Why it is necessary to translate curcumin into clinical practice for the prevention and treatment of metabolic syndrome?

Therapeutic potential of curcumin in autophagy modulation: Insights into the role of transcription factor EB

Transcription factor EB (TFEB) is a basic Helix-Loop-Helix/Leucine Zipper (bHLHZip) class of DNA-binding proteins, which can control the expression of genes included in the autophagy-lysosomal pathway. TFEB regulates the autophagic flux by enhancing lysosome biogenesis, forming autophagosomes, and fusion with lysosomes, thereby facilitating cellular clearance of pathogenic protein structures. Curcumin is a natural polyphenolic molecule with pharmacological properties that make it a potential therapeutic candidate for a wide range of diseases. One of the important curcumin mechanisms of action includes modulation of autophagy through affecting various signaling components such as TFEB. This review discusses in vitro and in vivo evidence on the effects of curcumin on autophagy process via modulating TFEB activity in different disorders.

Comparative Effects of Gymnema sylvestre and Berberine on Adipokines, Body Composition, and Metabolic Parameters in Obese Patients: A Randomized Study

Gymnema sylvestre (GS) and berberine (BBR) are natural products that have demonstrated therapeutic potential for the management of obesity and its comorbidities, as effective and safe alternatives to synthetic drugs. Although their anti-obesogenic and antidiabetic properties have been widely studied, comparative research on their impact on the gene expression of adipokines, such as resistin (Res), omentin (Ome), visfatin (Vis) and apelin (Ap), has not been reported.

METHODOLOGY

We performed a comparative study in 50 adult Mexican patients with obesity treated with GS or BBR for 3 months. The baseline and final biochemical parameters, body composition, blood pressure, gene expression of Res, Ome, Vis, and Ap, and safety parameters were evaluated.

RESULTS

BBR significantly decreased (p < 0.05) body weight, blood pressure and Vis and Ap gene expression and increased Ome, while GS decreased fasting glucose and Res gene expression (p < 0.05). A comparative analysis of the final measurements revealed a lower gene expression of Ap and Vis (p < 0.05) in patients treated with BBR than in those treated with GS. The most frequent adverse effects in both groups were gastrointestinal symptoms, which attenuated during the first month of treatment.

CONCLUSION

In patients with obesity, BBR has a better effect on body composition, blood pressure, and the gene expression of adipokines related to metabolic risk, while GS has a better effect on fasting glucose and adipokines related to insulin resistance, with minimal side effects.

Curcumin protects against lamotrigine-induced chronic ovarian and uterine toxicity in rats by regulating PPAR-γ and ROS production

Lamotrigine (LTG) is an antiepileptic drug with possible adverse effects on the female reproductive system. Curcumin was declared to improve ovarian performance. Therefore, this study aimed to clarify ovulatory dysfunction (OD) associated with LTG and the role of curcumin in ameliorating this dysfunction. Adult female Wister albino rats were assigned into four groups: negative control (received saline), positive control (received curcumin only), LTG, and LTG with curcumin groups. Drugs were administered for 90 days. The hormonal profile, including testosterone, estrogen, progesterone, luteinizing hormone, and follicle-stimulating hormone, in addition to the lipid profile and glycemic analysis, were tested. Oxidative stress biomarkers analysis in the ovaries and uterus and peroxisome proliferator-activated receptor-γ (PPAR-γ) gene expression were also included. Histopathological examination of ovarian and uterine tissues and immunohistochemical studies were also performed. Curcumin could improve the OD related to chronic LTG intake. That was proved by the normalization of the hormonal profile, glycemic control, lipidemic status, oxidative stress markers, and PPAR-γ gene expression. The histopathological and immunohistochemical examination of ovarian and uterine tissues revealed an improvement after curcumin administration. The results describe an obvious deterioration in ovarian performance with LTG through the effect on lipidemic status, PPAR-γ gene, and creating an oxidative stress condition in the ovaries of chronic users, with a prominent improvement with curcumin addition to the treatment protocol.

The effects of curcumin-piperine supplementation on inflammatory, oxidative stress and metabolic indices in patients with ischemic stroke in the rehabilitation phase: a randomized controlled trial

BACKGROUND

Stroke is a leading cause of death worldwide, which is associated with a heavy economic and social burden. The purpose of this study was to investigate the effects of supplementation with curcumin-piperine combination in patients with ischemic stroke in the rehabilitation stage.

METHODS

In this randomized controlled trial, 66 patients with stroke were randomized into two groups receiving curcumin-piperine tablets (500 mg curcumin + 5 mg piperine) and matched placebo tablets for 12 weeks. High-sensitivity C-reactive protein (hs-CRP), carotid intima-media thickness (CIMT), thrombosis, total antioxidant capacity (TAC), lipid profile, anthropometric indices, blood pressure, and quality of life were assessed before and after the intervention. Statistical data analysis was done using SPSS22 software.

RESULTS

A total of 56 patients with a mean age of 59.80 ± 4.25 years completed the trial. Based on ANCOVA test, adjusted for baseline values, curcumin-piperine supplementation for 12 weeks resulted in significant reductions in serum levels of hs-CRP (p = 0.026), total cholesterol (TC) (p = 0.009), triglycerides (TG) (p = 0.001), CIMT (p = 0.002), weight (P = 0.001), waist circumference (p = 0.024), and systolic and diastolic blood pressure (p < 0.001), and a significant increase in TAC (p < 0.001) in comparison to the placebo. Pain score significantly increased in both groups; however, its increase was significantly higher in the placebo group compared with the intervention group (p = 0.007). No significant changes were observed between the two groups in terms of serum fibrinogen, low-density lipoprotein (LDL), high-density lipoprotein (HDL), and quality of life indices.

