Impaired redox signaling and mitochondrial uncoupling contributes vascular inflammation and cardiac dysfunction in type 1 diabetes: Protective role of arjunolic acid

Potential pathogenic roles of ferroptosis and cuproptosis in cadmium-induced or exacerbated cardiovascular complications in individuals with diabetes

Diabetes and its complications are major diseases that affect human health. Diabetic cardiovascular complications such as cardiovascular diseases (CVDs) are the major complications of diabetes, which are associated with the loss of cardiovascular cells. Pathogenically the role of ferroptosis, an iron-dependent cell death, and cuproptosis, a copper-dependent cell death has recently been receiving attention for the pathogenesis of diabetes and its cardiovascular complications. How exposure to environmental metals affects these two metal-dependent cell deaths in cardiovascular pathogenesis under diabetic and nondiabetic conditions remains largely unknown. As an omnipresent environmental metal, cadmium exposure can cause oxidative stress in the diabetic cardiomyocytes, leading to iron accumulation, glutathione depletion, lipid peroxidation, and finally exacerbate ferroptosis and disrupt the cardiac. Moreover, cadmium-induced hyperglycemia can enhance the circulation of advanced glycation end products (AGEs). Excessive AGEs in diabetes promote the upregulation of copper importer solute carrier family 31 member 1 through activating transcription factor 3/transcription factor PU.1, thereby increasing intracellular Cu+ accumulation in cardiomyocytes and disturbing Cu+ homeostasis, leading to a decline of Fe-S cluster protein and reactive oxygen species accumulation in cardiomyocytes mitochondria. In this review, we summarize the available evidence and the most recent advances exploring the underlying mechanisms of ferroptosis and cuproptosis in CVDs and diabetic cardiovascular complications, to provide critical perspectives on the potential pathogenic roles of ferroptosis and cuproptosis in cadmium-induced or exacerbated cardiovascular complications in diabetic individuals.

Modulation of the Cardiovascular Risk in Type 1 Diabetic Rats by Endurance Training in Combination with the Prebiotic Xylooligosaccharide

Diabetic cardiomyopathy is a major etiological factor in heart failure in diabetic patients, characterized by mitochondrial oxidative metabolism dysfunction, myocardial fibrosis, and marked glycogen elevation. The aim of the present study is to evaluate the effect of endurance training and prebiotic xylooligosaccharide (XOS) on the activity of key oxidative enzymes, myocardial collagen, and glycogen distribution as well as some serum biochemical risk markers in streptozotocin-induced type 1 diabetic rats. Male Wistar rats (n = 36) were divided into four diabetic groups (n = 9): sedentary diabetic rats on a normal diet (SDN), trained diabetic rats on a normal diet (TDN), trained diabetic rats on a normal diet with an XOS supplement (TD-XOS), and sedentary diabetic rats with an XOS supplement (SD-XOS). The results show that aerobic training managed to increase the enzyme activity of respiratory Complex I and II and the lactate dehydrogenase in the cardiomyocytes of the diabetic rats. Furthermore, the combination of exercise and XOS significantly decreased the collagen and glycogen content. No significant effects on blood pressure, heart rate or markers of inflammation were detected. These results demonstrate the beneficial effects of exercise, alone or in combination with XOS, on the cardiac mitochondrial enzymology and histopathology of diabetic rats.

Recent Advances of Natural Pentacyclic Triterpenoids as Bioactive Delivery System for Synergetic Biological Applications

Bioactive compounds have drawn much attention according to their various health benefits. However, poor dissolvability, low stability and limited bioavailability largely narrow their applications. Although a variety of nontoxic ingredients have been rapidly developed as vehicles to deliver bioactive compounds in the last few years, most of them are non-bioactive. Pentacyclic triterpenoids, owing to their unique self-assembly and co-assembly behaviors and different physiological functions, can construct bioactive carriers due to their higher biodegradability, biocompatibility and lower toxicity. In this paper, the basic classification, biological activities and physicochemical properties of pentacyclic triterpenoids were summarized. Additionally, applications of self-assembled and co-assembled pentacyclic triterpenoids as bioactive delivery systems to load bioactive components and future research directions were discussed. This study emphasizes the potential of pentacyclic triterpenoids as bioactive delivery systems, offering a new perspective for constructing self- or co-assemblies for further synergetic biological applications.

Arjunolic acid protects the intestinal epithelial barrier, ameliorating Crohn's disease-like colitis by restoring gut microbiota composition and inactivating TLR4 signalling

BACKGROUND AND AIMS

Crohn's disease (CD) is characterized by an overabundance of epithelial cell death and an imbalance in microflora, both of which contribute to the dysfunction of the intestinal barrier. Arjunolic acid (AA) has anti-apoptotic effects and regulates microbiota efficacy. The objective of this study was to assess the impact of the treatment on colitis resembling Crohn's disease, along with exploring the potential underlying mechanism.

METHODS

CD animal models were created using Il-10-/- mice, and the impact of AA on colitis in mice was evaluated through disease activity index, weight fluctuations, pathological examination, and assessment of intestinal barrier function. To clarify the direct role of AA on intestinal epithelial cell apoptosis, organoids were induced by LPS, and TUNEL staining was performed. To investigate the potential mechanisms of AA in protecting the intestinal barrier, various methods including bioinformatics analysis and FMT experiments were employed.

