Anti-hyperglycemic and insulin sensitizer effects of turmeric and its principle constituent curcumin

Effect of nano-curcumin supplementation on cardiometabolic risk factors, physical and psychological quality of life, and depression in patients with coronary slow flow phenomenon: a randomized double-blind clinical trial

BACKGROUND

Extensive evidence has suggested the cardio-protective properties of the polyphenol curcumin. The aim of this study was to investigate the effects of a highly bioavailable curcumin supplement on cardiometabolic risk factors, health-related quality of life, and depression in patients with coronary slow flow phenomenon (CSFP).

METHODS

This randomized double-blind placebo-controlled clinical trial was conducted in 42 patients with CSFP (age 35-70 years, 25 ≤ body mass index < 40 kg/m2). Patients received either 80 mg/day nano-curcumin or placebo for 12 weeks. Serum levels of visfatin, high-sensitivity C-reactive protein (hs-CRP), and glycemic indices were measured before and after the intervention. The short form 36-item quality of life (SF-36) and Beck's Depression Inventory-II (BDI-II) questionnaires were assessed, as well.

RESULTS

No significant improvements were observed in circulating hs-CRP and visfatin following the intervention. A significant increase was observed in pre- to post-fasting blood glucose (- 0.9 ± 12.2 vs. 7.7 ± 12.4 mg/dl, p = 0.02) and hemoglobin A1C (- 0.1 ± 0.8 vs. 0.5 ± 0.8%, p = 0.04) levels, in the placebo compared with the intervention group. Physical (8.2 ± 8.1 vs. - 1.2 ± 6.5, p < 0.001) and mental (6.8 ± 11.8 vs. - 1.1 ± 10.4, p = 0.02) component summary scores were significantly improved in the nano-curcumin than the placebo group. Additionally, the number of patients with lower degrees of depression was significantly better in the intervention than the placebo group following the supplementation (p = 0.046).

CONCLUSION

Curcumin supplementation prevented deterioration of glycemic control and improved physical and psychological quality of life and depression in patients with CSFP.

TRIAL REGISTRATION

Iranian Registry of Clinical Trials (IRCT20131125015536N8), June 19, 2019.

Herbal Products as Complementary or Alternative Medicine for the Management of Hyperglycemia and Dyslipidemia in Patients with Type 2 Diabetes: Current Evidence Based on Findings of Interventional Studies

Type 2 diabetes (T2D) is known as a major public health problem with a noticeable adverse impact on quality of life and health expenditures worldwide. Despite using routine multiple pharmacological and nonpharmacological interventions, including diet therapy and increasing physical activity, controlling this chronic disease remains a challenging issue, and therapeutic goals are often not achieved. Therefore, recently, other therapeutic procedures, such as using herbal products and functional foods as complementary or alternative medicine (CAM), have received great attention as a new approach to managing T2D complications, according to the literature. We reviewed the existing evidence that supports using various fundamental medicinal herbs, including cinnamon, saffron, ginger, jujube, turmeric, and barberry, as CAM adjunctive therapeutic strategies for T2D patients. The current review addressed different aspects of the potential impact of the abovementioned herbal products in improving glycemic indices and lipid profiles, including the effect size reported in the studies, their effective dose, possible side effects, herbs-drug interactions, and their potential action mechanisms.

Can Polyherbal Medicine be used for the Treatment of Diabetes? - A Review of Historical Classics, Research Evidence and Current Prevention Programs

Diabetes mellitus (DM), a chronic medical condition, has attained a global pandemic status over the last few decades affecting millions of people. Despite a variety of synthetic drugs available in the market, the use of herbal medicines for managing diabetes is gaining importance because of being comparatively safer. This article reviews the result of a substantial literature search on polyherbal formulations (PHFs) developed and evaluated with potential for DM. The accumulated data in the literature allowed us to enlist 76PHFs consisting of different parts of 147 plant species belonging to 58 botanical families. The documented plant species are laden with bioactive components with anti-diabetic properties and thus draw attention. The most favoured ingredient for PHFs was leaves of Gymnema sylvestre and seeds of Trigonella foenum-graecum used in 27 and 22 formulations, respectively. Apart from herbs, shilajit (exudates from high mountain rocks) formed an important component of 9 PHFs, whereas calcined Mytilus margaritiferus and goat pancreas were used in Dolabi, the most commonly used tablet form of PHF in Indian markets. The healing properties of PHFs against diabetes have been examined in both pre-clinical studies and clinical trials. However, the mechanism(s) of action of PHFs are still unclear and considered the pitfalls inherent in understanding the benefits of PHFs. From the information available based on experimental systems, it could be concluded that plant-derived medicines will have a considerable role to play in the control of diabetes provided the challenges related to their bioavailability, bioefficacy, optimal dose, lack of characterization, ambiguous mechanism of action, and clinical efficiency are addressed.

Role of polyphenols in the management of diabetic complications

BACKGROUND

Diabetes Mellitus is an endocrine disorder that will affect, about 693 million adults by 2045 worldwide, (>50% increase from 2017). The conventional treatment of the disease, include the oral hypoglycemic drugs which are given in combination with other drugs and are known to possess various adverse effects like gastrointestinal disturbance, nausea, water retention etc. PURPOSE: Due to the urgent need of combating this disorder without side effects, the alternative and complementary therapies should be explored due to their natural origins and comparable safety. Herbal sources serve as new leads, due to the presence of phytoconstituents with potential therapeutic properties, efficacy and safety. In this review, we tried to summarise the polyphenolic phytoconstituents effective in the treatment of diabetic complications.

METHODS

A systematic literature search was conducted using 4 databases (Google scholar, Pubmed, Scopus, Embase) for the identification of relevant data. Search was performed using various key words such as "diabetes", "polyphenols", "marine sources","anti-diabetic polyphenols". The in vitro studies involving the cell lines used in diabetes and animal models were also considered for inclusion. Additional research papers were identified by reviewing abstracts, scrutinizing reference lists, and reviewing previously published review articles.

RESULTS

Polyphenols, a group of phytoconstituents are known worldwide for their tremendous antioxidant potential. So, various research groups have explored their mechanism and therapeutic value in diabetic complications, to improve the insulin sensitivity and glucose metabolism, in controlling the glycemic conditions.

CONCLUSION

Polyphenols exhibit effective therapeutic potential in managing diabetic complications through their multifaceted mechanism of action. They exhibit antioxidative, anti-inflammatory, and anti-glycemic properties, which collectively contribute to their beneficial effects in mitigating diabetic complications. Thus, the inclusion of polyphenols into the diet, may be cosidered as an approach of managing diabetes on long term basis. In this review, we have tried to identify polyphenols effective in diabetes and summarize their mechanism of action along with their potential, for the treatment of diabetic complications.

The Golden Spice for Life: Turmeric with the Pharmacological Benefits of Curcuminoids Components, Including Curcumin, Bisdemethoxycurcumin, and Demethoxycurcumins

BACKGROUND

Turmeric (Curcuma longa L.), belonging to the Zingiberaceae family, is a perennial rhizomatous plant of tropical and subtropical regions. The three major chemical components responsible for the biological activities of turmeric are curcumin, demethoxycurcumin, and bisdemethoxycurcumin.

METHODS

The literature search included review articles, analytical studies, randomized control experiments, and observations, which have been gathered from various sources, such as Scopus, Google Scholar, PubMed, and ScienceDirect. A review of the literature was carried out using the keywords: turmeric, traditional Chinese medicine, traditional Iranian medicine, traditional Indian medicine, curcumin, curcuminoids, pharmaceutical benefits, turmerone, demethoxycurcumin, and bisdemethoxycurcumin. The main components of the rhizome of the leaf are α-turmerone, β-turmerone, and arturmerone.

RESULTS

The notable health benefits of turmeric are antioxidant activity, gastrointestinal effects, anticancer effects, cardiovascular and antidiabetic effects, antimicrobial activity, photoprotector activity, hepatoprotective and renoprotective effects, and appropriate for the treatment of Alzheimer's disease and inflammatory and edematic disorders.

DISCUSSION

Curcuminoids are phenolic compounds usually used as pigment spices with many health benefits, such as antiviral, antitumour, anti-HIV, anti-inflammatory, antiparasitic, anticancer, and antifungal effects. Curcumin, bisdemethoxycurcumin, and demethoxycurcumin are the major active and stable bioactive constituents of curcuminoids. Curcumin, which is a hydroponic polyphenol, and the main coloring agent in the rhizomes of turmeric, has anti-inflammatory, antioxidant, anti-cancer, and anticarcinogenic activities, as well as beneficial effects for infectious diseases and Alzheimer's disease. Bisdemethoxycurcumin possesses antioxidant, anti-cancer, and anti-metastasis activities. Demethoxycurcumin, which is another major component, has anti-inflammatory, antiproliferative, and anti-cancer activities and is the appropriate candidate for the treatment of Alzheimer's disease.

CONCLUSION

The goal of this review is to highlight the health benefits of turmeric in both traditional and modern pharmaceutical sciences by considering the important roles of curcuminoids and other major chemical constituents of turmeric.

