Curcuminoid Treatment for Knee Osteoarthritis: A Randomized Double-Blind Placebo-Controlled Trial

A Systematic Review of the Clinical Use of Curcumin for the Treatment of Osteoarthritis

Osteoarthritis is characterized by degeneration of joint structure over time, resulting in limitation of joint mobility. There is growing evidence that curcumin has anti-inflammatory properties and could be a potential therapeutic option for chronic inflammatory diseases. Hence, curcumin could potentially have a positive impact on osteoarthritis symptoms. This systematic review aimed to estimate the effects of curcumin on osteoarthritis. We systematically searched PubMed, ISI, Scopus, and Google Scholar up to March 4, 2020 to identify randomized controlled trials that evaluated the effects of consumption of all types of curcumin compounds in the treatment of osteoarthritis, especially in patients with knee osteoarthritis. Seventeen trials were identified. The duration of the included studies varied from 4 weeks to 8 months. Across all trials, 13 studies involved screening using Western Ontario and McMaster Universities (WOMAC) scores and 11 studies used visual analog scales (VAS) for recording pain from baseline to post-intervention. There was a significant improvement in VAS and overall WOMAC scores with oral administration of various types of curcumin formulations with no severe adverse effects. In conclusion, different types of curcumin compounds may be beneficial as an alternative or complementary agent for the management of osteoarthritis. Moreover, certain curcumin compounds with higher bioavailability tended to show more positive effects.

Turmeric and Curcumin: From Traditional to Modern Medicine

The rhizome of turmeric (Curcuma longa L.) has been used as an herbal medicine, coloring agent, spice, and food additive for thousands of years in different parts of the world particularly in Asian countries. It has been used for a range of diseases in many traditional medical schools, including Islamic traditional medicine, Chinese traditional medicine, and Ayurveda. It has been used mainly for digestive problems, as a cardio-, hepato-, and neuroprotective agent as well as in many inflammatory conditions such as arthritis and for enhancing immune system. Curcumin, a diarylheptanoid derivative found in turmeric, has anti-inflammatory, antioxidant, and anticancer properties; controls obesity and metabolic problems; and improves memory and mood disorders. Therapeutically, curcumin exhibits promising potential in preclinical and clinical studies and is currently in human trials for a variety of conditions, including metabolic syndrome, nonalcoholic fatty liver disease, rheumatoid arthritis, migraine, premenstrual syndrome, ulcerative colitis, knee osteoarthritis, polycystic ovarian syndrome, atherosclerosis, liver cirrhosis, amyotrophic lateral sclerosis, depression, psoriasis, and Alzheimer's disease. Among all beneficial activities reported for curcumin, the research toward the obesity and metabolic-preventing/suppressing aspects of curcumin is growing. These findings emphasize that most of the traditional applications of turmeric is due to the presence of its key constituent, curcumin. According to the traditional background of turmeric use and clinical values of curcumin, further preclinical studies for unstudied properties and clinical studies with larger sample sizes for confirmed activities are expected.

Efficacy of some Herbal Medicines in Osteoarthritis with a Focus on Topical Agents: A Systematic Review

Osteoarthritis (OA) is a leading cause of musculoskeletal disorders that mainly affects the elderly population. Some herbal medicines have the potential to alleviate the pain associated with OA and improve physical activity mostly through anti-inflammatory and anti-oxidative properties. The aim of this study was to investigate the effects of herbal medicines, especially topical types, on osteoarthritis. In this systematic review, the keywords "osteoarthritis", "herbal compounds", "herbal medicine", "topical drug", "hydrogels", "cream" and "treatment" were used to search publications published from 2010 to 2019 and indexed in databases including PubMed, SCOPUS, Web of Science and Google Scholar. After screening of titles and abstracts and detection of duplicate publications, 38 eligible articles were included in the main review. We also included herbal formulations in vivo. Bioactive fractions of herbal medicines mostly worked on OA through suppression of interleukin-1β (IL-1β), inducing nuclear factor-κB (NF-κB) activation by inhibition of inhibitor of NF-κB (IκBα) phosphorylation, IκBα degradation, p65 phosphorylation, and p65 nuclear translocation, downregulation of NF-κB targets including COX-2 and MMPs, upregulation of collagen type II, cartilage-specific proteoglycans (CSPGs), β1-integrin, and expression of cartilage-specific transcription factor SOX-9 protein. Noticeably, herbal medicines do not produce desirable effects, thereby using their combinations with other therapeutic agents seem to exert substantial clinical outcomes. Herbal gels have demonstrated robustly significant healing effects on knee pain, stiffness and mobility. It is worth considering that because OA is a chronic disease, longer duration of the studies/trials would even lead to obtaining more reliable judgments regarding topical treatment tolerability, safety and efficacy and clarify local or systemic adverse effects. Stability and standardization of a defined amount or concentrations of herbal gels would give promising effects on OA treatment and pain relief.

Anti-inflammatory effects of oral supplementation with curcumin: a systematic review and meta-analysis of randomized controlled trials

CONTEXT

Chronic inflammation is a major contributor to the development of noncommunicable diseases. Curcumin, a bioactive polyphenol from turmeric, is a well-known anti-inflammatory agent in preclinical research. Clinical evidence remains inconclusive because of discrepancies regarding optimal dosage, duration, and formulation of curcumin.

OBJECTIVE

The aim of this systematic review, conducted and reported in accordance with Preferred Reporting Items for Systematic Reviews and Meta-Analyses guidelines and checklist, was to evaluate the efficacy of curcumin supplementation on systemic inflammatory mediators, comparing dose, duration, and bioavailability status of interventions.

DATA SOURCES

The Medline, CINAHL, EMBASE, Scopus, and Cochrane literature databases were searched from 1980 to May-end 2019. Randomized controlled trials investigating effects of dietary curcumin on inflammatory mediators in humans not receiving anti-inflammatory treatment were eligible for inclusion. Two authors independently assessed titles and abstracts of identified articles for potential eligibility and respective, retrieved, full-text articles; disagreements were resolved by a third author. Evidence quality was critically appraised using the Quality Criteria Checklist for Primary Research.

DATA EXTRACTION

Thirty-two trials (N = 2,038 participants) were included and 28 were meta-analyzed using a random-effects model; effect sizes were expressed as Hedges' g (95%CI).

DATA ANALYSIS

Pooled data (reported here as weighted mean difference [WMD]; 95%CI) showed a reduction in C-reactive protein (-1.55 mg/L; -1.81 to -1.30), interleukin-6 (-1.69 pg/mL, -2.56 to -0.82), tumor necrosis factor α (-3.13 pg/mL; -4.62 to -1.64), IL-8 (-0.54 pg/mL; -0.82 to -0.28), monocyte chemoattractant protein-1 (-2.48 pg/mL; -3.96 to -1.00), and an increase in IL-10 (0.49 pg/mL; 0.10 to 0.88), with no effect on intracellular adhesion molecule-1.

CONCLUSION

These findings provide evidence for the anti-inflammatory effects of curcumin and support further investigation to confirm dose, duration, and formulation to optimize anti-inflammatory effects in humans with chronic inflammation.

