Curcumin analog L3 alleviates diabetic atherosclerosis by multiple effects

The beneficial effects of curcumin on aging and age-related diseases: from oxidative stress to antioxidant mechanisms, brain health and apoptosis

Aging and age-related disease are among the most common and challenging issues worldwide. During the aging process, the accumulation of oxidative stress, DNA damage, telomere dysfunction, and other related changes lead to cellular dysfunction and the development of diseases such as neurodegenerative and cardiovascular conditions. Curcumin is a widely-used dietary supplement against various diseases such as cancer, diabetes, cardiovascular diseases and aging. This agent mediates its effects through several mechanisms, including the reduction of reactive oxygen species (ROS) and oxidative stress-induced damage, as well as the modulation of subcellular signaling pathways such as AMPK, AKT/mTOR, and NF-κB. These pathways are involved in cellular senescence and inflammation, and their modulation can improve cell function and help prevent disease. In cancer, Curcumin can induce apoptosis in a variety of different tumor cell lines. Curcumin also activates redox reactions within cells inducing ROS production that leads to the upregulation of apoptosis receptors on the tumor cell membrane. Curcumin can also upregulate the expression and activity of p53 that inhibits tumor cell proliferation and increases apoptosis. Furthermore, curcumin has a potent inhibitory effect on the activity of nuclear factor kappa B (NF-κB) and cyclooxygenase-2 (COX-2), which are involved in the overexpression of antiapoptosis genes such as Bcl-2. It can also attenuate the regulation of antiapoptosis phosphoinositide 3-kinases (PI3K) signaling and increase the expression of mitogen-activated protein kinases (MAPKs) to induce endogenous production of ROS. Therefore, herein, we aim to summarize how curcumin affect different epigenetic processes (such as apoptosis and oxidative stress) in order to change aging-related mechanisms. Furthermore, we discuss its roles in age-related diseases, such as Alzheimer, Parkinson, osteoporosis, and cardiovascular diseases.

Regulatory effects of curcumin on nitric oxide signaling in the cardiovascular system

The continuously rising prevalence of cardiovascular disease (CVD) globally substantially impacts the economic growth of developing countries. Indeed, one of the leading causes of death worldwide is unfavorable cardiovascular events. Reduced nitric oxide (NO) generation is the pathogenic foundation of endothelial dysfunction, which is regarded as the first stage in the development of a number of CVDs. Nitric oxide exerts an array of biological effects, including vasodilation, the suppression of vascular smooth muscle cell proliferation and the functional control of cardiac cells. Numerous treatment strategies aim to increase NO synthesis or upregulate downstream NO signaling pathways. The major component of Curcuma longa, curcumin, has long been utilized in traditional medicine to treat various illnesses, especially CVDs. Curcumin improves CV function as well as having important pleiotropic effects, such as anti-inflammatory and antioxidant, through its ability to increase the bioavailability of NO and to positively impact NO-related signaling pathways. In this review, we discuss the scientific literature relating to curcumin's positive effects on NO signaling and vascular endothelial function.

Targeting endothelial cells with golden spice curcumin: A promising therapy for cardiometabolic multimorbidity

Cardiometabolic multimorbidity (CMM) is an increasingly significant global public health concern. It encompasses the coexistence of multiple cardiometabolic diseases, including hypertension, stroke, heart disease, atherosclerosis, and T2DM. A crucial component to the development of CMM is the disruption of endothelial homeostasis. Therefore, therapies targeting endothelial cells through multi-targeted and multi-pathway approaches hold promise for preventing and treatment of CMM. Curcumin, a widely used dietary supplement derived from the golden spice Carcuma longa, has demonstrated remarkable potential in treatment of CMM through its interaction with endothelial cells. Numerous studies have identified various molecular targets of curcumin (such as NF-κB/PI3K/AKT, MAPK/NF-κB/IL-1β, HO-1, NOs, VEGF, ICAM-1 and ROS). These findings highlight the efficacy of curcumin as a therapeutic agent against CMM through the regulation of endothelial function. It is worth noting that there is a close relationship between the progression of CMM and endothelial damage, characterized by oxidative stress, inflammation, abnormal NO bioavailability and cell adhesion. This paper provides a comprehensive review of curcumin, including its availability, pharmacokinetics, pharmaceutics, and therapeutic application in treatment of CMM, as well as the challenges and future prospects for its clinical translation. In summary, curcumin shows promise as a potential treatment option for CMM, particularly due to its ability to target endothelial cells. It represents a novel and natural lead compound that may offer significant therapeutic benefits in the management of CMM.

