/proteins are critical in initiation/progression of NAFLD. Natural products may modulate these genes/proteins. Curcumin improves steatosis, inflammation, and fibrosis progression. Here, bioinformatic tools, gene−drug and gene-disease databases were utilized to explore targets, interactions, and pathways through which curcumin could impact NAFLD. METHODS: Significant curcumin−protein interaction was identified (high-confidence:0.7) in the STITCH database. Identified proteins were investigated to determine association with NAFLD. gene ontology (GO) and Kyoto Encyclopedia of Genes and Genomes (KEGG) were analyzed for significantly involved targets (p < 0.01). Specificity of obtained targets with NAFLD was estimated and investigated in Tissue/Cells−gene associations (PanglaoDB Augmented 2021, Mouse Gene Atlas) and Disease−gene association-based EnrichR algorithms (Jensen DISEASES, DisGeNET). RESULTS: Two collections were constructed: 227 protein−curcumin interactions and 95 NAFLD-associated genes. By Venn diagram, 14 significant targets were identified, and their biological pathways evaluated. Based on gene ontology, most targets involved stress and lipid metabolism. KEGG revealed chemical carcinogenesis, the AGE-RAGE signaling pathway in diabetic complications and NAFLD as the most common significant pathways. Specificity to diseases database (EnrichR algorithm) revealed specificity for steatosis/steatohepatitis. CONCLUSION: Curcumin may improve, or inhibit, progression of NAFLD through activation/inhibition of NAFLD-related genes.

Efficacy of Curcuminoids in managing postoperative pain after total laparoscopic hysterectomy: A randomized controlled, open-label trial

BACKGROUND AND AIMS

Curcuminoids, which are substances extracted from turmeric (Curcuma longa), have anti-inflammatory and analgesic effects and a good safety profile. This study aimed to evaluate the clinical efficacy of curcuminoid extracts on reducing pain among patients who underwent laparoscopic hysterectomy. Experimental procedure: From November 2016 to December 2017, 98 participants were included in this clinical trial, and they were randomly assigned to the experimental and control arms according to blocks of four. The intraoperative findings did not significantly differ between the two groups. The experimental group received one tablet of curcuminoid extract 250 mg four times a day on postoperative days 1-3. Pain was evaluated at 24 and 72 h postoperatively using a 10-point visual analog scale (VAS).

RESULTS AND CONCLUSION

The mean visual analog scale (VAS) scores at 24 h after surgery were 4.9 in the experimental group and 4.3 in the control group. Hence, the results did not significantly differ (p = 0.129). The mean VAS scores at 72 h after surgery were 1.8 in the experimental group and 2.8 in the control group (p = 0.001). The side effects in both groups were similar. Hence, curcuminoids can be an effective supplement for reducing pain after laparoscopic hysterectomy. The conclusion from this study is, that curcuminoids may be an effective supplement to reduce postoperative pain following laparoscopic hysterectomy.

Intra-Articular Injections of Curcumin Monoglucuronide TBP1901 Suppresses Articular Cartilage Damage and Regulates Subchondral Bone Alteration in an Osteoarthritis Rat Model

OBJECTIVE

Curcumin monoglucuronide (TBP1901) is highly water soluble and can convert to free form curcumin, which has pharmacological effects, on intravenous administration. This study aimed to investigate the effectiveness of TBP1901 intra-articular injections in an osteoarthritis (OA) rat model.

METHODS

Sixty-four male Wistar rats (12 weeks old) who underwent destabilized medial meniscus (DMM) surgery were randomly separated into the TBP1901 injection or saline solution (control) injection group. They were sacrificed at 1, 2, 6, or 10 weeks postoperatively (weeks 1, 2, 6, and 10; n = 8 for each group). TBP1901 (30 mg/mL) or saline solution of 50 μL was injected into the knee joints twice a week during weeks 1 and 2 to investigate the effects in the acute phase of posttraumatic (PT) OA or once a week during weeks 6 and 10 to investigate it in the chronic phase of PTOA. Histology, immunohistochemistry, and micro-computed tomography were performed to evaluate the changes in OA.