SYSTEMATIC REVIEW REGISTRATION

PROSPERO registration no. CRD42019148682.

Curcumin, autoimmune and inflammatory diseases: going beyond conventional therapy - a systematic review

Autoimmune and inflammatory diseases affect innumerous people and are considered a significant cause of morbidity and mortality worldwide and Curcuma sp can work as important therapies in the approach of these diseases. For this reason the aim of this review is to evaluate the effects of Curcuma or curcumin in five autoimmune and/or inflammatory diseases for instance, Inflammatory Bowel Disease, Osteoarthritis, Systemic Lupus Erythematous, Psoriasis, and Sclerosis. MEDLINE, EMBASE, and Cochrane Library were searched and PRISMA guidelines were used to build this systematic review. Curcuma sp or curcumin have been gaining ground in the treatment of autoimmune and inflammatory diseases due to the wide range of bioactive compounds capable of exerting substantial anti-inflammatory and antioxidant actions. The effects can be associated with improvement of symptoms and induction of remission in Inflammatory Bowel Disease patients; reduction of erythema and induration of lesions in psoriasis; and slow down the disease progression in patients with sclerosis. Furthermore, curcumin shows effects equivalent to ibuprofen and diclofenac, without the adverse effects generally reported by patients. Curcuma or its derivatives can be used safely and efficiently as adjuvants or as a main therapy for these diseases that increase year by year in the world population.

Influence of a low-dose supplementation of curcumagalactomannoside complex (CurQfen) in knee osteoarthritis: A randomized, open-labeled, active-controlled clinical trial

A 6-week, randomized, open-label, active-controlled clinical trial was conducted to evaluate the influence of a low-dose curcumagalactomannosides (CGM) (400 mg once daily) in OA subjects. The treatment was compared with a standard combination of 500 mg glucosamine hydrochloride (GLN) and 415 mg chondroitin sulphate (CHN), supplied as a single oral dose twice a day. Out of 84 subjects randomized, 72 subjects who have completed the study were evaluated for the safety and efficacy of the treatments at baseline and subsequent visits (day 28 and 42), by measuring walking performance, VAS, KPS, and WOMAC scores. CGM exhibited 47.02, 21.43, and 206% improvement in VAS, KPS, and walking performance, respectively, compared to the baseline. Similarly, there was 31.17, 32.93, 36.44, and 35% improvement in the pain, stiffness, physical function, and total WOMAC scores. CGM also caused a substantial reduction in the serum inflammatory marker levels. The results indicate that a short-term supplementation of a low dosage CGM exerted superior beneficial effects than a high-dosage CHN-GLN combination in alleviating the pain and symptoms of OA subjects. Further clinical trials of extended duration in a larger population is required to substantiate the efficacy of CGM in the long-term management of OA.

Effects of Curcumin in a Mouse Model of Very High Fat Diet-Induced Obesity

Worldwide rates of Western-diet-induced obesity epidemics are growing dramatically. Being linked with numerous comorbidities and complications, including cardiovascular disease, type 2 diabetes, cancer, chronic inflammation, and osteoarthritis (OA), obesity represents one of the most threatening challenges for modern healthcare. Mouse models are an invaluable tool for investigating the effects of diets and their bioactive components against high fat diet (HFD)-induced obesity and its comorbidities. During recent years, very high fat diets (VHFDs), providing 58–60% kcal fat, have become a popular alternative to more traditional HFDs, providing 40–45% total kcal fat, due to the faster induction of obesity and stronger metabolic responses. This project aims to investigate if the 60% fat VHFD is suitable to evaluate the protective effects of curcumin in diet-induced obesity and osteoarthritis. B6 male mice, prone to diet-induced metabolic dysfunction, were supplemented with VHFD without or with curcumin for 13 weeks. Under these experimental conditions, feeding mice a VHFD for 13 weeks did not result in expected robust manifestations of the targeted pathophysiologic conditions. Supplementing the diet with curcumin, in turn, protected the animals against obesity without significant changes in white adipocyte size, glucose clearance, and knee cartilage integrity. Additional research is needed to optimize diet composition, curcumin dosage, and duration of dietary interventions to establish the VHFD-induced obesity for evaluating the effects of curcumin on metabolic dysfunctions related to obesity and osteoarthritis.

Turmeric and Its Major Compound Curcumin on Health: Bioactive Effects and Safety Profiles for Food, Pharmaceutical, Biotechnological and Medicinal Applications

Curcumin, a yellow polyphenolic pigment from the Curcuma longa L. (turmeric) rhizome, has been used for centuries for culinary and food coloring purposes, and as an ingredient for various medicinal preparations, widely used in Ayurveda and Chinese medicine. In recent decades, their biological activities have been extensively studied. Thus, this review aims to offer an in-depth discussion of curcumin applications for food and biotechnological industries, and on health promotion and disease prevention, with particular emphasis on its antioxidant, anti-inflammatory, neuroprotective, anticancer, hepatoprotective, and cardioprotective effects. Bioavailability, bioefficacy and safety features, side effects, and quality parameters of curcumin are also addressed. Finally, curcumin's multidimensional applications, food attractiveness optimization, agro-industrial procedures to offset its instability and low bioavailability, health concerns, and upcoming strategies for clinical application are also covered.

Co-administration of Pregabalin and Curcumin Synergistically Decreases Pain-Like Behaviors in Acute Nociceptive Pain Murine Models

Analgesic drugs in a combination-form can achieve greater efficacy with lesser side effects compared to either drug alone. The combination of drugs acting at different targets or mechanisms of action has been recognized as an alternative approach for achieving optimal analgesia. In this study, the analgesic effects of pregabalin (30, 60, 100, 200 mg/kg), curcumin (15, 30, 60, 100, 120 mg/kg), and 1:1 fixed-dose ratio of the pregabalin-curcumin combination were assessed using two acute nociceptive pain models, the acetic acid-induced writhing and tail-flick tests in mice. The pregabalin-curcumin combination produced a dose-dependent decrease in mean of writhes and an increase in the percentage of antinociception by the acetic acid-induced writhing test. In the tail-flick test, the combination also showed an improvement in antinociception indicated by the tail-flick latency, % antinociception, and area under the curve (AUC). Isobolographic analysis of interactions demonstrated a significant synergistic interaction effect between pregabalin and curcumin in both acute nociceptive pain models with the experimental ED₅₀ below the predicted additive line and the combination index < 1. These findings demonstrate that the combination of pregabalin and curcumin exhibits a synergistic interaction in mouse models of acute nociceptive pain.

The Efficacy and Safety of Highly-Bioavailable Curcumin for Treating Knee Osteoarthritis: A 6-Month Open-Labeled Prospective Study

Background

We previously developed a surface-controlled water-dispersible form of curcumin that we called Theracurmin^®. The area under the blood concentration-time curve (AUC) of Theracurmin in humans was 27-fold higher than that of curcumin powder. Previously, we reported on the anti-inflammatory effects of Theracurmin for knee osteoarthritis.

Hypothesis/Purpose

We determined the clinical effects of orally administered Theracurmin in patients with knee osteoarthritis over a 6-month period.

Study Design

Open prospective study.