The upregulation of NLRP3 inflammasome in dorsal root ganglion by ten-eleven translocation methylcytosine dioxygenase 2 (TET2) contributed to diabetic neuropathic pain in mice

BACKGROUND

The nucleotide oligomerization domain (NOD)-like receptor family pyrin domain containing 3 (NLRP3) in dorsal root ganglion (DRG) contributes to pain hypersensitivity in multiple neuropathic pain models, but the function of the NLRP3 in diabetic neuropathic pain (DNP) and the regulation mechanism are still largely unknown. Epigenetic regulation plays a vital role in the controlling of gene expression. Ten-eleven translocation methylcytosine dioxygenase 2 (TET2) is a DNA demethylase that contributes to transcriptional activation. TET2 is also involved in high glucose (HG)-induced pathology.

METHODS

DNP was induced in mice via the intraperitoneal injection of streptozotocin (STZ) for five consecutive days and the mechanical threshold was evaluated in STZ-diabetic mice by using von Frey hairs. The expression level of the NLRP3 pathway and TET2 in DRG were determined through molecular biology experiments. The regulation of the NLRP3 pathway by TET2 was examined in in vitro and in vivo conditions.

RESULTS

In the present research, we first established the DNP model and found that NLRP3 pathway was activated in DRG. The treatment of NLRP3 inhibitor MCC950 alleviated the mechanical allodynia of DNP mice. Then we revealed that in STZ-diabetic mice DRG, the genomic DNA was demethylated, and the expression of DNA demethylase TET2 was increased evidently. Using RNA-sequencing analysis, we found that the expression of Txnip, a gene that encodes a thioredoxin-interacting protein (TXNIP) which mediates NLRP3 activation, was elevated in the DRG after STZ treatment. In addition, knocking down of TET2 expression in DRG using TET2-siRNA suppressed the mRNA expression of Txnip and subsequently inhibited the expression/activation of NLRP3 inflammasome in vitro and in vivo as well as relieved the pain sensitivity of DNP animals.

CONCLUSION

The results suggested that the upregulation of the TXNIP/NLRP3 pathway by TET2 in DRG was involved in the pain hypersensitivity of the DNP model.

Curcumin as a Natural Remedy for Atherosclerosis: A Pharmacological Review

Curcumin, a natural polyphenolic compound present in Curcuma longa L. rhizomes, shows potent antioxidant, anti-inflammatory, anti-cancer, and anti-atherosclerotic properties. Atherosclerosis is a comprehensive term for a series of degenerative and hyperplasic lesions such as thickening or sclerosis in large- and medium-sized arteries, causing decreased vascular-wall elasticity and lumen diameter. Atherosclerotic cerebro-cardiovascular disease has become a major concern for human health in recent years due to its clinical sequalae of strokes and heart attacks. Curcumin concoction treatment modulates several important signaling pathways related to cellular migration, proliferation, cholesterol homeostasis, inflammation, and gene transcription, among other relevant actions. Here, we provide an overview of curcumin in atherosclerosis prevention and disclose the underlying mechanisms of action of its anti-atherosclerotic effects.

Chinese Herbal Medicines and Active Metabolites: Potential Antioxidant Treatments for Atherosclerosis

Atherosclerosis is a complex chronic disease that occurs in the arterial wall. Oxidative stress plays a crucial role in the occurrence and progression of atherosclerotic plaques. The dominance of oxidative stress over antioxidative capacity generates excess reactive oxygen species, leading to dysfunctions of the endothelium and accelerating atherosclerotic plaque progression. Studies showed that Chinese herbal medicines and traditional Chinese medicine (TCM) might regulate oxidative stress; they have already been used to treat diseases related to atherosclerosis, including stroke and myocardial infarction. This review will summarize the mechanisms of oxidative stress in atherosclerosis and discuss studies of Chinese herbal medicines and TCM preparations treating atherosclerosis, aiming to increase understanding of TCM and stimulate research for new drugs to treat diseases associated with oxidative stress.

