Co-Administration of Iron and Bioavailable Curcumin Reduces Levels of Systemic Markers of Inflammation and Oxidative Stress in a Placebo-Controlled Randomised Study

A Review of Recent Curcumin Analogues and Their Antioxidant, Anti-Inflammatory, and Anticancer Activities

Curcumin, as the main active component of turmeric (Curcuma longa), has been demonstrated with various bioactivities. However, its potential therapeutic applications are hindered by challenges such as poor solubility and bioavailability, rapid metabolism, and pan-assay interference properties. Recent advancements have aimed to overcome these limitations by developing novel curcumin analogues and modifications. This brief review critically assesses recent studies on synthesising different curcumin analogues, including metal complexes, nano particulates, and other curcumin derivatives, focused on the antioxidant, anti-inflammatory, and anticancer effects of curcumin and its modified analogues. Exploring innovative curcumin derivatives offers promising strategies to address the challenges associated with its bioavailability and efficacy and valuable insights for future research directions.

Obesity aggravates the role of C-reactive protein on knee pain: A cross-sectional analysis with NHANES data

OBJECTIVE

To examine the relationship between C-reactive protein (CRP) and knee pain, and further explore whether this association is mediated by obesity.

METHODS

The population was derived from 1999 to 2004 National Health and Nutrition Examination Survey. Logistic regression was used to analyze the relationship between CRP and knee pain in three different models, and the linear trend was analyzed. A restricted cubic spline model to assess the nonlinear dose-response relationship between CRP and knee pain. Mediation analyses were used to assess the potential mediating role of obesity. Subgroup analyses and sensitivity analyses were performed to ensure robustness.

RESULTS

Compared with adults with lower CRP (first quartile), those with higher CRP had higher risks of knee pain (odds ratio 1.39, 95% confidence interval 1.12-1.72 in third quartile; 1.56, 1.25-1.95 in fourth quartile) after adjusting for covariates (except body mass index [BMI]), and the proportion mediated by BMI was 76.10% (p < .001). BMI and CRP were linear dose-response correlated with knee pain. The odds ratio for those with obesity compared with normal to knee pain was 2.27 (1.42-3.65) in the first quartile of CRP, 1.99 (1.38-2.86) in the second, 2.15 (1.38-3.33) in the third, and 2.92 (1.72-4.97) in the fourth.

CONCLUSION

Obesity mediated the systemic inflammation results in knee pain in US adults. Moreover, higher BMI was associated with higher knee pain risk in different degree CRP subgroups, supporting an important role of weight loss in reducing knee pain caused by systemic inflammation.

Curcumin as a potential therapeutic agent for treating neurodegenerative diseases

Neurodegenerative diseases are characterized by the progressive loss of neuronal structure and function, posing a tremendous burden on health systems worldwide. Although the underlying pathological mechanisms for various neurodegenerative diseases are still unclear, a common pathological hallmark is the abundance of neuroinflammatory processes, which affect both disease onset and progression. In this review, we explore the pathways and role of neuroinflammation in various neurodegenerative diseases and further assess the potential use of curcumin, a natural spice with antioxidant and anti-inflammatory properties that has been extensively used worldwide as a traditional medicine and potential therapeutic agent. Following the examination of preclinical and clinical studies that assessed curcumin as a potential therapeutic agent, we highlight the bioavailability of curcumin in the body and discuss both the challenges and benefits of using curcumin as a therapeutic compound for treating neurodegeneration. Although elucidating the involvement of curcumin in aging and neurodegeneration has great potential for developing future CNS-related therapeutic targets, further research is required to elucidate the mechanisms by which Curcumin affects brain physiology, especially BBB integrity, under both physiological and disease conditions.