Methods

Fifty patients Kellgren-Lawrence grade II, III, or IV knee osteoarthritis who were above 40 years old were enrolled in this clinical study. Theracurmin containing 180 mg/day of curcumin was administered orally every day for 6 months. To monitor for adverse events, blood biochemistry analyses were performed before and after 6 months of each intervention. The patients' knee symptoms were evaluated at 0, 1, 2, 3, 4, 5, and 6 months based on the Japanese Knee Osteoarthritis Measure, the knee pain visual analog scale, and the knee scoring system of the Japanese Orthopedic Association.

Results

Five cases dropped out during the study, but no cases dropped out because of major problems. No major side effects were observed with Theracurmin treatment, including the blood biochemistry analysis results. The effective group included 34 cases (75.6%), while the not-effective group included 11 cases.

Conclusion

This study demonstrates the safety and good efficacy of Theracurmin for various types of knee osteoarthritis. Theracurmin shows great potential for the treatment of human knee osteoarthritis.

Efficacy of high-dissolution turmeric-sesame formulation for pain relief in adult subjects with acute musculoskeletal pain compared to acetaminophen: A randomized controlled study

BACKGROUND

Acetaminophen (paracetamol) is one of the most commonly used over-the-counter for pain relief. Management of acute pain with plant-based nutrients has remained suboptimal due to an absence of data supporting acute relief of pain. In the present study, it was hypothesized that high-dissolution liquid treatment of black sesame extract oil, Curcuma longa and Boswellia serrata may provide pain relief in people with acute musculoskeletal pain as quickly as acetaminophen.

METHODS

In this randomized active controlled open label study, 88 healthy subjects with acute musculoskeletal pain were randomized to receive treatment capsule (Rhuleave-K; 1,000 mg/d) or 1,000 mg/d acetaminophen for 7 days. Change in pain intensity and pain relief at first 6 hours, 3 days, and 7 days were measured. The onset of analgesia was measured by perceptible pain relief and meaningful pain relief. Other measures were McGill Pain Questionnaire and Patient Global Impression Change.

RESULTS

The treatment formulation resulted in average magnitude of pain relief comparable to the acetaminophen. Sixty-six percent of subjects in the treatment group reported positive response in pain relief (≥50% max TOTPAR; total pain relief) after 6 hours, compared to 73% of control. Seventy-three percent of subjects on treatment were considered positive responders, compared to 80% in the control group. The average time of onset of analgesia was 1 hour for the treatment group, versus 0.83 hour for control. At the end of day 3 and 7, there was significant improvement (P < .001 for day 3 and day 7) in the pain condition of treatment group and was comparable to control (P = .436 for day 3 and P = .529 for day 7). The total McGill Pain score showed significant reduction in pain with the treatment irrespective of the pain intensity statistically equal (P = .468) to control. Both the groups were equal in providing sensory pain relief (P = .942), but the treatment was 8.57 times significantly better (P = .027) than acetaminophen in reducing the unpleasantness and emotional aspects (affective domain) involved with acute pain.

CONCLUSION

The results showed that the treatment used in the study may act as a natural, fast acting, and safe alternative for acute pain relief comparable to acetaminophen.

Conditional Recommendations for Specific Dietary Ingredients as an Approach to Chronic Musculoskeletal Pain: Evidence-Based Decision Aid for Health Care Providers, Participants, and Policy Makers

OBJECTIVE

Approximately 55-76% of Service members use dietary supplements for various reasons; although such use has become popular for a wide range of pain conditions, decisions to use supplements are often driven by information that is not evidence-based. This work evaluates whether the current research on dietary ingredients for chronic musculoskeletal pain provides sufficient evidence to inform decisions for practice and self-care, specifically for Special Operations Forces personnel.

METHODS

A steering committee convened to develop research questions and factors required for decision-making. Key databases were searched through August 2016. Eligible systematic reviews and randomized controlled trials were assessed for methodological quality. Meta-analysis was applied where feasible. GRADE was used to determine confidence in the effect estimates. A decision table was constructed to make evidence-informed judgments across factors required for decision-making, and recommendations were made for practice and self-care use.

RESULTS

Nineteen dietary ingredients were included. Conditional evidence-based recommendations were made for the use of avocado soybean unsaponifiables, capsaicin, curcuma, ginger, glucosamine, melatonin, polyunsaturated fatty acids, and vitamin D. In these cases, desirable effects outweighed undesirable effects, but there was uncertainty about the trade-offs, either because the evidence was low quality or because benefits and downsides were closely balanced.

CONCLUSIONS

The evidence showed that certain dietary ingredients, when taken as part of a balanced diet and/or as a supplement (e.g., pill, tablet, capsule, cream), may alleviate musculoskeletal pain with no to minimal risk of harm. This finding emphasizes and reinforces the critical importance of shared decision-making between Operators and their health care providers.

The effect of curcuminoids for treating knee osteoarthritis: A protocol for systematic review and meta analysis

BACKGROUND

Knee osteoarthritis (KOA) is 1 of the commonest cause of disability with joint pain in adults and a burden on healthcare resources. The limitations of current KOA treatment necessitate further researches to discover the more efficacious and safety treatments. There are increasing clinical studies investigating the potential protective effects of Curcuminoids in the alleviation of symptoms in patients suffering from KOA. However, the convincing evidence indicating the efficacy of curcuminoids for patients suffering from KOA remains unclear.

METHODS

Several databases including PubMed, Web of Science, Cochrane Library, Embase, Chinese Biomedical Literature Database, Chinese National Knowledge Infrastructure, and Wanfang Database will be searched. And the language was not limited. We will include all Randomized controlled trials that use curcuminoids to treat patients with KOA, regardless of blinding. If the pre-crossover data can be analyzed to avoid carryover effects, the crossover randomized trials also are included. Meanwhile, We will exclude non-randomized controlled trials, qualitative studies, uncontrolled clinical trials and laboratory studies. The primary end point include Western Ontario and McMaster Universities Osteoarthritis Index, visual analog scale scores and Lequesne's pain functional index. The secondary end points are total effective rate and adverse effects. The Review Manager Version 5.3 will be used to perform the data synthesis and subgroup analysis.

DISCUSSION

There are evidences that supports the potential protective effects of Curcuminoids in the alleviation of symptoms in patients suffering from KOA. This systematic review and meta-analysis would provide convincing evidence indicating that curcuminoids relieve the symptoms of patients suffering from KOA.

REGISTRATION

Open Science Framework (OSF) registries (https://osf.io/fz29b) with the registration DOI: 10.17605/OSF.IO/FZ29B.