Enhanced anti-hepatoma effect of a novel curcumin analog C086 via solid dispersion technology

The novel curcumin analog C086, previously identified as an oral novel heat shock protein 90 (Hsp90) inhibitor, was found to exhibit anti-hepatoma activity in vitro and in vivo. However, owing to its limited aqueous solubility, the usage of C086 in the clinical application was restricted. This research focused on the increase of the aqueous solubility and bioavailability of C086 via a solid dispersion preparation to improve its accumulation in the liver, which accordingly enhanced anti-hepatoma activity. C086-solid dispersion (C086-SD) was successfully prepared by using solvent evaporation technology. As compared with bulk compound, aqueous solubility obtained with the optimal formulation (C086/PVP k30:1/6 (w/w)) was increased by 1.741 million-fold, and in the following oral administration experiment, bioavailability was found to be improved by an approximately 28-fold relative to C086-Suspension and accumulate preferably in the liver. Accordingly, C086-SD exhibited stronger potent anti-proliferative effects against liver cancer cell line (i.e. HepG2) than pure C086. Moreover, C086-SD was found to have an enhanced anti-hepatoma effect using the orthotopic hepatocellular carcinoma xenograft in BALB/C nude mice. The results above suggested the potential application of C086-SD in the treatment of liver cancer.

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

OBJECTIVE

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

METHODS

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

RESULTS

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

CONCLUSIONS

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

Sonodynamic therapy in atherosclerosis by curcumin nanosuspensions: Preparation design, efficacy evaluation, and mechanisms analysis

Previous studies have shown that curcumin (Cur) induced by ultrasound has protective effects on atherosclerosis even if low bioavailability of the Cur. The enhancement of bioavailability of the Cur further improved the curative effect of sonodynamic therapy (SDT) on atherosclerosis through nanotechnology. Nanosuspensions as a good drug delivery system had obvious advantages in increasing the solubility and improving the effectiveness of insoluble drugs. The aim of this study was to develop curcumin nanosuspensions (Cur-ns) which used polyvinylpyrrolidone (PVPK30) and sodium dodecyl sulfate (SDS) as stabilizers to improve poor water solubility and bioavailability of the Cur. And then the therapeutic effects of Cur-ns-SDT on atherosclerotic plaques and its possible mechanisms would be investigated and elucidated. Cur-ns with a small particle size has been successfully prepared and the data have confirmed that Cur-ns could be more easily engulfed into RAW264.7 cells than free Cur and accumulated more under the stimulation of the ultrasound. Reactive oxygen species (ROS) inside RAW264.7 cells after SDT led to the decrease of mitochondrial membrane potential (MMP) and the higher expression of cleaved caspase-9/3. The results of in vivo experiments showed that Cur-ns-SDT reduced the level of total cholesterol (TC) and low density lipoprotein (LDL) and promoted the transformation from M1 to M2 macrophages, relieved atherosclerosis syndrome. Therefore, Cur-ns-SDT was a potential treatment of anti-atherosclerosis by enhancing macrophages apoptosis through mitochondrial pathway and inhibiting the progression of plaques by interfering with macrophages polarization.

The effect of curcumin supplementation on circulating adiponectin: A systematic review and meta-analysis of randomized controlled trials

OBJECTIVE

Our objective was to perform a systematic review and meta-analysis on randomized controlled trials (RCTs) assessing the effect of curcumin on serum adiponectin concentration.

METHODS

We searched PubMed/Medline, Scopus, ISI Web of Science, Cochrane Library, and Google scholar databases up to April 2019. RCTs conducted among human adults studied the effects of curcumin on serum adiponectin concentrations as an outcome variable was included. The weighted mean differences (WMD) and standard deviations (SD) of change in serum adiponectin levels were calculated. The random effects model was used for deriving a summary of mean estimates with their corresponding SDs.