The Role of Cdc42 in the Insulin and Leptin Pathways Contributing to the Development of Age-Related Obesity

Age-related obesity significantly increases the risk of chronic diseases such as type 2 diabetes, cardiovascular diseases, hypertension, and certain cancers. The insulin-leptin axis is crucial in understanding metabolic disturbances associated with age-related obesity. Rho GTPase Cdc42 is a member of the Rho family of GTPases that participates in many cellular processes including, but not limited to, regulation of actin cytoskeleton, vesicle trafficking, cell polarity, morphology, proliferation, motility, and migration. Cdc42 functions as an integral part of regulating insulin secretion and aging. Some novel roles for Cdc42 have also been recently identified in maintaining glucose metabolism, where Cdc42 is involved in controlling blood glucose levels in metabolically active tissues, including skeletal muscle, adipose tissue, pancreas, etc., which puts this protein in line with other critical regulators of glucose metabolism. Importantly, Cdc42 plays a vital role in cellular processes associated with the insulin and leptin signaling pathways, which are integral elements involved in obesity development if misregulated. Additionally, a change in Cdc42 activity may affect senescence, thus contributing to disorders associated with aging. This review explores the complex relationships among age-associated obesity, the insulin-leptin axis, and the Cdc42 signaling pathway. This article sheds light on the vast molecular web that supports metabolic dysregulation in aging people. In addition, it also discusses the potential therapeutic implications of the Cdc42 pathway to mitigate obesity since some new data suggest that inhibition of Cdc42 using antidiabetic drugs or antioxidants may promote weight loss in overweight or obese patients.

A randomized, controlled, comparative, proof-of-concept study to evaluate the efficacy and safety of Nisha-Amalaki capsules in prediabetic patients for preventing progression to diabetes

BACKGROUND

Prediabetes is an intermediate state of hyperglycemia, which acts as a precursor to Diabetes mellitus if left untreated. Nisha (Curcuma longa) and Amalaki (Emblica officinalis) combination has been advocated as drugs of choice to treat the early manifestations of Diabetes mellitus.

OBJECTIVE

This prospective, randomized, single-blind, placebo-controlled, comparative study was planned to assess the efficacy and safety of Nisha-Amalaki capsules in preventing progression to Diabetes mellitus in prediabetic patients when administered for 6 months.

METHODS

The study was conducted on prediabetic participants randomized to receive either Nisha-Amalaki (500 mg) or placebo one capsule twice a day for six months. The effect of study medications on IDRS (Indian Diabetes Risk Score), BMI (Body Mass Index), blood sugar, serum insulin, HOMA-IR (Homeostasis Model Assessment-Estimated Insulin Resistance), HbA1c (glycated hemoglobin), oxidative markers, Ayurvedic symptoms and Quality of Life (QoL) scores was assessed at regular intervals.

RESULTS

58 of the 62 participants enrolled completed the study. Significant fall in IDRS score [p < 0.001], BMI [p < 0.001], fasting, and 2 h post-OGTT sugar, insulin, HbA1c, HOMA-IR, and oxidative stress markers [p < 0.001] was observed in patients receiving Nisha-Amalaki at 6 months. Ayurvedic symptoms and QoL scores also improved at 6 months in the treatment group.

CONCLUSION

Treatment with Nisha-Amalaki capsules improved all study parameters including insulin sensitivity at 6 months as compared to placebo in prediabetic patients. Thus Nisha-Amalaki should be considered as prophylactic therapy in prediabetics to delay progression to diabetes.

Curcumin and targeting of molecular and metabolic pathways in multiple sclerosis

Multiple sclerosis (MS) is a life-threading disease that poses a great threat to the human being lifestyle. Having said extensive research in the realm of underlying mechanisms and treatment procedures, no definite remedy has been found. Over the past decades, many medicines have been disclosed to alleviate the symptoms and marking of MS. Meanwhile, the substantial efficacy of herbal medicines including curcumin must be underscored. Accumulated documents demonstrated the fundamental role of curcumin in the induction of the various signaling pathways. According to evidence, curcumin can play a role in mitochondrial dysfunction and apoptosis, autophagy, and mitophagy. Also, by targeting the signaling pathways AMPK, PGC-1α/PPARγ, and PI3K/Akt/mTOR, curcumin interferes with the metabolism of MS. The anti-inflammatory, antioxidant, and immune regulatory effects of this herbal compound are involved in its effectiveness against MS. Thus, the present review indicates the molecular and metabolic pathways associated with curcumin's various pharmacological actions on MS, as well as setting into context the many investigations that have noted curcumin-mediated regulatory effects in MS.

The Efficacy of Nigella sativa L. and Curcumin Nanomicelle Alone or Together on Lipid Profile, Glycemic Control Indices, and Serum 17-Β Estradiol in Postmenopausal Women

Introduction

Menopause is a condition for metabolic disorders. This study aimed to evaluate the effect of Nigella sativa (NS), curcumin nanomicelle (CN), lipid profile, glycemic status and 17-β estradiol (ES) levels in postmenopausal women.

Methods

Triple-blind randomized clinical trial was conducted on 120 postmenopausal women. Participants were randomly assigned to four groups: 1) NS capsule 1000 mg and CN placebo, 2) 80 mg CN capsule and NS placebo, 3) both NS and CN capsules and 4) NS and CN placebo. Participants received a single dose daily for 6 months. The serum lipid profile, glycemic control biomarkers, and ES were measured pre-and post-intervention using biochemical methods.

Results

Total cholesterol (TC), triglyceride (TG), high-density lipoprotein (HDL) and low-density lipoprotein (LDL) cholesterol, fasting blood sugar (FBS), fasting insulin (FI), insulin resistance (IR), and ES showed significant improvement in NS group. CN significantly reduced TC, FI, and IR, and significantly increased ES. The combination of NS-CN significantly decreased TC, LDL, FI, and IR, and increased HDL and ES. The comparison of the studied with the placebo groups showed that these changes were significant in glycemic indices and NS significantly increased estrogen.

Conclusion

NS, CN and NS-CN improved lipid profiles, blood sugar, and hormone levels. However, this improvement was significant in glycemic indices and estrogen levels compared to the placebo group. No superiority of combined NS-CN over NS or CN was found in this trial.

The Homoleptic Curcumin-Copper Single Crystal (ML2): A Long Awaited Breakthrough in the Field of Curcumin Metal Complexes

The first single crystal structure of the homoleptic copper (II) ML2 complex (M=Cu (II), L = curcumin) was obtained and its structure was elucidated by X-ray diffraction showing a square planar geometry, also confirmed by EPR. The supramolecular arrangement is supported by C-H···O interactions and the solvent (MeOH) plays an important role in stabilizing the crystal packing Crystallinity was additionally assessed by XRD patterns. The log P value of the complex (2.3 ± 0.15) was determined showing the improvement in water solubility. The cytotoxic activity of the complex against six cancer cell lines substantially surpasses that of curcumin itself, and it is particularly selective against leukemia (K562) and human glioblastoma (U251) cell lines, with similar antioxidant activity to BHT. This constitutes the first crystal structure of pristine curcumin complexed with a metal ion.

Natural Drugs: A New Direction for the Prevention and Treatment of Diabetes

Insulin resistance, as a common pathological process of many metabolic diseases, including diabetes and obesity, has attracted much attention due to its relevant influencing factors. To date, studies have mainly focused on the shared mechanisms between mitochondrial stress and insulin resistance, and they are now being pursued as a very attractive therapeutic target due to their extensive involvement in many human clinical settings. In view of the complex pathogenesis of diabetes, natural drugs have become new players in diabetes prevention and treatment because of their wide targets and few side effects. In particular, plant phenolics have received attention because of their close relationship with oxidative stress. In this review, we briefly review the mechanisms by which mitochondrial stress leads to insulin resistance. Moreover, we list some cytokines and genes that have recently been found to play roles in mitochondrial stress and insulin resistance. Furthermore, we describe several natural drugs that are currently widely used and give a brief overview of their therapeutic mechanisms. Finally, we suggest possible ideas for future research related to the unique role that natural drugs play in the treatment of insulin resistance through the above targets.

Potentials of curcumin against polycystic ovary syndrome: Pharmacological insights and therapeutic promises

Polycystic ovary syndrome (PCOS) is a common hormonal disorder among women (4%-20%) when the ovaries create abnormally high levels of androgens, the male sex hormones that are typically present in women in trace amounts. The primary characteristics of PCOS include oxidative stress, inflammation, hyperglycemia, hyperlipidemia, hyperandrogenism, and insulin resistance. Generally, metformin, spironolactone, eflornithine and oral contraceptives are used to treat PCOS, despite their several side effects. Therefore, finding a potential candidate for treating PCOS is necessary. Curcumin is a major active natural polyphenolic compound derived from turmeric (Curcuma longa). A substantial number of studies have shown that curcumin has anti-inflammatory, anti-oxidative stress, antibacterial, and anti-apoptotic activities. In addition, curcumin reduces hyperglycemia, hyperlipidemia, hyperandrogenism, and insulin resistance in various conditions, including PCOS. The review highlighted the therapeutic aspects of curcumin against the pathophysiology of PCOS. We also offer a hypothesis to improve the development of medicines based on curcumin against PCOS.

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.