Therapeutic Potential of Curcumin in the Treatment of Glioblastoma Multiforme

Glioblastoma multiforme (GBM) is the most common primary malignant brain tumor. Despite standard multimodality treatment, the highly aggressive nature of GBM makes it one of the deadliest human malignancies. The anti-cancer effects of dietary phytochemicals like curcumin provide new insights to cancer treatment. Evaluation of curcumin's efficacy against different malignancies including glioblastoma has been a motivational research topic and widely studied during the recent decade. In this review, we discuss the recent observations on the potential therapeutic effects of curcumin against glioblastoma. Curcumin can target multiple signaling pathways involved in developing aggressive and drug-resistant features of glioblastoma, including pathways associated with glioma stem cell activity. Notably, combination therapy with curcumin and chemotherapeutics like temozolomide, the GBM standard therapy, as well as radiotherapy has shown synergistic response, highlighting curcumin's chemo- and radio-sensitizing effect. There are also multiple reports for curcumin nanoformulations and targeted forms showing enhanced therapeutic efficacy and passage through blood-brain barrier, as compared with natural curcumin. Furthermore, in vivo studies have revealed significant anti-tumor effects, decreased tumor size and increased survival with no notable evidence of systemic toxicity in treated animals. Finally, a pharmacokinetic study in patients with GBM has shown a detectable intratumoral concentration, thereby suggesting a potential for curcumin to exert its therapeutic effects in the brain. Despite all the evidence in support of curcumin's potential therapeutic efficacy in GBM, clinical reports are still scarce. More studies are needed to determine the effects of combination therapies with curcumin and importantly to investigate the potential for alleviating chemotherapy- and radiotherapy-induced adverse effects.

Accelerated Muscle Recovery After In Vivo Curcumin Supplementation

The currently available treatment options for muscle injuries are suboptimal and often delay muscle recovery. In this study, the effects of curcumin on inflammation and skeletal muscle regeneration after contusion-induced injury in mice were investigated. The mice were randomly assigned to 4 groups, namely normal control (NC), with induced injury (mass-drop injury, MDI) and without treatment (MDI [M]), with induced injury and diclofenac (DCF) treatment (MDI + DCF [M + D]), and with induced injury and curcumin treatment (MDI + curcumin [M + C]). Contusion-induced injury was inflicted on the left gastrocnemius muscle, and DCF or curcumin was orally administered after injury once per day for 7 days. The M group exhibited significantly higher lipid peroxidation, myeloperoxidase (MPO), and desmin than the NC group. The M + D and M + C groups have lower lipid peroxidation and neutrophils (decrease in MPO protein) and higher muscle satellite cell regeneration (increase in desmin protein) than the M group. Additionally, for the contusion-induced muscle injury, curcumin could affect the specific proteins of inflammation, neutrophils, and differentiation of satellite cells, including Ikk-α/ß, MPO, and myogenin. In conclusion, curcumin potentially accelerates muscle recovery; therefore, it may be a potential candidate for further research as an effective treatment to enhance muscle repair.

Analgesic Herbal Medicines in the Treatment of Knee Osteoarthritis: A Systematic Review

Background:

Osteoarthritis (OA) is a type of progressive rheumatoid disease, which leads to the degeneration of the articular cartilage, synovium, subchondral bone, tendons, and the surrounding ligaments.There are various treatments for knee OA, including pharmaceutical, nonpharmaceutical, and surgical treatments. Considering the chronic nature of the disease as well as the necessity for the long-term use of chemical medications, various side effects could occur that include gastrointestinal bleeding, hypertension, congestive heart failure, hyperkalemia, and kidney failure. Therefore, suitable treatments with fewer side effects should be recommended. Recent investigations suggest increased tendency in people to use Complementary and Alternative Medicine (CAM) for knee OA treatment.

Objective:

This systematic review aimed to assess the effectiveness and safety of herbal preparations for the treatment of OA.

Methods:

The searched databases were Cochrane, Scopus, and PubMed. All the selected papers pertained to randomized controlled trials until August 8, 2017 in English in which one or several specific herbs had been used in knee OA treatment.

Results:

We included 24 randomized trials (involving 2399 women and men). There were several different herbal medicines used within the included trials.

Conclusion:

The results show that the methods used in these trials may reduce symptoms and the extent of NSAID consumption and enhance the quality of life. Additional trials are suggested to investigate the safety and efficacy of herbs for the treatment of patients with OA.

Curcumin: hopeful treatment of hemophilic arthropathy via inhibition of inflammation and angiogenesis

Introduction: Hemophilic arthropathy (HA) is a serious complication among hemophilic patients causing a wide range of morbidity due to the inflammatory reactions followed by repeated episodes of bleeding. This condition has recently been shown to be accompanied by angiogenesis. The cascade starts with iron accumulation leading to an increase in CD⁶⁸⁺ and CD^11b+ cells responsible for initiating the inflammation.Areas covered: During inflammation, different factors and cytokines such as interleukin 1 (IL-1), IL-6, and tumor necrosis factor α (TNF-α) actively play parts in the pathogenesis of HA and also angiogenesis. It has been demonstrated that different pro-angiogenic and angiogenic factors such as hypoxia-inducible factor 1α (HIF-1α), vascular endothelial growth factor (VEGF), oxidative stress and matrix metalloproteinases (MMPs) are also important in the pathogenesis of HA. Curcumin is known for its strong anti-inflammatory and anti-angiogenic potentials. This agent is able to inhibit the mentioned inflammatory and angiogenic factors such as IL-1, IL-6, TNF-α, VEGF, MMPs, and HIF-1α. Also, as well as anti-angiogenic and anti-inflammatory activity, curcumin has a strong antioxidant potential and can decrease oxidative stress.Expert opinion: It seems that curcumin could be considered as a possible agent for the treatment of HA through inhibition of inflammation, oxidative stress, and angiogenesis.

A Unique Formulation of Cardioprotective Bio-Actives: An Overview of Their Safety Profile

The burden of cardiovascular disease (CVD) remains high globally and in the United States despite the availability of pharmaceuticals aimed at its prevention and treatment. An invention by Summit Innovation Labs, which is a formula consisting of a unique blend of select polyphenols (i.e., curcumin, quercetin, resveratrol), vitamin K2 as menaquinone-7, and magnesium, was recently developed to modulate the impact of the specific drivers of CVD, namely, vascular calcification, oxidative stress, and chronic inflammation. The SIL formulation is a dietary supplement that was designed leveraging the more bioavailable forms of ingredients with poor absorption, such as curcumin and quercetin. Each ingredient within the SIL formulation has been shown to contribute to CVD risk reduction by moderating the effect of CVD triggers, thereby providing a holistic prevention strategy for CVD in the healthy population. This review focuses on recently published clinical data to support the safety profile of these ingredients following oral administration. The preponderance of clinical trial data reviewed support the overall safety of the bioactives when used singly or in combination. The most commonly reported adverse effects were generally mild dose-related gastrointestinal disturbances, which may be alleviated with diet in some cases. In light of these, we conclude that the combination of the ingredients in the SIL formulation is reasonably expected to be safe.

Curcumin-Synthetic Analogs Library Screening by Docking and Quantitative Structure-Activity Relationship Studies for AXL Tyrosine Kinase Inhibition in Cancers

AXL is an important drug target for cancers. Two-dimensional quantitative structure-activity relationship (2D-QSAR) tests were performed to elucidate a relationship between molecular structures and the activity of a series of 400 curcumin derivatives subjected to AXL kinase by ATP competition in the catalytic site. The partial least square regression method implanted in molecular operating environment software was applied to develop QSAR models, which were further validated for statistical significance by internal and external validation. The best model has proven to be statistically robust with a good predictive correlation of R ²  = 0.996 and a significant cross-validation correlation coefficient of q ²  = 0.707. Docking analysis reveled that three curcumin derivatives have the best affinity for AXL and formed a hydrogen bond with the important amino acid residues in the binding pocket. As treated in this article, the docking studies and 2D-QSAR approach will pave the way for the development of new drugs while highlighting curcumin and its derivatives.