Scientific opinion on the tolerable upper intake level for iron

Following a request from the European Commission, the EFSA Panel on Nutrition, Novel Foods and Food Allergens (NDA) was asked to deliver a scientific opinion on the tolerable upper intake level (UL) for iron. Systematic reviews were conducted to identify evidence regarding high iron intakes and risk of chronic diseases, adverse gastrointestinal effects and adverse effects of iron supplementation in infancy, young childhood and pregnancy. It is established that systemic iron overload leads to organ toxicity, but no UL could be established. The only indicator for which a dose-response could be established was black stools, which reflect the presence of large amounts of unabsorbed iron in the gut. This is a conservative endpoint among the chain of events that may lead to systemic iron overload but is not adverse per se. Based on interventions in which black stools did not occur at supplemental iron intakes of 20-25 mg/day (added to a background intake of 15 mg/day), a safe level of intake for iron of 40 mg/day for adults (including pregnant and lactating women) was established. Using allometric scaling (body weight0.75), this value was scaled down to children and adolescents and safe levels of intakes between 10 mg/day (1-3 years) and 35 mg/day (15-17 years) were derived. For infants 7-11 months of age who have a higher iron requirement than young children, allometric scaling was applied to the supplemental iron intakes (i.e. 25 mg/day) and resulted in a safe level of supplemental iron intake of 5 mg/day. This value was extended to 4-6 month-old infants and refers to iron intakes from fortified foods and food supplements, not from infant and follow-on formulae. The application of the safe level of intake is more limited than a UL because the intake level at which the risk of adverse effects starts to increase is not defined.

Innovative Delivery Systems for Curcumin: Exploring Nanosized and Conventional Formulations

Curcumin, a polyphenol with a rich history spanning two centuries, has emerged as a promising therapeutic agent targeting multiple signaling pathways and exhibiting cellular-level activities that contribute to its diverse health benefits. Extensive preclinical and clinical studies have demonstrated its ability to enhance the therapeutic potential of various bioactive compounds. While its reported therapeutic advantages are manifold, predominantly attributed to its antioxidant and anti-inflammatory properties, its efficacy is hindered by poor bioavailability stemming from inadequate absorption, rapid metabolism, and elimination. To address this challenge, nanodelivery systems have emerged as a promising approach, offering enhanced solubility, biocompatibility, and therapeutic effects for curcumin. We have analyzed the knowledge on curcumin nanoencapsulation and its synergistic effects with other compounds, extracted from electronic databases. We discuss the pharmacokinetic profile of curcumin, current advancements in nanoencapsulation techniques, and the combined effects of curcumin with other agents across various disorders. By unifying existing knowledge, this analysis intends to provide insights into the potential of nanoencapsulation technologies to overcome constraints associated with curcumin treatments, emphasizing the importance of combinatorial approaches in improving therapeutic efficacy. Finally, this compilation of study data aims to inform and inspire future research into encapsulating drugs with poor pharmacokinetic characteristics and investigating innovative drug combinations to improve bioavailability and therapeutic outcomes.

Nutrition in chronic inflammatory conditions: Bypassing the mucosal block for micronutrients

Nutritional Immunity is one of the most ancient innate immune responses, during which the body can restrict nutrients availability to pathogens and restricts their uptake by the gut mucosa (mucosal block). Though this can be a beneficial strategy during infection, it also is associated with non-communicable diseases-where the pathogen is missing; leading to increased morbidity and mortality as micronutritional uptake and distribution in the body is hindered. Here, we discuss the acute immune response in respect to nutrients, the opposing nutritional demands of regulatory and inflammatory cells and particularly focus on some nutrients linked with inflammation such as iron, vitamins A, Bs, C, and other antioxidants. We propose that while the absorption of certain micronutrients is hindered during inflammation, the dietary lymph path remains available. As such, several clinical trials investigated the role of the lymphatic system during protein absorption, following a ketogenic diet and an increased intake of antioxidants, vitamins, and minerals, in reducing inflammation and ameliorating disease.

Curcumin/turmeric supplementation could improve blood pressure and endothelial function: A grade-assessed systematic review and dose-response meta-analysis of randomized controlled trials

BACKGROUND AND PURPOSE

A number of studies have examined the impact of curcumin/turmeric on blood pressure and the factors allegedly responsible for hypertension. In this systematic review and meta-analysis, we tried to sum up the existing literature on randomized controlled trials (RCTs) investigating this hypothesis.

METHODS

Online databases (PubMed, Scopus, Web of Science Core Collection, Cochrane Library, and Google Scholar) were searched from inception up to October 2022. We used the cochrane quality assessment tool to evaluate the risk of bias. Outcomes of interest included systolic blood pressure (SBP), diastolic blood pressure (DBP), blood levels of vascular cell adhesion molecule-1 (VCAM-1) and intracellular adhesion molecule-1 (ICAM-1), flow-mediated vasodilation (FMD), and pulse-wave velocity (PWV). Weighted mean differences (WMDs) were derived and reported. In case of significant between-study heterogeneity, subgroup analyses were carried out. Significance level was considered as P-values<0.05.