RESULTS

Out of 313 records, 6 trials that enrolled 652 subjects were included. The pooled results showed that curcumin supplementation significantly increased adiponectin concentrations in comparison with placebo (WMD: 0.82 Hedges' g; 95% confidence interval (CI): 0.33 to 1.30, P˂0.001). Greater effects on adiponectin were observed in trials lasting ≤10 weeks (WMD: 1.05 Hedges' g; 95% CI: 0.64 to 1.45, P˂0.001).

CONCLUSION

Curcumin significantly improves adiponectin concentrations. However, due to some limitations in this study, further studies are needed to reach a definitive conclusion about the effect of curcumin on the levels of adiponectin.

Mechanics insights of curcumin in myocardial ischemia: Where are we standing?

Cardiovascular disorders are known as one of the main health problems which are associated with mortality worldwide. Myocardial ischemia (MI) is improper blood supply to myocardium which leads from serious complications to life-threatening problems like AMI, atherosclerosis, hypertension, cardiac-hypertrophy as well as diabetic associated complications as diabetic atherosclerosis/cardiomyopathy/hypertension. Despite several efforts, the current therapeutic platforms are not related with significant results. Hence, it seems, developing novel therapies are required. In this regard, increasing evidences indicated, curcumin (CRC) acts as cardioprotective agent. Given that CRC and its analogs exert their cardioprotective effects via affecting on a variety of cardiovascular diseases-related mechanisms (i.e., Inflammation, and oxidative stress). Herein, for first time, we have highlighted the protective impacts of CRC against MI. This review might be a steppingstone for further investigation into the clinical implications of the CRC against MI. Furthermore, it pulls in light of a legitimate concern for scientific community, seeking novel techniques and characteristic dynamic biopharmaceuticals for use against myocardial ischemia.

The pleiotropic role of interleukin-17 in atherosclerosis

Atherosclerosis is the main cause of cardiovascular diseases (CVDs), which considers the leading cause of mortality worldwide. Atherosclerosis is a chronic inflammatory condition of arterials' wall in which the development and the destabilization of plaque occur. Both innate and adaptive immunity play a significant role in modifying lipoproteins in arterials' wall. Recent investigations have demonstrated the opposing roles of CD4⁺ T cells subtypes in atherosclerosis. T helper-1 (Th1) response and pro-inflammatory cytokines possess proatherogenic effects, whereas T regulatory (Treg) cells have an atheroprotective role. Th17 cells have emerged as a new CD4⁺ T-cell subtype, which produce IL-17 that plays a crucial role in numerous inflammatory and autoimmune diseases. Recently, several studies have investigated the potential role of IL-17 in atherosclerosis. Some investigations have suggested a proatherogenic effect, however the others proposed an atheroprotective role. Hence, the exact role of IL-17 in the disease development and plaque stability is still debatable. In this review, we summarize the current knowledge on both atherogenesis and atheroprotective roles of IL-17. In addition, the synergistic and antagonistic effects of IL-17 with other cytokines in atherosclerosis will be discussed. On the basis of the current understanding of these roles, the possibility of developing novel therapeutic strategies against atherosclerosis may be evolved.

Feruloylated oligosaccharides from maize bran alleviate the symptoms of diabetes in streptozotocin-induced type 2 diabetic rats

This study investigated the therapeutic effect of feruloylated oligosaccharides (FOs) extracted from maize bran on type 2 diabetic rats and its potential mechanism. Streptozotocin (STZ) induced type 2 diabetic male rats were orally administered with different levels of FOs for 8 weeks, and ferulic acid (FA) treatment was conducted as the positive control. Among all the treatments, the oral administration of 600 mg per kg bw per d FOs showed the best therapeutic effects on the diabetic rats by significantly lowering the levels of fasting plasma glucose (FPG), fasting insulin, TG, LDL-c, aspartate transaminase, creatine kinase and lactate dehydrogenase in plasma, while increasing the level of plasma HDL-c. In addition, the intake of FOs at 600 mg per kg bw per d exhibited the best antioxidant effects in the plasma, liver, kidney and heart of the diabetic rats, and the highest inhibitory effects on the formation of AGEs and CML in the organs, which might explain the alleviating effects of FOs on abdominal aorta injury observed in the current study. FOs presented better regulation effects on FPG, plasma lipid and the protection of abdominal aorta than FA under the same administered dosage. Based on these outcomes, FOs from maize bran could be beneficial for prevention or early treatment of diabetes mellitus.

