Inhibitory effect on protein kinase Ctheta by Crocetin attenuates palmitate-induced insulin insensitivity in 3T3-L1 adipocytes

The Therapeutic Role of Saffron and Its Components Mediated Through Nrf2 in Diabetes and Related Pathologies

Today, diabetes is considered a growing global epidemic. In the diabetic environment, a large amount of reactive oxygen species are produced. This type of active oxygen causes severe damage to cell membranes, proteins, and DNA. Therefore, finding a solution to deal with and reduce this type of reactive oxygen is very important. One of the most effective ways to deal with oxidative damage and inflammation is the modulation of the nuclear factor erythroid 2 (Nrf2) signaling pathway. One of the useful natural substances that can be used for treatment in the signaling system is saffron. In this article, research evaluating the medicinal effects of saffron and its compounds and their mechanisms of action, especially the Nrf2 signaling pathway, have been investigated and studied. The results show that saffron and its components have the potential to treat diabetes due to their unique properties.

Identification of Crocetin as a Dual Agonist of GPR40 and GPR120 Responsible for the Antidiabetic Effect of Saffron

Crocin, a glycoside of crocetin, has been known as the principal component responsible for saffron's antidiabetic, anticancer, and anti-inflammatory effects. Crocetin, originating from the hydrolytic cleavage of crocin in biological systems, was subjected to ligand-based virtual screening in this investigation. Subsequent biochemical analysis unveiled crocetin, not crocin, as a novel dual GPR40 and GPR120 agonist, demonstrating a marked preference for GPR40 and GPR120 over peroxisome proliferator-activated receptors (PPAR)γ. This compound notably enhanced insulin and GLP-1 secretion from pancreatic β-cells and intestinal neuroendocrine cells, respectively, presenting a dual mechanism of action in glucose-lowering effects. Docking simulations showed that crocetin emulates the binding characteristics of natural ligands through hydrogen bonds and hydrophobic interactions, whereas crocin's hindered fit within the binding pocket is attributed to steric constraints. Collectively, for the first time, this study unveils crocetin as the true active component of saffron, functioning as a GPR40/120 agonist with potential implications in antidiabetic interventions.

Potential of natural products in combination with arsenic trioxide: Investigating cardioprotective effects and mechanisms

Over the past few decades, clinical trials conducted worldwide have demonstrated the efficacy of arsenic trioxide (ATO) in the treatment of relapsed acute promyelocytic leukemia (APL). Currently, ATO has become the frontline treatments for patients with APL. However, its therapeutic applicability is severely constrained by ATO-induced cardiac side effects. Any cardioprotective agents that can ameliorate the cardiac side effects and allow exploiting the full therapeutic potential of ATO, undoubtedly gain significant attention. The knowledge and use of natural products for evidence-based therapy have grown rapidly in recent years. Here we discussed the potential mechanism of ATO-induced cardiac side effects and reviewed the studies on cardiac side effects as well as the research history of ATO in the treatment of APL. Then, We summarized the protective effects and underlying mechanisms of natural products in the treatment of ATO-induced cardiac side effects. Based on the efficacy and safety of the natural product, it has a promising future in the development of cardioprotective agents against ATO-induced cardiac side effects.

Ameliorative effects of half-dose saffron and chamomile combination on Psycho-endocrinological changes in a diabetic murine model

INTRODUCTION

Diabetes mellitus is a chronic metabolic disorder with an increasing prevalence worldwide. Reduction in blood insulin level alters brain function by inducing oxidative stress with changes in dopamine and norepinephrine neurotransmission, ultimately leading to neuropsychological symptoms. The efficacy of currently available psychotropic drugs is not satisfactory. Therefore, this study was conducted to explore the beneficial effects of a combination of the natural herbs, saffron and chamomile, in treating diabetes and its resultant neuropsychological effects using a rodent model of diabetes mellitus.

METHOD

The rats were randomly divided in to eight groups (n = 10), healthy control (HC), diabetic control (DC) and six groups of diabetic rats treated with various concentrations and combinations of saffron and chamomile. Diabetic treatment groups individually received methanolic extract and water decoction of chamomile (30 mg/kg) and saffron (10mg/kg) and their combined half doses (saffron 5mg/kg and chamomile 15mg/kg) for two weeks. Open field test (OFT) and forced swim test (FST) were used to measure the anxiolytic and antidepressant effects of herbs, respectively. Finally, biochemical, and neurochemical estimations were made.