RESULTS

The treatment for AA enhanced the condition of colitis and the function of the intestinal barrier in Il-10-/- mice. This was demonstrated by the amelioration of weight loss, reduction in tissue inflammation score, and improvement in intestinal permeability. Moreover, AA suppressed the apoptosis of intestinal epithelial cells in Il-10-/- mice and LPS-induced colon organoids, while also reducing the levels of Bax and C-caspase-3. In terms of mechanism, AA suppressed the activation of TLR4 signaling in Il-10-/- mice and colon organoids induced by LPS. In addition, AA increased the abundance of short-chain fatty acid-producing bacteria in the stool of Il-10-/- mice, and transplantation of feces from AA-treated mice improved CD-like colitis.

CONCLUSIONS

The results of our study demonstrate that AA has a protective effect on the intestinal barrier in Crohn's disease-like colitis by preventing apoptosis. Additionally, this groundbreaking study reveals the capacity of AA to hinder TLR4 signaling and alter the makeup of the intestinal microbiome. The findings present fresh possibilities for treating individuals diagnosed with Crohn's disease. AA offers a hopeful novel strategy for managing Crohn's disease by obstructing crucial pathways implicated in intestinal inflammation and enhancing the gut microbiota.

Cardioprotective effects of arjunolic acid in LPS-stimulated H9C2 and C2C12 myotubes via the My88-dependent TLR4 signaling pathway

CONTEXT

Arjunolic acid (AA) is a triterpenoid saponin found in Terminalia arjuna (Roxb.) Wight & Arn. (Combretaceae). It exerts cardiovascular protective effects as a phytomedicine. However, it is unclear how AA exerts the effects at the molecular level.

OBJECTIVE

This study investigates the cardioprotective effects of arjunolic acid (AA) via MyD88-dependant TLR4 downstream signaling marker expression.

MATERIALS AND METHODS

The MTT viability assay was used to assess the cytotoxicity of AA. LPS induced in vitro cardiovascular disease model was developed in H9C2 and C2C12 myotubes. The treatment groups were designed such as control (untreated), LPS control, positive control (LPS + pyrrolidine dithiocarbamate (PDTC)-25 µM), and treatment groups were co-treated with LPS and three concentrations of AA (50, 75, and 100 µM) for 24 h. The changes in the expression of TLR4 downstream signaling markers were evaluated through High Content Screening (HCS) and Western Blot (WB) analysis.

RESULTS

After 24 h of co-treatment, the expression of TLR4, MyD88, MAPK, JNK, and NF-κB markers were upregulated significantly (2-6 times) in the LPS-treated groups compared to the untreated control in both HCS and WB experiments. Evidently, the HCS analysis revealed that MyD88, NF-κB, p38, and JNK were significantly downregulated in the H9C2 myotube in the AA treated groups. In HCS, the expression of NF-κB was downregulated in C2C12. Additionally, TLR4 expression was downregulated in both H9C2 and C2C12 myotubes in the WB experiment.

DISCUSSION AND CONCLUSIONS

TLR4 marker expression in H9C2 and C2C12 myotubes was subsequently decreased by AA treatment, suggesting possible cardioprotective effects of AA.

Natural Products as Modulators of Mitochondrial Dysfunctions Associated with Cardiovascular Diseases: Advances and Opportunities

The mitochondria have an important role in modulating cell cycle progression, cell survival, and apoptosis. In the adult heart, the cardiac mitochondria have a unique spatial arrangement and occupy nearly one-third the volume of a cardiomyocyte, being highly efficient for converting the products of glucose or fatty acid metabolism into adenosine triphosphate (ATP). In cardiomyocytes, the decline of mitochondrial function reduces ATP generation and increases the production of reactive oxygen species, which generates impaired heart function. This is because mitochondria play a key role in maintaining cytosolic calcium concentration and modulation of muscle contraction, as ATP is required to dissociate actin from myosin. Beyond that, mitochondria have a significant role in cardiomyocyte apoptosis because it is evident that patients who have cardiovascular diseases (CVDs) have increased mitochondrial DNA damage to the heart and aorta. Many studies have shown that natural products have mitochondria-modulating effects in cardiac diseases, determining them as potential candidates for new medicines. This review outlines the leading plant secondary metabolites and natural compounds derived from microorganisms as modulators of mitochondrial dysfunctions associated with CVDs.

Arjunolic acid downregulates elevated blood sugar and pro-inflammatory cytokines in streptozotocin (STZ)-nicotinamide induced type 2 diabetic rats

BACKGROUND

Type 2 diabetes mellitus (T2DM) is a worldwide health issue primarily due to failure of pancreatic β-cells to release sufficient insulin.

PURPOSE

The present work aimed to assess the antidiabetic potential of arjunolic acid (AA) isolated from Terminalia arjuna in type 2 diabetic rats.

STUDY DESIGN

After extraction, isolation and purification, AA was orally administered to type 2 diabetic Sprague Dawley rats to investigate antidiabetic effect of AA.

METHOD

T2DM was induced via single intraperitoneal injection of streptozotocin-nicotinamide (STZ-NIC) in adult male rats. After 10 days, fasting and random blood glucose (FBG and RBG), body weight (BW), food and water intake, serum C-peptide, insulin and glycated hemoglobin (HbA1c) was measured to confirm T2DM development. Dose dependent effects of orally administered AA (25 and 50 mg/kg/day) for 4 weeks was investigated by measuring BW variation, fasting and postprandial hyperglycemia, oral glucose tolerance test (OGTT), and levels of serum HbA1c, serum total cholesterol (TC), triglyceride (TG), low density lipoprotein (LDL), high density lipoprotein (HDL), serum and pancreatic C-peptide, insulin, growth differentiation factor 15 (GDF-15), serum and pancreatic inflammatory cytokines.