Effect of Curcumin on Serum Cathepsin D in Patients with Metabolic Syndrome

BACKGROUND

Inflammation has been shown to accompany Metabolic Syndrome (MetS) and its features. Cathepsin D is one of a proinflammatory mediator. In the current study, we aimed to investigate the effect of curcumin supplementation on serum cathepsin D levels in patients with MetS.

METHODS

The current study was conducted on 18-65 years old individuals with MetS diagnosed according to the International Diabetes Federation guidelines. A total of 80 participants were randomly divided into treatment and control groups. The first group (n=40) was given 2 capsules containing 500 mg of phosphatidylcholine complex of curcumin, and the other group (n=40) was given two 500 mg placebo capsules for 6 weeks. Before (week 0) and after (week 6) the intervention, anthropometric indices and blood pressure were measured and blood samples were taken. Serum cathepsin D was measured using an ELISA kit.

RESULTS

There was no significant difference between treatment and control groups in terms of weight, body mass index, waist circumference and serum cathepsin D levels before and after the intervention. In addition, there was no significant difference between pre- and post-trial values of serum cathepsin D.

CONCLUSION

The present results do not suggest any effect of curcumin on cathepsin D levels in patients with MetS.

The effect of curcumin supplementation on circulating adiponectin: A systematic review and meta-analysis of randomized controlled trials

OBJECTIVE

Our objective was to perform a systematic review and meta-analysis on randomized controlled trials (RCTs) assessing the effect of curcumin on serum adiponectin concentration.

METHODS

We searched PubMed/Medline, Scopus, ISI Web of Science, Cochrane Library, and Google scholar databases up to April 2019. RCTs conducted among human adults studied the effects of curcumin on serum adiponectin concentrations as an outcome variable was included. The weighted mean differences (WMD) and standard deviations (SD) of change in serum adiponectin levels were calculated. The random effects model was used for deriving a summary of mean estimates with their corresponding SDs.

RESULTS

Out of 313 records, 6 trials that enrolled 652 subjects were included. The pooled results showed that curcumin supplementation significantly increased adiponectin concentrations in comparison with placebo (WMD: 0.82 Hedges' g; 95% confidence interval (CI): 0.33 to 1.30, P˂0.001). Greater effects on adiponectin were observed in trials lasting ≤10 weeks (WMD: 1.05 Hedges' g; 95% CI: 0.64 to 1.45, P˂0.001).

CONCLUSION

Curcumin significantly improves adiponectin concentrations. However, due to some limitations in this study, further studies are needed to reach a definitive conclusion about the effect of curcumin on the levels of adiponectin.

Antitumor effects of curcumin: A lipid perspective

Lipid metabolism plays an important role in cancer development due to the necessities of rapidly dividing cells to increase structural, energetic, and biosynthetic demands for cell proliferation. Basically, obesity, type 2 diabetes, and other related diseases, and cancer are associated with a common hyperactivated "lipogenic state." Recent evidence suggests that metabolic reprogramming and overproduction of enzymes involved in the synthesis of fatty acids are the new hallmarks of cancer, which occur in an early phase of tumorigenesis. As the first evidence to confirm dysregulated lipid metabolism in cancer cells, the overexpression of fatty acid synthase (FAS) was observed in breast cancer patients and demonstrated the role of FAS in cancer. Other enzymes of fatty acid synthesis have recently been found to be dysregulated in cancer, including ATP-dependent citrate lyase and acetyl-CoA carboxylase, which further underscores the connection of these metabolic pathways with cancer cell survival and proliferation. The degree of overexpression of lipogenic enzymes and elevated lipid utilization in tumors is closely associated with cancer progression. The question that arises is whether the progression of cancer can be suppressed, or at least decelerated, by modulating gene expression related to fatty acid metabolism. Curcumin, due to its effects on the regulation of lipogenic enzymes, might be able to suppress, or even cause regression of tumor growth. This review discusses recent evidence concerning the important role of lipogenic enzymes in the metabolism of cancer cells and whether the inhibitory effects of curcumin on lipogenic enzymes is therapeutically efficacious.

Therapeutic effects of turmeric in several diseases: An overview

A nutraceutical product can be defined as a substance that has a physiological benefit or provides protection against chronic diseases. The term nutraceutical is a hybrid term derived from the union of "nutrition" and "pharmaceutical". The list of studied nutraceuticals is constantly changing and reflects ongoing market developments, research and consumer interest. Spices, in addition to giving color and taste to foods, are also important nutraceutical. Spices have been an integral part of human diets and commerce for millennia but recently, the recognition of the link between health and nutrition has strengthened their importance in the food sector and sparked the interest of researchers who increasingly engage in trying to determine the mechanisms of action of spices and the countless beneficial properties attributed to them. Among the many existing spices, turmeric is one of the most studied for its antioxidant, anti-inflammatory, antibacterial and anticancer properties. The purpose of this review is to briefly summarize the fundamental characteristics of turmeric and give an overview of the use of this spice in several diseases.

Traditional Chinese medicine combined with hepatic targeted drug delivery systems: A new strategy for the treatment of liver diseases

Liver diseases are clinically common and present a substantial public health issue. Many of the currently available drugs for the treatment of liver diseases suffer from limitations that include low hepatic distribution, lack of target effects, poor in vivo stability and adverse effects on other organs. Consequently, conventional treatment of hepatic diseases is ineffective. TCM is commonly used in the treatment of liver diseases worldwide, particularly in China, and has advantages over conventional therapy. HTDDS can be designed to enhance clinical efficacy in the treatment of liver diseases. We have conducted an extensive review of 335 studies reported since 1964. These included about 166 references involving the treatment of liver diseases with TCM (covering active components of TCM, single TCM and Chinese medicine formulas), 169 reports on HTDDS and background studies on liver-related diseases. Here we review the long history of TCM in the treatment of liver diseases.We have also reviewed the status of studies on active components of TCM using nanotechnology-based targeted delivery systems to provide support for further research and development of TCM-based targeted preparations for the treatment of liver disease.

Efficacy of curcuminoids for reducing postoperative pain after laparoscopic gynecologic surgery: A pilot randomized trial

Background Curcuminoids, which are substances extracted from turmeric, have been proved to have anti-inflammatory and analgesic effects along with a good safety profile. This study aimed to evaluate the clinical efficacy of curcuminoids for reducing postoperative pain in patients who undergo laparoscopic gynecologic surgery. Methods From November 2016 to December 2017, participants were randomly assigned, by blocks of four, to the intervention and control arms of the study. Altogether, 60 patients who were to undergo laparoscopic gynecologic surgery at our institution were enrolled. Intraoperative findings were not significantly different between the two groups. One tablet of curcuminoid extract 250 mg was given to patients in the intervention group 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 The median VAS score 24 h after surgery was 3 (1-6) in the intervention group and 4.5 (3-7) in the control group, with the difference reaching statistical significance (p=0.001). The median VAS at 72 h after surgery was 1 (0-2) in the intervention group and 2 (1-5) in the control group (p<0.001). Conclusion Curcuminoids may be an effective supplement to reduce pain severity postoperatively following laparoscopic gynecologic surgery. Trial Registration TCTR20180215001 www.clinicaltrials.in.th.