CONCLUSION

Curcumin-piperine supplementation had beneficial effects on CIMT, serum hs-CRP, TC, TG, TAC, and systolic and diastolic blood pressure in patients with ischemic stroke in the rehabilitation stage.

The effect of curcumin on anthropometric indices, blood pressure, lipid profiles, fasting blood glucose, liver enzymes, fibrosis, and steatosis in non-alcoholic fatty livers

Background

Non-alcoholic fatty liver disease (NAFLD) is the most common form of liver disease. Curcumin is a natural polyphenol that may be effective against liver steatosis and steatohepatitis. The present study aimed to evaluate the effects of phytosomal curcumin on lipid profile, fasting blood sugar, anthropometric indices, liver enzymes, fibrosis, and steatosis in non-alcoholic fatty liver patients.

Methods

The participants were randomized to the curcumin-phosphatidylserine phytosomal receiving group and the placebo receiving group and were followed up for 12 weeks. Data on anthropometric indices, lipid profile, blood glucose, blood pressure, liver enzymes, hepatic steatosis, and fibrosis were collected at the beginning and the end of the clinical trial.

Results

Supplementation for 12 weeks with phytosomal curcumin significantly reduced fibrosis and steatosis in the phytosomal curcumin receiving group compared with the placebo group (p < 0.05). Phytosomal curcumin also significantly reduced waist circumference and blood pressure compared with the placebo group (p < 0.05). There was no significant difference between the phytosomal curcumin and the placebo groups regarding changes in weight, body mass index, fasting blood glucose, liver enzymes, and lipid profile.

Conclusion

Curcumin, at a dose of 250 mg per day, might be effective in treating patients with NAFLD. Further studies are necessary to confirm these findings and to discover the underlying mechanisms.

Clinical trial registration

https://www.irct.ir/trial/43730, identifier: IRCT20121216011763N39.

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 suppresses cell proliferation and reduces cholesterol absorption in Caco-2 cells by activating the TRPA1 channel

BACKGROUND

Curcumin (Cur) is a bioactive dietary polyphenol of turmeric with various biological activities against several cancers. Colorectal cancer (CRC) is one of the leading causes of cancer-related deaths. Intestinal cholesterol homeostasis is associated with CRC. Chemotherapy for CRC is related to varied adverse effects. Therefore, natural products with anti-cancer properties represent a potential strategy for primary prevention of CRC.

METHODS

The present study used Cur as a therapeutic approach against CRC using the Caco-2 cell line. The cells were treated with different concentrations of Cur for different duration of time and then the proliferation ability of cells was assessed using Cell Counting Kit-8 and 5-Ethynyl-2'-deoxyuridine assays. Oil red O staining and cholesterol assay kit were used to evaluate cellular lipid content and cholesterol outward transportation. Finally, the protein expressions of cholesterol transport-related protein and signal transduction molecules were assessed using Western blot assay.

RESULTS

Cur inhibited cell proliferation in Caco-2 cells in a dose- and time-dependent manner by activating the transient receptor potential cation channel subfamily A member 1 (TRPA1) channel. Activation of the TRPA1 channel led to increased intracellular calcium, peroxisome proliferator-activated receptor gamma (PPARγ) upregulation, and the subsequent downregulation of the specificity protein-1 (SP-1)/sterol regulatory element-binding protein-2 (SREBP-2)/Niemann-Pick C1-like 1 (NPC1L1) signaling pathway-related proteins, and finally reduced cholesterol absorption in Caco-2 cells.

CONCLUSIONS

Cur inhibits cell proliferation and reduces cholesterol absorption in Caco-2 cells through the Ca²⁺/PPARγ/SP-1/SREBP-2/NPC1L1 signaling by activating the TRPA1 channel, suggesting that Cur can be used as a dietary supplement for the primary prevention of CRC. In Caco-2 cells, Cur first stimulates calcium influx by activating the TRPA1 channel, further upregulates PPARγ and downregulates SP-1/SREBP-2/NPC1L1 signaling pathway, and finally inhibits the absorption of cholesterol. TRPA1, transient receptor potential cation channel subfamily A member 1; NPC1L1, Niemann-Pick C1-like 1; PPARγ, peroxisome proliferator-activated receptor gamma; SP-1, specificity protein-1; SREBP-2, sterol regulatory element-binding protein-2; Cur, curcumin.

Anti-proliferative and pro-apoptotic effects of curcumin on skin cutaneous melanoma: Bioinformatics analysis and in vitro experimental studies

Objective: To reveal the potential mechanisms of curcumin for the treatment of skin cutaneous melanoma (SKCM) and its identify novel prognostic biomarkers.

Methods: We searched the Cancer Genome Atlas and Traditional Chinese Medicine Systems Pharmacology database for the data on SKCM and curcumin. We conducted data analysis using R and online tools. The propagation and migration of SKCM cells were assessed with CCK-8 and scratch wound assays, respectively. We assessed apoptosis by TUNEL assay and western blot.

Results: The survival analysis revealed that the mRNA expressions of DPYD, DPYS, LYN, PRKCQ, and TLR1 were significantly related to a favorable overall survival in SKCM patients. Additionally, the mRNA expression level of DPYD was associated with GPI, LYN, PCSK9, PRKCQ, and TLR1 mRNAs. GSEA results showed that the prognostic hub genes were augmented with ultraviolet, apoptosis, and metastasis. Curcumin expressed proliferation and migration of SK-MEL-1 cells (p < 0.05), and induced apoptosis (p < 0.05) significantly.