RESULTS

The oral administration of AA in preclinical model of T2DM significantly normalized FBG and RBG, restored BW, controlled polyphagia, polydipsia and glucose tolerance. In addition, AA notably reduced serum HbA1c, TC, TG, LDL with non-significant increase in HDL. On the other hand, significant increase in serum and pancreatic C-peptide and insulin was observed with AA treatment, while serum and pancreatic GDF-15 were non-significantly altered in AA treated diabetic rats. Moreover, AA showed dose dependent reduction in serum and pancreatic proinflammatory cytokines including TNF-α, IL-1β and IL-6.

CONCLUSION

For the first time our findings highlighted AA as a potential candidate in type 2 diabetic conditions.

A Systematic Review of Orthosiphon stamineus Benth. in the Treatment of Diabetes and Its Complications

(1) Background: Orthosiphon stamineus Benth. is a traditional medicine used in the treatment of diabetes and chronic renal failure in southern China, Malaysia, and Thailand. Diabetes is a chronic metabolic disease and the number of diabetic patients in the world is increasing. This review aimed to systematically review the effects of O. stamineus in the treatment of diabetes and its complications and the pharmacodynamic material basis. (2) Methods: This systematic review was conducted following Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA), using the databases ScienceDirect, PubMed, and Web of Science. (3) Results: Thirty-one articles related to O. stamineus and diabetes were included. The mechanisms of O. stamineus in the treatment of diabetes and its complications mainly included inhibiting α-amylase and α-glucosidase activities, antioxidant and anti-inflammatory activities, regulating lipid metabolism, promoting insulin secretion, ameliorating insulin resistance, increasing glucose uptake, promoting glycolysis, inhibiting gluconeogenesis, promoting glucagon-likepeptide-1 (GLP-1) secretion and antiglycation activity. Phenolic acids, flavonoids and triterpenoids might be the main components for hypoglycemia effects in O. stamineus. (4) Conclusion: O. stamineus could be an antidiabetic agent to treat diabetes and its complications. However, it needs further study on a pharmacodynamic substance basis and the mechanisms of effective constituents.

Anti-Diabetic Effects of Isolated Lipids from Natural Sources through Modulation of Angiogenesis

BACKGROUND

Aberrant angiogenesis plays a fateful role in the development of diabetes and diabetic complications. Lipids, as a diverse group of biomacromolecules, are able to relieve diabetes through the modulation of angiogenesis.

OBJECTIVE

Owing to the present remarkable anti-diabetic effects with no or few side effects of lipids, the aim of this study was to assess the state-of-the-art research on anti-diabetic effects of lipids via the modulation of angiogenesis.

METHODS

To study the effects of lipids in diabetes via modulation of angiogenesis, we have searched the electronic databases including Scopus, PubMed, and Cochrane.

RESULTS

The promising anti-diabetic effects of lipids were reported in several studies. Eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA) from fish oil (FO) were reported to significantly induce neovasculogenesis in high glucose (HG)-mediated endothelial progenitor cells (EPCs) neovasculogenic dysfunction in type 2 diabetic mice. Linoleic acid, mono-epoxy-tocotrienol-α (MeT3α), and ginsenoside Rg1 facilitate wound closure and vessel formation. N-Palmitoylethanolamine (PEA), α-linolenic acid (ALA), omega-3 (ω3) lipids from flaxseed (FS) oil, ω-3 polyunsaturated fatty acids (PUFA), lipoic acid, taurine, and zeaxanthin (Zx) are effective in diabetic retinopathy via suppression of angiogenesis. Lysophosphatidic acid, alkyl-glycerophosphate, crocin, arjunolic acid, α-lipoic acid, and FS oil are involved in the management of diabetes and its cardiac complications. Furthermore, in two clinical trials, R-(+)-lipoic acid (RLA) in combination with hyperbaric oxygenation therapy (HBOT) for treatment of chronic wound healing in DM patients, as well as supplementation with DHA plus antioxidants along with intravitreal ranibizumab were investigated for its effects on diabetic macular edema.

CONCLUSION

Proof-of-concept studies presented here seem to well shed light on the anti-diabetic effects of lipids via modulation of angiogenesis.

Advanced Glycation End Products: Potential Mechanism and Therapeutic Target in Cardiovascular Complications under Diabetes

The occurrence and development of cardiovascular complications are predominantly responsible for the increased morbidity and mortality observed in patients with diabetes. Oxidative stress under hyperglycemia is currently considered the initial link to diabetic cardiovascular complications and a key node for the prevention and treatment of diabetes-related fatal cardiovascular events. Numerous studies have indicated that the common upstream pathway in the context of oxidative stress in the cardiovascular system under diabetic conditions is the interaction of advanced glycation end products (AGEs) with their receptors (RAGEs). Therefore, a further understanding of the relationship between oxidative stress and AGEs is of great significance for the prevention and treatment of cardiovascular complications in patients with diabetes. In this review, we will briefly summarize the recent research advances in diabetes with an emphasis on oxidative stress and its association with AGEs in diabetic cardiovascular complications.