RESULTS

TBP1901 injections significantly reduced synovial inflammation at weeks 1 and 2, and tumor necrosis factor-α expression in the articular cartilage at week 6. The TBP1901 injections also significantly suppressed articular cartilage damage, subchondral bone (SB) plate thickening, SB plate perforation, and osteophyte formation at week 10.

CONCLUSIONS

TBP1901 intra-articular injections suppressed synovial inflammation in the acute phase of PTOA in DMM rats. In the chronic phase, TBP1901 suppresses articular cartilage damage and regulates SB plate changes.

Recent Progress in Nanotechnology for COVID-19 Prevention, Diagnostics and Treatment

The COVID-19 pandemic is currently an unprecedented public health threat. The rapid spread of infections has led to calls for alternative approaches to combat the virus. Nanotechnology is taking root against SARS-CoV-2 through prevention, diagnostics and treatment of infections. In light of the escalating demand for managing the pandemic, a comprehensive review that highlights the role of nanomaterials in the response to the pandemic is highly desirable. This review article comprehensively discusses the use of nanotechnology for COVID-19 based on three main categories: prevention, diagnostics and treatment. We first highlight the use of various nanomaterials including metal nanoparticles, carbon-based nanoparticles and magnetic nanoparticles for COVID-19. We critically review the benefits of nanomaterials along with their applications in personal protective equipment, vaccine development, diagnostic device fabrication and therapeutic approaches. The remaining key challenges and future directions of nanomaterials for COVID-19 are briefly discussed. This review is very informative and helpful in providing guidance for developing nanomaterial-based products to fight against COVID-19.

Efficacy of a curcumin extract (Curcugen™) on gastrointestinal symptoms and intestinal microbiota in adults with self-reported digestive complaints: a randomised, double-blind, placebo-controlled study

BACKGROUND

There is preliminary evidence to suggest curcumin can alleviate digestive symptoms in adults with self-reported digestive complaints and irritable bowel syndrome. However, in all these trials, curcumin was used as a component of a multi-herbal combination and there were consistent concerns associated with risk of bias in most studies. The goal of this study was to investigate the effects of a curcumin extract (Curcugen™) on gastrointestinal symptoms, mood, and overall quality of life in adults presenting with self-reported digestive complaints. Moreover, to determine the potential therapeutic mechanisms of action associated with curcumin, its effects on intestinal microbiota and small intestinal bowel overgrowth (SIBO) were examined.

METHODS

In this 8-week, parallel-group, double-blind, randomised controlled trial, 79 adults with self-reported digestive complaints were recruited and randomised to receive either a placebo or 500 mg of the curcumin extract, Curcugen™. Outcome measures included the Gastrointestinal Symptom Rating Scale (GSRS), intestinal microbial profile (16S rRNA), Depression, Anxiety, and Stress Scale - 21 (DASS-21), Short Form-36 (SF-36), and SIBO breath test.

RESULTS

Based on self-report data collected from 77 participants, curcumin was associated with a significantly greater reduction in the GSRS total score compared to the placebo. There was also a greater reduction in the DASS-21 anxiety score. No other significant between-group changes in self-report data were identified. An examination of changes in the intestinal microbial profile and SIBO test revealed curcumin had no significant effect on these parameters. Curcumin was well-tolerated with no significant adverse events.

CONCLUSIONS

The curcumin extract, Curcugen™, administered for 8 weeks at a dose of 500 mg once daily was associated with greater improvements in digestive complaints and anxiety levels in adults with self-reported digestive complaints. Compared to the placebo, there were no significant changes in intestinal microbiota or SIBO; however, further research using larger samples and testing methods that allow more detailed microbial analyses will be important. An investigation into other potential mechanisms associated with curcumin's gastrointestinal-relieving effects will also be important such as examining its influence on the intestinal barrier function, inflammation, neurotransmitter activity, and visceral sensitivity.