Curcumin in Autoimmune and Rheumatic Diseases

Over recent decades, many clinical trials on curcumin supplementation have been conducted on various autoimmune diseases including osteoarthritis, type 2 diabetes, and ulcerative colitis patients. This review attempts to summarize the highlights from these clinical trials. The efficacy of curcumin either alone or in conjunction with existing treatment was evaluated. Sixteen clinical trials have been conducted in osteoarthritis, 14 of which yielded significant improvements in multiple disease parameters. Eight trials have been conducted in type 2 diabetes, all yielding significant improvement in clinical or laboratory outcomes. Three trials were in ulcerative colitis, two of which yielded significant improvement in at least one clinical outcome. Additionally, two clinical trials on rheumatoid arthritis, one clinical trial on lupus nephritis, and two clinical trials on multiple sclerosis resulted in inconclusive results. Longer duration, larger cohort size, and multiple dosage arm trials are warranted to establish the long term benefits of curcumin supplementation. Multiple mechanisms of action of curcumin on these diseases have been researched, including the modulation of the eicosanoid pathway towards a more anti-inflammatory pathway, and the modulation of serum lipid levels towards a favorable profile. Overall, curcumin supplementation emerges as an effective therapeutic agent with minimal-to-no side effects, which can be added in conjunction to current standard of care.

Biological properties of metal complexes of curcumin

Curcumin, a naturally occurring phenolic compound isolated from Curcuma longa, has different pharmacological effects, including antiinflammatory, antimicrobial, antioxidant, and anticancer properties. However, curcumin has been found to have a limited bioavailability because of its hydrophobic nature, low-intestinal absorption, and rapid metabolism. Therefore, there is a need for enhancing the bioavailability and its solubility in water in order to increase the pharmacological effects of this bioactive compound. One strategy is curcumin complexation with transition metals to circumvent the abovementioned problems. Curcumin can undergo chelation with various metal ions to form metallo-complexes of curcumin, which may show greater effects as compared with curcumin alone. Promising results with metal curcumin complexes have been observed with regard to antioxidant, anticancer, and antimicrobial activity, as well as in treatment of Alzheimer's disease. The present review provides a concise summary of the characterization and biological properties of curcumin-metal complexes. © 2019 BioFactors, 45(3):304-317, 2019.

Curcumin: Total-Scale Analysis of the Scientific Literature

The current study aimed to provide a comprehensive bibliometric overview of the literature on curcumin, complementing the previous reviews and meta-analyses on its potential health benefits. Bibliometric data for the current analysis were extracted from the Web of Science Core Collection database, using the search string TOPIC=(“curcumin*”), and analyzed by the VOSviewer software. The search yielded 18,036 manuscripts. The ratio of original articles to reviews was 10.4:1. More than half of the papers have been published since 2014. The major contributing countries were the United States, China, India, Japan, and South Korea. These publications were mainly published in journals representing the following scientific disciplines: biochemistry, chemistry, oncology, and pharmacology. There was a significant positive correlation between the total publication count and averaged citations per manuscript for affiliations, but not for countries/regions and journals. Chemicals that were frequently mentioned in the keywords of evaluated curcumin publications included curcuminoids, resveratrol, chitosan, flavonoids, quercetin, and polyphenols. The literature mainly focused on curcumin’s effects against cancer, inflammation, and oxidative stress. Cancer types most frequently investigated were breast, colon, colorectal, pancreatic, and prostate cancers.

Strawberries decrease circulating levels of tumor necrosis factor and lipid peroxides in obese adults with knee osteoarthritis

OBJECTIVE

Knee osteoarthritis (OA) is increasingly prevalent in obese people, who often have high cardio-metabolic risk factors. Among the few available non-surgical approaches, nutraceuticals have gained popularity, and dietary berries have mitigated arthritis symptoms in observational and animal studies. Clinical studies in OA are sparse, but recently we reported that strawberry supplementation can mitigate pain and reduce inflammatory markers in adults with knee OA. This study extends those observations.

METHODS

We conducted a randomized cross-over double-blind placebo-controlled trial on the effects of dietary freeze-dried strawberries on obesity-related hormones, biomarkers of inflammation and lipid peroxidation. Seventeen subjects (4 men, 13 women; age 57 ± 3 year) were randomized to strawberry supplements (50 g day-1 for 12 weeks) vs. placebo (50 g day-1, matched for calories and fiber), for two 12-week intervention periods, separated by 2-week washout phase.

RESULTS

Among 24 biomarkers of inflammation examined (Bioplex-Pro human inflammation panel), 12 were detectable in all samples. Among these, high-sensitivity TNF-α (hs-TNF-α) and the soluble tumor necrosis factor receptor (sTNF-R2) were significantly decreased after strawberry consumption (p < 0.05). There were no changes in other biomarkers of the TNF super family, such as APRIL and BAFF. Among serum biomarkers of oxidative stress, 4-hydroxy-2-nonenal (4-HNE) and conjugated dienes were also reduced (p < 0.05). No changes were observed in body weight, serum obesity-related hormones, or osteocalcin.

CONCLUSION

Strawberries lowered TNF-α, and lipid peroxidation products in obese adults with knee OA. Since, they also mitigate pain, these findings merit further investigation in larger trials.

Demethoxycurcumin: A naturally occurring curcumin analogue for treating non-cancerous diseases

Turmeric extracts contain three primary compounds, which are commonly referred to as curcuminoids. They are curcumin, demethoxycurcumin (DMC), and bisdemethoxycurcumin. While curcumin has been the most extensively studied of the curcuminoids, it suffers from low overall oral bioavailability due to extremely low absorption as a result of low water solubility and instability at acidic pH, as well as rapid metabolism and clearance from the body. However, DMC, which lacks the methoxy group on the benzene ring of the parent structure, has much greater chemical stability at physiological pH and has been recently reported to exhibit antitumor properties. However, the treatment of noncancerous diseases with DMC has not been comprehensively reviewed. Therefore, here we evaluate published scientific literature on the therapeutic properties of DMC. The beneficial pharmacological actions of DMC include anti-inflammatory, neuroprotective, antihypertensive, antimalarial, antimicrobial, antifungal, and vasodilatory properties. In addition, DMC's ability to ameliorate the effects of free radicals and an environment characterized by oxidative stress caused by the accumulation of advanced glycation end-products associated with diabetic nephropathy, as well as DMC's capacity to inhibit the migration and proliferation of vascular smooth muscle cells following balloon angioplasty are also addressed. This review collates the available literature regarding the therapeutic possibilities of DMC in noncancerous conditions.

Safety of Symptomatic Slow-Acting Drugs for Osteoarthritis: Outcomes of a Systematic Review and Meta-Analysis

BACKGROUND

Symptomatic slow-acting drugs for osteoarthritis (SYSADOAs) are an important drug class in the treatment armamentarium for osteoarthritis (OA).