RESULTS

The present study suggests the therapeutic effects of herbs especially in co-administrated decoction, against diabetes with improved antioxidant profile and enhanced levels of dopamine and norepinephrine. Anxiolytic and antidepressant effects were evident with improvements in the OFT and FST. Examination of the cortex of the diabetic group revealed cellular damage and tangle formation, which indicates advanced stages of dementia.

CONCLUSION

This study shows that the use of a combination of saffron and chamomile improves diabetes control and reduces its related psychiatric effects.

The landscape of potential health benefits of carotenoids as natural supportive therapeutics in protecting against Coronavirus infection

The Coronavirus Disease-2019 (COVID-19) pandemic urges researching possibilities for prevention and management of the effects of the virus. Carotenoids are natural phytochemicals of anti-oxidant, anti-inflammatory and immunomodulatory properties and may exert potential in aiding in combatting the pandemic. This review presents the direct and indirect evidence of the health benefits of carotenoids and derivatives based on in vitro and in vivo studies, human clinical trials and epidemiological studies and proposes possible mechanisms of action via which carotenoids may have the capacity to protect against COVID-19 effects. The current evidence provides a rationale for considering carotenoids as natural supportive nutrients via antioxidant activities, including scavenging lipid-soluble radicals, reducing hypoxia-associated superoxide by activating antioxidant enzymes, or suppressing enzymes that produce reactive oxygen species (ROS). Carotenoids may regulate COVID-19 induced over-production of pro-inflammatory cytokines, chemokines, pro-inflammatory enzymes and adhesion molecules by nuclear factor kappa B (NF-κB), renin-angiotensin-aldosterone system (RAS) and interleukins-6- Janus kinase-signal transducer and activator of transcription (IL-6-JAK/STAT) pathways and suppress the polarization of pro-inflammatory M1 macrophage. Moreover, carotenoids may modulate the peroxisome proliferator-activated receptors γ by acting as agonists to alleviate COVID-19 symptoms. They also may potentially block the cellular receptor of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), human angiotensin-converting enzyme 2 (ACE2). These activities may reduce the severity of COVID-19 and flu-like diseases. Thus, carotenoid supplementation may aid in combatting the pandemic, as well as seasonal flu. However, further in vitro, in vivo and in particular long-term clinical trials in COVID-19 patients are needed to evaluate this hypothesis.

Crocetin: A Systematic Review

Crocetin is an aglycone of crocin naturally occurring in saffron and produced in biological systems by hydrolysis of crocin as a bioactive metabolite. It is known to exist in several medicinal plants, the desiccative ripe fruit of the cape jasmine belonging to the Rubiaceae family, and stigmas of the saffron plant of the Iridaceae family. According to modern pharmacological investigations, crocetin possesses cardioprotective, hepatoprotective, neuroprotective, antidepressant, antiviral, anticancer, atherosclerotic, antidiabetic, and memory-enhancing properties. Although poor bioavailability hinders therapeutic applications, derivatization and formulation preparation technologies have broadened the application prospects for crocetin. To promote the research and development of crocetin, we summarized the distribution, preparation and production, total synthesis and derivatization technology, pharmacological activity, pharmacokinetics, drug safety, drug formulations, and preparation of crocetin.

Crocetin Exerts Its Anti-inflammatory Property in LPS-Induced RAW264.7 Cells Potentially via Modulation on the Crosstalk between MEK1/JNK/NF-κB/iNOS Pathway and Nrf2/HO-1 Pathway