Conclusion: Curcumin may have potential therapeutic effects in SKCM by inhibiting cell proliferation and migration and inducing apoptosis by regulating oxygen-related signaling pathways. The hub genes might be identified as novel biomarkers for SKCM.

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.

Investigation of the Effects of Difluorinated Curcumin on Glycemic Indices in Streptozotocin-Induced Diabetic Rats

BACKGROUND

Curcumin is an antioxidant agent that improves glycemia in animal models of diabetes. Clinically curcumin use is limited due to poor solubility, weak absorption, and low bioavailability; therefore, this study to investigate the effects of curcumin's analog, difluorinated curcumin (CDF), on fasting blood glucose (FBG), oral glucose tolerance test (OGTT), and insulin tolerance test (ITT), in streptozotocin (STZ)-induced diabetic rats was undertaken.

METHODS

STZ-induced diabetes rats were randomly assigned to six groups (7 rats per group). They were treated daily by oral gavage with curcumin (200 and 100 mg/kg/day), CDF (200 and 100 mg/kg/day), and metformin (200 mg/kg/day) as a positive control group, for 4 weeks. Two diabetic control (DC) and normal control (NC) groups (non-diabetic rats) received normal saline and citrate buffer, respectively. FBG was measured at the beginning and end of the treatment (Day 0 and week 4) and OGTT and ITT were performed to determine glucose tolerance and insulin sensitivity.

RESULTS

Cur100, CDF 100, and CDF200 significantly decreased FBG levels after 4 weeks oral administration by -34% (-150 mg/dL ± 70, p = 0.02), -36% (123 mg/dL ±67, p < 0.04), and - 40% (-189 mg/dL ± 91, p = 0.03), respectively. Glucose sensitivity by OGTT showed a significant improvement in glucose tolerance ability in all treated groups compared with DC group. ITT demonstrated that insulin response improved significantly in Cur100 and CDF 200 groups.

CONCLUSION

Overall, CDF improved glucose tolerance and insulin sensitivity, while reducing FBG compared to curcumin, suggesting that curcumin analogs may have therapeutic utility in diabetes.

Dehydrozingerone inhibits renal lipotoxicity in high-fat diet-induced obese mice

Ectopic fat accumulation in the kidneys causes oxidative stress, inflammation and cell death. Dehydrozingerone (DHZ) is a curcumin analog that exhibits antitumour, antioxidant and antidiabetic effects. However, the efficacy of DHZ in diabetic nephropathy (DN) is unknown. Here, we verified the efficacy of DHZ on DN. We divided the experimental animals into three groups: regular diet, 60% high‐fat diet (HFD) and HFD with DHZ for 12 weeks. We analysed levels of renal triglycerides and urinary albumin and albumin‐creatinine ratio, renal morphological changes and molecular changes via real‐time polymerase chain reaction and immunoblotting. Furthermore, high glucose (HG)‐ or palmitate (PA)‐stimulated mouse mesangial cells or mouse podocytes were treated with DHZ for 24 h. As a result, DHZ markedly reduced renal glycerol accumulation and albuminuria excretion through improvement of thickened glomerular basement membrane, podocyte loss and slit diaphragm reduction. In the renal cortex in the HFD group, phospho‐AMPK and nephrin expression reduced, whereas arginase 2 and CD68 expression increased; however, these changes were recovered after DHZ administration. Increased reactive oxygen species (ROS) stimulated by HG or PA in podocytes was inhibited by DHZ treatment. Collectively, these findings indicate that DHZ ameliorates DN via inhibits of lipotoxicity‐induced inflammation and ROS formation.

Effects of Curcumin on Depression and Anxiety: A Narrative Review of the Recent Clinical Data

Depressive and anxiety disorders affect a significant proportion of the global population and constitute one of the highest disease burdens worldwide. Conventional pharmacological treatments are traditionally the first line of therapy for individuals affected by these conditions although these are only successful approximately half of the time and are often associated with undesirable side effects. This review describes the use of the natural substance curcumin as a potential alternative treatment of these mental disorders. With this in mind, we analyzed the effects of curcumin in eight clinical studies of depression and five studies of anxiety and assessed these using psychiatric symptom scores and molecular biomarker readouts.

Effect of Curcumin on Glycemic Control in Patients with Type 2 Diabetes: A Systematic Review of Randomized Clinical Trials

Type 2 diabetes mellitus (T2DM) is a chronic metabolic condition, which carries considerable morbidity and mortality. There is growing evidence that curcumin could modulate glucose homeostasis and improve vascular risk in patients with T2DM. The aim of this systematic review was to study the effect of curcumin on glycemic indices in patients with diabetes. A comprehensive search was conducted in PubMed, Scopus, Embase, and Google Scholar up to March 5, 2020, to identify randomized control trials investigating the effect of curcumin supplementation on glycemic indices including fasting blood glucose (FBS), hemoglobin A1c (HbA1C), and the homeostatic model assessment for insulin resistance (HOMA-IR). Eleven articles comprising 1131 individuals with T2DM were included in the study. Treatment with curcumin significantly reduced the level of FBS and HbA1c in 8 and 7 studies, respectively. HOMA-IR was evaluated in five studies, and this was reduced significantly by curcumin supplementation in three of those studies. Patients who took curcumin supplementation over longer periods (≥12 weeks) showed a significant reduction in glycemic indices. The current systematic review showed that curcumin can improve glycemic control in patients with T2DM. However, further studies are required to determine the optimum conditions for these effects of curcumin, particularly regarding readouts of insulin resistance.