OBJECTIVE

We aimed to re-assess the safety of various SYSADOAs in a comprehensive meta-analysis of randomized placebo-controlled trials, using, as much as possible, data from full safety reports.

METHODS

We performed a systematic review and random-effects meta-analyses of randomized, double-blind, placebo-controlled trials that assessed adverse events (AEs) with various SYSADOAs in patients with OA. The databases MEDLINE, Cochrane Central Register of Controlled Trials (Ovid CENTRAL) and Scopus were searched. The primary outcomes were overall severe and serious AEs, as well as AEs involving the following Medical Dictionary for Regulatory Activities (MedDRA) system organ classes (SOCs): gastrointestinal, cardiac, vascular, nervous system, skin and subcutaneous tissue, musculoskeletal and connective tissue, renal and urinary system.

RESULTS

Database searches initially identified 3815 records. After exclusions according to the selection criteria, 25 studies on various SYSADOAs were included in the qualitative synthesis, and 13 studies with adequate data were included in the meta-analyses. Next, from the studies previously excluded according to the protocol, 37 with mainly oral nonsteroidal anti-inflammatory drugs (NSAIDs) permitted as concomitant medication were included in a parallel qualitative synthesis, from which 18 studies on various SYSADOAs were included in parallel meta-analyses. This post hoc parallel inclusion was conducted because of the high number of studies allowing concomitant anti-OA medications. Indeed, primarily excluding studies with concomitant anti-OA medications was crucial for a meta-analysis on safety. The decision for parallel inclusion was made for the purpose of comparative analyses. Glucosamine sulfate (GS), chondroitin sulfate (CS) and avocado soybean unsaponifiables (ASU; Piascledine®) were not associated with increased odds for any type of AEs compared with placebo. Overall, with/without concomitant OA medication, diacerein was associated with significantly increased odds of total AEs (odds ratio [OR] 2.22; 95% confidence interval [CI] 1.58-3.13; I2 = 52.8%), gastrointestinal disorders (OR 2.85; 95% CI 2.02-4.04; I2 = 62.8%) and renal and urinary disorders (OR 3.42; 95% CI 2.36-4.96; I2 = 17.0%) compared with placebo. In studies that allowed concomitant OA medications, diacerein was associated with significantly more dermatological disorders (OR 2.47; 95% CI 1.42-4.31; I2 = 0%) and more dropouts due to AEs (OR 3.18; 95% CI 1.85-5.47; I2 = 13.4%) than was placebo. No significant increase in serious or severe AEs was found with diacerein versus placebo.

CONCLUSIONS

GS and CS can be considered safe treatments for patients with OA. All eligible studies on ASU included in our analysis used the proprietary product Piascledine® and allowed other anti-OA medications; thus, the safety of ASU must be confirmed in future studies without concomitant anti-OA medications. Given the safety concerns with diacerein, its usefulness in patients with OA should be assessed, taking into account individual patient characteristics.

Phytosomal Curcumin Elicits Anti-tumor Properties Through Suppression of Angiogenesis, Cell Proliferation and Induction of Oxidative Stress in Colorectal Cancer

Background:

Colorectal cancer (CRC) is one of the most common causes of cancer-associated mortality in the world. Anti-tumor effect of curcumin has been shown in different cancers; however, the therapeutic potential of novel phytosomal curcumin, as well as the underlying molecular mechanism in CRC, has not yet been explored.

Methods:

The anti-proliferative, anti-migratory and apoptotic activity of phytosomal curcumin in CT26 cells was assessed by MTT assay, wound healing assay and Flow cytometry, respectively. Phytosomal curcumin was also tested for its in-vivo activity in a xenograft mouse model of CRC. In addition, oxidant/antioxidant activity was examined by DCFH-DA assay in vitro, measurement of malondialdehyde (MDA), Thiol and superoxidedismutase (SOD) and catalase (CAT) activity and also evaluation of expression levels of Nrf2 and GCLM by qRT-PCR in tumor tissues. In addition, the effect of phytosomal curcumin on angiogenesis was assessed by the measurement of VEGF-A and VEGFR-1 and VEGF signaling regulatory microRNAs (miRNAs) in tumor tissue.

Results:

Phytosomal curcumin exerts anti-proliferative, anti-migratory and apoptotic activity in-vitro. It also decreases tumor growth and augmented 5-fluorouracil (5-FU) anti-tumor effect in-vivo. In addition, our data showed that induction of oxidative stress and inhibition of angiogenesis through modulation of VEGF signaling regulatory miRNAs might be underlying mechanisms by which phytosomal curcumin exerted its antitumor effect.

Conclusion:

Our data confirmed this notion that phytosomal curcumin administrates anticancer effects and can be used as a complementary treatment in clinical settings.

A pilot, randomized, double-blind, placebo-controlled trial to assess the safety and efficacy of a novel Boswellia serrata extract in the management of osteoarthritis of the knee

A double-blind, placebo-controlled human trial was conducted to evaluate the safety and efficacy of a standardized oral supplementation of Boswellin®, a novel extract of Boswellia serrata extract (BSE) containing 3-acetyl-11-keto-β-boswellic acid (AKBBA) with β-boswellic acid (BBA). A total of 48 patients with osteoarthritis (OA) of the knee were randomized and allocated to the BSE and placebo groups for intervention. Patients were administered BSE or placebo for a period of 120 days. The trial results revealed that BSE treatment significantly improved the physical function of the patients by reducing pain and stiffness compared with placebo. Radiographic assessments showed improved knee joint gap and reduced osteophytes (spur) confirming the efficacy of BSE treatment. BSE also significantly reduced the serum levels of high-sensitive C-reactive protein, a potential inflammatory marker associated with OA of the knee. No serious adverse events were reported. This is the first study with BSE conducted for a period of 120 days, longer than any other previous clinical trial on patients with OA of the knee. The findings provide evidence that biologically active constituents of BSE, namely, AKBBA and BBA, act synergistically to exert anti-inflammatory/anti-arthritic activity showing improvement in physical and functional ability and reducing the pain and stiffness.

Chitosan-based delivery systems for curcumin: A review of pharmacodynamic and pharmacokinetic aspects

Effective drug delivery is one of the most important issues associated with the administration of therapeutic agents that have low oral bioavailability. Curcumin is an active ingredient in the turmeric plant, which has low oral bioavailability due to its poor aqueous solubility. One strategy that has been considered for enhancing the aqueous solubility, and, thus, its oral bioavailability, is the use of chitosan as a carrier for curcumin. Chitosan is a biodegradable and biocompatible polymer that is relatively water-soluble. Therefore, various studies have sought to improve the aqueous solubility of chitosan. The use of different pharmaceutical excipients and formulation strategies has the potential to improve aqueous solubility, formulation processing, and the overall delivery of hydrophobic drugs. This review focuses on various methods utilized for chitosan-based delivery of curcumin.