TRIAL REGISTRATION

Australian New Zealand Clinical Trials Registry, Trial ID. ACTRN12619001236189 . Registered 6 September 2019.

Interaction between Gut Microbiota and Curcumin: A New Key of Understanding for the Health Effects of Curcumin

Curcumin, a lipophilic polyphenol contained in the rhizome of Curcuma longa (turmeric), has been used for centuries in traditional Asian medicine, and nowadays it is widely used in food as dietary spice worldwide. It has received considerable attention for its pharmacological activities, which appear to act primarily through anti-inflammatory and antioxidant mechanisms. For this reason, it has been proposed as a tool for the management of many diseases, among which are gastrointestinal and neurological diseases, diabetes, and several types of cancer. However, the pharmacology of curcumin remains to be elucidated; indeed, a discrepancy exists between the well-documented in vitro and in vivo activities of curcumin and its poor bioavailability and chemical instability that should limit any therapeutic effect. Recently, it has been hypothesized that curcumin could exert direct regulative effects primarily in the gastrointestinal tract, where high concentrations of this polyphenol have been detected after oral administration. Consequently, it might be hypothesized that curcumin directly exerts its regulatory effects on the gut microbiota, thus explaining the paradox between its low systemic bioavailability and its wide pharmacological activities. It is well known that the microbiota has several important roles in human physiology, and its composition can be influenced by a multitude of environmental and lifestyle factors. Accordingly, any perturbations in gut microbiome profile or dysbiosis can have a key role in human disease progression. Interestingly, curcumin and its metabolites have been shown to influence the microbiota. It is worth noting that from the interaction between curcumin and microbiota two different phenomena arise: the regulation of intestinal microflora by curcumin and the biotransformation of curcumin by gut microbiota, both of them potentially crucial for curcumin activity. This review summarizes the most recent studies on this topic, highlighting the strong connection between curcumin and gut microbiota, with the final aim of adding new insight into the potential mechanisms by which curcumin exerts its effects.

Synthesis, Anticancer Activity, and Preliminary Pharmacokinetic Evaluation of 4,4-Disubstituted Curcuminoid 2,2-bis(Hydroxymethyl)Propionate Derivatives

Compound 1 is a curcumin di-O-2,2-bis(hydroxymethyl)propionate that shows significant in vitro and in vivo inhibitory activity against MDA-MB-231 cells with eight to ten-fold higher potency than curcumin. Here, we modified the α-position (C-4 position) of the central 1,3-diketone moiety of 1 with polar or nonpolar functional groups to afford a series of 4,4-disubstituted curcuminoid 2,2-bis(hydroxymethyl)propionate derivatives and evaluated their anticancer activities. A clear structure-activity relationship of compound 1 derivatives focusing on the functional groups at the C-4 position was established based on their anti-proliferative effects against the MDA-MB-231 and HCT-116 cell lines. Compounds 2-6 are 4,4-dimethylated, 4,4-diethylated, 4,4-dibenzylated, 4,4-dipropargylated and 4,4-diallylated compound 1, respectively. Compounds 2m-6m, the ester hydrolysis products of compounds 2-6, respectively, were synthesized and assessed for anticancer activity. Among all compound 1 derivatives, compound 2 emerged as a potential chemotherapeutic agent for colon cancer due to the promising in vivo anti-proliferative activities of 2 (IC50 = 3.10 ± 0.29 μM) and its ester hydrolysis product 2m (IC50 = 2.17 ± 0.16 μM) against HCT-116. The preliminary pharmacokinetic evaluation of 2 implied that 2 and 2m are main contributors to the in vivo efficacy. Compound 2 was further evaluated in an animal study using HCT-116 colon tumor xenograft bearing nude mice. The results revealed a dose-dependent efficacy that led to tumor volume reductions of 27%, 45%, and 60% at 50, 100, and 150 mg/kg doses, respectively. The established structure-activity relationship and pharmacokinetic outcomes of 2 is the guidance for future development of 4,4-disubstituted curcuminoid 2,2-bis(hydroxymethyl)- propionate derivatives as anticancer drug candidates.