Curcumin: A small molecule with big functionality against amyloid aggregation in neurodegenerative diseases and type 2 diabetes

Amyloidosis is a concept that implicates disorders and complications that are due to abnormal protein accumulation in different cells and tissues. Protein aggregation-associated diseases are classified according to the type of aggregates and deposition sites, such as neurodegenerative disorders and type 2 diabetes mellitus. Polyphenolic phytochemicals such as curcumin and its derivatives have anti-amyloid effects both in vitro and in animal models; however, the underlying mechanisms are not understood. In this review, we summarized possible mechanisms by which curcumin could interfere with self-assembly processes and reduce amyloid aggregation in amyloidosis. Furthermore, we discuss clinical trials in which curcumin is used as a therapeutic agent for the treatment of diseases linking to protein aggregates.

The Effects of Medicinal Plants and Bioactive Natural Compounds on Homocysteine

BACKGROUND

Among non-communicable diseases, cardiovascular diseases (CVDs) are the leading cause of mortality and morbidity in global communities. By 2030, CVD-related deaths are projected to reach a global rise of 25 million. Obesity, smoking, alcohol, hyperlipidemia, hypertension, and hyperhomocysteinemia are several known risk factors for CVDs. Elevated homocysteine is tightly related to CVDs through multiple mechanisms, including inflammation of the vascular endothelium. The strategies for appropriate management of CVDs are constantly evolving; medicinal plants have received remarkable attention in recent researches, since these natural products have promising effects on the prevention and treatment of various chronic diseases. The effects of nutraceuticals and herbal products on CVD/dyslipidemia have been previously studied. However, to our knowledge, the association between herbal bioactive compounds and homocysteine has not been reviewed in details. Thus, the main objective of this study is to review the efficacy of bioactive natural compounds on homocysteine levels according to clinical trials and animal studies.

RESULTS

Based on animal studies, black and green tea, cinnamon, resveratrol, curcumin, garlic extract, ginger, and soy significantly reduced the homocysteine levels. According to the clinical trials, curcumin and resveratrol showed favorable effects on serum homocysteine. In conclusion, this review highlighted the beneficial effects of medicinal plants as natural, inexpensive, and accessible agents on homocysteine levels based on animal studies. Nevertheless, the results of the clinical trials were not uniform, suggesting that more well-designed trials are warranted.

Targeting microRNAs by curcumin: implication for cancer therapy

In spite of all the investigations in the past 20 years that established a great body of knowledge in cancer therapy, utilizing some elderly methods such as plant compound administration might still be useful. Curcumin is a bioactive polyphenol, which has many anticancer properties but its capability in modulating miRNA expression has opened new doors in the field of cancer-targeted therapy. MiRNAs are a class of small noncoding RNAs that are able to regulate gene expression and signaling. In addition, some other effects of these RNAs such as modulating cell differentiation and regulation of cell cycle have made miRNAs great candidates for personalized cancer treatment. In this review, we try to find some answers to the questions on how curcumin exerts its impacts on cancer hallmarks through miRNAs and whether chemotherapy can be replaced by this beneficial plant compound.

Research progress in use of traditional Chinese medicine monomer for treatment of non-alcoholic fatty liver disease

With the improvement of people's living standards and the change of eating habits, non-alcoholic fatty liver disease (NAFLD) has gradually become one of the most common chronic liver diseases in the world. However, there are no effective drugs for the treatment of NAFLD. Therefore, it is urgent to find safe, efficient, and economical anti-NAFLD drugs. Compared with western medicines that possess fast lipid-lowering effect, traditional Chinese medicines (TCM) have attracted increasing attention for the treatment of NAFLD due to their unique advantages such as multi-targets and multi-channel mechanisms of action. TCM monomers have been proved to treat NAFLD through regulating various pathways, including inflammation, lipid production, insulin sensitivity, mitochondrial dysfunction, autophagy, and intestinal microbiota. In particular, peroxisome proliferator-activated receptor α (PPAR-α), sterol regulatory element-binding protein 1c (SREBP-1c), nuclear transcription factor kappa (NF-κB), phosphoinositide 3-kinase (PI3K), sirtuin1 (SIRT1), AMP-activated protein kinase (AMPK), p53 and nuclear factor erythroid 2-related factor 2 (Nrf2) are considered as important molecular targets for ameliorating NAFLD by TCM monomers. Therefore, by searching PubMed, Web of Science and SciFinder databases, this paper updates and summarizes the experimental and clinical evidence of TCM monomers for the treatment of NAFLD in the past six years (2015-2020), thus providing thoughts and prospects for further exploring the pathogenesis of NAFLD and TCM monomer therapies.

The Use of Curcumin for the Treatment of Renal Disorders: A Systematic Review of Randomized Controlled Trials

Chronic kidney disease (CKD) is one of the significant causes of morbidity and mortality worldwide, which could develop and progress to end-stage renal disease. Increased inflammation and reduced antioxidant capacity commonly occur in CKD and hemodialysis patients. Curcumin is a natural bioactive compound with antioxidant and anti-inflammatory properties. This systematic review was undertaken with the main aim of assessing the effects of curcumin/turmeric supplementation on renal diseases based on clinical trials. A comprehensive search was performed in PubMed/MEDLINE, Scopus, ISI Web of Science, and Google Scholar from inception up to April 6, 2020 to identify clinical trials assessing the effects of curcumin or turmeric alone, or in combination with other herbs or nutrients on renal diseases. Twelve studies met the eligibility criteria. These randomized controlled trials (RCTs) comprised 631 patients with either chronic kidney diseases (CKD), hemodialysis, diabetic proteinuria and nephropathy, and lupus nephritis. Curcumin/turmeric supplementation had favorable effects on renal diseases, particularly in terms of inflammation and oxidative stress. However, with the exception for proteinuria, their impact on clinical parameters, such as blood urea nitrogen, creatinine, glomerular filtration rate (GFR), and serum albumin, was weak and not significant. No serious adverse effects were reported following curcumin/turmeric supplementation. Within the limitations of this review, it can be concluded that curcumin/turmeric supplementation might have some beneficial effects on inflammatory and oxidative stress parameters of patients but no considerable positive impact on clinical outcomes of kidney diseases, apart from proteinuria.

