Influence of tetrahydrocurcumin on hepatic and renal functional markers and protein levels in experimental type 2 diabetic rats

COVID-19-Associated Sepsis: Potential Role of Phytochemicals as Functional Foods and Nutraceuticals

The acute manifestations of coronavirus disease 2019 (COVID-19) exhibit the hallmarks of sepsis-associated complications that reflect multiple organ failure. The inflammatory cytokine storm accompanied by an imbalance in the pro-inflammatory and anti-inflammatory host response to severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection leads to severe and critical septic shock. The sepsis signature in severely afflicted COVID-19 patients includes cellular reprogramming and organ dysfunction that leads to high mortality rates, emphasizing the importance of improved clinical care and advanced therapeutic interventions for sepsis associated with COVID-19. Phytochemicals of functional foods and nutraceutical importance have an incredible impact on the healthcare system, which includes the prevention and/or treatment of chronic diseases. Hence, in the present review, we aim to explore the pathogenesis of sepsis associated with COVID-19 that disrupts the physiological homeostasis of the body, resulting in severe organ damage. Furthermore, we have summarized the diverse pharmacological properties of some potent phytochemicals, which can be used as functional foods as well as nutraceuticals against sepsis-associated complications of SARS-CoV-2 infection. The phytochemicals explored in this article include quercetin, curcumin, luteolin, apigenin, resveratrol, and naringenin, which are the major phytoconstituents of our daily food intake. We have compiled the findings from various studies, including clinical trials in humans, to explore more into the therapeutic potential of each phytochemical against sepsis and COVID-19, which highlights their possible importance in sepsis-associated COVID-19 pathogenesis. We conclude that our review will open a new research avenue for exploring phytochemical-derived therapeutic agents for preventing or treating the life-threatening complications of sepsis associated with COVID-19.

The role of tetrahydrocurcumin in disease prevention and treatment

In recent decades, natural compounds derived from herbal medicine or dietary sources have played important roles in prevention and treatment of various diseases and have attracted more and more attention. Curcumin, extracted from the Curcumae Longae Rhizoma and widely used as food spice and coloring agent, has been proven to possess high pharmacological value. However, the pharmacological application of curcumin is limited due to its poor systemic bioavailability. As a major active metabolite of curcumin, tetrahydrocurcumin (THC) has higher bioavailability and stability than curcumin. Increasing evidence confirmed that THC had a wide range of biological activities and significant treatment effects on diseases. In this paper, we reviewed the research progress on the biological activities and therapeutic potential of THC on different diseases such as neurological disorders, metabolic syndromes, cancers, and inflammatory diseases. The extensive pharmacological effects of THC involve the modulation of various signaling transduction pathways including MAPK, JAK/STAT, NF-κB, Nrf2, PI3K/Akt/mTOR, AMPK, Wnt/β-catenin. In addition, the pharmacokinetics, drug combination and toxicology of THC were discussed, thus providing scientific basis for the safe application of THC and the development of its dietary supplements and drugs.

The Effects of Curcumin Administration on Carotid Intima-Media Thickness and Pulse Wave Velocity in Diabetic Hemodialysis Patients: A Randomized, Double-Blinded, Placebo-Controlled Trial

Background

Prior studies have reported that curcumin is inversely associated with reduced markers of atherosclerosis risk, including carotid intima-media thickness (CIMT). This study was designed to assess the effects of curcumin on CIMT and pulse wave velocity (PWV) in diabetic hemodialysis (HD) patients.

Methods

This randomized, double-blinded, placebo-controlled trial was conducted on 39 diabetic HD patients. People were assigned to receive curcumin or placebo (starch) for 24 weeks. Individuals in the curcumin group (n = 26) received 80 mg/day. CIMT and PWV levels were taken at baseline and after 24 weeks of intervention.

Results

After 24 weeks of intervention, curcumin intake did not affect mean levels of left (P = 0.83) and right (P = 0.47) CIMT and maximum levels of left (P = 0.84) and right (P = 0.11) CIMT, and PWV (P = 0.12) compared to the placebo. Furthermore, within-group difference demonstrated a significant reduction in mean levels of PWV (P = 0.01) in the curcumin group. We did not observe any significant change in C-reactive protein (CRP) concentrations after curcumin intake (P = 0.69).

Conclusions

Curcumin intake did not affect mean levels of left and right CIMT and maximum levels of left and right CIMT, PWV, and CRP levels compared to the placebo. Additionally, within-group difference demonstrated a significant reduction in mean levels of PWV in the curcumin group.This trial was registered at www.irct.ir as http://www.irct.ir: IRCT20200527047584N1.

Statistical optimization of tetrahydrocurcumin loaded solid lipid nanoparticles using Box Behnken design in the management of streptozotocin-induced diabetes mellitus

In the past, curcumin was the go-to medication for diabetes, but recent studies have shown that tetrahydrocurcumin is more effective. The problem is that it's not very soluble in water or very bioavailable. So, our research aims to increase the bioavailability and anti-diabetic efficacy of tetrahydrocurcumin in streptozotocin-induced diabetic rats by synthesizing tetrahydrocurcumin-loaded solid lipid nanoparticles. Box Behnken Design was employed for the optimization of tetrahydrocurcumin-loaded solid lipid nanoparticles (THC-SLNs). The optimal formulation was determined by doing an ANOVA to examine the relationship between the independent variables (drug-to-lipid ratio, surfactant concentration, and co-surfactant concentration) and the dependent variables (particle size, percent entrapment efficiency, and PDI). Particle size, PDI, and entrapment efficiency all showed statistical significance based on F-values and p-values. The optimized batch was prepared using a drug-to-lipid ratio (1:4.16), 1.21% concentration of surfactant, and 0.4775% co-surfactant (observed with a particle size of 147.1 nm, 83.58 ± 0.838 % entrapment efficiency, and 0.265 PDI, and the values were found very close with the predicted ones. As the THC peak vanishes from the DSC thermogram of the improved formulation, this indicates that the drug has been transformed from its crystalline form into its amorphous state. TEM analysis of optimized formulation demonstrated mono-dispersed particles with an average particle size of 145 nm which are closely related to zetasizer's results. In-vitro release study of optimized formulation demonstrated burst release followed by sustained release up to 71.04% throughout 24 hrs. Increased bioavailability of the adjusted THC-SLN was found in an in vivo pharmacokinetics research with 9.47 folds higher AUC(0-t) compared to plain THC-suspension. Additionally, pharmacodynamic experiments of optimized formulation demonstrated a marked decrease in blood glucose level to 63.7% and increased body weight from 195.8 ± 7.223 to 231.2 ± 7.653 on the 28th day of the study and showed a better anti-diabetic effect than plain drug suspension. Results of stability studies revealed that formulation can be stored for longer periods at room temperature. Tetrahydrocurcumin can be effectively administered by SLN for the treatment of diabetes.

Food Polyphenols and Type II Diabetes Mellitus: Pharmacology and Mechanisms

Type II diabetes mellitus and its related complications are growing public health problems. Many natural products present in our diet, including polyphenols, can be used in treating and managing type II diabetes mellitus and different diseases, owing to their numerous biological properties. Anthocyanins, flavonols, stilbenes, curcuminoids, hesperidin, hesperetin, naringenin, and phenolic acids are common polyphenols found in blueberries, chokeberries, sea-buckthorn, mulberries, turmeric, citrus fruits, and cereals. These compounds exhibit antidiabetic effects through different pathways. Accordingly, this review presents an overview of the most recent developments in using food polyphenols for managing and treating type II diabetes mellitus, along with various mechanisms. In addition, the present work summarizes the literature about the anti-diabetic effect of food polyphenols and evaluates their potential as complementary or alternative medicines to treat type II diabetes mellitus. Results obtained from this survey show that anthocyanins, flavonols, stilbenes, curcuminoids, and phenolic acids can manage diabetes mellitus by protecting pancreatic β-cells against glucose toxicity, promoting β-cell proliferation, reducing β-cell apoptosis, and inhibiting α-glucosidases or α-amylase. In addition, these phenolic compounds exhibit antioxidant anti-inflammatory activities, modulate carbohydrate and lipid metabolism, optimize oxidative stress, reduce insulin resistance, and stimulate the pancreas to secrete insulin. They also activate insulin signaling and inhibit digestive enzymes, regulate intestinal microbiota, improve adipose tissue metabolism, inhibit glucose absorption, and inhibit the formation of advanced glycation end products. However, insufficient data are available on the effective mechanisms necessary to manage diabetes.

