Cardiovascular antioxidant therapy: a review of supplements, pharmacotherapies, and mechanisms

Mitigating Effects of Tanacetum balsamita L. on Metabolic Dysfunction-Associated Fatty Liver Disease (MAFLD)

The metabolic syndrome and its associated co-morbidities have been recognized as predisposing risk factors for the development of metabolic-associated fatty liver disease (MAFLD). The present study reports on the beneficial effect of the Tanacetum balsamita methanol-aqueous extract (ETB) at 150 and 300 mg/kg bw on biochemical parameters related to oxidative stress, metabolic syndrome, and liver function in rat animal models with induced MAFLD. ETB was found to be non-toxic with LD50 > 3000 mg/kg and did not affect cell viability of hepatic HEP-G2 cells in a concentration up to 800 μg/mL. The pathology was established by a high-calorie diet and streptozotocin. Acarbose and atorvastatin were used as positive controls. At the higher dose, ETB reduced significantly (p < 0.05) the blood glucose levels by about 20%, decreased lipase activity by 52%, total cholesterol and triglycerides by 50% and 57%, respectively, and restored the amylase activity and leukocytes compared to the MAFLD group. ETB ameliorated oxidative stress biomarkers reduced glutathione and malondialdehyde in a dose-dependent manner. At 300 mg/kg, the beneficial effect of the extract on antioxidant enzymes was evidenced by the elevated catalase, glutathione peroxidase, and superoxide dismutase activity by 70%, 29%, and 44%, accordingly, compared to the MAFLD rats. ETB prevents the histopathological changes related to MAFLD. ETB, rich in 3,5-dicafeoylquinic, chlorogenic, and rosmarinic acids together with the isorhamnetin- and luteolin-glucoside provides a prominent amelioration of MAFLD.

The Acid Sphingomyelinase Inhibitor Amitriptyline Ameliorates TNF-α-Induced Endothelial Dysfunction

PURPOSE

Inflammation associated endothelial cell (EC) dysfunction is key to atherosclerotic disease. Recent studies have demonstrated a protective role of amitriptyline in cardiomyocytes induced by hypoxia/reoxygenation. However, the mechanism by which amitriptyline regulates the inflammatory reaction in ECs remains unknown. Thus, the aim of this study was to investigate whether amitriptyline protects against inflammation in TNF-α-treated ECs.

METHODS

HUVECs were incubated with amitriptyline (2.5 μM) or TNF-α (20 ng/ml) for 24 h. EdU, tube formation, transwell, DHE fluorescence staining, and monocyte adhesion assays were performed to investigate endothelial function. Thoracic aortas were isolated from mice, and vascular tone was measured with a wire myograph system. The levels of ICAM-1, VCAM-1, MCP-1, phosphorylated MAPK and NF-κB were detected using western blotting.

RESULTS

Amitriptyline increased the phosphorylation of nitric oxide synthase (eNOS) and the release of NO. Amitriptyline significantly inhibited TNF-α-induced increases in ASMase activity and the release of ceramide and downregulated TNF-α-induced expression of proinflammatory proteins, including ICAM-1, VCAM-1, and MCP-1 in ECs, as well as the secretion of sICAM-1 and sVCAM-1. TNF-α treatment obviously increased monocyte adhesion and ROS production and impaired HUVEC proliferation, migration and tube formation, while amitriptyline rescued proliferation, migration, and tube formation and decreased monocyte adhesion and ROS production. Additionally, we demonstrated that amitriptyline suppressed TNF-α-induced MAPK phosphorylation as well as the activity of NF-κB in HUVECs. The results showed that the relaxation response of aortic rings to acetylcholine in the WT-TNF-α group was much lower than that in the WT group, and the sensitivity of aortic rings to acetylcholine in the WT-TNF-α group and WT-AMI-TNF-α group was significantly higher than that in the WT-TNF-α group.

CONCLUSION

These results suggest that amitriptyline reduces endothelial inflammation, consequently improving vascular endothelial function. Thus, the identification of amitriptyline as a potential strategy to improve endothelial function is important for preventing vascular diseases.