Medicinal Plants and Phytochemicals Regulating Insulin Resistance and Glucose Homeostasis in Type 2 Diabetic Patients: A Clinical Review

Diabetes is a major health problem affecting more than four hundred million adults worldwide. The transition from normal glucose tolerance to type 2 diabetes (T2D) is preceded by increased Insulin resistance (IR), an independent predictor of the development of T2D in high risk (e.g. obese populations, pre-diabetes) individuals. Insulin deficiency resulting from increased IR results in progressive glucose homeostasis dysfunction. Data has shown that IR is affected by many different factors such as genetics, age, exercise, dietary nutrients, obesity, and body fat distribution. One of the most important factors is diet, which plays an essential role in addressing T2D and metabolic syndrome. Nutraceuticals and medicinal plants have been shown to have efficacy in preventing chronic diseases like cancer, non-alcoholic fatty liver disease (NAFLD), cardiovascular disease, diabetes mellitus and metabolic syndrome, likely through the anti-inflammatory properties found in nutraceuticals. However, the effect of these compounds, including traditional plant medicines, herbal formulations or their extracts on IR have not been systematically investigated. The objective of this review was to assess the reported effects of medicinal plants and bioactive natural compounds on IR. The findings confirm that most of the herbal bioactive compounds including resveratrol, garlic, curcumin, cinnamon, ginger, nuts, berberine, anthocyanin, soybean, flaxseed, vegetable oils, and soluble fibers have benefit in their efficacy for decreasing IR, fasting blood sugar (FBS), fasting insulin and HbA1c.

Natural Insulin Sensitizers for the Management of Diabetes Mellitus: A Review of Possible Molecular Mechanisms

Diabetes mellitus is a growing health challenge globally which is increasing in epidemic proportion. Naturally occurring pharmacological agents are more likely to provide beneficial therapeutic effects without undesirable side effects compared to the synthetic agents. There is a growing evidence that some naturally occurring pharmacological agents derived from plants have potential antihyperglycemic effects. In this study, we have reviewed the molecular mechanism behind potential hypoglycemic properties of four well-known herbal-based agents, namely, ginger, curcumin, garlic, and cinnamon. Also, we present the related clinical data confirming experimental results aiming to develop novel therapeutic strategies based on these herbal agents potentially for the management of patients with diabetes.

The Clinical Use of Curcumin for the Treatment of Rheumatoid Arthritis: A Systematic Review of Clinical Trials

Rheumatoid arthritis (RA) is a chronic inflammatory disease of the joints, which is prevalent in about 0.5-1.0% of the world population. Newer therapies for RA have only minimal efficacy in some cases and some adverse effects. Curcumin with anti-antioxidant, anti-inflammatory, and immunomodulatory properties might have beneficial effects on RA. We have carried out a systematic review with the main aim of estimating the effect of curcumin supplementation on RA. A systematic search of the medical databases, PubMed, Scopus, ISI, and Google Scholar was performed up to March 21, 2020 to identify clinical trials assessing the effect of turmeric or curcumin on RA. Six studies, comprising 259 patients with RA of 6-12 weeks duration, were included. Disease activity was assessed using 28 joints (DAS-28), visual analog scale (VAS), and American College of Rheumatology (ACR-20) scores. Treatment with curcumin significantly reduced DAS-28 scores in four out of five studies and VAS scores for pain in all three studies and significantly increased ACR-20 scores in all three studies in which it was measured. Erythrocyte sedimentation rate (ESR) and circulating C-reactive protein (CRP) were assessed in six and five studies, respectively, out of which four studies reported significant reductions in these parameters in response to curcumin treatment. Rheumatoid factor (RF) was significantly reduced after consumption of curcumin in all three relevant studies. None of the studies reported serious adverse effects with curcumin consumption. The present systematic review suggests that curcumin could be used as a safe agent to treat RA. Thus, further validation is justified.

Curcumin analog CUR5-8 ameliorates nonalcoholic fatty liver disease in mice with high-fat diet-induced obesity

OBJECTIVE

Nonalcoholic fatty liver disease (NAFLD) occurs when excess fat storage in the liver and it is strongly linked with metabolic syndrome including obesity, insulin resistance, dyslipidemia and hypertension. Curcumin5-8 (CUR5-8) is a synthetic derivative of naturally active curcumin (CUR) that has anti-oxidative and anti-inflammatory properties. In the present study, we investigated the effects of CUR5-8, a novel CUR analog, on hepatic steatosis in mice with high-fat diet (HFD)-induced obesity.

METHODS

Based on their diets for 13 weeks, the mice were categorized into the following six groups: regular diet (RD, n = 10), RD with CUR (RD + CUR, 100 mg/kg/day, n = 10), RD with CUR5-8 (RD + CUR5-8, 100 mg/kg/day, n = 10), high-fat diet-induced obese mice (HFD, n = 10), HFD with CUR (HFD + CUR, 100 mg/kg/day, n = 10), and HFD with CUR5-8 (HFD + CUR5-8, 100 mg/kg/day, n = 10) for 13 weeks. Hematoxylin and eosin (H&E) staining of the sections revealed hepatic steatosis.