Ursolic acid ameliorates oxidative stress, inflammation and fibrosis in diabetic cardiomyopathy rats

Diabetic cardiomyopathy is a major and severe cardiovascular complication of diabetes mellitus. Ursolic acid, a pentacyclic triterpene compound widespread in fruits and plants, performs a variety of pharmacological activities including lowering blood glucose, anti-oxidation, anti-inflammation and anti-fibrosis. Our present study aimed to investigate the cardioprotective effects of ursolic acid on diabetic cardiomyopathy rats and uncover its underlying mechanism. Diabetes mellitus was induced by a single injection of STZ-only (40 mg/ kg, i.v.) in male SD rats. Animals were divided into three groups (n=10): control group (normal saline, i.g.), diabetic group (normal saline, i.g.) and diabetic+ursolic acid group (35 mg/kg UA + normal saline, i.g.). Rats were administered for 8 weeks from 5th to 12th week. After the last administration, cardiac function was evaluated; HWI was calculated; FBG, CK, LDH in serum and SOD, MDA in cardiac tissue were detected. HE staining and Masson trichrome staining were employed to observe pathological alterations. Immunohistochemistry and western blotting were taken to determine the expression levels of TNF-α, MCP-1, TGF-β1 and MMP-2 in the heart. The results dramatically showed increased levels of FBG, CK, LDH, MDA and a decreased activity of SOD in diabetic group, in which left ventricular dysfunction, cardiac myocytes hypertrophy, inflammatory cell infiltration and myocardial interstitial fibrosis had also been found. What's more, the expressions of TNF-α, MCP-1 and TGF-β1 were significantly up-regulated and the expression of MMP-2 was markedly down-regulated in myocardium. Interestingly, treatment with ursolic acid remarkably ameliorated these changes. Collectively, our study strongly showed that ursolic acid is capable of improving the cardiac structure and function in STZ-induced diabetic cardiomyopathy rats by attenuating oxidative stress, inflammation and fibrosis.

Prophylactic role of taurine and its derivatives against diabetes mellitus and its related complications

Taurine is a conditionally essential amino acid present in the body in free form. Mammalian taurine is synthesized in the pancreas via the cysteine sulfinic acid pathway. Anti-oxidation and anti-inflammation are two main properties through which it exerts its therapeutic effects. Many studies have shown its excellent therapeutic potential against diabetes mellitus and related complications like diabetic neuropathy, retinopathy, nephropathy, hematological dysfunctions, reproductive dysfunctions, liver and pancreas related complications etc. Not only taurine, a number of its derivatives have also been reported to be important in ameliorating diabetic complications. The present review has been aimed to describe the importance of taurine and its derivatives against diabetic metabolic syndrome and related complications.

Curcumin attenuates oxidative stress induced NFκB mediated inflammation and endoplasmic reticulum dependent apoptosis of splenocytes in diabetes

The present study was aimed to determine the curative role of curcumin against diabetes induced oxidative stress and its associated splenic complications. Diabetes was induced in the experimental rats via the intraperitoneal administration of a single dose of STZ (65mgkg-1body weight). Increased blood glucose and intracellular ROS levels along with decreased body weight, the activity of cellular antioxidant enzymes and GSH/GSSG ratio were observed in the diabetic animals. Histological assessment showed white pulp depletion and damaged spleen anatomy in these animals. Oral administration of curcumin at a dose of 100mgkg-1 body weight daily for 8weeks, however, restored these alterations. Investigation of the mechanism of hyperglycemia induced oxidative stress mediated inflammation showed upregulation of inflammatory cytokines, chemokines, adhesion molecules and increased translocation of NFκB into the nucleus. Moreover, ER stress dependent cell death showed induction of eIF2α and CHOP mediated signalling pathways as well as increment in the expression of GRP78, Caspase-12, Calpain-1, phospho JNK, phospho p38 and phospho p53 in the diabetic group. Alteration of Bax/Bcl-2 ratio; disruption of mitochondrial membrane potential, release of cytochrome-C from mitochondria and upregulation of caspase 3 along with the formation of characteristic DNA ladder in the diabetic animals suggest the involvement of mitochondria dependent apoptotic pathway in the splenic cells. Treatment with curcumin could, however, protect cells from inflammatory damage and ER as well as mitochondrial apoptotic death by restoring the alterations of these parameters. Our results suggest that curcumin has the potential to act as an anti-diabetic, anti-oxidant, anti-inflammatory and anti-apoptotic therapeutic against diabetes mediated splenic damage.

Pancreatic mitochondrial complex I exhibits aberrant hyperactivity in diabetes

It is well established that NADH/NAD+ redox balance is heavily perturbed in diabetes, and the NADH/NAD+ redox imbalance is a major source of oxidative stress in diabetic tissues. In mitochondria, complex I is the only site for NADH oxidation and NAD+ regeneration and is also a major site for production of mitochondrial reactive oxygen species (ROS). Yet how complex I responds to the NADH/NAD+ redox imbalance and any potential consequences of such response in diabetic pancreas have not been investigated. We report here that pancreatic mitochondrial complex I showed aberrant hyperactivity in either type 1 or type 2 diabetes. Further studies focusing on streptozotocin (STZ)-induced diabetes indicate that complex I hyperactivity could be attenuated by metformin. Moreover, complex I hyperactivity was accompanied by increased activities of complexes II to IV, but not complex V, suggesting that overflow of NADH via complex I in diabetes could be diverted to ROS production. Indeed in diabetic pancreas, ROS production and oxidative stress increased and mitochondrial ATP production decreased, which can be attributed to impaired pancreatic mitochondrial membrane potential that is responsible for increased cell death. Additionally, cellular defense systems such as glucose 6-phosphate dehydrogenase, sirtuin 3, and NQO1 were found to be compromised in diabetic pancreas. Our findings point to the direction that complex I aberrant hyperactivity in pancreas could be a major source of oxidative stress and β cell failure in diabetes. Therefore, inhibiting pancreatic complex I hyperactivity and attenuating its ROS production by various means in diabetes might serve as a promising approach for anti-diabetic therapies.