Curcumin Inhibits ERK/c-Jun Expressions and Phosphorylation against Endometrial Carcinoma

Curcumin has been shown to have anticancer effects in a variety of tumors. However, there are fewer studies on the role of curcumin in endometrial carcinoma (EC). The purpose of this experiment was to examine the inhibitory effect of curcumin on endometrial carcinoma cells and ERK/c-Jun signaling pathway. We first predicted the mechanism of action of curcumin on endometrial carcinoma by network pharmacology. Then, we found that curcumin can decrease the cell viability of Ishikawa cells, inhibit the migration of cancer cells, induce apoptosis, and cause cell cycle arrest in the S phase. For molecular mechanism, curcumin reduced the mRNA expression levels of ERK2 and JUN genes and inhibited the phosphorylation of ERK and c-Jun. This suggests that curcumin inhibits the proliferation of endometrial carcinoma cells by downregulating ERK/c-Jun signaling pathway activity.

Bio-optimized Curcuma longa extract is efficient on knee osteoarthritis pain: a double-blind multicenter randomized placebo controlled three-arm study

Objectives

Comparison of two doses of bio-optimized Curcuma longa extract (BCL) in the management of symptomatic knee osteoarthritis (OA).

Methods

A prospective, randomized, 3-month, double-blind, multicenter, three-group, placebo-controlled trial assessing Patient Global Assessment of Disease Activity (PGADA) and serum sColl2-1, a biomarker of cartilage degradation, as co-primary endpoints. Pain on visual analog scale (VAS), Knee injury and Osteoarthritis Outcome Score (KOOS), and paracetamol/non-steroidal anti-inflammatory drug (NSAID) consumption were used as secondary endpoints.

Results

One hundred fifty patients with knee OA were followed for 90 days. Low and high doses of BCL showed a greater decrease of PGADA than placebo. Analysis of sColl2-1 showed in the placebo and BCL low-dose groups, but not in the BCL high-dose group, a transient but non-significant increase of sColl2-1 between T0 and T1. Thereafter, in all groups, sColl2-1 decreased between T1 and T3 (all p < 0.01), but no difference between the groups was found. Pain reduction at day 90 in the low- and high-dose BCL groups (− 29.5 mm and − 36.5 mm) was higher than that in the placebo (− 8 mm; p = 0.018). The global KOOS significantly decreased overtime, but changes were comparable across treatment arms. The ratio of patients with adverse events (AE) related to the product was similar in the placebo and treatment groups, but the number of AE linked to the product was higher in the high-dose BCL group compared to the placebo (p = 0.012).

Conclusions

BCL appeared safe and well-tolerated with no evidence of severe adverse effects. Efficacy analysis suggested positive trends for measurements of PGADA and serum levels of an OA biomarker and showed a rapid and significant decrease of pain in knee OA (Trial registration: ISRCTN, ISRCTN12345678. Registered 21 September 2016—retrospectively registered, https://clinicaltrials.gov/ct2/show/NCT02909621?term=osteoarthritis+curcumin&rank=5—Evaluation of FLEXOFYTOL® Versus PLACEBO (COPRA) NCT02909621).

Electronic supplementary material

The online version of this article (10.1186/s13075-019-1960-5) contains supplementary material, which is available to authorized users.