RESULTS

CUR5-8 administration prevented increase in body and liver weights in mice with HFD-induced obesity. Compared to the HFD group, insulin resistance was significantly improved in the HFD + CUR5-8 group. Serum alanine aminotransferase level, which is an indicator of liver damage, was also decreased after CUR5-8 administration. H&E staining revealed that CUR5-8 treatment decreased hepatic steatosis in mice with HFD-induced obesity. Interestingly, CUR5-8, and not CUR, decreased the elevated liver triglyceride level induced by the HFD.

CONCLUSIONS

These findings suggest that CUR5-8 ameliorates insulin resistance and hepatic steatosis in mice with HFD-induced obesity.

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.

Curcumin micelles suppress gastric tumor cell growth by upregulating ROS generation, disrupting redox equilibrium and affecting mitochondrial bioenergetics

A proposed novel mechanism of anticancer activity of curcumin micelles through redox equilibrium in gastric cancer.

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

BACKGROUND

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

METHODS

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

RESULTS

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

CONCLUSION

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

Modulatory effects of curcumin on heat shock proteins in cancer: A promising therapeutic approach

Cancer metastasis represents a multistep process, including alteration of cell adhesion/motility in the microenvironment and sustained angiogenesis, which is essential for supporting cancer growth in tissues that are distant from the primary tumor. There is growing evidence suggesting that heat shock proteins (HSPs) (also known as heat stress proteins), which constitute a family of stress-inducible proteins, may be involved in the pathogenesis of cancer. Curcumin (diferuloylmethane) is a potent anti-inflammatory, antioxidant, antimicrobial, and antitumor agent. Curcumin has been shown to regulate different members of HSPs including HSP27, HSP40, HSP60, HSP70, and HSP90 in cancer. Here, we present extent findings suggesting that curcumin may act as a potential therapeutic agent for the treatment of cancer through its regulation of HSPs.

Efficacy of phospholipidated curcumin in nonalcoholic fatty liver disease: a clinical study

Curcumin is a safe and dietary phytochemical that can improve different pathophysiologic features of non-alcoholic fatty liver disease (NAFLD). Here, we investigated the efficacy of phospholipidated curcumin supplementation in NAFLD patients. In this single-arm study, 36 patients were recruited. Each patient received three capsules a day (each containing 500 mg of phospholipidated curcumin [overall content of curcuminoids per capsule: 100 mg]) for a period of 8 weeks. The results indicated that phospholipidated curcumin supplementation reduced NAFLD severity and ameliorated ultrasonographic and biochemical measures (including liver transaminases and lipid profile) associated with disease progression.

The role of curcumin and its derivatives in sensory applications

Curcumin has recently attracted much attention due to the wide range of its physiological actions such as anti-tumor, anti-inflammatory, anti-thrombotic, anti-diabetic and anti-microbial effects. This phytochemical can be used as a sensing material for the detection of chemicals due to its optical properties as a fluorescent polyphenol. Curcumin and its derivatives can make complexes with many cations such as Cu²⁺, Fe²⁺, Hg²⁺, Pt²⁺, Re³⁺ and Al³⁺via bearing 1,3-diketones with keto-enol isomerization. The complexation of curcumin with certain metal ions leads to its solubility in water and producing various hues of colors as well as cytotoxic and antimicrobial effects. Curcumin can also form complexes with certain metal ions and thus serve as a chelating agent for anions such as ClO^-, CN^-, F^- and S^2-. Moreover, conjugation of curcumin with some organic compounds such as cysteine and poly-glycerol acrylate provides an efficient fluorescence detection system for picric acid and 2-vinyl pyridine in aqueous media. In this review, we focused on curcumin as a key element in a membrane composition of chemical sensors. In addition, the latest sensing platforms based on curcumin and its derivatives are briefly described.

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

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

Curcumin in tissue engineering: A traditional remedy for modern medicine

Curcumin is the principal polyphenolic compound present in turmeric with broad applications in tissue engineering and regenerative medicine. It has some important inherent properties with the potential to facilitate tissue healing, including anti-inflammatory, anti-oxidant, and antibacterial activities. Therefore, curcumin has been used for the treatment of various damaged tissues, especially wound injuries. There are different forms of curcumin, among which nano-formulations are of a great importance in regenerative medicine. It is also important to design sophisticated delivery systems for controlled/localized delivery of curcumin to the target tissues and organs. Although there are many reports on the advantages of this compound, further research is required to fully explore its clinical usage. The review describes the physicochemical and biological properties of curcumin and the current state of the evidence on its applications in tissue engineering. © 2018 BioFactors, 45(2):135-151, 2019.

Medicinal plants in treatment of hypertriglyceridemia: A review based on their mechanisms and effectiveness

BACKGROUND

Hypertriglyceridemia (HTg) defines as high amounts of triglyceride (TG) in the blood which can lead to serious complications over time. HTg is usually a part of metabolic disorders such as diabetes mellitus, metabolic syndrome, and dyslipidemia. Different medications have been used to treat HTg but experimentally, many herbs have been recommended for treating HTg as an adjuvant therapy. In most cases, the recommendations are based on animal studies and limited evidences exist about their mechanisms and clinical usefulness.

PURPOSE

This review focused on the herbs which have been shown TG lowering effect.

METHOD

The search was done in PubMed, Science Direct, Scopus, Web of Science and Google Scholar databases a 20-year period between 1997 to 2017 with keywords search of medicinal plant, plant extract, hypertriglyceridemia, dyslipidemia, hyperlipidemia, lipoprotein lipase and apolipoprotein.