A comparative study of effects of curcumin and its nanoparticles on the growth, immunity and heat stress resistance of Nile tilapia (Oreochromis niloticus)

This study evaluated the effects of dietary supplementation with free- or nano-curcumin on the growth performance, immune status and heat stress resistance of Nile tilapia (Oreochromis niloticus). Seven isonitrogenous (28% protein) and isocaloric (445 kcal/100 g DM) diets were prepared. Six diets were supplemented with three levels of nano-curcumin (50 (CN50), 100 (CN100), 200 (CN200) mg kg^-1 diet) or free-curcumin (50 (C50), 100 (C100), 200 (C200) mg kg^-1 diet), and the control diet was left without an additive (CON). Fish (13.54 ± 0.32 g) (mean ± SD) fed the experimental diets for 65 days. Following the feeding trial, the fish were exposed to the acute heat stress by gradually raising the water temperature from 25 to 40 °C within 3 h. The fish were then exposed to 40 °C for 4 h. Results revealed the superiority of nano-curcumin over its free-form in enhancing the growth performance, with the highest results obtained at CN100, followed by CN200. Only heat stress, not the experimental diets, increased the platelets, mean corpuscular volume (MCV), mean corpuscular hemoglobin (MCH), leukocytes and neutrophils count, while lymphocytes decreased. The CN50 and CN100 groups showed lower activity of liver enzymes (alanine aminotransferase (ALT) and aspartate aminotransferase (AST)) than the other treatments, while C200 gave the highest activity of these enzymes. The highest immunoglobulin (IgM) levels were detected in CN100, CN200, C100 and C200, followed by CN50. The C200 group showed higher levels of complement 3 and complement 4 (C3 and C4, respectively) than the other treatments. The C50 and CON groups gave the lowest values of IgM, C3 and C4. Cortisol levels were significantly lower in the CN50 and CN100 groups compared to the other groups. After the heat stress, ALT, AST, IgM, C3, C4, cortisol and glucose increased. Thus, nano-curcumin is more effective than its free-form in enhancing the resistance to heat stress, inducing innate immunity, lowering the stress indicators and promoting growth performance of Nile tilapia with the best concentration at 100 mg kg^-1 diet.

Curcumin-resveratrol nano-formulation counteracting hyperammonemia in rats

Malnutrition and low dietary protein intake could be risk factors for developing peripheral and central hyperammonemia, especially in pediatrics. Both curcumin and resveratrol proved to be effective against several hepatic and cerebral injuries. They were reported to be beneficial in lowering circulating ammonia levels, yet both are known for their low bioavailability. The use of pharmaceutical nano-formulations as delivery systems for these two nutraceuticals could solve the aforementioned problem. Hence, the present study aimed to investigate the valuable outcome of using a combination of curcumin and resveratrol in a nanoemulsion formulation, to counteract protein-deficient diet (PDD)-induced hyperammonemia and the consequent complications in male albino rats. Results revealed that using a nanoemulsion containing both curcumin and resveratrol at a dose of (5 + 5 mg/kg) effectively reduced hepatic and brain ammonia levels, serum ALT and AST levels, hepatic and brain nitric oxide levels, oxidative DNA damage as well as disrupted cellular energy performance. In addition, there was a substantial increase in brain levels of monoamines, and a decrease in glutamate content. Therefore, it can be concluded that the use of combined curcumin and resveratrol nanoemulsion is an effective means of ameliorating the hepatic and cerebral adverse effects resulting from PDD-induced hyperammonemia in rats.

A Review of the Role of Curcumin in Metal Induced Toxicity

Metal toxicity poses a potential global threat to the environment and living beings. Their numerous agricultural, medical, industrial, domestic, and technological applications result in widespread distribution in the environment which raises concern on the potential effects of metals in terms of health hazards and environmental pollution. Chelation therapy has been the preferred medical treatment for metal poisoning. The chelating agent bounds metal ions to form complex cyclic structures known as 'chelates' to intensify their excretion from the body. The main disadvantage of synthetic chelators is that the chelation process removes vital nutrients along with toxic metals. Natural compounds are widely available, economical, and have minimal adverse effects compared to classical chelators. Herbal preparations can bind to the metal, reduce its absorption in the intestines, and facilitate excretion from the body. Curcumin, a bioactive substance in turmeric, is widely used as a dietary supplement. Most studies have shown that curcumin protects against metal-induced lipid peroxidation and mitigates adverse effects on the antioxidant system. This review article provides an analysis to show that curcumin imparts promising metal toxicity-ameliorative effects that are related to its intrinsic antioxidant activity.

Strategies for Improving Bioavailability, Bioactivity, and Physical-Chemical Behavior of Curcumin

Curcumin (CCM) is one of the most frequently explored plant compounds with various biological actions such as antibacterial, antiviral, antifungal, antineoplastic, and antioxidant/anti-inflammatory properties. The laboratory data and clinical trials have demonstrated that the bioavailability and bioactivity of curcumin are influenced by the feature of the curcumin molecular complex types. Curcumin has a high capacity to form molecular complexes with proteins (such as whey proteins, bovine serum albumin, β-lactoglobulin), carbohydrates, lipids, and natural compounds (e.g., resveratrol, piperine, quercetin). These complexes increase the bioactivity and bioavailability of curcumin. The current review provides these derivatization strategies for curcumin in terms of biological and physico-chemical aspects with a strong focus on different type of proteins, characterization methods, and thermodynamic features of protein–curcumin complexes, and with the aim of evaluating the best performances. The current literature review offers, taking into consideration various biological effects of the CCM, a whole approach for CCM-biomolecules interactions such as CCM-proteins, CCM-nanomaterials, and CCM-natural compounds regarding molecular strategies to improve the bioactivity as well as the bioavailability of curcumin in biological systems.

Effects of curcumin and/or coenzyme Q10 supplementation on metabolic control in subjects with metabolic syndrome: a randomized clinical trial

Background

Metabolic syndrome (MetS) as a cluster of conditions including hyperlipidemia, hypertension, hyperglycemia, insulin resistance, and abdominal obesity is linked to cardiovascular diseases and type 2 diabetes. Evidence suggested that intake of curcumin and coenzyme Q10 may have therapeutic effects in the management of MetS.

Aims

We investigated the effects of curcumin and/or coenzyme Q10 supplementation on metabolic syndrome components including systolic blood pressure (SBP), diastolic blood pressure (DBP), waist circumference (WC), triglyceride (TG), high density lipoprotein-cholesterol (HDL-c) and fasting plasma glucose (FPG) as primary outcomes, and total cholesterol (TC), low density lipoprotein-cholesterol (LDL-c) and body mass index (BMI) as secondary outcomes in subjects with MetS.

Methods

In this 2 × 2 factorial, randomized, double-blinded, placebo-controlled study, 88 subjects with MetS were randomly assigned into four groups including curcumin plus placebo (CP), or coenzyme Q10 plus placebo (QP), or curcumin plus coenzyme Q10 (CQ), or double placebo (DP) for 12 weeks.

Results

The CP group compared with the three other groups showed a significant reduction in HDL-c (P = 0.001), TG (P <  0.001), TC (P <  0.001), and LDL-c (P <  0.001). No significant differences were seen between the four groups in terms of SBP, DBP, FPG, WC, BMI and weight.

Conclusion

Curcumin improved dyslipidemia, but had no effect on body composition, hypertension and glycemic control. Furthermore, coenzyme Q10 as well as the combination of curcumin and coenzyme Q10 showed no therapeutic effects in subjects with MetS. The trial was registered on 09/21/2018 at the Iranian clinical trials website (IRCT20180201038585N2), URL: https://www.irct.ir/trial/32518.

Cinnamaldehyde and Curcumin Prime Akt2 for Insulin-Stimulated Activation

In this study, the effects of cinnamaldehyde and curcumin on Akt2, a serine/threonine protein kinase central to the insulin signaling pathway, were examined in preadipocytes. Cinnamaldehyde or curcumin treatment increased Akt2 phosphorylation at multiple sites including T450 and Y475, but had no effect on Akt2 phosphorylation at S474, which is critical for Akt2 activation. Surprisingly, insulin treatment with cinnamaldehyde or curcumin increased p-Akt2 (S474) by 3.5-fold versus insulin treatment alone. Furthermore, combined cinnamaldehyde, curcumin, and insulin treatment increased p-Akt2 (S474) by 7-fold versus insulin treatment alone. Interestingly, cinnamaldehyde and curcumin inhibited both serine/threonine phosphatase 2A (PP2A) and protein tyrosine phosphatase 1B (PTP1B). Akt2 activation is a multistep process that requires phosphorylation at T450 for proper folding and maturation, and phosphorylation of both Y475 and S474 for stabilization of the catalytic domain. It is plausible that by inhibiting PP2A and PTP1B, cinnamaldehyde and curcumin increase phosphorylation at T450 and Y475, and prime Akt2 for insulin-stimulated phosphorylation at S474. Notably, the combination of a PP2A inhibitor, okadaic acid, and a PTP1B inhibitor increased p-Akt2 (S474), even in the absence of insulin. Future combinations of PP2A and PTP1B inhibitors provide a rational platform to engineer new therapeutics for insulin resistance syndrome.