RESULTS

Finally, 35 RCTs out of 4182 studies were included. Our findings suggested that curcumin/turmeric supplementation significantly improved SBP (WMD: -2.02 mmHg; 95 % CI: -2.85, -1.18), DBP (WMD: -0.82 mmHg; 95 % CI: -1.46, -0.18), VCAM-1 (WMD: -39.19 ng/mL; 95 % CI: -66.15, -12.23), and FMD (WMD: 2.00 %; 95 % CI: 1.07, 2.94). However, it did not significantly change levels of ICAM-1 (WMD: -17.05 ng/ml; 95 % CI: -80.79, 46.70), or PWV (WMD: -79.53 cm/s; 95 % CI: -210.38, 51.33).

CONCLUSION

It seems that curcumin/turmeric supplementation could be regarded as a complementary method to improve blood pressure and endothelial function. However, further research is needed to clarify its impact on inflammatory adhesion molecules in the circulation.

Impact on oxidative stress of oral, high-dose, iron supplementation for management of iron deficiency after bariatric surgery, a preliminary study

OBJECTIVES

High-dose oral iron supplementation for patients who develop iron deficiency after bariatric surgery may induce oxidative stress in the gastrointestine. The study's objective was to test this hypothesis by determining the impact of high-dose oral iron on systemic oxidative stress.

METHODS

We used archived plasma samples from a randomized controlled clinical trial (NCT02404012) comparing FeSO4 (195 mg/day, NatureMade®, West Hills, CA) with a heme iron polypeptide (HIP, 60.4 mg/day, Proferrin®, Colorado Biolabs, Lafayette, CO) for 8 weeks. Systemic oxidative stress was measured using malondialdehyde and total antioxidant capacity (MDA, Abcam, ab238537 and TAC, Abcam, ab65329 Cambridge, UK) assays. Data was log-transformed and presented as means and standard deviations; a mixed model was used to determine the effects of time (0, 2, 4, and 8 weeks) and treatment (FeSO4 versus HIP) on oxidative stress.

RESULTS

The FeSO4 (N = 8) and HIP (N = 5) participants were balanced in body mass index (35.0 ± 5.5 kg/m2), race (93 % White), time post-surgery (7.3 ± 3.3 years), as well as serum concentrations of iron (P > 0.05). The FeSO4 group tended to be older (44.3 ± 4.5 years) and they had lower concentrations of serum ferritin (6.5 ± 2.7 µg/mL) than the HIP (38.2 ± 9.3 years, and 12.9 ± 16.8 µg/mL) group (P = 0.080, and P = 0.017 respectively). We observed a larger increase in serum iron in the FeSO4 group during the 8 weeks of Fe supplementation, compared to that in the HIP group (p = 0.004). We observed a decreasing trend in MDA over the 8 weeks (p = 0.080) in the FeSO4 treatment group. There were no significant differences in TAC between and within FeSO4 and HIP groups over the 8 week supplementation period.

CONCLUSIONS

This preliminary study suggests that high-dose oral iron supplementation for iron deficiency does not adversely impact systemic oxidative stress in patients undergoing bariatric surgery.

Effect of Antioxidant Supplementation on NET Formation Induced by LPS In Vitro; the Roles of Vitamins E and C, Glutathione, and N-acetyl Cysteine

Neutrophil extracellular traps (NETs) require reactive oxygen species (ROS) to eliminate pathogens by inducing oxidative stress. However, this process can also cause tissue damage to the host. Neutrophils contain high concentrations of vitamin C (1.5 mM) compared to the bloodstream (0.1 mM), and this antioxidant can interact with vitamin E and glutathione (GSH) inside the cell to maintain the redox balance. Previous studies have investigated the effect of vitamins E or C and N-acetyl cysteine (NAC) on NET formation, but the interactions of these molecules in neutrophils remain unknown. In this study, we investigated the effect of antioxidants alone and two combinations on NET formation and oxidative stress. Neutrophils were pre-loaded with GSH + NAC or vitamin E + vitamin C + GSH + NAC (termed ALL), and LPS-induced NET formation was assessed using fluorometry and immunofluorescence. Antioxidant effects were evaluated by measuring the total antioxidant capacity (TAC), GSH/GSSG ratio, ROS production, nitrite + nitrate levels, and lipid peroxidation. Our results showed that even low doses of antioxidants are capable of decreasing NETs. Furthermore, the combinations augmented TAC and GSH/GSSG ratio and decreased ROS, nitrites + nitrates, and malondialdehyde (MDA) levels in supplemented neutrophils in vitro.