Protective effects of curcumin on ischemia/reperfusion injury

Ischemia/reperfusion (I/R) injury is a term used to describe phenomena connected to the dysfunction of various tissue damage due to reperfusion after ischemic injury. While I/R may result in systemic inflammatory response syndrome or multiple organ dysfunction syndrome, there is still a long way to improve therapeutic outcomes. A number of cellular metabolic and ultrastructural alterations occur by prolonged ischemia. Ischemia increases the expression of proinflammatory gene products and bioactive substances within the endothelium, such as cytokines, leukocytes, and adhesion molecules, even as suppressing the expression of other "protective" gene products and substances, such as thrombomodulin and constitutive nitric oxide synthase (e.g., prostacyclin, nitric oxide [NO]). Curcumin is the primary phenolic pigment derived from turmeric, the powdered rhizome of Curcuma longa. Numerous studies have shown that curcumin has strong antiinflammatory and antioxidant characteristics. It also prevents lipid peroxidation and scavenges free radicals like superoxide anion, singlet oxygen, NO, and hydroxyl. In our study, we highlight the mechanisms of protective effects of curcumin against I/R injury in various organs.

Chemopreventive effects of Costus comosus Linn against diethylnitrosamine-induced hepatocellular carcinoma in rats

Introduction: Costus comosus is a potential medicinal plant used traditionally to treat various ailments. The present study aimed to evaluate antioxidant status, lipid peroxidation, and the ameliorative effect of its ethanolic leaf extract against diethylnitrosamine (DEN)-induced hepatocellular carcinoma (HCC) in rats. Methods: HCC was induced by 0.01 % v/v DEN through the drinking water for 16 weeks. The animals were treated with ethanolic leaf extract of C. comosus (EECC) at 200 and 400 mg/kg for 16 weeks. In this study, tumour incidence, tumour volume, tumour burden, lipid peroxidation, antioxidant activity, liver marker enzymes, and histological responses were measured in the animals. At the end of the study, rats were sacrificed, their livers were removed and the levels of antioxidant enzymes were measured in the liver homogenate. Results: In DEN-treated animals, there were 100% tumour occurrences probably due to an imbalance in carcinogen metabolizing enzymes and cellular redox state. The oral administration of ethanolic leaf extract of C. comosus therapy at a dose of 200 and 400 mg/kg reduced lipid peroxide levels and restored the increased activities of liver marker enzymes and antioxidant status to near normal. The biochemical findings corroborate histological findings, indicating that the leaf extract has a significant hepatoprotective impact in a dose-dependent manner. Conclusion: The results of the present study showed the promising anti-carcinogenic effects of ethanolic leaf extract of C. comosus against the DEN-induced HCC in rats.

The Effect of Oral Nutritional Formula With Three Different Proteins on Type 2 Diabetes Mellitus in vivo

Oral nutritional (ON) products are an effective way to treat patients with type 2 diabetes mellitus (T2DM) whose gastrointestinal functions are normal. The influence of ON formula prepared with three different proteins on T2DM was studied. The hyperglycaemic mouse model using a high-fat diet (HFD) combined with an intraperitoneal injection of streptozotocin (STZ) was used to simulate T2DM. The study was done for 15 weeks using seven groups of mice: control group (CG, normal mice, and normal food), non-treated group (BG, diabetic mice, and normal food), positive control group (PG, diabetic mice, and HFD), soybean protein group (SPG, diabetic mice, and HFD), silkworm pupa protein group (SPPG, diabetic mice, and HFD), whey protein group (LPG, diabetic mice, and HFD), and whey protein combined with silkworm pupa protein group (LCSSPG, diabetic mice, and HFD). The plasma levels of total cholesterol (TC), triglycerides (TG), low-density lipoprotein cholesterol (LDL-C), and high-density lipoprotein cholesterol (HDL-C) were analyzed on weeks 2, 10, 12, 14, and 15. The concentration of total protein (TP) and albumin (ALB) of the plasma was increased in SPG, SPPG, and PG comparing with BG (p < 0.05). The TC, TG, and LDL-C levels were decreased, and HDL-C level was increased in SPG, PG, SPPG, PG comparing with BG (p < 0.05). Blood glucose (BLG) levels were decreased 47, 34, 24, and 21% in SPG, LCSSPG, SPPG, and PG, respectively. While BLG was not significantly changed (p ≥ 0.05) in LG after 5 weeks of treatment. Overall, the data suggested that consumption of SP, SPP, LCSSPG Oral-formula may be beneficial for the treatment of T2DM.

Tetrahydrocurcumin protects against sepsis-induced acute kidney injury via the SIRT1 pathway

Sepsis-induced acute kidney injury (AKI) continues to be associated with poor outcomes in critical care patients. Previous research has revealed that tetrahydrocurcumin (THC) exerts renoprotective effects in multiple nephritic disorders by modulating inflammation and oxidative stress. However, the effects of THC on sepsis-induced AKI and the underlying mechanisms remain unclear. In this study, a mouse model of sepsis-induced AKI, generated by cecal ligation and puncture operation, was used to investigate the protective effects of THC and the role of SIRT1. Histological manifestation and TUNEL analysis were observed to determine the severity of kidney damage. Levels of BUN, SCr, KIM-1, and UAlb/Cr were calculated to assess the renal function. Expressions of IL-1β, IL-6, and TNF-α were measured to evaluate the inflammatory response. MDA content, SOD, GSH, CAT, and GPx activities and DHE staining were analyzed to estimate the degree of oxidative stress. Protein expressions of SIRT1, Ac-p65, and Ac-foxo1 were detected to explore the underlying mechanisms. We observed that THC not only increased the survival rate, improved the kidney function and ameliorated the renal histological damage of septic mice, but also inhibited inflammatory response, prohibited oxidative stress, and prevented cell apoptosis in renal tissues in septic mice. Mechanistically, THC remarkably increased the expression of SIRT1, accompanied by decreased expressions of downstream molecules Ac-p65 and Ac-foxo1. Meanwhile, the beneficial effects of THC were clearly abolished by the SIRT1-specific inhibitor EX527. These results delineate that THC prevents sepsis-induced AKI by suppressing inflammation and oxidative stress through activating the SIRT1 signaling.

Abbreviation: Ac-p65: acetylated p65; Ac-foxo 1: acetylated forkhead box O1; AKI: acute kidney injury; BUN: blood urea nitrogen; CAT: catalase; DHE: dihydroethidium; GPx: glutathione peroxidase; GSH: reduced glutathione; IL-1β: Interleukin-1 beta; IL-6: Interleukin-6; KIM-1: kidney injury molecule 1; MDA: malondialdehyde; SCr: serum creatinine; SIRT1: silent information regulator 1; SOD: superoxide dismutase; THC: tetrahydrocurcumin; TNF-α: tumor necrosis factor-alpha; TUNEL: TdT-mediated dUTP Nick-End Labeling; UAlb/Cr: urine micro albumin/creatinine.

An Update on the Pharmacological Usage of Curcumin: Has it Failed in the Drug Discovery Pipeline?

The pharmacological propensities of curcumin have been reported in a plethora of pre-clinical and clinical studies. However, innate attributes account for extremely low oral bioavailability which impedes its development as a therapeutic agent. Regardless, these drawbacks have not deterred researchers from optimizing its potentials. This review discussed the pharmacokinetic properties of curcumin relative to its outlook as a lead compound in drug discovery. Also, we highlighted therapeutic strategies that have expedited improvements in curcumin oral bioavailability and delivery to target sites over the years. Recent implementations of these strategies were also covered. More research efforts should be directed towards investigating the pharmacokinetic impacts of these novel curcumin formulations in human clinical studies since inter-species disparities could limit the accuracies of animal studies. We envisaged that integrative-clinical research would help determine 'actual' improvements in curcumin pharmacokinetics coupled with suitable administrative routes, optimal dosing, and drug-enzyme or drug-drug interactions. In addition, this could help determine formulations for achieving higher systemic exposure of parent curcumin thereby providing a strong impetus towards the development of curcumin as a drug candidate in disease treatment.