The Effect of Curcumin on Lipid Profile and Glycemic Status of Patients with Type 2 Diabetes Mellitus: A Systematic Review and Meta-Analysis

Type 2 diabetes mellitus (T2DM) is a progressive metabolic disorder, some natural compounds are thought to be beneficial in improving the metabolic status of patients with T2DM. Curcumin is the main bioactive agent of turmeric, the impact of curcumin on T2DM is still controversial. This meta-analysis aimed to evaluate the effects of curcumin on lipids profile and glucose status in patients with T2DM. Randomized controlled trials (RCTs) examining the effects of curcumin on lipids profile and glycemic control of T2DM patients were searched in PubMed, Embase, Web of Science and Cochrane Library. Pooled estimates of weighted mean difference (WMD) were calculated between intervention and control groups using random-effects or fixed-effects model. Subgroup and sensitivity analyses were conducted to assess the effects. Nine eligible RCT with 604 subjects were included. The estimated pooled mean changes with curcumin were -18.97 mg/dL (95% CI: -36.47 to -1.47; P=0.03) for triglyceride (TG), -8.91 mg/dL (95% CI: -14.18 to -3.63, P=0.001) for total cholesterol (TC), -4.01 mg/dL (95% CI: -10.96 to 2.95, P=0.259) for low density lipoprotein cholesterol (LDL-c), 0.32 mg/dL (95% CI: -0.74 to 1.37, P=0.557) for high density lipoprotein cholesterol (HDL-c), -8.85 mg/dL (95% CI: -14.4 to -3.29, P=0.002) for fasting blood glucose (FBG), -0.54 (95% CI: -0.81 to -0.27, P ≤ 0.001) for glycated hemoglobin (HbA1c) (%) compared with controls. There was a significant heterogeneity for the influence of curcumin on TG, LDL-c, FBG and HbA1c. Subgroup analysis revealed that the heterogeneity mainly attributed to trial period, curcumin dosage and other therapy. The results of this study showed that curcumin supplementation had beneficial effects on glycemic status and some lipid parameters in patients with T2DM. Further studies with large-scale are still needed to confirm the results.

Effects of turmeric (Curcuma longa) and its constituent (curcumin) on the metabolic syndrome: An updated review

Metabolic syndrome (MS) involves people with the following risk factors: obesity, hypertension, high glucose level and hyperlipidemia. It can increase the risk of heart disease, stroke and type 2 diabetes mellitus. The prevalence of MS in the world's adult population is about 20%-25%. Today, there is much care to use medicinal plants. Turmeric (Curcuma longa) as well as curcumin which is derived from the rhizome of the plant, has been shown beneficial effects on different components of MS. Thus, the purpose of this manuscript was to introduce different in vitro, in vivo and human studies regarding the effect of turmeric and its constituent on MS. Moreover, different mechanisms of action by which this plant overcomes MS have been introduced. Based on studies, turmeric and its bioactive component, curcumin, due to their anti-inflammatory and antioxidant properties, have antidiabetic effects through increasing insulin release, antihyperlipidemic effects by increasing fatty acid uptake, anti-obesity effects by decreasing lipogenesis, and antihypertensive effects by increasing nitric oxide. According to several in vivo, in vitro and human studies, it can be concluded that turmeric or curcumin has important values as a complementary therapy in MS. However, more clinical trials should be done to confirm these effects.

Curcumin prevents proteins expression changes of oxidative phosphorylation, cellular stress response, and lipid metabolism proteins in liver of mice fed a high-fructose diet

Increased fructose consumption has been associated with the development of metabolic diseases due to the modification in protein expression, altering metabolic and signaling pathways. Curcumin is a natural compound with a regulatory effect on genes and metabolic pathways. To identify the fructose-induced protein expression changes and the effect of curcumin on the change of protein expression in the liver of mice fed a standard diet and a high fructose diet, to elucidate the global role of curcumin. Four groups (n = 4/group) of male mice (C57BL6J) of six-weeks-old were formed. One group received a standard diet (C); another received curcumin at 0.75% w/w in the feed (C + C); one more received 30% w/v fructose in drinking water (F); and one group received 30% w/v fructose in drinking water and 0.75% w/w curcumin in food (F + C); for 15 weeks. Proteomic analysis was performed by LC-MS/MS, using the label-free technique with the MaxQuant programs for identification and Perseus for expression change analysis. Differentially expressed proteins (fold change ≥1.5 and p < 0.5) were analyzed by gene ontology and KEGG. A total of 1047 proteins were identified, of which 113 changed their expression in mice fed fructose, compared to the control group, and curcumin modified the expression of 64 proteins in mice fed fructose and curcumin compared to mice that only received fructose. Curcumin prevented the change of expression of 13 proteins involved in oxidative phosphorylation (NDUFB8, NDUFB3, and ATP5L) in the cellular response to stress (PSMA5, HIST1H1D) and lipid metabolism (THRSP, DGAT1, ECI1, and ACOT13). Curcumin in mice fed the standard diet increased the expression of proteins related to oxidative phosphorylation, ribosomes, and PPAR pathways. In addition to fructose, increased expression of proteins involved in oxidative phosphorylation, ribosomes, lipid metabolism, and carbon metabolism. However, curcumin prevented expression change in 13 hepatic proteins of fructose-fed mice involved in oxidative phosphorylation, cellular stress response, and lipid metabolism. SIGNIFICANCE: Curcumin is a natural compound with a regulatory effect on proteins and metabolic pathways. So, curcumin prevents the change of expression in 13 hepatic proteins of fructose-fed mice involved in oxidative phosphorylation, cellular stress response and lipid metabolism, as a supplement with protector activity on fructose-induced toxic effects.

The Curcumin Supplementation with Piperine Can Influence the Acute Elevation of Exercise-Induced Cytokines: Double-Blind Crossover Study

Simple Summary

Inflammation is an immune response to harmful stimuli, such as pathogens and damaged cells. Intense exercise can induce a local and systemic inflammatory response as well. We believe that exercise-induced inflammatory responses are essential for muscle repair and regeneration. However, uncontrolled acute inflammation in athletes during the training process and competition could reduce the level of performance. In this study, we investigate the effects of curcumin and piperine on the exercise-induced inflammatory response.

Abstract

Background: to evaluate the effects of one week of supplementation with curcumin combined with piperine on physical performance, immune system cell counts, muscle damage, and plasma levels of inflammatory markers after a treadmill running training session. Methods: This study is a double-blind, crossover-balanced clinical trial with a three-week intervention. Sixteen male runners with a mean age of 36 ± 9 years and VO2 max of 60.6 ± 9.03 mL.kg ⁻¹ min ⁻¹ were recruited and randomly divided into 2 groups: the first group (CPG) was supplemented daily for 7 days with 500 mg of curcumin + 20 mg piperine, and the second group (PG) was supplemented with 540 mg of cellulose. After the 7th day of supplementation, the volunteers participated in the experimental running protocol, where blood samples were collected before, after, and one hour after exercise for analysis of the number of leukocytes, creatine kinase, and cytokine concentration (IL-2, TNF-α, IFN, IL-6, and IL-10) using flow cytometry. This process was repeated, reversing the supplementation offered to the groups. Results: curcumin and piperine supplementation could not change the physical performance, immune cell counts, and muscle damage; however, the aerobic fatiguing exercise protocol inhibited the elevation of the plasmatic levels of some cytokines. The running exercise protocol could elevate the circulating levels of IL-2 (from 49.7 to 59.3 pg/mL), TNF-α (from 48.5 to 51.5 pg/mL), INF (from 128.8 to 165.0 pg/mL), IL-6 (from 63.1 to 77.3 pg/mL), and IL-10 (from 48.9 to 59.6 pg/mL) 1 h after the end of the running protocol. However, the curcumin and piperine supplementation could inhibit this elevation. Conclusions: curcumin and piperine supplementation had no effect on physical performance, immune cell counts, or muscle damage; however, the supplementation could modulate the kinetics of IL-2, TNF-α, INF, IL-6, and IL-10 1 h after the end of exercise.

Effects of curcumin supplementation on metabolic parameters, inflammatory factors and obesity values in women with rheumatoid arthritis: A randomized, double-blind, placebo-controlled clinical trial

Rheumatoid arthritis (RA) is a chronic inflammatory disease that leads to cartilage damage with mostly accompanied by metabolic disorders. This study aimed to investigate the effects of curcumin supplementation on metabolic parameters (lipid profile and glycemic indices), inflammatory factors, visfatin levels, and obesity values in women with RA. This randomized, double-blind, placebo-controlled clinical trial was conducted on 48 women with RA. The patients were treated with curcumin (500 mg once a day) or placebo for 8 weeks. Fasting blood samples, anthropometric measurements, dietary intakes, and physical activity levels of subjects were collected at baseline and the end of the study. Curcumin supplementation significantly decreased homeostatic model assessment for insulin resistance (HOMA-IR), erythrocyte sedimentation rate, serum levels of high-sensitivity C-reactive protein and triglycerides, weight, body mass index, and waist circumference of patients compared with the placebo at the end of the study (p < .05 for all). HOMA-IR and triglyceride levels significantly increased within the placebo group. Changes in fasting blood sugar, insulin, other lipids profile, and visfatin levels were not significant in any of the groups (p > .05). These results support the consumption of curcumin, as a part of an integrated approach to modulate metabolic factors, inflammation, and adiposity in women with RA.