Antioxidant and anticholinesterase activities of amentoflavone isolated from Ouratea fieldingiana (Gardner) Engl. through in vitro and chemical-quantum studies

Ouratea fieldingiana, popularly known as batiputá, is a tree species easily found in the coastal part of northeastern Brazil. Its leaves are rich in biflavonoids, its major compound being amentoflavone. Biflavonoids are well studied due to their high antioxidant capacity. Alzheimer's disease (AD) is a disease characterized by the progressive loss of neurons. Currently, the pharmacological treatment of AD has four drugs: donepezil, galantamine, rivastigmine and memantine. Where these drugs, with the exception of memantine, are inhibitors of acetylcholinesterase, thus inhibiting the enzyme that destroys acetylcholine, thus increasing the availability of this neurotransmitter. This article aims to determine in vitro and in silico the antioxidant and anticholinesterase action of amentoflavone isolated from the leaves of Ouratea fieldingiana. The antioxidant capacity of amentoflavone was evaluated using the DPPH* free radical scavenging method, with an IC₅₀ of 5.73 ± 0.08 µg/mL. The antiradical properties of the molecule were also studied in silico through several HAT, SET-PT and SPLET mechanisms via DFT M06-2X/6-311++G(d,p). It was found that in the hydrogen atom transfer mechanism (HAT) the best trend was obtained as an anti-radical mechanism. Amentoflavone has the ability to inhibit acetylcholinesterase when tested in vitro, having an IC₅₀ of 8.68 ± 0.73 µg/mL, corroborating its effect in the in silico test, presenting four strong covalent hydrogen bonds for having a bond length up to 2.5 Å. Thus, amentoflavone is an important target for further testing against Alzheimer's disease. Communicated by Ramaswamy H. Sarma.

Development of HPTLC method for the simultaneous estimation of quercetin, curcumin, and ascorbic acid in herbal formulations

Antioxidants can scavenge free radicals in the human body and have been associated with a protective effect on the human body against a variety of diseases. As a part of normal cellular function, free radical production occurs continuously within the body at a cellular level. Excess-free radical production from endogenous or exogenous sources may result in a variety of diseases. Vitamins (A, C, and E), carotenoids, polyphenols, and flavonoids are some examples of common natural antioxidants. Among the different antioxidants quercetin, curcumin, and ascorbic acids have been extensively studied, and numerous reports on their antioxidant activity are available in the literature. Antioxidants are regarded as a key player in the current pandemic situation, and they play a key role as a preventive and controlling tool. There are a variety of herbal formulations and immune booster therapies available, many of which claim to contain various antioxidants and are effective against covid-19. Numerous herbal formulations and immune booster therapies are available and claimed to have different antioxidants and other constituents. In the present study simple, rapid, accurate, precise, and sensitive high-performance thin-layer chromatographic analytical method was developed for simultaneous estimation of quercetin, curcumin, and ascorbic acid. The developed method can effectively employ for different polyherbal formulations. The developed method was validated according to ICH guidelines. In the present study, an aluminum plate precoated with 60F 254 silica gel was used as a stationary phase whereas chloroform: ethyl acetate: formic acid (6:6:2.5 v/v/v) was used as a mobile phase. Chromatographic detection was performed with a Camag TLC scanner at 265 nm. The linearity range for the proposed method was found to be 500–1000 ng/band for all three analytes. The antioxidant potentiality of selected antioxidants was evaluated by an optimized UV visible spectroscopic-reducing power method. The reducing power method was optimized for the concentration and volume of reagent, incubation temperature, and time. The results of the study revealed that quercetin is having the best antioxidant potential compared to curcumin and ascorbic acid.

Non-mercaptalbumin is significantly associated with the coronary plaque burden and the severity of coronary artery disease

Human non-mercaptalbumin (HNA), oxidized form of serum albumin, has been reported as a useful marker in oxidative stress-related diseases; however, few reports have examined the association between HNA and the severity of coronary artery disease (CAD). The present study evaluated whether the HNA fraction is correlated with coronary artery stenosis in 140 patients considered to have a high risk of CAD or who were suspected of having acute coronary syndrome. The severity of CAD was defined by the number of stenotic coronary vessels and a severity score system (the Gensini score). HNA measurements were performed using our newly established high-performance liquid chromatography methodology. The results had shown that HNA was significantly increased in patients with three-vessel disease, compared with those without CAD or with single-vessel disease (p = 0.025), and was positively correlated with the Gensini score (ρ = 0.421, p < 0.001). A multivariate analysis showed that the number of stenotic vessels was an independent and significant factor associated with HNA (ρ = 1.246, p = 0.012). A logistic regression analysis showed that HNA was a strong predictor of multivessel CAD (odds ratio, 1.12; 95% confidence interval, 1.020–1.229; p = 0.017). These findings indicate that the measurement of HNA could be clinically practical for predicting the severity of coronary artery stenosis.