Crocetin is a main bioactive component with a carotenoid skeleton in Gardenia jasminoides, a typical traditional Chinese medicine with a long history in Southeast Asia. Crocetin is being commonly consumed as spices, dyes, and food colorants. Recent pharmacological studies had implied that crocetin may possess potent anti-inflammatory properties; however, the underlying molecular mechanism is not fully elucidated. In the present study, the regulatory effect of crocetin on redox balance was systematically investigated in lipopolysaccharide- (LPS-) stimulated RAW264.7 cells. The results showed that crocetin dose-dependently inhibited LPS-induced nitric oxide production and inducible nitric oxide synthase (iNOS) expression in RAW264.7 cells. Molecular data revealed that crocetin exerted its anti-inflammatory property by inhibiting the MEK1/JNK/NF-κB/iNOS pathway and activating the Nrf2/HO-1 pathway. The shRNA-knockdown (KD) of MEK1 and ERK1 confirmed that the activation of MEK1 and inhibition of JNK mediated the anti-inflammatory effect of crocetin. Moreover, the pull-down assay and computational molecule docking showed that crocetin could directly bind to MEK1 and JNK1/2. It is noticed that both KD and knockout (KO) of HO-1 gene blocked this action. More detailed data have shown that HO-1-KO blocked the inhibition of p-IκB-α by crocetin. These data indicated that crocetin exerted its anti-inflammatory property via modulating the crosstalk between the MEK1/JNK/NF-κB/iNOS pathway and the Nrf2/HO-1 pathway, highlighting HO-1 as a major player. Therefore, the present study reveals that crocetin can act as a potential candidate for redox-balancing modulation in charge of its anti-inflammatory and chemopreventive effect, which strengthens its potency in the subsequent clinic application in the near future.

Involvement of miR-3180-3p and miR-4632-5p in palmitic acid-induced insulin resistance

Insulin resistance is defined as a failure to trigger the activation of the PI3K-AKT pathway by normal levels of insulin; therefore, it is well linked to metabolic disorders. Although multiple mechanisms contribute to insulin resistance, one major cause is elevated concentrations of plasma free fatty acids, which are known to suppress insulin signaling. However, the underlying mechanism is still elusive. Here, we found that palmitic acid increased the expression of two miRNAs, miR-3180-3p and miR-4632-5p, in HepG2 cells. Transfection of HepG2 cells with miR-3180-3p or miR-4632-5p reduced insulin-induced activation of the PI3K-AKT pathway. Moreover, palmitic acid or two miRNAs inhibited insulin-induced phosphorylation of Tyr612 on IRS-1 without affecting insulin receptor activation. Therefore, two miRNAs are suggested to be involved in palmitic acid-induced insulin resistance through suppression of insulin-induced IRS-1 phosphorylation. Identification of miR-3180-3p and miR-4632-5p targets could provide valuable information for the development of therapeutic drugs for type 2 diabetes.

The Effect of Saffron Supplementation on Blood Pressure in Adults: A Systematic Review and Dose-Response Meta-Analysis of Randomized Controlled Trials

Background: The favorable influences of saffron supplementation on metabolic diseases have previously been shown. We aimed to assess the effects of saffron supplementation on blood pressure in adults. Methods: A systematic search was performed in Scopus, Embase, and the Cochrane library databases to find randomized controlled trials (RCTs) related to the effect of saffron supplementation on blood pressure in adults up to March 2021. The primary search yielded 182 publications, of which eight RCTs were eligible. Results: Our results showed that saffron supplementation resulted in a significant decrease in systolic blood pressure (weighted mean difference (WMD): −0.65 mmHg; 95% CI: −1.12 to −0.18, p = 0.006) and diastolic blood pressure (DBP) (WMD: −1.23 mmHg; 95% CI: −1.64 to −0.81, p < 0.001). Moreover, saffron supplementation reduced DBP in a non-linear fashion, based on duration (r = −2.45, p-nonlinearity = 0.008). Conclusions: Saffron supplementation may significantly improve both systolic and diastolic blood pressure in adults. It should be noted that the hypotensive effects of saffron supplementation were small and may not reach clinical importance.

Nutrient regulation of inflammatory signalling in obesity and vascular disease

Despite obesity and diabetes markedly increasing the risk of developing cardiovascular diseases, the molecular and cellular mechanisms that underlie this association remain poorly characterised. In the last 20 years it has become apparent that chronic, low-grade inflammation in obese adipose tissue may contribute to the risk of developing insulin resistance and type 2 diabetes. Furthermore, increased vascular pro-inflammatory signalling is a key event in the development of cardiovascular diseases. Overnutrition exacerbates pro-inflammatory signalling in vascular and adipose tissues, with several mechanisms proposed to mediate this. In this article, we review the molecular and cellular mechanisms by which nutrients are proposed to regulate pro-inflammatory signalling in adipose and vascular tissues. In addition, we examine the potential therapeutic opportunities that these mechanisms provide for suppression of inappropriate inflammation in obesity and vascular disease.