Curcumin: a potent agent to reverse epithelial-to-mesenchymal transition

BACKGROUND

Epithelial-to-mesenchymal transition (EMT) is involved in tumor progression, invasion, migration and metastasis. EMT is a process by which polarized epithelial cells acquire motile mesothelial phenotypic features. This process is initiated by disassembly of cell-cell contacts through the loss of epithelial markers and replacement of these markers by mesenchymal markers. Reconstruction of the cytoskeleton and degradation of the tumor basement membrane ensures the spread of invasive malignant tumor cells to distant locations. Accumulating evidence indicates that curcumin, as a well-known phytochemical, can inhibit EMT/metastasis through various mechanisms and pathways in human tumors.

CONCLUSIONS

In this review, we summarize the mechanisms by which curcumin may affect EMT in cells under pathological conditions to understand its potential as a novel anti-tumor agent. Curcumin can exert chemo-preventive effects by inhibition and reversal of the EMT process through both TGF-β-dependent (e.g. in hepatoma and retinal pigment epithelial cancer) and -independent (e.g. in oral cancer, colorectal cancer, pancreatic cancer, hepatocellular carcinoma, breast cancer, melanoma, prostate cancer, bladder cancer, thyroid cancer and lung cancer) pathways. Curcumin can also mitigate chemoresistance through EMT suppression and promotion of the antiproliferative effects of conventional chemotherapeutics. Therefore, curcumin has the potential to be used as a novel adjunctive agent to prevent tumor metastasis, which may at least partly be attributed to its hampering of the EMT process.

Safety and efficacy of curcumin versus diclofenac in knee osteoarthritis: a randomized open-label parallel-arm study

Background

The purpose of this study was to compare the efficacy and safety of curcumin with those of diclofenac in the treatment of knee osteoarthritis (OA).

Methods

In this randomized, open-label, parallel, active controlled clinical study, 139 patients with knee OA were randomly assigned to receive either a curcumin 500-mg (BCM-95^®) capsule three times daily or a diclofenac 50-mg tablet two times daily for 28 days. Patients underwent assessment at baseline and days 7, 14, and 28. The main outcome measure was severity of pain using visual analogue scale score at days 14 and 28. Knee Injury and Osteoarthritis Outcome Score (KOOS) (at days 14 and 28), anti-flatulent effect (at day 7), anti-ulcer effect, weight-lowering effect, and patient’s and physician’s global assessment of therapy at day 28 were included as secondary outcome measures. Safety after treatment was evaluated by recording adverse events and laboratory investigation.

Results

At days 14 and 28, patients receiving curcumin showed similar improvement in severity of pain and KOOS scale when compared with diclofenac, and the difference was not statistically significant. At day 7, the patients who received curcumin experienced a significantly greater reduction in the number of episodes of flatulence compared with diclofenac (P <0.01). At day 28, a weight-lowering effect (P <0.01) and anti-ulcer effect (P <0.01) of curcumin were observed. None of the patients required H2 blockers in the curcumin group, and 19 patients required H2 blockers in the diclofenac group (0% versus 28%, respectively; P <0.01). Adverse effects were significantly less in the curcumin group (13% versus 38% in the diclofenac group; P <0.01). Patient’s and physician’s global assessment of therapy was similar in the two treatment groups.

Conclusion

Curcumin has similar efficacy to diclofenac but demonstrated better tolerance among patients with knee OA. Curcumin can be an alternative treatment option in the patients with knee OA who are intolerant to the side effects of non-steroidal anti-inflammatory drugs.

Trial registration

ISRCTN, ISRCTN10074826. Registered 21 November 2017 - Retrospectively registered.

Micro-Particle Curcumin for the Treatment of Chronic Kidney Disease-1: Study Protocol for a Multicenter Clinical Trial

Background

The progression to end-stage renal disease (ESRD) is the most important complication of chronic kidney disease (CKD). Patients with ESRD require dialysis or transplantation to survive, incur numerous complications, and have high mortality rates. Slowing the progression of CKD is an important goal. Unfortunately, even when current treatments are appropriately applied, patients with CKD still progress to ESRD. Current treatments do not address the inflammation and fibrosis that mediate progression to ESRD, but micro-particle curcumin, a natural health product, has both anti-inflammatory and anti-fibrotic properties and may be an effective treatment for patients with CKD.