Mechanisms of apoptosis modulation by curcumin: Implications for cancer therapy

Cancer incidences are growing and cause millions of deaths worldwide. Cancer therapy is one of the most important challenges in medicine. Improving therapeutic outcomes from cancer therapy is necessary for increasing patients' survival and quality of life. Adjuvant therapy using various types of antibodies or immunomodulatory agents has suggested modulating tumor response. Resistance to apoptosis is the main reason for radioresistance and chemoresistance of most of the cancers, and also one of the pivotal targets for improving cancer therapy is the modulation of apoptosis signaling pathways. Apoptosis can be induced by intrinsic or extrinsic pathways via stimulation of several targets, such as membrane receptors of tumor necrosis factor-α and transforming growth factor-β, and also mitochondria. Curcumin is a naturally derived agent that induces apoptosis in a variety of different tumor cell lines. Curcumin also activates redox reactions within cells inducing reactive oxygen species (ROS) production that leads to the upregulation of apoptosis receptors on the tumor cell membrane. Curcumin can also upregulate the expression and activity of p53 that inhibits tumor cell proliferation and increases apoptosis. Furthermore, curcumin has a potent inhibitory effect on the activity of NF-κB and COX-2, which are involved in the overexpression of antiapoptosis genes such as Bcl-2. It can also attenuate the regulation of antiapoptosis PI3K signaling and increase the expression of MAPKs to induce endogenous production of ROS. In this paper, we aimed to review the molecular mechanisms of curcumin-induced apoptosis in cancer cells. This action of curcumin could be applicable for use as an adjuvant in combination with other modalities of cancer therapy including radiotherapy and chemotherapy.

Impact of curcumin on toll-like receptors

Toll-like receptors (TLRs) have a pivotal role in the activation of innate immune response and inflammation. TLRs can be divided into two subgroups including extracellular TLRs that recognize microbial membrane components (TLR1, 2, 4, 5, 6, and 10), and intracellular TLRs that recognize microbial nucleic acids (TLR3, 7, 8, and 9). Curcumin is a dietary polyphenol from Curcuma longa L. that is reputed to have diverse biological and pharmacological effects. Extensive research has defined the molecular mechanisms through which curcumin mediates its therapeutic effects. One newly defined and important target of curcumin is the TLR, where it exerts an inhibitory effect. In the current study, we focus upon the TLR antagonistic effect of curcumin and curcumin's therapeutic effect as mediated via TLR inhibition. The available evidence indicates that curcumin inhibits the extracellular TLR 2 and 4 and intracellular TLR9 and thereby exerts a therapeutic effect in diseases such as cancer, inflammation, infection, autoimmune, and ischemic disease. Curcumin effectively modulates the TLR response and thereby exerts its potent therapeutic effects.

Curcumin as a therapeutic agent in leukemia

Leukemia comprises a group of hematological malignancies responsible for 8% of all cancers and is the most common cancer in children. Despite significant improvements in leukemia treatment, the efficacy of conventional chemotherapeutic agents is low and the disease carries a poor prognosis with frequent relapses and high mortality. Curcumin is a yellow polyphenol compound with diverse pharmacological actions including anticancer, antioxidant, antidiabetic, anti-inflammatory, immunomodulatory, hepatoprotective, lipid-regulating, antidepressant, and antiarthritic. Many cellular and experimental studies have reported the benefits of curcumin in treating leukemia. Curcumin's anticancer effects are exerted via various mechanisms. Here, we review the effects of curcumin on various types of leukemia whilst considering its mechanisms of action.

Macrophage plasticity, polarization and function in response to curcumin, a diet-derived polyphenol, as an immunomodulatory agent

Monocytes and macrophages are important cells of the innate immune system that have diverse functions, including defense against invading pathogens, removal of dead cells by phagocytosis, antigen presentation in the context of MHC class I and class II molecules, and production of various pro-inflammatory cytokines and chemokines such as IL-1β, IL-6, TNF-α and MCP-1. In addition, pro-inflammatory (M1) and anti-inflammatory (M2) macrophages clearly play important roles in the progression of several inflammatory diseases. Therefore, therapies that target macrophage polarization and function by either blocking their trafficking to sites of inflammation, or skewing M1 to M2 phenotype polarization may hold clinical promise in several inflammatory diseases. Dietary-derived polyphenols have potent natural anti-oxidative properties. Within this group of polyphenols, curcumin has been shown to suppress macrophage inflammatory responses. Curcumin significantly reduces co-stimulatory molecules and also inhibits MAPK activation and the translocation of NF-κB p65. Curcumin can also polarize/repolarize macrophages toward the M2 phenotype. Curcumin-treated macrophages have been shown to be highly efficient at antigen capture and endocytosis via the mannose receptor. These novel findings provide new perspectives for the understanding of the immunopharmacological role of curcumin, as well as its therapeutic potential for impacting macrophage polarization and function in the context of inflammation-related disease. However, the precise effects of curcumin on the migration, differentiation, polarization and immunostimulatory functions of macrophages remain unknown. Therefore, in this review, we summarized whether curcumin can influence macrophage polarization, surface molecule expression, cytokine and chemokine production and their underlying pathways in the prevention of inflammatory diseases.

The therapeutic potential of curcumin: A review of clinical trials

Curcuma longa L., its derived extracts and even its major compound curcumin has a long history of use and doubtless effectiveness, reported through increasingly detailed in vitro, ex vivo, in vivo and even clinical trials. Regarding its biological effects, multiple health-promoting, disease-preventing and even treatment attributes has been remarkably highlighted. Clinical trials, although have increased in a progressive manner, significant disproportionalities have been stated in terms of biological effects assessment. In this sense, the present report aims to provide an extensive overview to curcumin therapeutic effects in human subjects. For that, clinical trials assessing the curcumin effect on inflammation, skin, eye, central nervous system, respiratory, cardiovascular, gastrointestinal, urogenital and metabolic disorders are here presented and discussed. A special emphasis was also given to curcumin activity on intoxications and multiple malignant diseases.

Hormetic effects of curcumin: What is the evidence?

Curcumin (diferuloylmethane), a component of the yellow powder prepared from the roots of Curcuma longa or Zingiberaceae (known as turmeric) is not only widely used to color and flavor food but also used as a pharmaceutical agent. Curcumin demonstrates anti-inflammatory, anticarcinogenic, antiaging, and antioxidant activity, as well as efficacy in wound healing. Notably, curcumin is a hormetic agent (hormetin), as it is stimulatory at low doses and inhibitory at high doses. Hormesis by curcumin could be also a particular function at low doses (i.e., antioxidant behavior) and another function at high dose (i.e., induction of autophagy and cell death). Recent findings suggest that curcumin exhibits biphasic dose-responses on cells, with low doses having stronger effects than high doses; examples being activation of the mitogen-activated protein kinase signaling pathway or antioxidant activity. This indicates that many effects induced by curcumin are dependent on dose and some effects might be greater at lower doses, indicative of a hormetic response. Despite the consistent occurrence of hormetic responses of curcumin in a wide range of biomedical models, epidemiological and clinical trials are needed to assess the nature of curcumin's dose-response in humans. Fortunately, more than one hundred clinical trials with curcumin and curcumin derivatives are ongoing. In this review, we provide the first comprehensive analysis supportive of the hormetic behavior of curcumin and curcumin derivatives.