Dietary Succinoglycan Riclin Improves Glycemia Control in Mice with Type 2 Diabetes

Riclin is a typical succinoglycan produced by an agrobacterium isolate. Our previous investigation has revealed that oral riclin restores the islet function in type 1 diabetic mice. However, whether dietary riclin improves glycemic control in type 2 diabetes (T2D) is unknown. Here, we found that dietary riclin (20 and 40 mg/kg) for 4 weeks significantly decreased fasting blood glucose (55 and 67%), improved insulin sensitivity, and decreased insulin resistance in high-fat-diet/streptozocin (HFD/STZ)-induced T2D. Riclin reduced the proportion of T helper 1 cell subsets in diabetic mice, alleviated pancreatic inflammation, and protected islet function. Moreover, dietary riclin enriched the diversity of gut microflora and restored the relative abundance of several bacterial genera in diabetes, including the strains of Clostridium, Parasutterella, Klebsiella, and Bacteroides. In db/db diabetic mice, riclin also improves glycemia control as observed in HFD/STZ-induced T2D mice. These data suggest that riclin has potential to be a functional food to treat T2D.

Bisacurone attenuates diabetic nephropathy by ameliorating oxidative stress, inflammation and apoptosis in rats

BACKGROUND

Diabetes nephropathy (DN) is a serious diabetic problem that may progress to renal failure. The root of Curcuma longa L., often known as turmeric, provides various health benefits. Bisacurone is a bioactive terpenoid found in small amounts in turmeric that possesses anti-inflammatory and antioxidant properties. The present study focuses on the potential protective effects of bisacurone against DN via reducing renal inflammation, oxidative stress, and apoptosis.

METHODS

Type 2 diabetes was created in rats by feeding them a high-fat/high-sugar diet for 8 weeks, followed by a low dose of streptozotocin and Bisacurone (50 and 100 μg/kg bisacurone) given for 4 weeks.

RESULTS

In diabetic rats, bisacurone reduced hyperglycemia, protected against body weight (BW) loss, lowered renal markers, reduced lipid profile alterations and avoided histological abnormalities. Bisacurone treatment reduced oxidative stress by decreasing malondialdehyde (MDA) levels while enhancing antioxidant defenses through superoxide dismutase (SOD), catalase (CAT), and glutathione peroxidase (GPx) levels. Furthermore, bisacurone treatment activated the renal Nrf2/Keap1 signaling pathway but attenuated the high levels of NFκB p65, TNF-α, IL-1β, IL-6, Cox2, and iNOS. Bisacurone also reduced Bax, caspase-3, caspase-9 and cytochrome c but increased Bcl-2 in the kidneys of diabetic rats.

CONCLUSION

In the present study, bisacurone reduces DN by reducing hyperglycemia, oxidative stress, inflammation, and apoptosis, while also increasing Nrf2/HO-1 signaling.

Hypericum Perforatum L. Hairy Root Extracts – Regulation of Glycemic, Metabolic, Serum Enzyme and Lipid Profile in Stz - Induced Diabetic Rats

Apart from currently available therapeutics for the treatment of diabetes mellitus, much attention has been paid to discover phytochemicals from natural resources, mainly due to their low side-effects. Hypericum perforatum hairy root (HR) transformed with Agrobacterium rhizogenes A4 represent prospective experimental system enriched in xanthones, known as potent antidiabetic agents. Thus, the aim of this study was to evaluate HR extracts for their potential antihyperglycemic activity in streptozotocin (STZ)-induced diabetic rats, also compared to the effects of wild-growing Hyperici herba (HH). We conducted an acute-toxicity study, multiple dose study, and 24h blood glucose measurements after a single dose administration of HH and HR (200 mg/kg) in diabetic rats. Furthermore, we examined the effects of 14-days administration of HH and HR extracts on blood glucose levels, metabolic parameters, enzyme, and lipid status in healthy and diabetic rats. Both extracts produced a fall of about 70% in blood glucose level after 24h of administration. Two-week treatment with HH and HR induced a significant decrease (70-72%) in blood glucose levels. Moreover, we found an improvement of the dysregulated metabolic parameters (body weight, food, and water consumption and urine output). Serum enzyme (AST, ALT, and γ-GT) and lipid profile parameters (CHOL, TAG, and HDL) were also improved by both extracts. These findings might provide a new insight for managing diabetic hyperglycemia and dysregulated serum enzyme and lipid profile, using extracts from transgenic roots cultures from H. perforatum.

Curcumin is a Potential Adjuvant to Alleviates Diabetic Retinal Injury via Reducing Oxidative Stress and Maintaining Nrf2 Pathway Homeostasis

Curcumin is a natural polyphenol compound with anti-diabetic, anti-oxidative, and anti-inflammatory effects. Although many studies have reported the protective effect of curcumin in diabetes mellitus or diabetic nephropathy, there is a lack of research on curcumin in diabetic retinopathy. The purpose of this study was to investigate the therapeutic effects of curcumin on the diabetic retinal injury. Streptozotocin (STZ)-induced diabetic rats (60, n = 12 each) were respectively given curcumin orally (200 mg/kg/day), insulin subcutaneously (4–6 IU/day), and combined therapy with curcumin and insulin for 4 weeks. Retinal histopathological changes, oxidative stress markers, and transcriptome profiles from each group were observed. Curcumin, insulin, or combination therapy significantly reduced blood glucose, alleviated oxidative stress, and improved pathological damage in diabetic rats. Curcumin not only significantly reduced retinal edema but also had a better anti-photoreceptor apoptosis effect than insulin. In the early stage of diabetes, the enhancement of oxidative stress in the retina induced the adaptive activation of the nuclear factor E2-associated factor 2 (Nrf2) pathway. Treatment of curcumin alleviated the compensatory activation of the Nrf2 pathway induced by oxidative stress, by virtue of its antioxidant ability to transfer hydrogen atoms to free radicals. When curcumin combined with insulin, the effect of maintaining Nrf2 pathway homeostasis in diabetic rats was better than that of insulin alone. Transcriptomic analyses revealed that curcumin either alone, or combined with insulin, inhibited the AGE-RAGE signaling pathway and the extracellular matrix (ECM)-receptor interaction in the diabetic retina. Thus, at the early stage of diabetes, curcumin can be used to alleviate diabetic retinal injury through its anti-oxidative effect. If taking curcumin as a potential complementary therapeutic option in combination with antihyperglycemic agents, which would lead to more effective therapeutic outcomes against diabetic complications.

Curcumin supplementation in pediatric patients: A systematic review of current clinical evidence

This systematic review was designed to determine the clinical efficacy and safety of curcumin supplementation for pediatric patients based on clinical trials in children. We systematically searched electronic databases including PubMed, EMBASE, Web of Science, and Scopus for all studies that investigated curcumin administration in the pediatric population without any time frame limitation. Finally, we identified 16 studies for this review. Clinical efficacy and safety of curcumin were assessed in children with inflammatory and immune disorders (including asthma, inflammatory bowel disease (IBD), and juvenile idiopathic arthritis (JIA)), metabolic disorders, autosomal dominant polycystic kidney disease (ADPKD), cystic fibrosis (CF), tetralogy of Fallot (TOF), and infectious diseases. Curcumin was administered in a wide range of doses (45 mg-4,000 mg daily) and durations (2-48 weeks). Overall, curcumin was well tolerated in all studies and improved the severity of inflammatory and immune disorders and metabolic diseases. However, more studies are needed to clarify the role of curcumin supplementation among children with ADPKD, CF, TOF, and infectious diseases. Because of substantial heterogeneity in methodological quality, design, outcomes, dose, duration of intake, formulations, and study populations across studies, no quantitative analysis was performed. Additional large-scale, randomized, placebo-controlled clinical trials are needed to confirm the results of the conducted studies.

Ameliorative effect of curcumin and zinc oxide nanoparticles on multiple mechanisms in obese rats with induced type 2 diabetes

The present study was carried out to investigate the therapeutic effect of synthesized naturally compounds, curcumin nanoparticles (CurNPs) and metal oxide, zinc oxide nanoparticles (ZnONPs) on a high-fat diet (HFD)/streptozotocin (STZ)-induced hepatic and pancreatic pathophysiology in type 2 diabetes mellitus (T2DM) via measuring AKT pathway and MAPK pathway. T2DM rats were intraperitoneally injected with a low dose of 35 mg/kg STZ after being fed by HFD for 8 weeks. Then the rats have orally received treatments for 6 weeks. HFD/STZ-induced hepatic inflammation, reflected by increased phosphorylation of p38-MAPK pathway's molecules, was significantly decreased after nanoparticle supplementation. In addition, both nanoparticles significantly alleviated the decreased phosphorylation of AKT pathway. Further, administration of ZnONPs, CurNPs, conventional curcumin, and ZnSO₄ (zinc sulfate), as well as metformin, effectively counteracted diabetes-induced oxidative stress and inflammation in the internal hepatic and pancreatic tissues. Based on the results of the current study, ZnONPs and CurNPs could be explored as a therapeutic adjuvant against complications associated with T2DM. Both nanoparticles could effectively delay the progression of several complications by activating AKT pathway and down-regulating MAPK pathway. Our findings may provide an experimental basis for the application of nanoparticles in the treatment of T2DM with low toxicity.