Curcumin therapy to treat vascular dysfunction in children and young adults with autosomal dominant polycystic kidney disease: Design and baseline characteristics of participants

Although often considered to be a disease of adults, complications of autosomal dominant polycystic kidney disease (ADPKD) begin in childhood. While the hallmark of ADPKD is the development and continued growth of multiple renal cysts that ultimately result in loss of kidney function, cardiovascular complications are the leading cause of death among affected patients. Vascular dysfunction (endothelial dysfunction and large elastic artery stiffness) is evident very early in the course of the disease and appears to involve increased oxidative stress and inflammation. Treatment options to prevent cardiovascular disease in adults with ADPKD are limited, thus childhood may represent a key therapeutic window. Curcumin is a safe, naturally occurring polyphenol found in the Indian spice turmeric. This spice has a unique ability to activate transcription of key antioxidants, suppress inflammation, and reduce proliferation. Here we describe our ongoing randomized, placebo-controlled, double-blind clinical trial to assess the effect of curcumin therapy on vascular function and kidney growth in 68 children and young adults age 6–25 years with ADPKD. Baseline demographic, vascular, and kidney volume data are provided. This study has the potential to establish a novel, safe, and facile therapy for the treatment of arterial dysfunction, and possibly renal cystic disease, in an understudied population of children and young adults with ADPKD.

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Evaluating a strategy to intervene early in the course of ADPKD.

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Assessing two major contributors to arterial dysfunction and CVD risk in ADPKD.

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Curcumin is a novel nutraceutical that is an safe, naturally occurring, and facile.

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Using a translational approach is used to assess physiological mechanisms.

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Gaining exploratory evidence on the efficacy of curcumin to slow kidney growth.

Formulation of More Efficacious Curcumin Delivery Systems Using Colloid Science: Enhanced Solubility, Stability, and Bioavailability

Curcumin is a bioactive constituent isolated from turmeric that has historically been used as a seasoning, pigment, and herbal medicine in food. Recently, it has become one of the most commonly studied nutraceuticals in the pharmaceutical, supplement, and food areas because of its myriad of potential health benefits. For instance, it is claimed to exhibit antioxidant, anti-inflammatory, antimicrobial, antiparasite, and anticancer activities when ingested as a drug, supplement, or food. Toxicity studies suggest that it is safe to consume, even at relatively high levels. Its broad-spectrum biological activities and low toxicity have meant that it has been widely explored as a nutraceutical ingredient for application in functional foods. However, there are several hurdles that formulators must overcome when incorporating curcumin into commercial products, such as its low water solubility (especially under acidic and neutral conditions), chemical instability (especially under neutral and alkaline conditions), rapid metabolism by enzymes in the human body, and limited bioavailability. As a result, only a small fraction of ingested curcumin is actually absorbed into the bloodstream. These hurdles can be at least partially overcome by using encapsulation technologies, which involve trapping the curcumin within small particles. Some of the most commonly used edible microparticles or nanoparticles utilized for this purpose are micelles, liposomes, emulsions, solid lipid particles, and biopolymer particles. Each of these encapsulation technologies has its own benefits and limitations for particular product applications and it is important to select the most appropriate one.

Impact of curcumin treatment on diabetic albino rats

The current study was aimed to study the effect of curcumin on the expression levels of brain glucose transporter 1 protein (GLUT1) and femoral muscle glucose transporter 4 protein (GLUT4), in addition to study its possible therapeutic role in ameliorating insulin resistance and the metabolic disturbance in the obese and type 2 diabetic male albino Wistar rat model. Diabetes was induced by a high-fat (HF) diet with low dose streptozotocin (STZ). Curcumin was administered intragastrically for 8 weeks (80 mg/kg BW/day). The HF-diet group developed obesity, hyperglycemia, hyperinsulinemia, reduced liver glycogen content with significant dyslipidemia. In the diabetic control group, hyperglycemia and insulin resistance high calculated homeostasis model assessment (HOMA-IR-index score) were pronounced, with reductions in liver and muscle glycogen contents, concomitant with dyslipidemia and significantly elevated malondialdehyde levels in liver and pancreas. GLUT1 and GLUT4 were down-regulated in the obese and the diabetic control groups, respectively. Curcumin, showed glucose-lowering effect and decreased insulin resistance, dyslipidemia and malondialdehyde levels in both tissues, it increased liver & muscle glycogen contents, compared to the diabetic control. Curcumin significantly up-regulated GLUT4 gene expression, compared to the diabetic control group. In conclusions, these results indicate a therapeutic role of curcumin in improving the diabetic status, obesity and enhancing the expression of GLUT4 gene.

Chronic treatment of curcumin improves hepatic lipid metabolism and alleviates the renal damage in adenine-induced chronic kidney disease in Sprague-Dawley rats

Background

Chronic kidney disease (CKD), including nephrotic syndrome, is a major cause of cardiovascular morbidity and mortality. The literature indicates that CKD is associated with profound lipid disorders due to the dysregulation of lipoprotein metabolism which progresses kidney disease. The objective of this study is to evaluate the protective effects of curcumin on dyslipidaemia associated with adenine-induced chronic kidney disease in rats.

Methods

Male SD rats (n = 29) were divided into 5 groups for 24 days: normal control (n = 5, normal diet), CKD control (n = 6, 0.75% w/w adenine-supplemented diet), CUR 50 (n = 6, 50 mg/kg/day curcumin + 0.75% w/w adenine-supplemented diet), CUR 100 (n = 6, 100 mg/kg/day curcumin + 0.75% w/w adenine-supplemented diet), and CUR 150 (n = 6, 150 mg/kg/day curcumin + 0.75% w/w adenine-supplemented diet). The serum and tissue lipid profile, as well as the kidney function test, were measured using commercial diagnostic kits.

Results

The marked rise in total cholesterol, low-density lipoprotein (LDL) cholesterol, very low-density lipoprotein (VLDL) cholesterol, triglycerides and free fatty acids in serum, as well as hepatic cholesterol, triglyceride and free fatty acids of CKD control rats were significantly protected by curcumin co-treatment (at the dose of 50, 100 and 150 mg/kg). Furthermore, curcumin significantly increased the serum high-density lipoprotein (HDL) cholesterol compared to the CKD control rats but did not attenuate the CKD-induced weight retardation. Mathematical computational analysis revealed that curcumin significantly reduced indicators for the risk of atherosclerotic lesions (atherogenic index) and coronary atherogenesis (coronary risk index). In addition, curcumin improved kidney function as shown by the reduction in proteinuria and improvement in creatinine clearance.

Conclusion

The results provide new scientific evidence for the use of curcumin in CKD-associated dyslipidaemia and substantiates the traditional use of curcumin in preventing kidney damage.

Curcumin: Biological, Pharmaceutical, Nutraceutical, and Analytical Aspects

Turmeric is a curry spice that originated from India, which has attracted great interest in recent decades because it contains bioactive curcuminoids (curcumin, demethoxycurcumin, and bisdemethoxycurcumin). Curcumin (1,7-bis-(4-hydroxy-3-methoxyphenyl)-hepta-1,6-diene-3,5-dione), a lipophilic polyphenol may work as an anticancer, antibiotic, anti-inflammatory, and anti-aging agent as suggested by several in vitro, in vivo studies and clinical trials. However, poor aqueous solubility, bioavailability, and pharmacokinetic profiles limit curcumin’s therapeutic usage. To address these issues, several curcumin formulations have been developed. However, suboptimal sample preparation and analysis methodologies often hamper the accurate evaluation of bioactivities and their clinical efficacy. This review summarizes recent research on biological, pharmaceutical, and analytical aspects of the curcumin. Various formulation techniques and corresponding clinical trials and in vivo outcomes are discussed. A detailed comparison of different sample preparation (ultrasonic, pressurized liquid extraction, microwave, reflux) and analytical (FT-IR, FT-NIR, FT-Raman, UV, NMR, HPTLC, HPLC, and LC-MS/MS) methodologies used for the extraction and quantification of curcuminoids in different matrices, is presented. Application of optimal sample preparation, chromatographic separation, and detection methodologies will significantly improve the assessment of different formulations and biological activities of curcuminoids.