Evaluation of the antioxidant, antibacterial, and antibiofilm activity of the sesquiterpene nerolidol

The aim of this study was to evaluate the antioxidant, antibacterial, and antibiofilm activities of nerolidol. The antioxidant activity of nerolidol was determined using the total antioxidant activity method. Antibacterial activity was performed using the microdilution method to determine the minimum inhibitory concentration (MIC) against seven standard strains of the ATCC and four bacterial clinical isolates with a resistance profile, following the Clinical and Laboratory Standards Institute (CLSI). The antibiofilm activity of nerolidol was performed using the crystal violet method. The results of the antioxidant test revealed a total antioxidant activity of 93.94%. Nerolidol inhibited the growth of Staphylococcus aureus (MIC = 1 mg/mL), Streptococcus mutans (MIC = 4 mg/mL), Pseudomonas aeruginosa (MIC = 0.5 mg/mL), and Klebsiella pneumoniae (MIC = 0.5 mg/mL). For clinical isolates, nerolidol showed an inhibitory potential against multidrug-resistant P. aeruginosa, K. pneumoniae carbapenemase (MIC = 0.5 mg/mL), methicillin-susceptible S. aureus (MIC = 2 mg/mL), and methicillin-resistant S. aureus (MIC = 2 mg/mL). Nerolidol showed similar antibacterial activity against ATCC strains and hospital clinical isolates with resistance profile, suggesting that even though these strains are resistant to antibiotics, they are still sensitive to nerolidol. Nerolidol exerted a dose-dependent effect on the inhibition of biofilm formation, even at subinhibitory concentrations. Nerolidol inhibited bacterial biofilms of ATCC strains at a rate ranging from 51 to 98%, at concentrations ranging from 0.5 to 4 mg/mL. For clinical bacterial isolates, biofilm inhibition ranged from 6 to 60%. Therefore, the present study showed the antioxidant, antibacterial, and antibiofilm properties of nerolidol.

Natural products: The role and mechanism in low-density lipoprotein oxidation and atherosclerosis

Atherosclerosis is a chronic inflammatory, metabolic, and epigenetic disease, which leads to the life-threatening coronary artery disease. Emerging studies from bench to bedside have demonstrated the pivotal role of low-density lipoprotein (LDL) oxidation in the initiation and progression of atherosclerosis. This article hereby reviews oxidation mechanism of LDL, and the pro-atherogenic and biomarker role of oxidized LDL in atherosclerosis. We also review the pharmacological effects of several representative natural products (vitamin E, resveratrol, quercetin, probucol, tanshinone IIA, epigallocatechin gallate, and Lycopene) in protecting against LDL oxidation and atherosclerosis. Clinical and basic research supports the beneficial effects of these natural products in inhibiting LDL oxidation and preventing atherosclerosis, but the data are still controversial. This may be related to factors such as the population and the dosage and time of taking natural products involved in different studies. Understanding the mechanism of LDL oxidation and effect of oxidized LDL help researchers to find novel therapies against atherosclerosis.

Redox Potential of Antioxidants in Cancer Progression and Prevention

The benevolent and detrimental effects of antioxidants are much debated in clinical trials and cancer research. Several antioxidant enzymes and molecules are overexpressed in oxidative stress conditions that can damage cellular proteins, lipids, and DNA. Natural antioxidants remove excess free radical intermediates by reducing hydrogen donors or quenching singlet oxygen and delaying oxidative reactions in actively growing cancer cells. These reducing agents have the potential to hinder cancer progression only when administered at the right proportions along with chemo-/radiotherapies. Antioxidants and enzymes affect signal transduction and energy metabolism pathways for the maintenance of cellular redox status. A decline in antioxidant capacity arising from genetic mutations may increase the mitochondrial flux of free radicals resulting in misfiring of cellular signalling pathways. Often, a metabolic reprogramming arising from these mutations in metabolic enzymes leads to the overproduction of so called ’oncometabolites’ in a state of ‘pseudohypoxia’. This can inactivate several of the intracellular molecules involved in epigenetic and redox regulations, thereby increasing oxidative stress giving rise to growth advantages for cancerous cells. Undeniably, these are cell-type and Reactive Oxygen Species (ROS) specific, which is manifested as changes in the enzyme activation, differences in gene expression, cellular functions as well as cell death mechanisms. Photodynamic therapy (PDT) using light-activated photosensitizing molecules that can regulate cellular redox balance in accordance with the changes in endogenous ROS production is a solution for many of these challenges in cancer therapy.