Effect of bis(hydroxymethyl) alkanoate curcuminoid derivative MTH-3 on cell cycle arrest, apoptotic and autophagic pathway in triple-negative breast adenocarcinoma MDA-MB-231 cells: An in vitro study

Curcumin has been shown to exert potential antitumor activity in vitro and in vivo involved in multiple signaling pathways. However, the application of curcumin is still limited because of its poor hydrophilicity and low bio-availability. In the present study, we investigated the therapeutic effects of a novel and water soluble bis(hydroxymethyl) alkanoate curcuminoid derivative, MTH-3, on human breast adenocarcinoma MDA-MB-231 cells. This study investigated the effect of MTH-3 on cell viability, cell cycle and induction of autophagy and apoptosis in MDA-MB-231 cells. After 24-h treatment with MTH-3, a concentration-dependent decrease in MDA-MB-231 cell viability was observed, and the IC₅₀ value was 5.37±1.22 μM. MTH-3 significantly triggered G₂/M phase arrest and apoptosis in MDA-MB-231 cells. Within a 24-h treatment, MTH-3 decreased the CDK1 activity by decreasing CDK1 and cyclin B1 protein levels. MTH-3-induced apoptosis was further confirmed by morphological assessment and Annexin V/PI staining assay. Induction of apoptosis caused by MTH-3 was accompanied by an apparent increase of DR3, DR5 and FADD and, as well as a marked decrease of Bcl-2 and Bcl-xL protein expression. MTH-3 also decreased the protein levels of Ero1, PDI, PERK and calnexin, as well as increased the expression of IRE1α, CHOP and Bip that consequently led to ER stress and MDA-MB-231 cell apoptosis. In addition, MTH-3-treated cells were involved in the autophagic process and cleavage of LC3B was observed. MTH-3 enhanced the protein levels of LC3B, Atg5, Atg7, Atg12, p62 and Beclin-1 in MDA-MB-231 cells. Finally, DNA microarray was carried out to investigate the level changes of gene expression modulated by MTH-3 in MDA-MB-231 cells. Taken together, our results suggest that MTH-3 might be a novel therapeutic agent for the treatment of triple-negative breast cancer in the near future.

Cellular and Molecular Mechanisms of Diabetic Atherosclerosis: Herbal Medicines as a Potential Therapeutic Approach

An increasing number of patients diagnosed with diabetes mellitus eventually develop severe coronary atherosclerosis disease. Both type 1 and type 2 diabetes mellitus increase the risk of cardiovascular disease associated with atherosclerosis. The cellular and molecular mechanisms affecting the incidence of diabetic atherosclerosis are still unclear, as are appropriate strategies for the prevention and treatment of diabetic atherosclerosis. In this review, we discuss progress in the study of herbs as potential therapeutic agents for diabetic atherosclerosis.

Preparation and characterisation of atorvastatin and curcumin-loaded chitosan nanoformulations for oral delivery in atherosclerosis

Atorvastatin known to be a potential inhibitor of HMG-CoA reductase involved in the synthesis of cholesterol. It is touted as miracle drug due to its profound effect in decreasing the low-density lipoproteins in blood. Unfortunately, the high dosage used poses side-effects relatively in comparison to other statins. On the other hand, curcumin has a diverse therapeutic potential in health and disease. However, the poor aqueous solubility and low bioavailability hinders the therapeutic potential of it when administrated orally. Therefore, it was thought to minimise the frequency of atorvastatin doses to avoid the possibility of drug resistance and also to overcome the limitations of curcumin for desirable therapeutic effects by using nanocarriers in drug delivery. In this investigation, synergistic effect of atorvastatin and curcumin nanocarriers was encapsulated by chitosan polymer. The chitosan nanocarriers prepared by ionic gelation method were characterised for their particle size, zeta potential, and other parameters. The drug-loaded nanocarriers exhibited good encapsulation efficiency (74.25%) and showed a slow and sustained release of atorvastatin and curcumin 60.36 and 61.44%, respectively, in a span of 48 h. The drug-loaded nanocarriers found to be haemocompatible and qualified for drug delivery in atherosclerosis.