The effects of delta-9-tetrahydrocannabinol on Krüppel-like factor-4 expression, redox homeostasis, and inflammation in the kidney of diabetic rat

Diabetes mellitus is a complex, multifactorial disorder that is attributed to pancreatic β cell dysfunction. Pancreatic β cell dysfunction results in declining utilization of glucose by peripheral tissues as kidney and it leads to nephropathy. Excessive production and accumulation of free radicals and incapable antioxidant defense system lead to impaired redox status. Macromolecular damage may occur due to impaired redox status and also immune imbalance. Δ9-Tetrahydrocannabinol (THC) is the main active ingredient in cannabis. THC acts as an immunomodulator and an antioxidant agent. Our aim was to evaluate the effects of THC in the diabetic kidney. We analyzed macromolecular damage biomarkers as protein carbonyl (PCO), lipid hydroperoxide (LHP), malondialdehyde (MDA), 8-hydroxy-2'-deoxyguanosine (8-OHdG), and antioxidant defense system biomarkers as thiol fractions (T-SH, NP-SH, P-SH) and Cu/Zn-superoxide dismutase activity for the antioxidative effects of THC. Furthermore, mRNA expression of Krüppel-like factor-4, secreted immunopositive cell number changes of interleukin-6, nuclear factor κβ (NF-κβ), and peroxisome proliferator-activated receptor-γ and tumor necrosis factor α (TNF-α) levels were analyzed for the immunomodulatory activity of THC. Diabetic rats showed significantly increased levels of PCO, LHP, MDA, and 8-OHdG when compared with controls (P < 0.05 for each parameter). THC significantly reduced the elevated levels of PCO and 8-OHdG (P < 0.05 for both parameters) and also LHP and MDA levels were insignificantly reduced by THC. Also, thiol fractions insignificantly increased in THC administered diabetic kidney when compared with diabetic rats. The NF-κβ cell number significantly decreased in the diabetic rats treated with THC compared with the diabetic group. According to our data, THC has ameliorative effects on the impaired redox status of diabetic kidney and also it acts as an immunomodulator. Therefore, THC might be used as a therapeutic agent for diabetic kidneys but its usage in the healthy kidney may show adverse effects.

Tetrahydrocurcumin Ameliorates Diabetic Cardiomyopathy by Attenuating High Glucose-Induced Oxidative Stress and Fibrosis via Activating the SIRT1 Pathway

Hyperglycemia-induced oxidative stress and fibrosis play a crucial role in the development of diabetic cardiomyopathy (DCM). Tetrahydrocurcumin (THC), a major bioactive metabolite of natural antioxidant curcumin, is reported to exert even more effective antioxidative and superior antifibrotic properties as well as anti-inflammatory and antidiabetic abilities. This study was designed to investigate the potential protective effects of THC on experimental DCM and its underlying mechanisms, pointing to the role of high glucose-induced oxidative stress and interrelated fibrosis. In STZ-induced diabetic mice, oral administration of THC (120 mg/kg/d) for 12 weeks significantly improved the cardiac function and ameliorated myocardial fibrosis and cardiac hypertrophy, accompanied by reduced reactive oxygen species (ROS) generation. Mechanically, THC administration remarkably increased the expression of the SIRT1 signaling pathway both in vitro and in vivo, further evidenced by decreased downstream molecule Ac-SOD2 and enhanced deacetylated production SOD2, which finally strengthened antioxidative stress capacity proven by repaired activities of SOD and GSH-Px and reduced MDA production. Additionally, THC treatment accomplished its antifibrotic effect by depressing the ROS-induced TGFβ1/Smad3 signaling pathway followed by reduced expression of cardiac fibrotic markers α-SMA, collagen I, and collagen III. Collectively, these finds demonstrated the therapeutic potential of THC treatment to alleviate DCM mainly by attenuating hyperglycemia-induced oxidative stress and fibrosis via activating the SIRT1 pathway.

Tetrahydrocurcumin and octahydrocurcumin, the primary and final hydrogenated metabolites of curcumin, possess superior hepatic-protective effect against acetaminophen-induced liver injury: Role of CYP2E1 and Keap1-Nrf2 pathway

Acetaminophen (APAP) overdose-induced hepatotoxicity is tightly associated with oxidative stress. Tetrahydrocurcumin (THC) and octahydrocurcumin (OHC), the primary and final hydrogenated metabolites of curcumin (CUR), possess stronger antioxidant activity in vitro. The present study was performed to investigate the potential and mechanism of OHC and THC against APAP-induced hepatotoxicity in parallel to CUR. Our results showed that OHC and THC dose-dependently enhanced liver function (ALT and AST levels) and alleviated histopathological deterioration. Besides, OHC and THC significantly restored the hepatic antioxidant status by miring level of MDA and ROS, and elevated levels of GSH, SOD, CAT and T-AOC. In addition, OHC and THC markedly suppressed the activity and expressions of CYP2E1, and bound to the active sites of CYP2E1. Moreover, OHC and THC activated the Keap1-Nrf2 pathway and enormously enhanced the translational activation of Nrf2-targeted gene (GCLC, GCLM, NQO1 and HO-1) against oxidative stress, via inhibiting the expression of Keap1 and blocking the interaction between Keap1 and Nrf2. Particularly, OHC and THC exerted superior hepato-protective and antioxidant activities to CUR. In conclusion, OHC and THC possess favorable hepato-protective effect through restoring antioxidant status, inhibiting CYP2E1 and activating Keap1-Nrf2 pathway, which might represent promising antioxidants for the treatment of APAP-induced hepatotoxicity.

A novel bioavailable hydrogenated curcuminoids formulation (CuroWhite™) improves symptoms and diagnostic indicators in rheumatoid arthritis patients - A randomized, double blind and placebo controlled study

Rheumatoid arthritis (RA) is an inflammatory disease that cause chronic pain, disability and joint destruction. The present placebo controlled randomized study aimed to evaluate the efficacy of a novel hydrogenated curcuminoid formulation-CuroWhite™, in rheumatoid arthritis (RA) patients. Twenty four RA patients were randomized in 1:1:1 ratio to receive 250 mg, 500 mg CuroWhite or placebo as one capsule a day, over a period of three months. Improvement in the ACR response, changes in disease activity assessed using the DAS 28 score, change in physical function assessed on change in ESR, CRP, RF values were evaluated before and after the study. Results suggested that patients who received CuroWhite both low and high doses reported statistically significant changes in their clinical symptoms towards end of the study when compared with placebo. There were significant changes in DAS28 (50–64%) VAS (63–72%) ESR (88–89%), CRP (31–45%) RF (80–84%) values and ACR response for CuroWhite groups in comparison with placebo. Thus, CuroWhite acts as the analgesic and anti-inflammatory product for management of RA by the reduction of the inflammatory action which was confirmed by improvement in ESR, CRP, VAS, RF, DAS-28 and ACR responses. CuroWhite was significantly effective against RA with highly safe without serious side effects and well tolerated.

Attenuation of diethylnitrosamine (DEN) - Induced hepatic cancer in experimental model of Wistar rats by Carissa carandas embedded silver nanoparticles

OBJECTIVE

Hepatic cancer is well known, and leading cancer around the world and remain asymptomatic diseases. Carissa carandas possess anti-proliferative, antioxidant, hepatoprotective property and used in hepatic cancer. The current study deals to evaluate the chemoprotective and therapeutic property of Carissa carandas embedded silver nanoparticles (CCAgNPs) against diethylnitrosamine (DEN) -induced hepatic cancer.