Globular CTRP9 protects cardiomyocytes from palmitic acid-induced oxidative stress by enhancing autophagic flux

BACKGROUND

Oxidative stress in cardiac myocytes is an important pathogenesis of cardiac lipotoxicity. Autophagy is a cellular self-digestion process that can selectively remove damaged organelles under oxidative stress, and thus presents a potential therapeutic target against cardiac lipotoxicity. Globular CTRP9 (gCTRP9) is a newly identified adiponectin paralog with established metabolic regulatory properties. The aim of this work is to investigate whether autophagy participates the protection effects of gCTRP9 in neonatal rat cardiac myocytes (NRCMs) under oxidative stress and the underlying mechanism.

RESULTS

NRCMs were treated with PA of various concentrations for indicated time period. Our results showed that PA enhanced intracellular ROS accumulation, decreased mitochondrial membrane potential (Δψm) and increased activation of caspases 3. These changes suggested lipotoxicity due to excessive PA. In addition, PA was observed to impair autophagic flux in NRCMs and impaired autophagosome clearance induced by PA contributes to cardiomyocyte death. Besides, we found that gCTRP9 increased the ratio of LC3II/I and the expression of ATG5 which was vital to the formation of autophagosomes and decreased the level of P62, suggesting enhanced autophagic flux in the absence or presence of PA. The result was further confirmed by the methods of infection with LC3-mRFP-GFP lentivirus and blockage of autophagosome-lysosome fusion by BafA1. Moreover, gCTRP9 reestablished the loss of mitochondrial membrane potential, suppressed ROS generation, and reduced PA -induced myocyte death. However, the protective effect of gCTRP9 on the cardiac lipotoxicity was partly abolished by blockade of autophagy by autophagy-related 5 (ATG5) siRNA, indicating that the effect of gCTRP9 on cell survival is critically mediated through regulation of autophagy.

CONCLUSION

Autophagy induction by gCTRP9 could be utilized as a potential therapeutic strategy against oxidative stress-mediated damage in cardiomyocytes.

Antioxidants: Friend or foe?

Reactive oxygen species are the intermediates that are formed during the normal metabolic process which are effectively neutralized by the antioxidant system of the body. Any imbalance in this neutralization process causes oxidative stress which has been implicated as one of the cause in diseases such as Alzheimer's disease, cardiovascular disorders, cancer etc. Research has enabled the use of antioxidants as therapeutic agents in the treatment of various diseases. Literature also puts forth the negative effects of using antioxidants in the treatment of diseases. This review is a compilation of both the beneficial and detrimental effects of use of antioxidants in the treatment of diseases such as cancer, cardiovascular diseases, diabetes and oral diseases.

Reactive oxygen species: key regulators in vascular health and diseases

ROS are a group of small reactive molecules that play critical roles in the regulation of various cell functions and biological processes. In the vascular system, physiological levels of ROS are essential for normal vascular functions including endothelial homeostasis and smooth muscle cell contraction. In contrast, uncontrolled overproduction of ROS resulting from an imbalance of ROS generation and elimination leads to the development of vascular diseases. Excessive ROS cause vascular cell damage, the recruitment of inflammatory cells, lipid peroxidation, activation of metalloproteinases and deposition of extracellular matrix, collectively leading to vascular remodelling. Evidence from a large number of studies has revealed that ROS and oxidative stress are involved in the initiation and progression of numerous vascular diseases including hypertension, atherosclerosis, restenosis and abdominal aortic aneurysm. Furthermore, considerable research has been implemented to explore antioxidants that can reduce ROS production and oxidative stress in order to ameliorate vascular diseases. In this review, we will discuss the nature and sources of ROS, their roles in vascular homeostasis and specific vascular diseases and various antioxidants as well as some of the pharmacological agents that are capable of reducing ROS and oxidative stress. The aim of this review is to provide information for developing promising clinical strategies targeting ROS to decrease cardiovascular risks.

LINKED ARTICLES

This article is part of a themed section on Spotlight on Small Molecules in Cardiovascular Diseases. To view the other articles in this section visit http://onlinelibrary.wiley.com/doi/10.1111/bph.v175.8/issuetoc.