Objective

Micro-particle curcumin for the treatment of CKD-1 (MPAC-CKD-1) will measure the effect of micro-particle curcumin on 2 important markers of CKD progression: albuminuria and estimated glomerular filtration rate (eGFR). Efficacy in either of these markers will justify a larger, international trial to investigate micro-particle curcumin's ability to lower the risk of ESRD in patients with CKD.

Design

MPAC-CKD-1 is a multicenter, double-blind prospective randomized controlled trial.

Setting

Four kidney disease clinics in Ontario, Canada (3 in London and 1 in Hamilton).

Patients

We will enroll patients with CKD, defined by an eGFR between 15 and 60 mL/min/1.73 m² and a daily albumin excretion of more than 300 mg (or a random urine sample albumin-to-creatinine ratio more than 30 mg/mmol).

Measurements

We will measure changes in the co-primary outcomes of urinary albumin-to-creatinine ratio and eGFR at 3 months and 6 months. We will also measure compliance, safety parameters, and changes in health-related quality of life.

Methods

Participants will be randomly assigned to receive micro-particle curcumin 90 mg once daily or matching placebo for 6 months. We will enroll at least 500 patients to exclude clinically meaningful 6-month changes in these 2 co-primary outcomes (16% difference in albuminuria, and a 2.3 mL/min/1.73 m² between-group difference in the 6-month change in eGFR, at a two-tailed alpha of 0.025, power of 0.80).

Results

Patient enrollment began on October 1, 2015, with 414 participants randomized as of July 2018. We expect to report the results in 2020.

Limitations

MPAC-CKD-1 is not powered to assess outcomes such as the need for renal replacement therapy or death.

Conclusions

MPAC-CKD-1 is a multicenter, double-blind prospective randomized controlled trial designed to test whether micro-particle curcumin reduces albuminuria and slows eGFR decline in patients with albuminuric CKD. MPAC-CKD-1 will also test the feasibility of this intervention and inform the need for a future larger scale trial (MPAC-CKD-2).

Trial registration

MPAC-CKD-1 is registered with U.S. National Institutes of Health at clinicaltrials.gov (NCT02369549). Protocol version 2.0, December 6, 2014.

Efficacy of curcumin and Boswellia for knee osteoarthritis: Systematic review and meta-analysis

PURPOSE

The unfavorable safety profiles of commonly prescribed knee osteoarthritis (OA) treatments have led clinicians and patients to seek safer alternatives. Research has suggested that curcuminoid and boswellia formulations could moderate key inflammatory pathways that are associated with worsening symptoms and disease progression. We conducted a systematic review and meta-analysis to assess the efficacy and safety of these treatments vs. placebo or NSAIDs for knee OA.

METHODS

We searched Medline, EMBASE, Google Scholar, Web of Science and the Cochrane database from inception to February 21, 2018. We also hand searched reference lists and reviewed conference proceedings. We included randomized clinical trials (RCTs) comparing curcuminoid or boswellia formulations with placebo or NSAIDs for knee OA. We calculated standardized mean differences (SMD) or risk ratios (RR) for all relevant outcomes. Meta-analyses were conducted using random effects models. Heterogeneity was assessed using the I2 statistic.

RESULTS

Eleven RCTs (N = 1009) were eligible for analysis. Study quality was low overall, and most included RCTs were conducted on fewer than 100 participants. Both curcuminoid and boswellia formulations were statistically significantly more effective than placebo for pain relief and functional improvement. There were no significant differences between curcuminoids or boswellia and placebo in safety outcomes. Curcuminoids showed no statistically significant differences in efficacy outcomes compared to NSAIDs; patients receiving curcuminoids were significantly less likely to experience gastrointestinal adverse events. No RCTs compared boswellia against approved NSAIDs.