MATERIAL AND METHOD

Wistar rats were divided into six groups and hepatic cancer was induced with diethylnitrosamine at the dose of 200 mg/kg BW. The animals were gastrogavaged with standard drug and CCAgNPs for 16 weeks. Serum biomarkers, haematological profile, antioxidants enzymes, inflammatory markers and membrane bound enzymes were assessed to find the anti-proliferative potential of silver nanoparticles. Histological evaluation and microscopic characterizations were also performed to authenticate the outcomes of the present work.

RESULTS

Biosynthesized CCAgNPs significantly down-regulated the serum marker enzymes of hepatic and non-hepatic parameter, elevated the levels of enzymatic and non-enzymatic antioxidant profile, elevation in membrane bound enzymes and diminish the levels of inflammatory markers (IL-6, TNF-α, and IL-1β) via NF-κB pathway. Histopathological features also showed recovery of a hepatic architecture in cancer-induced rats in a dose-dependent manner.

CONCLUSION

Our consequences established that such plant mediated silver nanoparticles shown a defensive impact against DEN-induced hepatocarcinogenesis, and serves as a better option to ameliorate the clinical results against hepatocellular carcinoma.

Spice-Derived Bioactive Ingredients: Potential Agents or Food Adjuvant in the Management of Diabetes Mellitus

Spices possess tremendous therapeutic potential including hypoglycemic action, attributed to their bioactive ingredients. However, there is no study that critically reviewed the hypoglycemic potency, safety and the bioavailability of the spice-derived bioactive ingredients (SDBI). Therefore, the aim of the study was to comprehensively review all published studies regarding the hypoglycemic action of SDBI with the purpose to assess whether the ingredients are potential hypoglycemic agents or adjuvant. Factors considered were concentration/dosages used, the extent of blood glucose reduction, the IC50 values, and the safety concern of the SDBI. From the results, cinnamaldehyde, curcumin, diosgenin, thymoquinone (TQ), and trigonelline were showed the most promising effects and hold future potential as hypoglycemic agents. Conclusively, future studies should focus on improving the tissue and cellular bioavailability of the promising SDBI to achieve greater potency. Additionally, clinical trials and toxicity studies are with these SDBI are warranted.

Therapeutic effects of balanitoside in streptozotocin-induced diabetic rats

OBJECTIVES

The objective of this study was to evaluate the therapeutic effects of balanitoside in diabetic rats.

METHODS

Twenty-five rats were divided into five groups. Rats in groups 2 to 5 were treated with streptozotocin to induce hyperglycemia. In addition, rats in groups 1 and 2 received 1 mL of distilled water, whereas those in groups 3, 4, and 5 received 10 and 20 mg/kg balanitoside and 6 U/kg insulin, respectively, for 14 days. All rats were sacrificed on day 15, blood samples were collected, and serum levels of alkaline phosphatase (ALP), alanine aminotransferase (ALT), and aspartate aminotransferase (AST) were measured. The liver was processed for examination under a light microscope.

RESULTS

The results showed a significant decrease in liver protein concentrations in diabetic control rats, compared to those in the normal control rats and rats treated with 10 mg/kg balanitoside (p < 0.05). There was no significant difference in ALP levels among all groups. However, a significant increase in ALT and AST levels was observed in the diabetic control rats, compared to those in the normal control rats (p < 0.05). Photomicrographs of the liver of the diabetic control rats showed fat and glycogen droplets, vacuolated nuclei, and loss of cellular boundaries, whereas those of the rats treated with balanitoside or insulin showed a small amount of microvesicular fat droplets and slight infiltration of lymphocytes.

CONCLUSION

The findings of this study suggest the therapeutic effects of balanitoside in the liver of diabetic rats.

Tetrahydrocurcumin ameliorates free fatty acid-induced hepatic steatosis and improves insulin resistance in HepG2 cells

Elevated levels of free fatty acids (FFAs) in the liver, resulting from either increased lipolysis or imbalanced FFAs flux, is a key pathogenic factor of hepatic steatosis. This study was conducted to examine the therapeutic effect of tetrahydrocurcumin (THC), a naturally occurring curcuminoid and a metabolite of curcumin, on oleic acid (OA)-induced steatosis in human hepatocellular carcinoma cells and to elucidate the underlying mechanism. HepG2 cells were incubated with OA to induce steatosis, and then treated with various concentrations of THC. The results showed that THC treatment significantly decreased lipid accumulation in OA-treated HepG2 cells, possibly, by inhibiting the expression of the lipogenic proteins, sterol regulatory element-binding protein 1 (SREBP-1c), peroxisome proliferator-activated receptor gamma (PPARγ), fatty acid synthase (FAS), and fatty acid-binding protein 4 (FABP4). Moreover, THC attenuated OA-induced hepatic lipogenesis in an adenosine monophosphate–activated protein kinase (AMPK)-dependent manner, which was reversed by pretreatment with an AMPK inhibitor. THC promoted lipolysis and upregulated the expression of genes involved in β-oxidation. Glucose uptake and insulin signaling impaired in HepG2 cells incubated with OA were abated by THC treatment, including phosphorylation of the insulin receptor substrate 1 (IRS-1)/phosphoinositide 3-kinase (PI3K)/Akt and downstream signaling pathways, forkhead box protein O1 (FOXO1) and glycogen synthase kinase 3 β (GSK3β), which are involved in gluconeogenesis and glycogen synthesis, respectively. Altogether, these results demonstrated the novel therapeutic benefit of THC against hepatic steatosis and, consequently, a potential treatment for non-alcoholic fatty liver disease (NAFLD).

Dietary tetrahydrocurcumin reduces renal fibrosis and cardiac hypertrophy in 5/6 nephrectomized rats

Tetrahydrocurcumin (THC) is the principal metabolite of curcumin and has antioxidant properties. In the present investigation, the effect of THC on renal and cardiovascular outcomes was studied in rats with chronic kidney disease (CKD). CKD rats were randomized following 5/6 nephrectomy to a special diet for 9 weeks which contained 1% THC (CKD+THC group). Low-dose polyenylphosphatidylcholine was used as a lipid carrier to increase bioavailability. Endpoints included tail blood pressure, normalized heart weight, plasma and urine biochemical data, and kidney tissue analyses. CKD animals demonstrated increased proteinuria, decreased creatinine clearance, hypertension, and cardiac hypertrophy. The antioxidant proteins CuZn SOD and glutathione peroxidase were decreased in the remnant kidney, while apoptosis (caspase-3) and fibrosis (alpha-SM actin) were increased. Renal fibrosis was confirmed histologically on trichrome staining. These pathologic changes were ameliorated in the CKD+THC group with significant decrease in proteinuria, hypertension, and kidney fibrosis. THC therapy restored levels of CuZn SOD and glutathione peroxidase. Consistent with prior reports, dietary THC did not improve nuclear Nrf2 levels. In summary, dietary THC therapy improved expression of antioxidant proteins in the remnant kidney, decreased renal fibrosis and proteinuria, and ameliorated hypertension in 5/6 nephrectomized rats.

Vitamin K2 alleviates type 2 diabetes in rats by induction of osteocalcin gene expression

OBJECTIVES

The biological mechanisms behind the association between vitamin K (Vit K) and glucose metabolism are uncertain. We aimed to analyze the expression of insulin 1 (Ins 1), insulin 2 (Ins 2) and cyclin D2, the expression of adiponectin and UCP-1 . In addition, we aimed to estimate the doses of Vit K2 able to affect various aspects of glucose and energy metabolism in type 2 diabetes.

METHODS

Thirty adult male rats were allocated equally into five groups: control group, diabetes mellitus group, and groups 3, 4, and 5, which received Vit K₂ at three daily dose levels (10, 15, and 30 mg/kg, respectively) for 8 wk. At the end of the study, blood samples were collected to quantify total osteocalcin, fasting plasma glucose, fasting insulin, and relevant variables. The expression of OC, Ins 1, Ins 2, cyclin D2, adiponectin, UCP-1 genes was analyzed by real-time polymerase chain reaction.