Sansevieria roxburghiana Schult. & Schult. F. (Family: Asparagaceae) Attenuates Type 2 Diabetes and Its Associated Cardiomyopathy

BACKGROUND

Sansevieria roxburghiana Schult. & Schult. F. (Family: Asparagaceae) rhizome has been claimed to possess antidiabetic activity in the ethno-medicinal literature in India. Therefore, present experiments were carried out to explore the protective role of edible (aqueous) extract of S. roxburghiana rhizome (SR) against experimentally induced type 2 diabetes mellitus (T2DM) and its associated cardiomyopathy in Wistar rats.

METHODS

SR was chemically characterized by GC-MS analysis. Antidiabetic activity of SR (50 and 100 mg/kg, orally) was measured in high fat diets (ad libitum) + low-single dose of streptozotocin (35 mg/kg, intraperitoneal) induced type 2 diabetic (T2D) rat. Fasting blood glucose level was measured at specific intermissions. Serum biochemical and inflammatory markers were estimated after sacrificing the animals. Besides, myocardial redox status, expressions of signal proteins (NF-κB and PKCs), histological and ultrastructural studies of heart were performed in the controls and SR treated T2D rats.

RESULTS

Phytochemical screening of the crude extract revealed the presence of phenolic compounds, sugar alcohols, sterols, amino acids, saturated fatty acids within SR. T2D rats exhibited significantly (p < 0.01) higher fasting blood glucose level with respect to control. Alteration in serum lipid profile (p < 0.01) and increased levels of lactate dehydrogenase (p < 0.01) and creatine kinase (p < 0.01) in the sera revealed the occurrence of hyperlipidemia and cell destruction in T2D rats. T2DM caused significant (p < 0.05-0.01) alteration in the biochemical markers in the sera. T2DM altered the redox status (p < 0.05-0.01), decreased (p < 0.01) the intracellular NAD and ATP concentrations in the myocardial tissues of experimental rats. While investigating the molecular mechanism, activation PKC isoforms was observed in the selected tissues. T2D rats also exhibited an up-regulation in nuclear NF-κB (p65) in the cardiac tissues. So, oral administration of SR (50 and 500 mg/kg) could reduce hyperglycemia, hyperlipidemia, membrane disintegration, oxidative stress, vascular inflammation and prevented the activation of oxidative stress induced signaling cascades leading to cell death. Histological and ultra-structural studies of cardiac tissues supported the protective characteristics of SR.

CONCLUSIONS

From the present findings it can be concluded that, SR could offer protection against T2DM and its associated cardio-toxicity via multiple mechanisms viz. hypoglycemic, antioxidant and anti-inflammatory actions.

Deciphering the role of ferulic acid against streptozotocin-induced cellular stress in the cardiac tissue of diabetic rats

The cardiomyocytes are one of the major sources of hyperglycemia induced ROS generation. The present study focuses on the ameliorative role of ferulic acid in combating cardiac complications in diabetic rats. Induction of diabetes by STZ in male Wistar rats (at a dose of 50 mg kg-1 body wt, i.p.) reduced body weight and plasma insulin level, enhanced blood glucose, disturbed the intra-cellular antioxidant machineries and disintegrated the normal radiation pattern of cardiac muscle fibers. Induction of ER stress (up-regulation in the levels of CHOP, GRP78, eIF2α signaling, increased calpain-1 expression), caspase-3 activation, PARP cleavage and DNA fragmentation were evidenced from immunoblot analyses and DNA fragmentation assay. However, ferulic acid administration, (at a dose of 50 mg kg-1 body wt, orally for eight weeks) in post-hyperglycemia could reverse such adverse effects. Also, the molecule increased GLUT-4 translocation to the cardiac membrane by enhanced phosphorylation of PI3Kinase, AKT and inactivation of GSK-3β thereby altering the hyperglycemic condition in the cardiac tissue of diabetic rats. Therefore, as a potential therapeutic, ferulic acid, exhibiting antioxidant and hypoglycemic effects, may hold promise in circumventing stress mediated diabetic cardiomyopathy in rats.

Cardiac-specific overexpression of catalase prevents diabetes-induced pathological changes by inhibiting NF-κB signaling activation in the heart

Catalase is an antioxidant enzyme that specifically catabolizes hydrogen peroxide (H2O2). Overexpression of catalase via a heart-specific promoter (CAT-TG) was reported to reduce diabetes-induced accumulation of reactive oxygen species (ROS) and further prevent diabetes-induced pathological abnormalities, including cardiac structural derangement and left ventricular abnormity in mice. However, the mechanism by which catalase overexpression protects heart function remains unclear. This study found that activation of a ROS-dependent NF-κB signaling pathway was downregulated in hearts of diabetic mice overexpressing catalase. In addition, catalase overexpression inhibited the significant increase in nitration levels of key enzymes involved in energy metabolism, including α-oxoglutarate dehydrogenase E1 component (α-KGD) and ATP synthase α and β subunits (ATP-α and ATP-β). To assess the effects of the NF-κB pathway activation on heart function, Bay11-7082, an inhibitor of the NF-κB signaling pathway, was injected into diabetic mice, protecting mice against the development of cardiac damage and increased nitrative modifications of key enzymes involved in energy metabolism. In conclusion, these findings demonstrated that catalase protects mouse hearts against diabetic cardiomyopathy, partially by suppressing NF-κB-dependent inflammatory responses and associated protein nitration.