CONCLUSIONS

The results of our study suggest that curcuminoid and boswellia formulations could be a valuable addition to the knee OA treatment regimens by relieving symptoms while reducing safety risks. The current body of evidence is not adequate in size or quality to make any meaningful clinical practice recommendations. Further research through large, high quality RCTs probably investigating the synergistic effect of these products with other OA treatments is warranted.

Neuroprotective Agents in the Intensive Care Unit: -Neuroprotective Agents in ICU

Neuroprotection or prevention of neuronal loss is a complicated molecular process that is mediated by various cellular pathways. Use of different pharmacological agents as neuroprotectants has been reported especially in the last decades. These neuroprotective agents act through inhibition of inflammatory processes and apoptosis, attenuation of oxidative stress and reduction of free radicals. Control of this injurious molecular process is essential to the reduction of neuronal injuries and is associated with improved functional outcomes and recovery of the patients admitted to the intensive care unit. This study reviews neuroprotective agents and their mechanisms of action against central nervous system damages.

Natural Products for Promoting Joint Health and Managing Osteoarthritis

PURPOSE OF REVIEW

Osteoarthritis, the most common joint disease, is associated with substantial medical costs, lost productivity, and reduced quality of life. However, available pharmaceutical treatments have limitations in terms of efficacy and long-term safety.

RECENT FINDINGS

In vitro evidence suggests that some natural products may possess anti-inflammatory and anti-oxidative properties and may inhibit the release of key osteoarthritis-related cytokines. There is, therefore, ongoing interest in identifying natural products that safely promote joint health and treat osteoarthritis. Numerous plant extracts, including curcumin, Boswellia extract, and pycnogenol, have shown effect sizes (ES) for reducing pain and functional disability larger than those observed with analgesics and products such as glucosamine and chondroitin. The ES for methylsulfonylmethane and avocado/soybean unsaponifiables are also considered to be clinically relevant. Data from a small number of studies using natural products for treating osteoarthritis are promising but require confirmation in further well-designed clinical trials.

Protective Effects of Curcumin Against Ischemia-Reperfusion Injury in the Nervous System

Ischemia-reperfusion injury (I/R injury) is a common feature of ischemic stroke which occurs when blood supply is restored after a period of ischemia. Although stroke is an important cause of death in the world, effective therapeutic strategies aiming at improving neurological outcomes in this disease are lacking. Various studies have suggested the involvement of different mechanisms in the pathogenesis of I/R injury in the nervous system. These mechanisms include oxidative stress, platelet adhesion and aggregation, leukocyte infiltration, complement activation, blood-brain barrier (BBB) disruption, and mitochondria-mediated mechanisms. Curcumin, an active ingredient of turmeric, can affect all these pathways and exert neuroprotective activity culminating in the amelioration of I/R injury in the nervous system. In this review, we discuss the protective effects of curcumin against I/R injury in the nervous system and highlight the studies that have linked biological functions of curcumin and I/R injury improvement.

Nutraceuticals in the management of patients with statin-associated muscle symptoms, with a note on real-world experience

There is considerable evidence for the role of low-density lipoprotein cholesterol (LDL-C) in the development of atherosclerotic cardiovascular disease. Although statin therapy remains the most frequency prescribed medication to reduce LDL-C and lower risk of cardiovascular disease, a considerable number of patients develop muscle-related side affects. This review summarizes recent literature supporting the role of nutraceuticals as LDL-C-lowering therapy in statin-intolerant patients, with evidence from our own clinical practices.

The Problem of Curcumin and Its Bioavailability: Could Its Gastrointestinal Influence Contribute to Its Overall Health-Enhancing Effects?