RESULTS

After administration of Vit K₂, a dose-dependent decrease in fasting plasma glucose, hemoglobin A1c and homeostatic model assessment method insulin resistance, and a dose-dependent increase in fasting insulin and homeostatic model assessment method β cell function levels, when compared with diabetes mellitus rats, were detected. There was significant upregulation of OC, Ins 1, Ins 2, or cyclin D2 gene expression in the three treated groups in a dose-dependent manner when compared with the diabetic rats. However, expression of adiponectin and UCP-1 were significantly increased at the highest dose (30 mg/kg daily) only.

CONCLUSIONS

Vit K₂ administration could improve glycemic status in type 2 diabetic rats by induction of OC gene expression. Osteocalcin could increase β-cell proliferation, energy expenditure, and adiponectin expression. Different concentrations of Vit K₂ were required to affect glucose metabolism and insulin sensitivity.

New Insights into the Mechanisms of Chinese Herbal Products on Diabetes: A Focus on the "Bacteria-Mucosal Immunity-Inflammation-Diabetes" Axis

Diabetes, especially type 2, has been rapidly increasing all over the world. Although many drugs have been developed and used to treat diabetes, side effects and long-term efficacy are of great challenge. Therefore, natural health product and dietary supplements have been of increasing interest alternatively. In this regard, Chinese herbs and herbal products have been considered a rich resource of product development. Although increasing evidence has been produced from various scientific studies, the mechanisms of action are lacking. Here, we have proposed that many herbal monomers and formulae improve glucose homeostasis and diabetes through the BMID axis; B represents gut microbiota, M means mucosal immunity, I represents inflammation, and D represents diabetes. Chinese herbs have been traditionally used to treat diabetes, with minimal side and toxic effects. Here, we reviewed monomers such as berberine, ginsenoside, M. charantia extract, and curcumin and herbal formulae such as Gegen Qinlian Decoction, Danggui Liuhuang Decoction, and Huanglian Wendan Decoction. This review was intended to provide new perspectives and strategies for future diabetes research and product.

Antidiabetic effects of Mangifera indica Kernel Flour-supplemented diet in streptozotocin-induced type 2 diabetes in rats

Our previous report showed that Mangifera indica kernel flour (MIKF) is a rich source of pharmacologically important flavonoids and phenolic acids; and that its methanolic extract inhibits some key enzymes linked to the pathology and complications of type 2 diabetes (T2D) in vitro. Hence, this study evaluated the antidiabetic effects of 10% and 20% MIKF-supplemented diets in T2D in rats. T2D was induced in rats using a high-fat diet (HFD), low-dose streptozotocin (HFD/STZ) model, by feeding the rats with HFD for 2 weeks followed by single dose administration of STZ (40 mg/kg body weight, intraperitoneally). The diabetic rats were later fed the MIKF-supplemented diets, or administered with metformin (25 mg/kg b.w.) for 21 days; the control rats were fed basal diet during this period. Intake of the MIKF-supplemented diets resulted in significant (P < 0.05) improvement in the fasting blood glucose, hepatic glycogen, glycosylated hemoglobin, lipid profile, plasma electrolytes, hepatic and pancreatic malonaldehyde, and the liver function markers of the diabetic rats, compared with the diabetic control rats. The ameliorative effect of 20% MIKF-supplemented was comparable (P > 0.05) with that of metformin administration in the diabetic rats. It is concluded that M. indica kernel flour has antidiabetic effects in T2D rats, and could therefore be a promising nutraceutical therapy for the management of T2D and its associated complications.

Recent Progress for the Utilization of Curcuma longa, Piper nigrum and Phoenix dactylifera Seeds against Type 2 Diabetes

Background

Diabetes mellitus is an important human disease afflicting many from various walks of life in different countries. Even though modern medicines contribute a variety of effective treatment options, they can have several unfavourable effects. The intention of this review is to organize and discuss various studies that have been previously conducted on the effectiveness of these herbal plants in diabetes.

Method

By using various electronic search databases, a comprehensive English literature search was conducted. Different search terms were used by combining all the search fields in titles, abstracts and keywords.

Results

Curcuma longa,a spice, is commonly known as turmeric and belongs to the family Zingiberaceae. Piper nigrumis also a spice, commonly called black pepper, and belongs to the family Piperaceae. Phoenix dactylifera, commonly known as date fruit, belongs to the family Arecaceae. From ancient times, they have been traditionally used for the treatment of various diseases. Among various activities, regulation of hyperglycaemia is considered one of their important effects. One of the aetiological factors implicated in the development of diabetes and its complications is the damage induced by free radicals. Antioxidant properties of antidiabetic compounds would be more beneficial. Extracts of these plants have shown hypoglycaemic and hypolipidaemic effects by the involvement of several mechanisms. In the future, further studies are needed to investigate the mechanisms involved in their hypoglycaemic potential and their active constituents as synthetic analogues.

Conclusions

This review focusses on some medicinal plants that have antidiabetic effect, thus contributing to the reduction of risk factors associated with diabetes, and related beneficial effects are compiled.

The beneficial role of curcumin on inflammation, diabetes and neurodegenerative disease: A recent update

The concept of using phytochemicals has ushered in a new revolution in pharmaceuticals. Naturally occurring polyphenols (like curcumin, morin, resveratrol, etc.) have gained importance because of their minimal side effects, low cost and abundance. Curcumin (diferuloylmethane) is a component of turmeric isolated from the rhizome of Curcuma longa. Research for more than two decades has revealed the pleiotropic nature of the biological effects of this molecule. More than 7000 published articles have shed light on the various aspects of curcumin including its antioxidant, hypoglycemic, anti-inflammatory and anti-cancer activities. Apart from these well-known activities, this natural polyphenolic compound also exerts its beneficial effects by modulating different signalling molecules including transcription factors, chemokines, cytokines, tumour suppressor genes, adhesion molecules, microRNAs, etc. Oxidative stress and inflammation play a pivotal role in various diseases like diabetes, cancer, arthritis, Alzheimer's disease and cardiovascular diseases. Curcumin, therefore, could be a therapeutic option for the treatment of these diseases, provided limitations in its oral bioavailability can be overcome. The current review provides an updated overview of the metabolism and mechanism of action of curcumin in various organ pathophysiologies. The review also discusses the potential for multifunctional therapeutic application of curcumin and its recent progress in clinical biology.

Curcumin protects renal tubular epithelial cells from high glucose-induced epithelial-to-mesenchymal transition through Nrf2-mediated upregulation of heme oxygenase-1

Curcumin has been observed to exhibit an anti-fibrotic effect in the liver, lung and gallbladder. However, the mechanisms underlying the cytoprotective effects of curcumin remain to be elucidated. The epithelial-to-mesenchymal transition (EMT) of mature tubular epithelial cells in the kidney is considered to contribute to the renal accumulation of matrix proteins associated with diabetic nephropathy. The EMT is also closely associated with the progression of renal interstitial fibrosis and oxidative stress. This process may occur through abrogation of high glucose (HG)-induced oxidative stress via activation of nuclear factor (erythroid-derived 2)-like 2 (Nrf2) and heme oxygenase-1 (HO-1) in kidney tubular epithelial cells. In the present study, the effect of curcumin on HG-induced EMT in the NRK-52E normal rat kidney tubular epithelial cell line was investigated, and whether the effect of curcumin was mediated by the induction of Nrf2 and HO-1 expression was examined. The present study revealed that curcumin was able to prevent events associated with EMT, including the downregulation of E-cadherin and the increased expression of α-smooth muscle actin. Further analysis revealed that the expression levels of Nrf2 and HO-1 protein were elevated to a greater extent in the curcumin pretreated NRK-52E cells compared with those of the control. Notably, knockdown of Nrf2 with small interfering RNA prevented the curcumin-induced elevation in expression of HO-1 and the associated anti-fibrotic effects. In conclusion, the present findings suggested that curcumin may be significant in cellular antioxidant defense, through the activation of Nrf2 and HO-1, thereby protecting the NRK-52E cells from HG-induced EMT.