RESULTS

According to the results, many plants showed positive effects but Allium sativum, Nigella sativa, Curcuma longa, Anethum graveolens and Commiphora mukul had the best TG lowering effect with exact mechanisms of action.

CONCLUSION

It seems that use of these plants as complementary therapeutics or extraction of their active ingredients along with currently available drugs will improve the management of HTg in patients.

Effects of curcumin on hypoxia-inducible factor as a new therapeutic target

Hypoxia-inducible factor-1 (HIF-1) is a transcription factor that consists of two subunits, the HIF-1α and HIF-1β (ARNT). Under hypoxic conditions, HIF-1 is an adaptive system that regulates the transcription of multiple genes associated with growth, angiogenesis, proliferation, glucose transport, metabolism, pH regulation and cell death. However, aberrant HIF-1 activation contributes to the pathophysiology of several human diseases such as cancer, ischemic cardiovascular disorders, and pulmonary and kidney diseases. A growing body of evidence indicates that curcumin, a natural bioactive compound of turmeric root, significantly targets both HIF-1 subunits, but is more potent against HIF-1α. In this review, we have summarized the knowledge about the pharmacological effects of curcumin on HIF-1 and the related molecular mechanisms that may be effective candidates for the development of multi-targeted therapy for several human diseases.

The Effects of Curcumin on Serum Heat Shock Protein 27 Antibody Titers in Patients with Metabolic Syndrome

Metabolic syndrome (MetS) is associated with an increased risk of cardiovascular disease and diabetes mellitus. Inflammation and oxidant stress are features of MetS that can enhance the expression and release of heat shock proteins (Hsps), including the small heat shock protein, Hsp 27, and that may subsequently lead to the production of Hsp27 antibodies (anti-Hsp 27). Curcumin is an anti-inflammatory and antioxidant phytochemical that may ameliorate these features of MetS. We investigated the effects of unformulated curcumin and phospholipidated curcumin on antibody titers to heat shock protein 27 (anti-Hsp 27) in patients with MetS. A randomized double-blind, placebo-controlled clinical trial design was used in 120 patients with MetS (diagnosed according to the International Diabetes Federation [IDF] criteria). Participants were randomly allocated to 3 groups, with 40 individuals per group, that received either 1 g/d curcumin, phospholipidated curcumin, or a placebo for 6 weeks. The changes in serum concentrations of anti-Hsp 27 did not differ significantly between study groups (p = .283). There was no significant difference between baseline and end-of-trial concentrations of anti-Hsp 27 in groups supplemented with curcumin (p = .177), phospholipidated curcumin (p = .798), or placebo (p = .663). Curcumin supplementation (1 g/d) has no significant effects on anti-Hsp 27 titers in patients with MetS.

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

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

The versatile role of curcumin in cancer prevention and treatment: A focus on PI3K/AKT pathway

Despite significant advances in treatment modalities, millions of cancer-related deaths continue to occur annually, often as a consequence of developing resistance against the range of available chemotherapeutic drugs. Furthermore, available anti-cancer chemotherapeutic agents show limited efficacy, often have severe side effects, and are expensive. Thus, the discovery of pharmacological agents that do not have these disadvantages is necessary. Curcumin, a polyphenolic compound derived from turmeric (Curcumin longa L.), is one such agent that has been widely studied for its anti-inflammatory and/or anti-cancer effects. Curcumin exerts its anti-cancer effect by suppressing the initiation, progression, and metastasis of a variety of cancers and appears to inhibit carcinogenesis by affecting two main processes: angiogenesis and tumor growth. These anti-cancer effects are largely mediated via negative regulation of various transcription factors, growth factors, inflammatory cytokines, protein kinases, and other oncogenic molecules. The PI3K/AKT pathway is commonly activated in cancer initiation and progression. Considered to be the key signaling pathway, the phosphatidylinositol-3-kinase (PI3K)/protein kinase B (AKT) pathway therefore represents a key target for cancer therapeutics. In the current review, we focus upon curcumin's targeting of PI3K/AKT in different malignancies to effect inhibition of cancer development and progression.

Risperidone-induced metabolic dysfunction is attenuated by Curcuma longa extract administration in mice

Antipsychotics, such as risperidone, increase food intake and induce alteration in glucose and lipid metabolism concomitantly with overweight and body fat increase, these biological abnormalities belong to the metabolic syndrome definition (high visceral adiposity, hypertriglyceridemia, hyperglycemia, low HDL-cholesterol and high blood pressure). Curcumin is a major component of traditional turmeric (Curcuma longa) which has been reported to improve lipid and glucose metabolism and to decrease weight in obese mice. We questioned the potential capacity of curcumin, contained in Curcuma longa extract (Biocurcuma™), to attenuate the risperidone-induced metabolic dysfunction. Two groups of mice were treated once a week, for 22 weeks, with intraperitoneal injection of risperidone (Risperdal) at a dose 12.5 mpk. Two other groups received intraperitoneal injection of the vehicle of Risperdal following the same schedule. Mice of one risperidone-treated groups and of one of vehicle-treated groups were fed a diet with 0.05% Biocurcuma™ (curcumin), while mice of the two other groups received the standard diet. Curcumin limited the capacity of risperidone to reduce spontaneous motricity, but failed to impede risperidone-induced increase in food intake. Curcumin did not reduce the capacity of risperidone to induce weight gain, but decreased visceral adiposity and decreased the risperidone-induced hepatomegaly, but not steatosis. Furthermore, curcumin repressed the capacity of risperidone to induce the hepatic over expression of enzymes involved in lipid metabolism (LXRα, FAS, ACC1, LPL, PPARγ, ACO, SREBP2) and decreased risperidone-induced glucose intolerance and hypertriglyceridemia. Curcumin decreased risperidone-induced increases in serum markers of hepatotoxicity (ALAT, ASAT), as well as of one major hepatic pro-inflammatory transcription factor (NFκB: p105 mRNA and p65 protein). These findings support that nutritional doses of curcumin contained in Curcuma longa extract are able to partially counteract the risperidone-induced metabolic dysfunction in mice, suggesting that curcumin ought to be tested to reduce the capacity of risperidone to induce the metabolic syndrome in human.