An Ayurvedic formulation of Emblica officinalis and Curcuma longa alleviates insulin resistance in diabetic rats: Involvement of curcuminoids and polyphenolics

BACKGROUND

Nishamalaki is an Ayurvedic herbal formulation used to treat type 2 diabetes mellitus (T2DM), comprises Emblica officinalis and Curcuma longa.

OBJECTIVE(S)

One of the main cause of T2DM is Insulin Resistance (IR) hence, this study was planned to evaluate IR lowering effect of a standardized Nishamalaki extract "EmbliQur" in high-fat diet (HFD) and streptozotocin (STZ) induced T2DM rats.

MATERIALS AND METHODS

Curcuminoids (23.89% w/w), gallic acid (5.27% w/w) and tannins (25.44% w/w) were quantified from EmbliQur. Rats were fed HFD throughout the study of 45 days and received STZ (40 mg/kg, i.p) on the 15th day of the study. Rats with more than 250 mg/dl of fasting blood glucose level (FBGL) were considered diabetic and selected for administration of EmbliQur (500 mg and 1000 mg/kg) or the standard drug metformin (120 mg/kg, p.o) from the 18th day of the study for the next 27 days. FBGL and insulin levels of all rats were measured weekly and an oral glucose tolerance test (OGTT) was done at the end of the study. The values of FBGL and insulin were used to calculate IR by the HOMA-IR, QUICKI and Matsuda methods.

RESULTS

Rats treated with STZ/HFD had significantly higher than normal FBGL and insulin levels throughout the study and exhibited skewed IR indices in the above three methods of IR assessment. EmbliQur treatment successfully lowered the HFD/STZ-elevated BGL and insulin levels, and ameliorated IR in all models of IR evaluation.

CONCLUSION

EmbliQur 1000 mg/kg was noted to be more effective than EmbliQur 500 mg/kg in alleviating IR.

Curcumin Improved Glucose Intolerance, Renal Injury, and Nonalcoholic Fatty Liver Disease and Decreased Chromium Loss through Urine in Obese Mice

Obesity-associated hyperglycemia underlies insulin resistance, glucose intolerance, and related metabolic disorders including type 2 diabetes, renal damage, and nonalcoholic fatty liver disease. Turmeric root is commonly used in Asia, and curcumin, one of its pharmacological components, can play a role in preventing and treating certain chronic physiological disorders. Accordingly, this study examined how high-fat diet (HFD)-induced hyperglycemia and hyperlipidemia are reduced by curcumin through changes in fatty liver scores, chromium distribution, and renal injury in mice. Relative to the control group, also fed an HFD, the curcumin group weighed less and had smaller adipocytes; it also had lower daily food efficiency, blood urea nitrogen and creatinine levels, serum alanine aminotransferase and aspartate aminotransferase levels, serum and hepatic triglyceride levels, and hepatic lipid regulation marker expression. The curcumin-treated obese group exhibited significantly lower fasting blood glucose, was less glucose intolerant, had higher Akt phosphorylation and glucose transporter 4 (GLUT4) expression, and had greater serum insulin levels. Moreover, the group showed renal damage with lower TNF-α expression along with more numerous renal antioxidative enzymes that included superoxide dismutase, glutathione peroxidase, and catalase. The liver histology of the curcumin-treated obese mice showed superior lipid infiltration and fewer FASN and PNPLA3 proteins in comparison with the control mice. Curcumin contributed to creating a positive chromium balance by decreasing the amount of chromium lost through urine, leading to the chromium mobilization needed to mitigate hyperglycemia. Thus, the results suggest that curcumin prevents HFD-induced glucose intolerance, kidney injury, and nonalcoholic fatty liver disease.

Curcumin prevents obesity by targeting TRAF4-induced ubiquitylation in m6 A-dependent manner

Obesity has become a major health problem that has rapidly prevailed over the past several decades worldwide. Curcumin, a natural polyphenolic compound present in turmeric, has been shown to have a protective effect on against obesity and metabolic diseases. However, its underlying mechanism remains largely unknown. Here, we show that the administration of curcumin significantly prevents HFD-induced obesity and decreases the fat mass of the subcutaneous inguinal WAT (iWAT) and visceral epididymal WAT (eWAT) in mice. Mechanistically, curcumin inhibits adipogenesis by reducing the expression of AlkB homolog 5 (ALKHB5), an m6 A demethylase, which leads to higher m6 A-modified TNF receptor-associated factor 4 (TRAF4) mRNA. TRAF4 mRNA with higher m6 A level is recognized and bound by YTHDF1, leading to enhanced translation of TRAF4. TRAF4, acting as an E3 RING ubiquitin ligase, promotes degradation of adipocyte differentiation regulator PPARγ by a ubiquitin-proteasome pathway thereby inhibiting adipogenesis. Thus, m6 A-dependent TRAF4 expression upregulation by ALKBH5 and YTHDF1 contributes to curcumin-induced obesity prevention. Our findings provide mechanistic insights into how m6 A is involved in the anti-obesity effect of curcumin.

Impact of curcumin on fatty acid metabolism

Free fatty acids (FFAs) and fatty acid synthesis (FAS) activity have significantly contributed to disease states such as insulin resistance, obesity, type 2 diabetes, myocardial infarction, blood pressure, and several types of cancer. Currently, several treatment options are available for patients with these conditions. Due to safety concerns, adverse effects, limited efficacy, and low tolerability associated with many medications, the identification of novel agents with less toxicity and a more favorable outcome is warranted. Curcumin is a phenolic compound derived from the turmeric plant with various biological activities, including anticarcinogenic, antioxidant, antiinflammatory, and hypolipidemic properties. PubMed, Scopus, and Web of Science were searched up to February 2020 for studies that demonstrated the efficacy and mechanisms of curcumin action on FFAs, FAS, and β-oxidation activity, as well as the desaturation system. Most of the evidence is in-vivo and in-vitro studies that demonstrate that curcumin possesses regulatory properties on FFAs levels through its effects on FAS and β-oxidation activity as well as desaturation system, which could improve insulin resistance, obesity, and other FFAs-related disorders. The present study provides a review of the existing in-vitro, in-vivo, and clinical evidence on the effect of curcumin on FFAs and FAS activity, β-oxidation, and desaturation system.

The effects of nanomicelle of curcumin on the matrix metalloproteinase (MMP-2, 9) activity and expression in patients with coronary artery disease (CAD): A randomized controlled clinical trial

BACKGROUND

Coronary artery disease (CAD) is the most common type of cardiovascular disease. Increasing the expression and activity of matrix metalloproteinases (MMPs) facilitates vascular remodeling and cardiovascular complications. Curcumin (the active ingredient of turmeric) is a potent natural anti-inflammatory agent, with cardiovascular protective effects. The present study was a clinical trial for investigating the effects of curcumin on activity and gene expression of MMP-2 and MMP-9 in patients with CAD.

METHODS

In this study, 70 patients with CAD (with 40%-50% stenosis) were randomly divided into two groups of curcumin (80 mg nanomicelle per day) and placebo. The intervention lasted 3 months. The activity levels of MMP-2 and MMP-9 in serum samples of patients were measured using gelatin zymography assay before and after the intervention. MMP-2 and MMP-9 gene expression in peripheral blood mononuclear cells (PBMCs) was also analyzed using real-time polymerase chain reaction (PCR). Statistical significance was set at P < 0.0500.

RESULTS

After 3 months of medication, the expression of MMP-9 produced by PBMCs significantly decreased in the curcumin group (0.811 ± 0.25) in comparison with the placebo group (2.23 ± 0.94) (P < 0.0001). Furthermore, the zymographic analysis showed that the administration of curcumin significantly inhibited the activity levels of MMP-2 (12469.7 ± 5308.64 pixels) and MMP-9 (14007.2 ± 5371.67 pixels) in comparison with that in patients receiving placebo (MMP-2: 17613.8 ± 5250.68 pixels; MMP-9: 20010.1 ± 3259.37 pixels) (P < 0.0500).

CONCLUSION

Our results show that curcumin can significantly reduce the expression and activity of MMP-2 and MMP-9. Because of the anti-inflammatory effects of curcumin, this compound can be considered as a new strategy for the prevention of cardiovascular events.

Curcumin protects radiation-induced liver damage in rats through the NF-κB signaling pathway

BACKGROUND

Curcumin has been demonstrated to exert anti-oxidant, anti-fibrotic, anti-inflammatory, and anti-cancer activities. This study was conducted to observe the effect and inner mechanism of curcumin in rats with radiation-induced liver damage (RILD).