Curcumin, from the spice turmeric, exhibits anti-inflammatory, antioxidant, anticancer, antiviral, and neurotrophic activity and therefore holds promise as a therapeutic agent to prevent and treat several disorders. However, a major barrier to curcumin's clinical efficacy is its poor bioavailability. Efforts have therefore been dedicated to developing curcumin formulations with greater bioavailability and systemic tissue distribution. However, it is proposed in this review that curcumin's potential as a therapeutic agent may not solely rely on its bioavailability, but rather its medicinal benefits may also arise from its positive influence on gastrointestinal health and function. In this review, in vitro, animal, and human studies investigating the effects of curcumin on intestinal microbiota, intestinal permeability, gut inflammation and oxidative stress, anaphylactic response, and bacterial, parasitic, and fungal infections are summarized. It is argued that positive changes in these areas can have wide-ranging influences on both intestinal and extraintestinal diseases, and therefore presents as a possible mechanism behind curcumin's therapeutic efficacy.

Principles of pharmacological research of nutraceuticals

LINKED ARTICLES

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

Curcumin, the golden nutraceutical: multitargeting for multiple chronic diseases

Curcumin, a yellow pigment in the Indian spice Turmeric (Curcuma longa), which is chemically known as diferuloylmethane, was first isolated exactly two centuries ago in 1815 by two German Scientists, Vogel and Pelletier. However, according to the pubmed database, the first study on its biological activity as an antibacterial agent was published in 1949 in Nature and the first clinical trial was reported in The Lancet in 1937. Although the current database indicates almost 9000 publications on curcumin, until 1990 there were less than 100 papers published on this nutraceutical. At the molecular level, this multitargeted agent has been shown to exhibit anti-inflammatory activity through the suppression of numerous cell signalling pathways including NF-κB, STAT3, Nrf2, ROS and COX-2. Numerous studies have indicated that curcumin is a highly potent antimicrobial agent and has been shown to be active against various chronic diseases including various types of cancers, diabetes, obesity, cardiovascular, pulmonary, neurological and autoimmune diseases. Furthermore, this compound has also been shown to be synergistic with other nutraceuticals such as resveratrol, piperine, catechins, quercetin and genistein. To date, over 100 different clinical trials have been completed with curcumin, which clearly show its safety, tolerability and its effectiveness against various chronic diseases in humans. However, more clinical trials in different populations are necessary to prove its potential against different chronic diseases in humans. This review's primary focus is on lessons learnt about curcumin from clinical trials.

LINKED ARTICLES

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

Efficacy of Elaeagnus Angustifolia extract in the treatment of knee osteoarthritis: a randomized controlled trial

Osteoarthritis (OA) is one of the most common musculoskeletal disorders all over the world. Available anti-arthritic medications have only partial efficacy and their long-term use is associated with adverse events. Elaeagnus Angustifolia (EA) is a medicinal plant with analgesic and anti-inflammatory properties. The present study evaluated the impact of two doses of EA extract compared with ibuprofen on the severity of disease in patients with knee OA. This study was designed as a randomized, double blind, active-controlled and parallel group trial. Patients with OA were randomized to receive 300 mg/day (n=33) or 600 mg/day (n=32) of EA aqueous extract, or 800 mg/day ibuprofen (n=32) for 7 weeks. EA extract contained 0.21 % (w/w) kaempferol according to HPLC. Efficacy of treatment was assessed using Western Ontario and McMaster Universities Osteoarthritis Index (WOMAC), Visual Analogue Scale (VAS) of pain, Lequesne's Pain-Function Index (LPFI), and patient's global assessment (PGA) index. The amount of kaempferol in the extract was determined by HPLC method to be 0.21 % w/w. There were significant reductions in WOMAC, VAS, LPFI and PGA scores by the end of trial with all three interventions. Comparison of the changes in WOMAC, VAS and LPFI scores among the treatment groups did not reveal any significant difference between EA and ibuprofen, and between low and high doses of EA. EA was safe and well tolerated during the course of trial and no adverse event was reported. The present results suggest beneficial effects of aqueous EA extract in reducing the symptoms of OA with an efficacy comparable to that of ibuprofen.