Curcumin differs from tetrahydrocurcumin for molecular targets, signaling pathways and cellular responses

Curcumin (diferuloylmethane), a golden pigment from turmeric, has been linked with antioxidant, anti-inflammatory, anticancer, antiviral, antibacterial, and antidiabetic properties. Most of the these activities have been assigned to methoxy, hydroxyl, α,β-unsaturated carbonyl moiety or to diketone groups present in curcumin. One of the major metabolites of curcumin is tetrahydrocurcumin (THC), which lacks α,β-unsaturated carbonyl moiety and is white in color. Whether THC is superior to curcumin on a molecular level is unclear and thus is the focus of this review. Various studies suggest that curcumin is a more potent antioxidant than THC; curcumin (but not THC) can bind and inhibit numerous targets including DNA (cytosine-5)-methyltransferase-1, heme oxygenase-1, Nrf2, β-catenin, cyclooxygenase-2, NF-kappaB, inducible nitric oxide synthase, nitric oxide, amyloid plaques, reactive oxygen species, vascular endothelial growth factor, cyclin D1, glutathione, P300/CBP, 5-lipoxygenase, cytosolic phospholipase A2, prostaglandin E2, inhibitor of NF-kappaB kinase-1, -2, P38MAPK, p-Tau, tumor necrosis factor-α, forkhead box O3a, CRAC; curcumin can inhibit tumor cell growth and suppress cellular entry of viruses such as influenza A virus and hepatitis C virus much more effectively than THC; curcumin affects membrane mobility; and curcumin is also more effective than THC in suppressing phorbol-ester-induced tumor promotion. Other studies, however, suggest that THC is superior to curcumin for induction of GSH peroxidase, glutathione-S-transferase, NADPH: quinone reductase, and quenching of free radicals. Most studies have indicated that THC exhibits higher antioxidant activity, but curcumin exhibits both pro-oxidant and antioxidant properties.

Piperine, a natural bioenhancer, nullifies the antidiabetic and antioxidant activities of curcumin in streptozotocin-diabetic rats

Knowing that curcumin has low bioavailability when administered orally, and that piperine has bioenhancer activity by inhibition of hepatic and intestinal biotransformation processes, the aim of this study was to investigate the antidiabetic and antioxidant activities of curcumin (90 mg/kg) and piperine (20 or 40 mg/kg), alone or co-administered, incorporated in yoghurt, in streptozotocin (STZ)-diabetic rats. The treatment for 45 days of STZ-diabetic rats with curcumin-enriched yoghurt improved all parameters altered in this experimental model of diabetes: the body weight was increased in association with the weight of skeletal muscles and white adipose tissues; the progressive increase in the glycemia levels was avoided, as well as in the glycosuria, urinary urea, dyslipidemia, and markers of liver (alanine and aspartate aminotransferases and alkaline phosphatase) and kidney (urinary protein) dysfunction; the hepatic oxidative stress was decreased, since the activities of the antioxidant enzymes superoxide dismutase, catalase and gluthatione peroxidase were increased, and the levels of malondialdehyde and protein carbonyl groups were reduced. The dose of 20 mg/kg piperine also showed antidiabetic and antioxidant activities. The treatment of STZ-diabetic rats with both curcumin and 20 mg/kg piperine in yoghurt did not change the antidiabetic and antioxidant activities of curcumin; notably, the treatment with both curcumin and 40 mg/kg piperine abrogated the beneficial effects of curcumin. In addition, the alanine aminotransferase levels were further increased in diabetic rats treated with curcumin and 40 mg/kg piperine in comparison with untreated diabetic rats. These findings support that the co-administration of curcumin with a bioenhancer did not bring any advantage to the curcumin effects, at least about the antidiabetic and antioxidant activities, which could be related to changes on its biotransformation.

The protective effect of curcumin administration on carbon tetrachloride (CCl4)-induced nephrotoxicity in rats

BACKGROUND

The aim of the present study was to examine the protective effect of curcumin (CUR) on carbon tetrachloride (CCl4)-induced nephrotoxicity to evaluate the detailed mechanisms by which CUR exerts its protective action.

METHODS

Thirty male Wistar-Albino rats weighing 250-300 g were randomly divided into three groups: administrations of olive oil (control, po), CCl4 (0.5mg/kg in olive oil sc) every other day for 3 weeks, and CCl4 (0.5mg/kg in olive oil sc) plus CUR (200mg/kg) every day for 3 weeks.

RESULTS

Administration of CCl4 significantly (p<0.001) increased the levels of renal function test such as creatinine and blood urea nitrogen (BUN). Furthermore, treatment of CCl4 significantly elevated the oxidant status of renal tissues while decreasing its anti-oxidant status (p<0.001). CUR displayed a renal protective effect as evident by significant decrease in inflammation and apoptosis during histopathological examination. The administration of CCl4 resulted in an increase in malondialdehyde (MDA) production due to an increase in membrane lipid peroxidation; however, the administration of CUR attenuated this, probably via its antioxidant and free radical scavenging properties.

CONCLUSION

The finding of our study indicates that CUR may have an important role to play in protecting the kidney from oxidative insult.

Effect of curcumin on rats/mice with diabetic nephropathy: a systematic review and meta-analysis of randomized controlled trials

OBJECTIVE

To assess the renal protective effects of curcumin administration on diabetic rats/mice.

METHODS

Databases were searched electronically and conference papers searched manually for search terms to find relevant studies. Articles were assessed independently by two reviewers. Review Manager 5.1 was used for data analysis.

RESULTS

Fourteen randomized controlled experiments were included. Meta-analysis demonstrated that blood sugar levels and kidney weight to body weight ratios in the model group were higher than those in the normal group, and the curcumin group had significantly lower mesangial area to glomerular area ratios compared with the model group, and also lower levels of urinary protein, blood urea nitrogen and serum creatinine.

CONCLUSION

Curcumin shows protective effects on the kidneys of rats/mice with diabetes.

Curcumin and diabetes: a systematic review

Turmeric (Curcuma longa), a rhizomatous herbaceous perennial plant of the ginger family, has been used for the treatment of diabetes in Ayurvedic and traditional Chinese medicine. The active component of turmeric, curcumin, has caught attention as a potential treatment for diabetes and its complications primarily because it is a relatively safe and inexpensive drug that reduces glycemia and hyperlipidemia in rodent models of diabetes. Here, we review the recent literature on the applications of curcumin for glycemia and diabetes-related liver disorders, adipocyte dysfunction, neuropathy, nephropathy, vascular diseases, pancreatic disorders, and other complications, and we also discuss its antioxidant and anti-inflammatory properties. The applications of additional curcuminoid compounds for diabetes prevention and treatment are also included in this paper. Finally, we mention the approaches that are currently being sought to generate a "super curcumin" through improvement of the bioavailability to bring this promising natural product to the forefront of diabetes therapeutics.

Renoprotective effect of the antioxidant curcumin: Recent findings

For years, there have been studies based on the use of natural compounds plant-derived as potential therapeutic agents for various diseases in humans. Curcumin is a phenolic compound extracted from Curcuma longa rhizome commonly used in Asia as a spice, pigment and additive. In traditional medicine of India and China, curcumin is considered as a therapeutic agent used in several foods. Numerous studies have shown that curcumin has broad biological functions particularly antioxidant and antiinflammatory. In fact, it has been established that curcumin is a bifunctional antioxidant; it exerts antioxidant activity in a direct and an indirect way by scavenging reactive oxygen species and inducing an antioxidant response, respectively. The renoprotective effect of curcumin has been evaluated in several experimental models including diabetic nephropathy, chronic renal failure, ischemia and reperfusion and nephrotoxicity induced by compounds such as gentamicin, adriamycin, chloroquine, iron nitrilotriacetate, sodium fluoride, hexavalent chromium and cisplatin. It has been shown recently in a model of chronic renal failure that curcumin exerts a therapeutic effect; in fact it reverts not only systemic alterations but also glomerular hemodynamic changes. Another recent finding shows that the renoprotective effect of curcumin is associated to preservation of function and redox balance of mitochondria. Taking together, these studies attribute the protective effect of curcumin in the kidney to the induction of the master regulator of antioxidant response nuclear factor erythroid-derived 2 (Nrf2), inhibition of mitochondrial dysfunction, attenuation of inflammatory response, preservation of antioxidant enzymes and prevention of oxidative stress. The information presented in this paper identifies curcumin as a promising renoprotective molecule against renal injury.