METHODS

Thirty SD rats were classified into Control, Radiation group and Curcumin (Cur) + Radiation group (n = 10 in each group). The changes in body weight of the rats were observed on the 3rd, 7th and 14th days after the treatment with curcumin. On the 14th day post treatment, the heart blood of the rats was drawn for measurement of liver function indices including total protein (TP), alanine aminotransfetase (ALT), alkaline phosphatase (ALP), lactate dehydrogenase (LDH) as well as aspartate aminotransfetase (AST). Subsequently, the rats were euthanized and liver tissues were taken to observe liver morphological changes using hematoxylin-eosin (HE), and to analyze apoptosis condition using transferase-mediated deoxyuridine triphosphate-biotin nick end labeling (TUNEL) assays. Meanwhile, the oxidative stress level in liver tissue homogenate was determined by biochemical analysis. The expression of nuclear factor kappa B (NF-κB) pathway-associated and apoptosis-associated proteins was detected using Western blot analysis, and the expression levels of inflammatory factors were measured by Enzyme-linked immunosorbent assay (ELISA).

RESULTS

The reduced body weight was observed in rats of the Radiation group compared to the Control and Cur + Radiation groups on day 14. In the Radiation group, hepatic cell edema and inflammatory cell infiltration could be visible under the light microscope, and the hepatocytes presented with vacuolar degeneration. In the Cur + Radiation group, the hepatocytes swelled under the microscope, but the pathological changes were alleviated in comparison with the Radiation group. RILD rats with curcumin treatment presented with decreased ALT, AST, ALP, LDH, and maleicdialdehyde (MDA) levels, and elevated TP, superoxide dismutase (SOD), caspase activated DNase (CAD) and glutathione (GSH) levels. Apoptosis and inflammation in rats with RILD were up-regulated, and the NF-κB pathway was activated, but they were reversed after continuously intragastric administration of curcumin for 14 days.

CONCLUSION

Our study highlights that curcumin treatment reduces the liver damage caused by radiation through the inhibition of the NF-κB pathway.

The effects of curcumin intake on wound healing and metabolic status in patients with diabetic foot ulcer: A randomized, double-blind, placebo-controlled trial

This study was conducted to determine the effects of curcumin intake on wound healing and metabolic status in patients with diabetic foot ulcer (DFU). The current randomized, double-blind, placebo-controlled trial was conducted among 60 patients with grade 3 DFU. Participants were randomly allocated into two groups (30 participants each group), received either 80 mg nanocurcumin daily for 12 weeks or placebo. Primary endpoints in this study were serum insulin levels and insulin resistance. Curcumin intake significantly decreased fasting plasma glucose (p = .02), insulin (p = .01), insulin resistance (p = .02), and significantly increased insulin sensitivity (p = .008) compared with the placebo. Moreover, curcumin intake led to a significant reduction in total- (p < .001), LDL-cholesterol (p < .001), and a significant increase in total antioxidant capacity (TAC) (p < .001) and total glutathione (GSH) (p = .01) compared with the placebo. However, there was no significant improvement in wound healing parameters. Overall, our study demonstrated that nanocurcumin intake in patients with DFU resulted in a significant improvement of glycemic control, total- and LDL-cholesterol, TAC, and GSH but did not affect the indicators of ulcer size.

Curcumin nanoparticles have potential antioxidant effect and restore tetrahydrobiopterin levels in experimental diabetes

Diabetes is associated with an increase in the production of free radicals, reduction of tetrahydrobiopterin (BH4, THB) levels and reduced bioavailability of nitric oxide (NO) in the vascular walls. In this contribution, we probed the effective role of curcumin nanoparticles (CUR-NPs) that prepared via solvent evaporation nanoprecipitation technique as potential system to attenuate endothelial dysfunction. In this technique, Tween 60 (polysorbate) was used as stabilizing agent for the prepared CUR-NPs and protect such nanoparticles from further agglomeration. BH4 levels and other parameters were estimated in diabetic rats. To this end, we dedicated 48 male albino rats, categorized into six groups; control (healthy rats), diabetic rats, along with four treated groups via oral administration of 0.2 mL/kg body weight/day of solutions of Tween 60 (60 mg/mL), free CUR (60 mg/mL), CUR-NPs1 (30 mg/mL), and CUR-NPs2 (60 mg/mL) for 30 days. Results showed that the mean level of malondialdehyde (MDA) has been significantly increased in diabetic group associated with a reduction of total antioxidant capacity, NO, and BH4 compared to control. These parameters were restored by the delivery of CUR-NPs - both doses in rats, compared with the two control groups that treated with Tween 60 and free CUR.

Nanocurcumin alleviates insulin resistance and pancreatic deficits in polycystic ovary syndrome rats: Insights on PI3K/AkT/mTOR and TNF-α modulations

INTRODUCTION AND AIMS

Polycystic ovary syndrome (PCOS) is a widespread endocrine disorder affecting females. Mechanisms underlying PCOS complicated pathology remain largely unknown, making current treatment only symptomatic. Increasing reports suggest impaired PI3K/AKT/mTOR pathway and tumor necrosis factor-α (TNF-α) levels are involved in cellular proliferation and metabolism-related disorders. However, rare data explored their role in PCOS. Hence, this study investigated TNF-α and pancreatic PI3K/AKT/mTOR levels in PCOS animal model and evaluated their effects on developed pancreatic deficits. Secondly; we explored the impact of nanocurcumin as powerful anti-inflammatory supplement against these developed pancreatic pathologies.

METHODS

PCOS was induced in rats using letrozole. Nanocurcumin was formulated to increase solubility and bioavailability of curcumin. Transmission electron microscopy (TEM), zeta potential and Infra-red spectroscopy (FT-IR) were used for characterization. Nanocurcumin was orally ingested for 15 days.

FINDINGS

PCOS group exhibited significant disturbance in sex hormones, oxidative stress markers, and TNF-α levels as determined by immunoassay. Western blotting revealed significant reduction of PI3K/AKT/mTOR levels leading to impaired insulin sensitivity, decreased β cells function and mass as confirmed by HOMA assessments and immunohistochemistry. Nanocurcumin significantly improved oxidative markers, glucose indices and TNF-α levels. It reinstated PI3K/AKT/mTOR levels, alleviated insulin resistance, and retained islets integrity consequently restoring normal sex hormonal levels.

SIGNIFICANCE

To the best of our knowledge, the study is the first to report pancreatic role of PI3K/AKT/mTOR and TNF-α in PCOS and the first to demonstrate nanocurcumin promising potential against PCOS-related pancreatic molecular and histological pathologies that can indeed offer better control of the disease.

Further Evidence of Benefits to Mood and Working Memory from Lipidated Curcumin in Healthy Older People: A 12-Week, Double-Blind, Placebo-Controlled, Partial Replication Study

Curcumin (a flavonoid isolated from turmeric) affects several processes involved in neurocognitive aging. We have previously reported that short term (4-weeks) administration of a highly bioavailable curcumin preparation (Longvida©) improved working memory and reduced fatigue and stress reactivity in a healthy older cohort. The present trial (ACTRN12616000484448) was a partial replication study, evaluating similar effects at 4 and 12-weeks Longvida© supplementation. A double-blind, placebo-controlled, parallel-groups trial was conducted. Eighty participants aged 50-80 years (mean = 68.1, SD = 6.34) were randomised to receive Longvida© (400 mg daily containing 80 mg curcumin) or a matching placebo. Assessment took place at baseline then following 4 and 12 weeks treatment. Outcome measures included cognitive performance, mood and biomarkers. Compared with placebo, curcumin was associated with several significant effects. These included better working memory performance at 12-weeks (Serial Threes, Serial Sevens and performance on a virtual Morris Water Maze), and lower fatigue scores on the Profile of Mood States (POMS) at both 4 and 12-weeks, and of tension, anger, confusion and total mood disturbance at 4-weeks only. The curcumin group had significantly elevated blood glucose. These results confirm that Longvida© improves aspects of mood and working memory in a healthy older cohort. The pattern of results is consistent with improvements in hippocampal function and may hold promise for alleviating cognitive decline in some populations.

The effects of curcumin supplementation on oxidative stress, Sirtuin-1 and peroxisome proliferator activated receptor γ coactivator 1α gene expression in polycystic ovarian syndrome (PCOS) patients: A randomized placebo-controlled clinical trial

BACKGROUND & AIMS

Curcumin is a biologically active phytochemical ingredient found in turmeric and has antioxidant pharmacologic actions that may benefit patients with polycystic ovarian syndrome (PCOS). The aim in this trial was to evaluate the efficacy of curcumin supplementation on oxidative stress enzymes, sirtuin-1 (SIRT1) and Peroxisome proliferator activated receptor γ coactivator 1α (PGC1α) gene expression in PCOS patients.

METHODS

Seventy-two patients with PCOS were recruited for this randomized, double-blinded, clinical trial. Thirty-six patients received curcumin, 1500 mg (three times per day), and 36 patients received placebo for 3 months. Gene expression of SIRT1, PGC1α and serum activity of glutathione peroxidase (Gpx) and superoxide dismutase (SOD) enzymes were evaluated at the beginning of trial and at 3-month follow-up.

RESULTS

Sixty-seven patients with PCOS completed the trial. Curcumin supplementation significantly increased gene expression of PGC1α (p = 0.011) and activity of the Gpx enzyme (p = 0.045). Curcumin also non-significantly increased gene expression of SIRT1 and activity of the SOD enzyme.

CONCLUSIONS

Curcumin seems to be an efficient reducer of oxidative stress related complications in patients with PCOS. Further studies on curcumin should strengthen our findings.