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.

Pleurotus ostreatus opposes mitochondrial dysfunction and oxidative stress in acetaminophen-induced hepato-renal injury

Background

Acetaminophen (APAP)-induced toxicity is a predominant cause of acute hepatic and renal failure. In both humans and rodents toxicity begins with a reactive metabolite that binds to proteins. This leads to mitochondrial dysfunction and nuclear DNA fragmentation resulting in necrotic cell death. Pleurotus ostreatus (an edible oyster mushroom) is well recognized as a flavourful food, as well as a medicinal supplement. In the present study, we evaluated the role of Pleurotus ostreatus in the protection against APAP-induced hepato-renal toxicity. We also explored the mechanism by which Pleurotus ostreatus exerts its effects.

Methods

Ninety adult male Swiss albino mice were divided into three groups (30 mice/group). Mice were offered normal diet (control and APAP groups), or diet supplemented with 10% Pleurotus ostreatus (APAP + Pleurotus ostreatus) for 10 days. Mice were either treated with vehicle (control group, single intra-peritoneal injection.), or APAP (APAP and APAP + Pleurotus ostreatus groups, single intra-peritoneal injection, 500 mg/kg), 24 hours after the last meal.

Results

APAP increased serum levels of alanine aminotransferase (ALT), aspartate aminotransferase (AST) glutamate dehydrogenase (GDH), creatinine, blood urea nitrogen (BUN), urinary kidney injury molecule-1 (KIM-1), and hepatic and renal malondialdehyde (MDA) content. APAP decreased hepatic and renal glutathione (GSH) content, as well as glutathione peroxidase (GSH-Px) and superoxide dismutase (SOD) activities. Supplementation with Pleurotus ostreatus significantly reduced APAP-induced elevated levels of ALT, AST, GDH, creatinine, BUN, KIM-1and MDA, while GSH level, and GSH-Px and SOD activities were significantly increased. Our findings were further validated by histopathology; treatment with Pleurotus ostreatus significantly decreased APAP-induced cell necrosis in liver and kidney tissues.

Conclusions

We report here that the antioxidant effect of Pleurotus ostreatus opposes mitochondrial dysfunction and oxidative stress accompanying APAP over-dose, with subsequent clinically beneficial effects on liver and kidney tissues.

Amelioration of cisplatin-induced nephrotoxicity in rats by triterpenoid saponin of Terminalia arjuna

BACKGROUND

Cisplatin is a potent anti-tumor compound. Nephrotoxicity-inducing oxidative stress is a common side effect. This study was conducted to find out whether, the triterpenoid saponin of Terminalia arjuna (TA), Arjunolic acid which is a natural antioxidant, could prevent cisplatin-induced renal toxicity and if so, explore its possible renoprotective mechanism.

METHODS

Thirty male Sprague-Dawley rats were divided into three groups:

CONTROL GROUP

rats received saline injection, cisplatin group: rats injected intraperitoneally with 7 mg/kg cisplatin and Arjunolic acid group: rats received 20 mg/kg Arjunolic acid daily for 10 days with cisplatin injection on day 5. Serum creatinine and blood urea nitrogen (BUN) were determined and kidney sections were obtained for histopathology. Oxidative stress was evaluated in kidney homogenates by measuring malondialdehyde (MDA), reduced glutathione (GSH) and nitric oxide (NO) levels. Renal gene expressions of transforming growth factor-beta (TGF-β), nuclear factor-kappa B (NF-κB), kidney injury molecule-1 (Kim-1) and B cell lymphoma-2 (Bcl-2) were estimated.

RESULTS

Cisplatin-treated rats showed a significant reduction in renal GSH and a significant elevation of serum creatinine, BUN, MDA and NO renal levels when compared with control. Moreover, upregulation of TGF-β, NF-κB and Kim-1 along with downregulation of Bcl-2 renal expressions were also observed in cisplatin-treated rats in comparison to control. All these markers were significantly reversed by TA triterpenoid saponin administration.

CONCLUSION

Arjunolic acid ameliorated the nephrotoxic biochemical changes induced by cisplatin supporting its renoprotective effects which may be mediated by attenuation of oxidative stress markers, downregulation of renal expressions of fibrotic (TGF-β), inflammatory (NF-κB) and kidney injury (Kim-1) markers along with upregulation of renal antiapoptotic marker (Bcl-2) gene expressions.

Combination approaches to attenuate hemorrhagic transformation after tPA thrombolytic therapy in patients with poststroke hyperglycemia/diabetes

To date, tissue type plasminogen activator (tPA)-based thrombolytic stroke therapy is the only FDA-approved treatment for achieving vascular reperfusion and clinical benefit, but this agent is given to only about 5% of stroke patients in the USA. This may be related, in part, to the elevated risk of symptomatic intracranial hemorrhage, and consequently limited therapeutic time window. Clinical investigations demonstrate that poststroke hyperglycemia is one of the most important risk factors that cause intracerebral hemorrhage and worsen neurological outcomes. There is a knowledge gap in understanding the underlying molecular mechanisms, and lack of effective therapeutics targeting the severe complication. This short review summarizes clinical observations and experimental investigations in preclinical stroke models of the field. The data strongly suggest that interactions of multiple pathogenic factors including hyperglycemia-mediated vascular oxidative stress and inflammation, ischemic insult, and tPA neurovascular toxicity in concert contribute to the BBB damage-intracerebral hemorrhagic transformation process. Development of combination approaches targeting the multiple pathological cascades may help to attenuate the hemorrhagic complication.