Ameliorative effects and mechanism of crocetin in arsenic trioxide‑induced cardiotoxicity in rats

Arsenic trioxide (ATO) is commonly used to treat patients with acute promyelocytic leukemia since it was authorized by the U.S. Food and Drug Administration in the 1970s, but its applicability has been limited by its cardiotoxic effects. Therefore, the aim of the present study was to investigate the cardioprotective effects and underlying mechanism of crocetin (CRT), the critical ingredient of saffron. Sprague-Dawley rats were then randomly divided into four groups (n=10/group): i) Control group; ii) ATO group, iii) CRT-low (20 mg/kg) group; and iv) CRT-high (40 mg/kg) group. Rats in the Control and ATO groups were intraperitoneally injected with equal volumes of 0.9% sodium chloride solution, and CRT groups were administered with either 20 and 40 mg/kg CRT. Following 6 h, all groups except the Control group were intraperitoneally injected with 5 mg/kg ATO over 10 days. Cardiotoxicity was indicated by changes in electrocardiographic (ECG) patterns, morphology and marker enzymes. Histomorphological changes in the heart tissue were observed by pathological staining. The levels of superoxide dismutase, glutathione peroxidase, malondialdehyde and catalase in the serum were analyzed using colometric commercial assay kits, and the levels of reactive oxygen species in the heart tissue were detected using the fluorescent probe dihydroethidium. The expression levels of inflammatory factors and activities of apoptosis-related proteins were analyzed using immunohistochemistry. The protein expression levels of silent information regulator of transcription 1 were measured using western blotting. Cardiotoxicity was induced in male Sprague-Dawley rats with ATO (5 mg/kg). CRT (20 and 40 mg/kg) and ATO were co-administered to evaluate possible cardioprotective effects. CRT significantly reduced the heart rate and J-point elevation induced by ATO in rats. Histological changes were evaluated via hematoxylin and eosin staining. CRT decreased the levels of creatine kinase and lactate dehydrogenase, increased the activities of superoxide dismutase, glutathione-peroxidase and catalase, and decreased the levels of malondialdehyde and reactive oxygen species. Moreover, CRT downregulated the expression levels of the pro-inflammatory factors IL-1, TNF-α, IL-6, Bax and p65, as well as increased the expression of Bcl-2. It was also identified that CRT enhanced silent information regulator of transcription 1 protein expression. Thus, the present study demonstrated that CRT treatment effectively ameliorated ATO-induced cardiotoxicity. The protective effects of CRT can be attributed to the inhibition of oxidative stress, inflammation and apoptosis. Therefore, CRT represents a promising therapeutic method for improving the cardiotoxic side effects caused by ATO treatment, and additional clinical applications are possible, but warrant further investigation.

Cyanidin-3-O-glucoside restores insulin signaling and reduces inflammation in hypertrophic adipocytes

Obesity is a metabolic disorder characterized by excess adipose tissue, macrophages infiltration, and inflammation which in turn lead to insulin-resistance. Epidemiological evidences reported that anthocyanins possess not only high antioxidant and antiinflammatory activities, but also improve metabolic complications associated with obesity. The aim of this work was to evaluate the in vitro beneficial effects of cyanidin-3-O-glucoside (C3G) in counteracting inflammation and insulin-resistance in 3T3-L1 hypertrophic adipocytes exposed to palmitic acid (PA). In the present study murine 3T3-L1 adipocytes were pretreated with C3G for 24 h and then exposed to palmitic acid (PA) for 24 h. Real-time PCR, western blotting analysis and Oil Red O staining were applied for investigating the mechanism involved in adipocytes dysfunction. C3G pretreatment reduced lipid accumulation, PPARγ pathway and NF-κB pathway induced by PA in murine adipocytes. In addition, our data demonstrated that PA reduced insulin signaling via IRS-1 Ser³⁰⁷phosphorylation while C3G dose-dependently improved insulin sensitivity restoring IRS-1/PI3K/Akt pathway. Furthermore, C3G improved adiponectin mRNA levels altered by PA in 3T3-L1 murine and SGBS human adipocytes. Herein reported data demonstrate that C3G ameliorated adipose tissue dysfunction, thus suggesting new potential roles for this compound of nutritional interest in the prevention of pathological conditions linked to obesity.