Role of Turmeric and Curcumin in Prevention and Treatment of Chronic Diseases: Lessons Learned from Clinical Trials

Turmeric (Curcuma longa) has been used for thousands of years for the prevention and treatment of various chronic diseases. Curcumin is just one of >200 ingredients in turmeric. Almost 7000 scientific papers on turmeric and almost 20,000 on curcumin have been published in PubMed. Scientific reports based on cell culture or animal studies are often not reproducible in humans. Therefore, human clinical trials are the best indicators for the prevention and treatment of a disease using a given agent/drug. Herein, we conducted an extensive literature survey on PubMed and Scopus following the Preferred Reporting Items for Systematic Reviews and Meta-Analyses guidelines. The keywords "turmeric and clinical trials" and "curcumin and clinical trials" were considered for data mining. A total of 148 references were found to be relevant for the key term "turmeric and clinical trials", of which 70 were common in both PubMed and Scopus, 44 were unique to PubMed, and 34 were unique to Scopus. Similarly, for the search term "curcumin and clinical trials", 440 references were found to be relevant, of which 70 were unique to PubMed, 110 were unique to Scopus, and 260 were common to both databases. These studies show that the golden spice has enormous health and medicinal benefits for humans. This Review will extract and summarize the lessons learned about turmeric and curcumin in the prevention and treatment of chronic diseases based on clinical trials.

Curcumin Formulations for Better Bioavailability: What We Learned from Clinical Trials Thus Far?

Curcumin has been credited with a wide spectrum of pharmacological properties for the prevention and treatment of several chronic diseases such as arthritis, autoimmune diseases, cancer, cardiovascular diseases, diabetes, hemoglobinopathies, hypertension, infectious diseases, inflammation, metabolic syndrome, neurological diseases, obesity, and skin diseases. However, due to its weak solubility and bioavailability, it has limited potential as an oral medication. Numerous factors including low water solubility, poor intestinal permeability, instability at alkaline pH, and fast metabolism contribute to curcumin's limited oral bioavailability. In order to improve its oral bioavailability, different formulation techniques such as coadministration with piperine, incorporation into micelles, micro/nanoemulsions, nanoparticles, liposomes, solid dispersions, spray drying, and noncovalent complex formation with galactomannosides have been investigated with in vitro cell culture models, in vivo animal models, and humans. In the current study, we extensively reviewed clinical trials on various generations of curcumin formulations and their safety and efficacy in the treatment of many diseases. We also summarized the dose, duration, and mechanism of action of these formulations. We have also critically reviewed the advantages and limitations of each of these formulations compared to various placebo and/or available standard care therapies for these ailments. The highlighted integrative concept embodied in the development of next-generation formulations helps to minimize bioavailability and safety issues with least or no adverse side effects and the provisional new dimensions presented in this direction may add value in the prevention and cure of complex chronic diseases.

The "ON-OFF" Switching Response of Reactive Oxygen Species in Acute Normobaric Hypoxia: Preliminary Outcome

Exposure to acute normobaric hypoxia (NH) elicits reactive oxygen species (ROS) accumulation, whose production kinetics and oxidative damage were here investigated. Nine subjects were monitored while breathing an NH mixture (0.125 F_IO₂ in air, about 4100 m) and during recovery with room air. ROS production was assessed by Electron Paramagnetic Resonance in capillary blood. Total antioxidant capacity, lipid peroxidation (TBARS and 8-iso-PFG2α), protein oxidation (PC) and DNA oxidation (8-OH-dG) were measured in plasma and/or urine. The ROS production rate (μmol·min^-1) was monitored (5, 15, 30, 60, 120, 240 and 300 min). A production peak (+50%) was reached at 4 h. The on-transient kinetics, exponentially fitted (t_1/2 = 30 min r² = 0.995), were ascribable to the low O₂ tension transition and the mirror-like related SpO₂ decrease: 15 min: -12%; 60 min: -18%. The exposure did not seem to affect the prooxidant/antioxidant balance. Significant increases in PC (+88%) and 8-OH-dG (+67%) at 4 h in TBARS (+33%) one hour after hypoxia offset were also observed. General malaise was described by most of the subjects. Under acute NH, ROS production and oxidative damage resulted in time and SpO₂-dependent reversible phenomena. The experimental model could be suitable for evaluating the acclimatation level, a key element in the context of mountain rescues in relation to technical/medical workers who have not had enough time for acclimatization-as, for example, during helicopter flights.