An update on oxidative stress-mediated organ pathophysiology

Exposure to environmental pollutants and drugs can result in pathophysiological situations in the body. Research in this area is essential as the knowledge on cellular survival and death would help in designing effective therapeutic strategies that are needed for the maintenance of the normal physiological functions of the body. In this regard, naturally occurring bio-molecules can be considered as potential therapeutic targets as they are normally available in commonly consumed foodstuffs and are thought to have minimum side effects. This review article describes the detailed mechanisms of oxidative stress-mediated organ pathophysiology and the ultimate fate of the cells either to survive or to undergo necrotic or apoptotic death. The mechanisms underlying the beneficial role of a number of naturally occurring bioactive molecules in oxidative stress-mediated organ pathophysiology have also been included in the review. The review provides useful information about the recent progress in understanding the mechanism(s) of various types of organ pathophysiology, the complex cross-talk between these pathways, as well as their modulation in stressed conditions. Additionally, it suggests possible therapeutic applications of a number of naturally occurring bioactive molecules in conditions involving oxidative stress.

Effect of Kombucha, a fermented black tea in attenuating oxidative stress mediated tissue damage in alloxan induced diabetic rats

Diabetic complications associated with increased oxidative stress can be suppressed by antioxidants. In the present study we investigated the antidiabetic and antioxidant effects of Kombucha (KT), a fermented black tea, in comparison to that of unfermented black tea (BT), in ALX-induced diabetic rats. ALX exposure lowered the body weight and plasma insulin by about 28.12% and 61.34% respectively and elevated blood glucose level and glycated Hb by about 3.79 and 3.73 folds respectively. The oxidative stress related parameters like lipid peroxidation end products (increased by 3.38, 1.7, 1.65, 1.94 folds respectively), protein carbonyl content (increased by 2.5, 2.35, 1.8, 3.26 folds respectively), glutathione content (decreased by 59.8%, 47.27%, 53.69%, 74.03% respectively), antioxidant enzyme activities were also altered in the pancreatic, hepatic, renal and cardiac tissues of diabetic animals. Results showed significant antidiabetic potential of the fermented beverage (150 mg lyophilized extract/kg bw for 14 days) as it effectively restored ALX-induced pathophysiological changes. Moreover, it could ameliorate DNA fragmentation and caspase-3 activation in the pancreatic tissue of diabetic rats. Although unfermented black tea is effective in the above pathophysiology, KT was found to be more efficient. This might be due to the formation of some antioxidant molecules during fermentation period.

Oxidative stress: the mitochondria-dependent and mitochondria-independent pathways of apoptosis

Oxidative stress basically defines a condition in which prooxidant-antioxidant balance in the cell is disturbed; cellular biomolecules undergo severe oxidative damage, ultimately compromising cells viability. In recent years, a number of studies have shown that oxidative stress could cause cellular apoptosis via both the mitochondria-dependent and mitochondria-independent pathways. Since these pathways are directly related to the survival or death of various cell types in normal as well as pathophysiological situations, a clear picture of these pathways for various active molecules in their biological functions would help designing novel therapeutic strategy. This review highlights the basic mechanisms of ROS production and their sites of formation; detail mechanism of both mitochondria-dependent and mitochondria-independent pathways of apoptosis as well as their regulation by ROS. Emphasis has been given on the redox-sensitive ASK1 signalosome and its downstream JNK pathway. This review also describes the involvement of oxidative stress under various environmental toxin- and drug-induced organ pathophysiology and diabetes-mediated apoptosis. We believe that this review would provide useful information about the most recent progress in understanding the mechanism of oxidative stress-mediated regulation of apoptotic pathways. It will also help to figure out the complex cross-talks between these pathways and their modulations by oxidative stress. The literature will also shed a light on the blind alleys of this field to be explored. Finally, readers would know about the ROS-regulated and apoptosis-mediated organ pathophysiology which might help to find their probable remedies in future.

Arjunolic acid: a new multifunctional therapeutic promise of alternative medicine

IMPORTANCE OF THE FIELD

In recent years, a number of studies describing the effective therapeutic strategies of medicinal plants and their active constituents in traditional medicine have been reported. Indeed, tremendous demand for the development and implementation of these plant derived biomolecules in complementary and alternative medicine is increasing and appear to be promising candidates for pharmaceutical industrial research. These new molecules, especially those from natural resources, are considered as potential therapeutic targets, because they are derived from commonly consumed foodstuff and are considered to be safe for humans.

AREAS COVERED IN THIS REVIEW

This review highlights the beneficial role of arjunolic acid, a naturally occurring chiral triterpenoid saponin, in various organ pathophysiology and the underlying mechanism of its protective action. Studies on the biochemistry and pharmacology suggest the potential use of arjunolic acid as a novel promising therapeutic strategy.