Effects of curcumin on body weight, glycemic control and serum lipids in women with polycystic ovary syndrome: A randomized, double-blind, placebo-controlled trial

OBJECTIVE

The aim of this study was to evaluate the effect of curcumin on body weight, glycemic control and serum lipids in women suffering from polycystic ovary syndrome (PCOS).

METHODS

The current randomized, double-blinded, placebo-controlled clinical trial was performed on 60 subjects with PCOS, aged 18-40 years old. Subjects were randomly allocated to take 500 mg/day curcumin (n = 30) or placebo (n = 30) for 12 weeks. Glycemic control and serum lipids were measured at baseline and after the 12-week intervention. Using RT-PCR method, gene expression related to insulin and lipid metabolism was evaluated.

RESULTS

Curcumin significantly decreased weight (-0.8 ± 0.9 vs. -0.2 ± 0.8 kg, P = 0.03) and BMI (-0.3 ± 0.4 vs. -0.1 ± 0.3 kg/m², P = 0.03). Curcumin, compared with the placebo, significantly reduced fasting glucose (β -2.63 mg/dL; 95% CI, -4.21, -1.05; P = 0.002), serum insulin (β -1.16 μIU/mL; 95% CI, -2.12, -0.19; P = 0.02), insulin resistance (β -0.26; 95% CI, -0.48, -0.03; P = 0.02), and significantly increased insulin sensitivity (β 0.006; 95% CI, 0.001, 0.01; P = 0.02). In addition, taking curcumin was associated with a significant reduction in total cholesterol (β -15.86 mg/dL; 95% CI, -24.48, -7.24; P = 0.001), LDL-cholesterol (β -16.09 mg/dL; 95% CI, -25.11, -7.06; P = 0.001) and total-/HDL-cholesterol ratio (β -0.62; 95% CI, -0.93, -0.30; P < 0.001), and a significant increase in HDL-cholesterol levels (β 2.14 mg/dL; 95% CI, 0.36, 3.92; P = 0.01) compared with the placebo. Additionally, curcumin administration up-regulated gene expression of peroxisome proliferator-activated receptor gamma (PPAR-γ) (P = 0.03) and low-density lipoprotein receptor (LDLR) (P < 0.001) compared with the placebo.

CONCLUSIONS

Overall, curcumin administration for 12 weeks to women with PCOS had beneficial effects on body weight, glycemic control, serum lipids except triglycerides and VLDL-cholesterol levels, and gene expression of PPAR-γ and LDLR. Registered under Clinical Trials.gov Identifier no. http://www.irct.ir: IRCT20170513033941N50.

The effect of hesperidin supplementation on metabolic profiles in patients with metabolic syndrome: a randomized, double-blind, placebo-controlled clinical trial

PURPOSE

Hesperidin as an antioxidant flavonoid exerts anti-adipogenic, anti-inflammatory, anti-oxidant and anti-hypercholesterolemic effects. Besides, the increasing prevalence of metabolic syndrome (MetS) and its allied complications, on the one hand, and the willingness of individuals to use natural products for curing their diseases, on the other hand, led to the design of this study to evaluate the efficacy of hesperidin in normalizing the metabolic abnormalities in patients with MetS.

METHODS

In this clinical trial with a parallel-group design, 49 patients with MetS received either 500-mg hesperidin or placebo, twice daily, for 12 weeks. Number of participants with treated MetS was considered as a primary end point. Anthropometric parameters, dietary intake, physical activity, lipid profile, glucose homeostasis parameter, tumor necrosis factor alpha (TNF-α), high-sensitivity C-reactive protein (hs-CRP) were assessed at the beginning and at the end of the study. This trial is registered at clinicaltrials.gov as NCT03734874.

RESULTS

Compared with the placebo group, hesperidin decreased fasting glucose level (- 6.07 vs. - 13.32 mg/dL, P = 0.043), triglyceride (- 8.83 vs. - 49.09 mg/dL, P = 0.049), systolic blood pressure (- 0.58 vs. - 2.68 mmHg, P = 0.048) and TNF-α (- 1.29 vs. - 4.44 pg/mL, P = 0.009). Based on the within-group analysis, hesperidin led to significant decrease in serum levels of glucose, insulin, triglyceride, total cholesterol, low density lipoprotein cholesterol, TNF-α and hs-CRP, while in control group only glucose and insulin significantly decreased.

CONCLUSIONS

The results indicate that hesperidin supplementation can improve metabolic abnormalities and inflammatory status in patients with MetS.

Effects of curcumin on cardiovascular risk factors in obese and overweight adolescent girls: a randomized clinical trial

BACKGROUND

Obese adolescents are at higher risk of development of cardiovascular risk factors and obesity in later life. Dietary intake of antioxidants, particularly curcumin, as an active ingredient of turmeric extract, may have noticeable effects on obesity and its important complications such as cardiovascular risk factors. Therefore, the aim of this study was to assess the effects of curcumin supplementation on cardiovascular risk factors among overweight and obese female adolescents.

DESIGN AND SETTING

Randomized placebo-controlled clinical trial; Pediatric Cardiovascular Research Center, Isfahan, Iran.

METHODS

60 adolescent girls (aged 13-18 years) were randomly assigned to receive either placebo or intervention. The adolescents were asked to consume one 500 mg tablet per day, containing either standardized 95% turmeric extract or placebo, and to undergo a weight maintenance or a mild weight loss diet for 10 weeks. Anthropometric and biochemical indices were assessed at the baseline and the end of the intervention.

RESULTS

Curcumin supplementation had beneficial effects on body mass index (P = 0.019), waist circumference (P = 0.008), hip circumference (P = 0.030), high-density lipoprotein levels (P = 0.042) and triglyceride/high-density lipoprotein ratio (P = 0.021). However, in univariate analysis of covariance, no significant differences were found between the intervention and placebo groups after 10 weeks of supplementation (P > 0.05).

CONCLUSIONS

Prescription of curcumin supplementation along with use of a slight weight loss diet might have beneficial effects on some cardiovascular risk factors among overweight and obese female adolescents. Larger clinical trials with higher curcumin doses and longer duration are needed to confirm the results from the current study.

CLINICAL TRIAL REGISTRATION

IRCT20171107037302N1.

Curcumin induces secretion of glucagon-like peptide-1 through an oxidation-dependent mechanism

Curcumin shows antiglycemic effects in animals. Curcumin is chemically unstable at physiological pH, and its oxidative degradation products were shown to contribute to its anti-inflammatory effects. Since the degradation products may also contribute to other effects, we analyzed their role in the antiglycemic activity of curcumin. We quantified curcumin-induced release of glucagon-like peptide 1 (GLP-1) from mouse STC-1 cells that represent enteroendocrine L-cells as a major source of this anti-diabetic hormone. Curcumin induced secretion of GLP-1 in a dose-dependent manner. Two chemically stable analogues of curcumin that do not readily undergo degradation, were less active while two unstable analogues were active secretagogues. Chromatographically isolated spiroepoxide, an unstable oxidative metabolite of curcumin with anti-inflammatory activity, also induced secretion of GLP-1. Stable compounds like the final oxidative metabolite bicyclopentadione, and the major plasma metabolite, curcumin-glucuronide, were inactive. GLP-1 secretion induced by curcumin and its oxidative degradation products was associated with activation of PKC, ERK, and CaM kinase II. Since activity largely correlated with instability of curcumin and the analogues, we tested the extent of covalent binding to proteins in STC-1 cells and found it occurred with similar affinity as N-ethylmaleimide, indicating covalent binding occurred with nucleophilic cysteine residues. These results suggest that oxidative metabolites of curcumin are involved in the antiglycemic effects of curcumin. Our findings support the hypothesis that curcumin functions as a pro-drug requiring oxidative activation to reveal its bioactive metabolites that act by binding to target proteins thereby causing a change in function.

Postprandial Responses of Serum Bile Acids in Healthy Humans after Ingestion of Turmeric before Medium/High-Fat Breakfasts

SCOPE

Bile acids (BAs) are known to regulate a number of metabolic activities in the body. However, very little is known about how BAs are affected by diet. This study aims to investigate whether a single dose of turmeric-based beverage (TUR) before ingestion of medium- (MF) or high-fat (HF) breakfasts would improve the BA profile in healthy subjects.

METHODS AND RESULTS

Twelve healthy subjects are assigned to a randomized crossover single-blind study. The subjects receive isocaloric MF or HF breakfasts after a drink containing flavored water with or without an extract of turmeric with at least 1-week wash-out period between the treatments. Postprandial BAs are measured using protein precipitation followed by ultra-high-performance liquid chromatography-mass spectrometry analysis. The concentration of BAs is generally higher after HF than MF breakfasts. Ingestion of TUR before MF breakfast increases the serum concentrations of free and conjugated forms of cholic (CA) and ursodeoxycholic acids (UDCA), as well as the concentrations of chenodeoxycholic acid (CDCA) and its taurine-conjugated forms. However, the concentration of conjugated forms of deoxycholic acid (DCA) decreases when TUR is taken before HF breakfast.

CONCLUSION

TUR ingestion before MF and HF breakfasts improve BA profiles and may therefore have potential health-promoting effects on BA metabolism.