Beneficial Contribution to Glucose Homeostasis by an Agro-Food Waste Product Rich in Abscisic Acid: Results from a Randomized Controlled Trial

The control of glucose homeostasis represents the primary goal for the prevention and management of diabetes and prediabetes. In recent decades, the hypoglycemic hormone abscisic acid (ABA) has attracted considerable interest in the scientific literature. In this regard, the high ABA concentration in immature fruits led us to consider these food matrices as candidates for diabetes control. Therefore, the beneficial efficacy of a nutraceutical formulation based on thinned nectarines (TNs) rich in ABA was tested through a three-month, three-arm, parallel-group, randomized controlled trial (RCT) conducted on sixty-one patients with type 2 diabetes (T2D). After 3 months, both the treatments with low doses of TN (500 mg 3 times/day) and high doses of TN (750 mg 3 times/day) showed a significant reduction in glycemic parameters compared to baseline. Treatment with low doses of TN showed a greater insulin-sparing effect (fasting plasma insulin, FPI: −29.2%, p < 0.05 vs. baseline) compared to the high-dose group (FPI: −16.5%, p < 0.05 vs. baseline). Moreover, a significant correlation between glycemia and ABA plasmatic levels was observed for both intervention groups at baseline and after 3 months. Overall, our data reasonably support TN as a promising and innovative nutraceutical product able to contribute to the management of glucose homeostasis.

Effects of Curcumin and Tetracycline Gel on Experimental Induced Periodontitis as an Anti-Inflammatory, Osteogenesis Promoter and Enhanced Bone Density through Altered Iron Levels: Histopathological Study

Adjunctive use of antimicrobials with scaling and root planing (SRP) is necessary to better eradicate dental biofilm. Tetracycline (T) is the most commonly used antimicrobial; however, it has limitations. This study evaluates the effect of curcumin (CU) as adjunct to SRP on inflammatory markers, collagen fiber deposition, and altered iron level. A total of 32 Wistar rats were divided into five groups: no experimental periodontitis (healthy control), experimental periodontitis (EPD), EPD treated with SRP alone (SRP), EPD treated with SRP+T (SRP+T), and EPD treated with SRP+CU (SRP+CU). After 2 and 4 weeks of treatment, tissue samples were assessed by hematoxylin and eosin, and special stains (Perls’ stain and Masson’s Trichrome) for counting of inflammatory cells, angiogenesis, collagen fibers, and iron deposition. Significant reductions in inflammatory cells infiltration and alveolar bone resorption with angiogenesis and collagen fibers deposition were detected after 2 and 4 weeks in both SRP+T and SRP+CU groups. SRP+CU resulted in a significant reduction in osteoclast numbers (week 2) and iron deposition (week 4) in bone trabeculae as compared to SRP and SRP+T groups. The adjunctive use of CU showed comparable results to T in the reduction in inflammation and bone resorption. Furthermore, CU has potential osteogenesis and healing effects.

Curcumin: The Golden Nutraceutical on the Road to Cancer Prevention and Therapeutics. A Clinical Perspective

Cancer is considered as the major public health scourge of the 21st century. Although remarkable strides were made for developing targeted therapeutics, these therapies suffer from lack of efficacy, high cost, and debilitating side effects. Therefore, the search for safe, highly efficacious, and affordable therapies is paramount for establishing a treatment regimen for this deadly disease. Curcumin, a known natural, bioactive, polyphenol compound from the spice turmeric (Curcuma longa), has been well documented for its wide range of pharmacological and biological activities. A plethora of literature indicates its potency as an anti-inflammatory and anti-cancer agent. Curcumin exhibits anti-neoplastic attributes via regulating a wide array of biological cascades involved in mutagenesis, proliferation, apoptosis, oncogene expression, tumorigenesis, and metastasis. Curcumin has shown a wide range of pleiotropic anti-proliferative effect in multiple cancers and is a known inhibitor of varied oncogenic elements, including nuclear factor kappa B (NF-κB), c-myc, cyclin D1, Bcl-2, VEGF, COX-2, NOS, tumor necrosis factor alpha (TNF-α), interleukins, and MMP-9. Further, curcumin targets different growth factor receptors and cell adhesion molecules involved in tumor growth and progression, making it a most promising nutraceutical for cancer therapy. To date, curcumin-based therapeutics have completed more than 50 clinical trials for cancer. Although creative experimentation is still elucidating the immense potential of curcumin, systematic validation by proper randomized clinical trials warrant its transition from lab to bedside. Therefore, this review summarizes the outcome of diverse clinical trials of curcumin in various cancer types.