Saturated Fatty Acids in Obesity-Associated Inflammation

Obesity is a major risk factor for the development of various pathological conditions including insulin resistance, diabetes, cardiovascular diseases, and non-alcoholic fatty liver disease (NAFLD). Central to these conditions is obesity-associated chronic low-grade inflammation in many tissues including adipose, liver, muscle, kidney, pancreas, and brain. There is increasing evidence that saturated fatty acids (SFAs) increase the phosphorylation of MAPKs, enhance the activation of transcription factors such as nuclear factor (NF)-κB, and elevate the expression of inflammatory genes. This paper focuses on the mechanisms by which SFAs induce inflammation. SFAs may induce the expression inflammatory genes via different pathways including toll-like receptor (TLR), protein kinase C (PKC), reactive oxygen species (ROS), NOD-like receptors (NLRs), and endoplasmic reticulum (ER) stress. These findings suggest that SFAs act as an important link between obesity and inflammation.

Oxidative stress induced by palmitic acid modulates KCa2.3 channels in vascular endothelium

Elevated plasma free fatty acids level has been implicated in the development of insulin resistance, inflammation, and endothelial dysfunction in diabetic and nondiabetic individuals. However, the underlying mechanisms still remain to be defined. Herein, we investigated the effect of palmitic acid (PA), the most abundant saturated fatty acid in the human body, on small-conductance Ca²⁺-activated potassium channels (K_Ca2.3)-mediated relaxation in rodent resistance arteries and the underlying molecular mechanism. The effect of PA on K_Ca2.3 in endothelium was evaluated using real-time PCR, Western blotting, whole-cell patch voltage-clamp, wire and pressure myograph system, and reactive oxygen species (ROS) were measured by using dihydroethidium and 2', 7'-dichlorofluorescein diacetate. K_Ca2.3-mediated vasodilatation responses to acetylcholine and NS309 (agonist of K_Ca2.3 and K_Ca3.1) were impaired by incubation of normal mesenteric arteries with 100 μM PA for 24 h. In cultured human umbilical vein endothelial cells (HUVECs), PA decreased K_Ca2.3 current and expression at mRNA and protein levels. Incubation with the NADPH oxidase (Nox) inhibitor dibenziodolium (DPI) partly inhibited the PA-induced ROS production and restored K_Ca2.3 expression. Inhibition of either p38-MAPK or NF-κB using specific inhibitors (SB203580, SB202190 or Bay11-7082, pyrrolidinedithiocarbamate) attenuated PA-induced downregulation of K_Ca2.3 and inhibition of p38-MAPK also attenuated PA-induced phosphorylation of NF-κB p65. Furthermore, DPI reversed the increment of phospho-p38-MAPK by PA. These results demonstrated that PA downregulated K_Ca2.3 expressions via Nox/ROS/p38-MAPK/NF-κB signaling leading to endothelial vasodilatory dysfunction.

A comprehensive review on biological activities and toxicology of crocetin

Natural products with high pharmacological potential and low toxicity have been considered as the novel therapeutic agents. Crocetin is an active constituent of saffron (Crocus sativus L.) stigma, which in its free-acid form is insoluble in water and most organic solvents. Crocetin exhibits various health-promoting properties including anti-tumor, neuroprotective effects, anti-diabetics, anti-inflammatory, anti-hyperlipidemia, etc. These therapeutic effects can be achieved with different mechanisms such as improvement of oxygenation in hypoxic tissues, antioxidant effects, inhibition of pro-inflammatory mediators, anti-proliferative activity and stimulation of apoptosis in cancer cells. It is also worth considering that crocetin could be tolerated without major toxicity at therapeutic dosage in experimental models. In the present review, we discuss the biosynthesis, pharmacokinetic properties of crocetin and provide a comprehensive study on the biological activities and toxicity along with the mechanism of actions and clinical trials data of crocetin.