Ventricular wall biomaterial injection therapy after myocardial infarction: Advances in material design, mechanistic insight and early clinical experiences

Intramyocardial biomaterial injection therapy for myocardial infarction has made significant progress since concept initiation more than 10 years ago. The interim successes and progress in the first 5 years have been extensively reviewed. During the last 5 years, two phase II clinical trials have reported their long term follow up results and many additional biomaterial candidates have reached preclinical and clinical testing. Also in recent years deeper investigations into the mechanisms behind the beneficial effects associated with biomaterial injection therapy have been pursued, and a variety of process and material parameters have been evaluated for their impact on therapeutic outcomes. This review explores the advances made in this biomaterial-centered approach to ischemic cardiomyopathy and discusses potential future research directions as this therapy seeks to positively impact patients suffering from one of the world's most common sources of mortality.

Nanosalina: A Tale of Saline-Loving Algae from the Lake's Agony to Cancer Therapy

The nanoparticles (NPs) that contain the therapeutic agent within themselves without further modifications can be coined as "self-therapeutic" NPs. The development of these agents especially when derived from natural resources can lead to a paradigm shift in the field of cancer nanotechnology as they can immensely facilitate the complex chemistry procedures and the follow up biological complications. Herein, we demonstrate that inherently therapeutic NPs "integrating" β-carotene can be synthesized from Dunaliella salina microalgae in a single step without complicated chemistry. The facile synthesis involved microwave irradiation of aqueous suspension of algae which resulted in water dispersible NPs with hydrodynamic diameter of ∼80 nm. Subsequently, extensive physiochemical characterizations were performed to confirm the integrity of the particles. The pro-oxidant activities of the integrated β-carotene were triggered by photoexcitation under UV lamp (362 nm). It was demonstrated that after UV exposure, the C32 human melanoma cells incubated with NPs experienced extensive cell death as opposed to nonilluminated samples. Further cellular analysis revealed that the significant reactive oxygen species (ROS) and in particular singlet oxygen were responsible for the cells' damage while the mode of cell death was dominated by apoptosis. Moreover, detailed endocytic inhibition studies specified that UV exposure affected NPs' cellular uptake mechanism. These inherently therapeutic NPs can open new avenues for melanoma cancer treatment via ROS generation in vitro.

Resveratrol, piperine and apigenin differ in their NADPH-oxidase inhibitory and reactive oxygen species-scavenging properties

BACKGROUND

Many plant-derived chemicals have been studied for their potential benefits in ailments including inflammation, cancer, neurodegeneration, and cardiovascular disease. The health benefits of phytochemicals are often attributed to the targeting of reactive oxygen species (ROS). However, it is not always clear whether these agents act directly as antioxidants to remove ROS, or whether they act indirectly by blocking ROS production by enzymes such as NADPH oxidase (NOX) enzymes, or by influencing the expression of cellular pro- and anti- oxidants.

HYPOTHESIS/PURPOSE

Here we evaluate the pro- and anti-oxidant and NOX-inhibiting qualities of four phytochemicals: celastrol, resveratrol, apigenin, and piperine.

STUDY DESIGN

This work was done using the H661 cell line expressing little or no NOX, modified H661 cells expressing NOX1 and its subunits, and an EBV-transformed B-lymphoblastoid cell line expressing endogenous NOX2. ROS were measured using Amplex Red and nitroblue tetrazolium assays. In addition, direct ROS scavenging of hydrogen peroxide or superoxide generated were measured using Amplex Red and methyl cypridina luciferin analog (MCLA).

RESULTS

Of the four plant-derived compounds evaluated, only celastrol displayed NOX inhibitory activities, while celastrol and resveratrol both displayed ROS scavenging activity. Very little impact on ROS was observed with apigenin, or piperine.

CONCLUSION

The results of this study reveal the differences that exist between cell-free and intracellular pro-oxidant and antioxidant activities of several plant-derived compounds.