Medicinal plants and bioactive natural compounds in the treatment of non-alcoholic fatty liver disease: A clinical review

Non-alcoholic fatty liver disease (NAFLD) is a major cause of liver diseases, and is closely related to metabolic syndrome and its related conditions, diabetes mellitus and dyslipidemia. On the other hand, NAFLD as a multisystem disease increases the risk of several chronic diseases include type 2 diabetes mellitus, cardiovascular disease (CVD), and chronic kidney disease. The main objective was to review the efficacy of bioactive natural compounds assessed by clinical trials. Search literature using four databases (PubMed, EBSCO, Web of Science, and Ovid Medline) to review publications that focused on the impact of bioactive natural compounds in NAFLD treatment. Due to the lack of effective pharmacological treatments available for NAFLD, lifestyle modifications such as following a healthy diet, vigorous physical activity, and weight reduction remain the first line of treatment for NAFLD. However, due to the poor adherence to this type of treatment, especially for long-term weight loss diets some of which may have harmful effects on the liver, finding novel therapeutic agents for NAFLD treatment and/or preventing NAFLD progression has garnered significant interest. Although the therapeutic agents of NAFLD treatment have been reviewed previously, to date, no summary has been conducted of clinical trials examining the effects of herbal compounds on NAFLD-related biomarkers. This review highlights the beneficial role of herbal bioactives and medicinal plants in NAFLD treatment, particularly as complementary to a healthy lifestyle. All natural products described in this review seem to have some benefits to improve oxidative stress, cellular inflammation and insulin-resistance, which always remain as the "primum movens" of NAFLD pathogenesis.

Nutraceutical approaches to metabolic syndrome

Metabolic Syndrome (MetS), affecting at least 30% of adults in the Western World, is characterized by three out of five variables, from high triglycerides, to elevated waist circumference and blood pressure. MetS is not characterized by elevated cholesterolemia, but is rather the consequence of a complex interaction of factors generally leading to increased insulin resistance. Drug treatments are of difficult handling, whereas well-characterized nutraceuticals may offer an effective alternative. Among these, functional foods, e.g. plant proteins, have been shown to improve insulin resistance and reduce triglyceride secretion. Pro- and pre-biotics, that are able to modify intestinal microbiome, reduce absorption of specific nutrients and improve the metabolic handling of energy-rich foods. Finally, specific nutraceuticals have proven to be of benefit, in particular, red-yeast rice, berberine, curcumin as well as vitamin D. All these can improve lipid handling by the liver as well as ameliorate insulin resistance. While lifestyle approaches, such as with the Mediterranean diet, may prove to be too complex for the single patient, better knowledge of selected nutraceuticals and more appropriate formulations leading to improved bioavailability will certainly widen the use of these agents, already in large use for the management of these very frequent patient groups. Key messages Functional foods, e.g. plant proteins, improve insulin resistance. Pro- and pre-biotics improve the metabolic handling of energy-rich foods. Nutraceutical can offer a significant help in handling MetS patients being part of lifestyle recommendations.

Efficacy and safety of turmeric and curcumin in lowering blood lipid levels in patients with cardiovascular risk factors: a meta-analysis of randomized controlled trials

Background

Dyslipidemia is an important and common cardiovascular risk factor in the general population. The lipid-lowering effects of turmeric and curcumin are unconfirmed. We performed a meta-analysis to assess the efficacy and safety of turmeric and curcumin in lowering blood lipids in patients at risk of cardiovascular disease (CVD).

Methods

A comprehensive literature search was conducted on PubMed, Embase, Ovid, Medline and Cochrane Library databases to identify randomized controlled trials (published as of November 2016) that assessed the effect of turmeric and curcumin on blood lipid levels including total cholesterol (TC), low-density lipoprotein cholesterol (LDL-C), high-density lipoprotein cholesterol (HDL-C), and triglycerides (TG). Pooled standardized mean difference (SMD) with 95% confidence interval (CI) was used to assess the effect.

Results

The analysis included 7 eligible studies (649 patients). Turmeric and curcumin significantly reduced serum LDL-C (SMD = −0.340, 95% confidence interval [CI]: −0.530 to −0.150, P < 0.0001) and TG (SMD = −0.214, 95% CI: −0.369 to −0.059, P = 0.007) levels as compared to those in the control group. These may be effective in lowering serum TC levels in patients with metabolic syndrome (MetS, SMD = −0.934, 95% CI: −1.289 to −0.579, P < 0.0001), and turmeric extract could possibly have a greater effect on reducing serum TC levels (SMD = −0.584, 95% CI: −0.980 to −0.188, P = 0.004); however, the efficacy is yet to be confirmed. Serum HDL-C levels were not obviously improved. Turmeric and curcumin appeared safe, and no serious adverse events were reported in any of the included studies.

Conclusions

Turmeric and curcumin may protect patients at risk of CVD through improving serum lipid levels. Curcumin may be used as a well-tolerated dietary adjunct to conventional drugs. Further research is required to resolve uncertainties related to dosage form, dose and medication frequency of curcumin.

Electronic supplementary material

The online version of this article (10.1186/s12937-017-0293-y) contains supplementary material, which is available to authorized users.