Regulatory roles of miR-155 and let-7b on the expression of inflammation-related genes in THP-1 cells: effects of fatty acids

The main aim of this investigation was to study the regulatory roles of let-7b and miR-155-3p on the expression of inflammation-associated genes in monocytes, macrophages, and lipopolysaccharide (LPS)-activated macrophages (AcM). A second goal was to analyze the potential modulatory roles of different fatty acids, including oleic, palmitic, eicosapentaenoic (EPA), and docosahexaenoic (DHA), on the expression of these miRNAs in the three cell types. This hypothesis was tested in human acute monocytic leukemia cells (THP-1), which were differentiated into macrophages with 2-O-tetradecanoylphorbol-13-acetate (TPA) and further activated with LPS for 24 h. Monocytes, macrophages, and AcM were transfected with a negative control, or mimics for miR-155-3p and miR-let-7b-5p. The expression of both miRNAs and some proinflammatory genes was analyzed by qRT-PCR. Interestingly, let-7b mimic reduced the expression of IL6 and TNF in monocytes, and SERPINE1 expression in LPS-activated macrophages. However, IL6, TNF, and SERPINE1 were upregulated in macrophages by let-7b mimic. IL6 expression was higher in the three types of cells after transfecting with miR-155-3p mimic. Similarly, expression of SERPINE1 was increased by miR-155-3p mimic in monocytes and macrophages. However, TLR4 was downregulated by miR-155-3p in monocytes and macrophages. Regarding the effects of the different fatty acids, oleic acid increased the expression of let-7b in macrophages and AcM and also increased the expression of miR-155 in monocytes when compared with DHA but not when compared with non-treated cells. Overall, these results suggest anti- and proinflammatory roles of let-7b and miR-155-3p in THP-1 cells, respectively, although these outcomes are strongly dependent on the cell type. Noteworthy, oleic acid might exert beneficial anti-inflammatory effects in immune cells (i.e., non-activated and LPS-activated macrophages) by upregulating the expression of let-7b.

Oxidative stress and calcium dysregulation by palmitate in type 2 diabetes

Free fatty acids (FFAs) are important substrates for mitochondrial oxidative metabolism and ATP synthesis but also cause serious stress to various tissues, contributing to the development of metabolic diseases. CD36 is a major mediator of cellular FFA uptake. Inside the cell, saturated FFAs are able to induce the production of cytosolic and mitochondrial reactive oxygen species (ROS), which can be prevented by co-exposure to unsaturated FFAs. There are close connections between oxidative stress and organellar Ca²⁺ homeostasis. Highly oxidative conditions induced by palmitate trigger aberrant endoplasmic reticulum (ER) Ca²⁺ release and thereby deplete ER Ca²⁺ stores. The resulting ER Ca²⁺ deficiency impairs chaperones of the protein folding machinery, leading to the accumulation of misfolded proteins. This ER stress may further aggravate oxidative stress by augmenting ER ROS production. Secondary to ER Ca²⁺ release, cytosolic and mitochondrial matrix Ca²⁺ concentrations can also be altered. In addition, plasmalemmal ion channels operated by ER Ca²⁺ depletion mediate persistent Ca²⁺ influx, further impairing cytosolic and mitochondrial Ca²⁺ homeostasis. Mitochondrial Ca²⁺ overload causes superoxide production and functional impairment, culminating in apoptosis. This vicious cycle of lipotoxicity occurs in multiple tissues, resulting in β-cell failure and insulin resistance in target tissues, and further aggravates diabetic complications.

Lipotoxic lethal and sublethal stress signaling in hepatocytes: relevance to NASH pathogenesis

The accumulation of lipids is a histologic and biochemical hallmark of obesity-associated nonalcoholic fatty liver disease (NAFLD). A subset of NALFD patients develops progressive liver disease, termed nonalcoholic steatohepatitis, which is characterized by hepatocellular apoptosis and innate immune system-mediated inflammation. These responses are orchestrated by signaling pathways that can be activated by lipids, directly or indirectly. In this review, we discuss palmitate- and lysophosphatidylcholine (LPC)-induced upregulation of p53-upregulated modulator of apoptosis and cell-surface expression of the death receptor TNF-related apoptosis-inducing ligand receptor 2. Next, we review the activation of stress-induced kinases, mixed lineage kinase 3, and c-Jun N-terminal kinase, and the activation of endoplasmic reticulum stress response and its downstream proapoptotic effector, CAAT/enhancer binding homologous protein, by palmitate and LPC. Moreover, the activation of these stress signaling pathways is linked to the release of proinflammatory, proangiogenic, and profibrotic extracellular vesicles by stressed hepatocytes. This review discusses the signaling pathways induced by lethal and sublethal lipid overload that contribute to the pathogenesis of NAFLD.