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Curcumin prevents mitochondrial dysfunction in nephrotoxicity.

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Curcumin prevents renal hemodynamic alterations in chronic renal failure.

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Curcumin is a therapeutic agent in chronic renal failure.

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Curcumin induces renal Nrf2 translocation.

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Curcumin is an antiinflammatory agent in renal injury.

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

Curcumin (diferuloylmethane) is the yellow-orange pigment of dried Curcuma longa L. rhizomes (turmeric). During the past two decades, there has been a large volume of published studies describing the biological and pharmacological properties of this phytochemical including anticancer, anti-inflammatory, antioxidant, antithrombotic, antiatherosclerotic, cardioprotective, neuroprotective, memory enhancing, antiparkinsonism, antirheumatic, anti-infectious, antiaging, antipsoriatic, and anticonvulsant activities. In addition, curcumin has been shown to be extremely safe and interact with multiple molecular targets that are involved in the pathogenesis of metabolic syndrome. Curcumin could favorably affect all leading components of metabolic syndrome including insulin resistance, obesity, hypertriglyceridemia, decreased HDL-C and hypertension, and prevent the deleterious complications of MetS including diabetes and cardiovascular disease. Owing to its antioxidant and anti-inflammatory properties, curcumin can also exert several pleiotropic effects and improve endothelial dysfunction, adipokine imbalances, and hyperuricemia which usually accompany MetS. Despite the potential tremendous benefit of this multifaceted phytopharmaceutical, no trial result has yet been publicized on this issue. This review seeks to briefly summarize the ample scientific evidence that supports the therapeutic efficacy of curcumin, at least as an adjunctive treatment, in patients with MetS.

Sustained delivery of IL-1Ra from PF127-gel reduces hyperglycemia in diabetic GK-rats

Interleukin-1beta (IL-1β) is a major cause for induction of various inflammatory mechanisms that are decisively involved to provoke pathogenesis of type 2 diabetes mellitus (T2DM). Interleukin-1 receptor antagonist (IL-1Ra) a naturally occurring anti-inflammatory antagonist of IL-1β has been recently approved for treatment of T2DM but due to its short half-life, higher doses and frequent dosing intervals are required. Pluronic F-127 (PF127) has previously shown to prolong the release of various proteinous drugs and their serum half-lives. Subsequently, in our previous work, we developed a new dosage form of IL-1Ra using PF127 and investigated its in-vitro and in-vivo effects. Here in present work, we have extended this approach using diabetic Goto-kakizaki (GK) rats. We administered IL-1Ra loaded in PF127 gel subcutaneously for one month into GK rats. IL-1Ra loaded in PF127 gel exhibited a sustained and prolonged hypoglycemic effects on treated animals. Intraperitoneal glucose tolerance test (IPGTT) results showed that IL-1Ra loaded in PF127 gel increased glucose tolerance along with increased insulin sensitivity and β-cell’s secretory function in treated rats. Moreover, significant reduction in pro-insulin/insulin ratio, lipid profiles and interleukin 6 (IL-6) were also observed. Immunohistochemical analysis showed slight macrophages infiltration in pancreatic islets. Histochemical analysis revealed no PF127-induced alteration in the normal physiology of skin and kidney of treated animals. Hence, we concluded that IL-1Ra loaded in PF127 gel has potential to exhibit broad spectrum anti-inflammatory effects alleviating the symptoms of T2DM.

Natural polyphenols in cancer therapy

Natural polyphenols are secondary metabolites of plants involved in defense against different types of stress. Extracts containing these compounds have been used for thousands of years in traditional eastern medicine. Polyphenols act on multiple targets in pathways and mechanisms related to carcinogenesis, tumor cell proliferation and death, inflammation, metastatic spread, angiogenesis, or drug and radiation resistance. Nevertheless, reported effects claimed for polyphenols are controversial, since correlations between in vitro effects and in vivo evidence are poorly established. The main discrepancy between health claims versus clinical observations is the frequent use of nonphysiologically relevant concentrations of these compounds and their metabolites in efficacy and mechanistic studies. The present review will discuss how in vivo administration correlates with polyphenol metabolism, toxicity, and bioavailability. Analysis of the general application of polyphenols in cancer therapy will be complemented by potential applications in the therapy of specific tumors, including melanoma, colorectal and lung cancers. Possible pharmaceutical formulations, structural modifications, combinations, and delivery systems aimed to increase bioavailability and/or biological effects will be discussed. Final remarks will include recommendations for future research and developments.

Curcumin ameliorates renal failure in 5/6 nephrectomized rats: role of inflammation

TNF-α and NF-κB play important roles in the development of inflammation in chronic renal failure (CRF). In hepatic cells, curcumin is shown to antagonize TNF-α-elicited NF-κB activation. In this study, we hypothesized that if inflammation plays a key role in renal failure then curcumin should be effective in improving CRF. The effectiveness of curcumin was compared with enalapril, a compound known to ameliorate human and experimental CRF. Investigation was conducted in Sprague-Dawley rats where CRF was induced by 5/6 nephrectomy (Nx). The Nx animals were divided into untreated (Nx), curcumin-treated (curcumin), and enalapril-treated (enalapril) groups. Sham-operated animals served as a control. Renal dysfunction in the Nx group, as evidenced by elevated blood urea nitrogen, plasma creatinine, proteinuria, segmental sclerosis, and tubular dilatation, was significantly reduced by curcumin and enalapril treatment. However, only enalapril significantly improved blood pressure. Compared with the control, the Nx animals had significantly higher plasma and kidney TNF-α, which was associated with NF-κB activation and macrophage infiltration in the kidney. These changes were effectively antagonized by curcumin and enalapril treatment. The decline in the anti-inflammatory peroxisome proliferator-activated receptor γ (PPARγ) seen in Nx animals was also counteracted by curcumin and enalapril. Studies in mesangial cells were carried out to further establish that the anti-inflammatory effect of curcumin in vivo was mediated essentially by antagonizing TNF-α. Curcumin dose dependently antagonized the TNF-α-mediated decrease in PPARγ and blocked transactivation of NF-κB and repression of PPARγ, indicating that the anti-inflamatory property of curcumin may be responsible for alleviating CRF in Nx animals.

Prophylactic role of curcumin in dextran sulfate sodium (DSS)-induced ulcerative colitis murine model

We have addressed in this study the possible protective role of the main principle of turmeric pigment; curcumin on a murine model of ulcerative colitis (UC). Colitis was induced by administration of dextran sulfate sodium (DSS) (3% W/V) in drinking water to male Swiss albino rats for 5 consecutive days. DSS challenge induced UC model that was well characterized morphologically and biochemically. DSS produced shrinkage of colon length and increased the relative colon weight/length ratio accompanied by mucosal edema and bloody stool. Histologically, DSS produced submucosal erosions, ulceration, inflammatory cell infiltration and crypt abscess as well as epithelioglandular hyperplasia. The model was confirmed biochemically, and the test battery entailed elevated serum tumor necrosis factor (TNF-alpha) and colonic activity of myleoperoxidase (MPO). Colonic glutathione-S-transferase (GST) activity and its substrate concentration; GSH, were notably reduced, while lipid peroxidation, expressed as malondialdehyde (MDA) level, and total nitric oxide (NO) were significantly increased. Prior administration of curcumin (100mg/kg, IP) for 7 consecutive days ahead of DSS challenge mitigated the injurious effects of DSS and ameliorated all the altered biochemical parameters. These results suggest that curcumin could possibly have a protective role in ulcerative colitis probably via regulation of oxidant/anti-oxidant balance and modulation of the release of some inflammatory endocoids, namely TNF-alpha and NO.