WHAT THE READERS WILL GAIN

The multifunctional therapeutic application of arjunolic acid has already been documented by its various biological functions including antioxidant, anti-fungal, anti-bacterial, anticholinesterase, antitumor, antiasthmatic, wound healing and insect growth inhibitor activities. The scientific basis behind its therapeutic application as a cardioprotective agent in traditional medicine is justified by its ability to prevent myocardial necrosis and apoptosis, platelet aggregation, coagulation and lowering of blood pressure, heart rate, as well as cholesterol levels. Its antioxidant property coupled with metal chelating property (by its two hydroxyl groups) protects different organs from metal and drug-induced organ pathophysiology. Arjunolic acid also plays a beneficial role in the pathogenesis of diabetes and its associated complications. The mechanism of cytoprotection of arjunolic acid, at least in part, results from the detoxification of reactive oxygen species (ROS) produced in the respective pathophysiology. In addition to its other biological functions, it also possesses vibrant insecticidal properties and it has the potential to be used as a structural molecular framework for the design of molecular receptors in the general area of supramolecular chemistry and nanochemistry. Esters of arjunolic acid function as organogelators which has wide application in designing thermochromic switches and sensor devices. Arjunolic acid derived crown ether is an attractive candidate for the design of molecular receptors, biomimetics and supramolecular systems capable of performing some biological functions.

HOME MESSAGE

This review would provide useful information about the recent progress of natural product research in the domain of clinical science. This review also aims to untie the multifunctional therapeutic application of arjunolic acid, a nanometer-long naturally occurring chiral triterpenoid biomolecule.

Lotus (Nelumbo nucifera Gaertn) plumule polysaccharide ameliorates pancreatic islets loss and serum lipid profiles in non-obese diabetic mice

To unravel possible protective effects of a newly isolated lotus plumule polysaccharide (LPPS) on type 1 diabetes (T1D), this study isolated LPPS and administered it to non-obese diabetic (NOD) female mice for 15 weeks. Oral glucose tolerance, serum ketone body, glucose, insulin, and lipid levels, as well as pancreatic islet cell numbers and the insulin secretion ability of the experimental mice were determined. The results showed that LPPS administration in vivo significantly (P<0.05) increased pancreatic islet cell numbers and slightly enhanced the basal insulin secretion ability compared to the control group. LPPS administration improved serum lipid profiles in the diabetic mice via relatively increasing serum high density lipoprotein-cholesterol, but decreasing low density lipoprotein-cholesterol and total cholesterol levels. The present study suggests that LPPS supplementation may ameliorate T1D progress and its complications through protecting pancreatic islets and modulating serum lipid profiles.

Rhinacanthus nasutus Ameliorates Cytosolic and Mitochondrial Enzyme Levels in Streptozotocin-Induced Diabetic Rats

The present study was conducted to evaluate the therapeutic efficacy of Rhinacanthus nasutus (R. nasutus) on mitochondrial and cytosolic enzymes in streptozotocin-induced diabetic rats. The rats were divided into five groups with 6 rats in each group. The methanolic extract of R. nasutus was orally administered at a dose of 200 mg/kg/day, and glibenclamide was administered at a dose of 50 mg/kg/day. All animals were treated for 30 days and were sacrificed. The activities of both intra- and extramitochondrial enzymes including glucose-6-phosphate dehydrogenase (G6PDH), succinate dehydrogenase (SDH), glutamate dehydrogenase (GDH), and lactate dehydrogenase (LDH) were measured in the livers of the animals. The levels of G6PDH, SDH, and GDH were significantly reduced in the diabetic rats but were significantly increased after 30 days of R. nasutus treatment. The increased LDH level in diabetic rats exhibited a significant reduction after treatment with R. nasutus. These results indicate that the administration of R. nasutus altered the activities of oxidative enzymes in a positive manner, indicating that R. nasutus improves mitochondrial energy production. Our data suggest that R. nasutus should be further explored for its role in the treatment of diabetes mellitus.

Arjunolic acid: beneficial role in type 1 diabetes and its associated organ pathophysiology

In this review article, we describe the most recent development of the beneficial effect of arjunolic acid (AA) in reducing type 1 diabetic pathophysiology. Diabetic mellitus is a serious and growing health problem worldwide. Increasing evidence suggest that oxidative stress plays a pivotal role in the pathogenesis of diabetes and its associated complications. Use of antioxidant supplements as a complimentary therapeutic approach in diabetes has, therefore, been seriously considered worldwide. AA, a natural pentacyclic triterpenoid saponin, is well known for various biological functions including antioxidant activity. It could prevent the increased production of ROS, RNS, AGEs, and the 8OHdG/2dG ratio and increase the intracellular antioxidant defence system. Signal transduction studies showed that AA could prevent hyperglycaemia induced activation of MAPKs, PKC, NF-κB signalling cascades and apoptotic cell death. Combining, AA supplements could be regarded as beneficial therapeutics in the treatment of diabetes and its associated complications.

Diabetes-related alterations in the enteric nervous system and its microenvironment

Gastric intestinal symptoms common among diabetic patients are often caused by intestinal motility abnormalities related to enteric neuropathy. It has recently been demonstrated that the nitrergic subpopulation of myenteric neurons are especially susceptible to the development of diabetic neuropathy. Additionally, different susceptibility of nitrergic neurons located in different intestinal segments to diabetic damage and their different levels of responsiveness to insulin treatment have been revealed. These findings indicate the importance of the neuronal microenvironment in the pathogenesis of diabetic nitrergic neuropathy. The main focus of this review therefore was to summarize recent advances related to the diabetes-related selective nitrergic neuropathy and associated motility disturbances. Special attention was given to the findings on capillary endothelium and enteric glial cells. Growing evidence indicates that capillary endothelium adjacent to the myenteric ganglia and enteric glial cells surrounding them are determinative in establishing the ganglionic microenvironment. Additionally, recent advances in the development of new strategies to improve glycemic control in type 1 and type 2 diabetes mellitus are also considered in this review. Finally, looking to the future, the recent and promising results of metagenomics for the characterization of the gut microbiome in health and disease such as diabetes are highlighted.