Saffron with resistance exercise improves diabetic parameters through the GLUT4/AMPK pathway in-vitro and in-vivo

Saffron is consumed as food and medicine to treat several illnesses. This study elucidates the saffron effectiveness on diabetic parameters in-vitro and combined with resistance exercise in-vivo. The antioxidant properties of saffron was examined. Insulin secretion and glucose uptake were examined by cultured RIN-5F and L6 myotubes cells. The expressions of GLUT2, GLUT4, and AMPKα were determined by Western blot. Diabetic and non-diabetic male rats were divided into: control, training, extract treatment, training + extract treatment and metformin. The exercise and 40 mg/kg/day saffron treatments were carried out for six weeks. The antioxidant capacity of saffron was higher compare to positive control (P < 0.01). High dose of saffron stimulated insulin release in RIN-5F cells and improved glucose uptake in L6 myotubes. GLUT4 and AMPKα expressions increased in both doses of saffron (P < 0.01), whereas GLUT2 not changed (p > 0.05). Serum glucose, cholesterol, triglyceride, low-density lipoprotein, very low-density lipoprotein, insulin resistance, and glycated hemoglobin levels decreased in treated rats compared to untreated (p < 0.01). However, no significant differences were observed in the high-density lipoprotein, insulin, adiponectin, and leptin concentration levels in all groups (p > 0.05). The findings suggest that saffron consuming alongside exercise could improve diabetic parameters through redox-mediated mechanisms and GLUT4/AMPK pathway to entrap glucose uptake.

Antiinflammatory, Antioxidant, and Immunomodulatory Effects of Crocus sativus L. and its Main Constituents

Crocus sativus L. (C. sativus), commonly known as saffron, is used as a food additive, preservative, and medicinal herb. Traditionally, it has been used as an alternative treatment for different diseases. C. sativus' medicinal effects are related to its major constituents like crocins, crocetin, and safranal. According to the literature, C. sativus and its constituents could be considered as an effective treatment for neurodegenerative disorders, coronary artery diseases, asthma, bronchitis, colds, fever, diabetes, and so on. Recently, numerous studies have reported such medicinal properties and found that the underlying mechanisms of action may be mediated by antioxidant, inflammatory, and immunomodulatory effects. C. sativus enhances the antioxidant capacity and acts as a free radical scavenger. As an antiinflammatory and immunomodulatory agent, it modulates inflammatory mediators, humoral immunity, and cell-mediated immunity responses. This review highlights in vitro and animal findings regarding antiinflammatory, antioxidant, and immunomodulatory effects of C. sativus and its constituents. Present review found that the C. sativus and its main constituents such as safranal, crocins, and crocetin could be effective against various diseases because of their antioxidant, anti-inflammation, and immunomodulatory effects. Copyright © 2016 John Wiley & Sons, Ltd.

Glucose starvation and hypoxia, but not the saturated fatty acid palmitic acid or cholesterol, activate the unfolded protein response in 3T3-F442A and 3T3-L1 adipocytes

Obesity is associated with endoplasmic reticulum (ER) stress and activation of the unfolded protein response (UPR) in adipose tissue. In this study we identify physiological triggers of ER stress and of the UPR in adipocytes in vitro. We show that two markers of adipose tissue remodelling in obesity, glucose starvation and hypoxia, cause ER stress in 3T3-F442A and 3T3-L1 adipocytes. Both conditions induced molecular markers of the IRE1α and PERK branches of the UPR, such as splicing of XBP1 mRNA and CHOP, as well as transcription of the ER stress responsive gene BiP. Hypoxia also induced an increase in phosphorylation of the PERK substrate eIF2α. By contrast, physiological triggers of ER stress in many other cell types, such as the saturated fatty acid palmitic acid, cholesterol, or several inflammatory cytokines including TNF-α, IL-1β, and IL-6, do not cause ER stress in 3T3-F442A and 3T3-L1 adipocytes. Our data suggest that physiological changes associated with remodelling of adipose tissue in obesity, such as hypoxia and glucose starvation, are more likely physiological ER stressors of adipocytes than the lipid overload or hyperinsulinemia associated with obesity.

The Novel PKCθ from Benchtop to Clinic

The protein kinases C (PKCs) are a family of serine/threonine kinases involved in regulating multiple essential cellular processes such as survival, proliferation, and differentiation. Of particular interest is the novel, calcium-independent PKCθ which plays a central role in immune responses. PKCθ shares structural similarities with other PKC family members, mainly consisting of an N-terminal regulatory domain and a C-terminal catalytic domain tethered by a hinge region. This isozyme, however, is unique in that it translocates to the immunological synapse between a T cell and an antigen-presenting cell (APC) upon T cell receptor-peptide MHC recognition. Thereafter, PKCθ interacts physically and functionally with downstream effectors to mediate T cell activation and differentiation, subsequently leading to inflammation. PKCθ-specific perturbations have been identified in several diseases, most notably autoimmune disorders, and hence the modulation of its activity presents an attractive therapeutic intervention. To that end, many inhibitors of PKCs and PKCθ have been developed and tested in preclinical and clinical studies. And although selectivity remains a challenge, results are promising for the future development of effective PKCθ inhibitors that would greatly advance the treatment of several T-cell mediated diseases.

Oleate prevents palmitate-induced mitochondrial dysfunction, insulin resistance and inflammatory signaling in neuronal cells

Elevated circulating levels of saturated free fatty acids (sFFAs; e.g. palmitate) are known to provoke inflammatory responses and cause insulin resistance in peripheral tissue. By contrast, mono- or poly-unsaturated FFAs are protective against sFFAs. An excess of sFFAs in the brain circulation may also trigger neuroinflammation and insulin resistance, however the underlying signaling changes have not been clarified in neuronal cells. In the present study, we examined the effects of palmitate on mitochondrial function and viability as well as on intracellular insulin and nuclear factor-κB (NF-κB) signaling pathways in Neuro-2a and primary rat cortical neurons. We next tested whether oleate preconditioning has a protective effect against palmitate-induced toxicity. Palmitate induced both mitochondrial dysfunction and insulin resistance while promoting the phosphorylation of mitogen-activated protein kinases and nuclear translocation of NF-κB p65. Oleate pre-exposure and then removal was sufficient to completely block subsequent palmitate-induced intracellular signaling and metabolic derangements. Oleate also prevented ceramide-induced insulin resistance. Moreover, oleate stimulated ATP while decreasing mitochondrial superoxide productions. The latter were associated with increased levels of peroxisome proliferator-activated receptor-γ coactivator-1α (PGC-1α). Inhibition of protein kinase A (PKA) attenuated the protective effect of oleate against palmitate, implicating PKA in the mechanism of oleate action. Oleate increased triglyceride and blocked palmitate-induced diacylglycerol accumulations. Oleate preconditioning was superior to docosahexaenoic acid (DHA) or linoleate in the protection of neuronal cells against palmitate- or ceramide-induced cytotoxicity. We conclude that oleate has beneficial properties against sFFA and ceramide models of insulin resistance-associated damage to neuronal cells.

Anticancer Effect and Molecular Targets of Saffron Carotenoids

Saffron carotenoids, crocin and crocetin, have shown anticancer activity in various animal models of cancer and against different cancerous cell lines. The radical scavenging property and activation of antioxidant defense system are two well-known characteristics of these compounds. However, the results of the studies indicated other mechanisms could also be involved in this function. Insights into various molecular mechanisms of action for crocin and crocetin have been obtained in recent years. The results indicated that despite the structural similarity of crocin and crocetin, their anticancer effects may exert through different mechanisms. Particular interest concerns the ROS-dependent signaling pathways of crocetin. Saffron compounds are safe and may provide inexpensive therapy for treating cancer. They also have protective potential in targeting other disorders including diabetes, Alzheimer's and cardiovascular disease, cognitive deficits, ischemia-induced retinal damage, and many other diseases.