Protection of Pentoxifylline against Testis Injury Induced by Intermittent Hypobaric Hypoxia

To investigate the effect of pentoxifylline (PTX) on spermatogenesis dysfunction induced by intermittent hypobaric hypoxia (IHH) and unveil the underlying mechanism, experimental animals were assigned to Control, IHH+Vehicle, and IHH+PTX groups and exposed to 4 cycles of 96 h of hypobaric hypoxia followed by 96 h of normobaric normoxia for 32 days. PTX was administered for 32 days. Blood and tissue samples were collected 7 days thereafter. Serum malondialdehyde levels were used to assess lipid peroxidation; ferric-reducing antioxidant power (FRAP), superoxide dismutase, and catalase and glutathione peroxidase enzyme activities were assessed to determine antioxidant capacity in various samples. Testis histopathology was assessed after hematoxylin-eosin staining by Johnsen's testicular scoring system. Meanwhile, testosterone synthase and vimentin amounts were assessed by immunohistochemistry. Sperm count, motility, and density were assessed to determine epididymal sperm quality. IHH treatment induced significant pathological changes in testicular tissue and enhanced serum lipid peroxide levels, while reducing serum FRAP, antioxidant enzyme activities, and testosterone synthase expression. Moreover, IHH impaired epididymal sperm quality and vimentin structure in Sertoli cells. Oral administration of PTX improved the pathological changes in the testis. IHH may impair spermatogenesis function of testicular tissues by inducing oxidative stress, but this impairment could be attenuated by administration of PTX.

Advanced glycation end products upregulate lysyl oxidase and endothelin-1 in human aortic endothelial cells via parallel activation of ERK1/2-NF-κB and JNK-AP-1 signaling pathways

Endothelial dysfunction involves deregulation of the key extracellular matrix (ECM) enzyme lysyl oxidase (LOX) and the vasoconstrictor protein, endothelin-1 (ET-1), whose gene expression can be modulated by the transcriptional activators nuclear factor kappa B (NF-κB) and activator protein-1 (AP-1). Advanced glycation end products (AGEs) present an aggravating factor of endothelial dysfunction which upon engagement to their receptor RAGE induce upregulation of mitogen-activated protein kinases (MAPKs), leading to NF-κB and AP-1 potentiation. We hypothesized that AGEs could induce NF-κΒ- and AP-1-dependent regulation of LOX and ET-1 expression via the AGE/RAGE/MAPK signaling axis. Western blot, real-time qRT-PCR, FACS analysis and electrophoretic mobility-shift assays were employed in human aortic endothelial cells (HAECs) following treatment with AGE-bovine serum albumin (AGE-BSA) to investigate the signaling pathway towards this hypothesis. Furthermore, immunohistochemical analysis of AGEs, RAGE, LOX and ET-1 expression was conducted in aortic endothelium of a rat experimental model exposed to high- or low-AGE content diet. HAECs exposed to AGE-BSA for various time points exhibited upregulation of LOX and ET-1 mRNA levels in a dose- and time-dependent manner. Exposure of HAECs to AGE-BSA also showed specific elevation of phospho(p)-ERK1/2 and p-JNK levels in a dose- and time-dependent fashion. AGE administration significantly increased NF-κΒ- and AP-1-binding activity to both LOX and ET-1 cognate promoter regions. Moreover, LOX and ET-1 overexpression in rat aortic endothelium upon high-AGE content diet confirmed the functional interrelation of these molecules. Our findings demonstrate that AGEs trigger NF-κΒ- and AP-1-mediated upregulation of LOX and ET-1 via the AGE/RAGE/MAPK signaling cascade in human endothelial cells, thus contributing to distorted endothelial homeostasis by impairing endothelial barrier function, altering ECM biomechanical properties and cell proliferation.

Genistein ameliorated endothelial nitric oxidase synthase uncoupling by stimulating sirtuin-1 pathway in ox-LDL-injured HUVECs

Endothelial nitric oxidase synthase (eNOS) uncoupling plays a causal role in endothelial dysfunction in atherosclerosis. Genistein consumption has been associated with the prevention of atherosclerosis. However, the effect of genistein on eNOS uncoupling has not been reported. A model of oxidized low-density lipoprotein (ox-LDL)-induced injury on human umbilical vein endothelial cells (HUVECs) was established to evaluate the effect of genistein on eNOS uncoupling. We investigated the effect of genistein on NADPH oxidase-dependent superoxide production, NOX4 expression, BH4 synthesis and oxidation, the expression of GTP cyclohydrolase 1 (GCH1) and dihydrofolate reductase (DHFR). The results showed that genistein decreased superoxide production and NOX4 expression, enhanced the ratio of BH4/BH2, augmented the expressions of GCH1 and DHFR. Accompanied with genistein ameliorating eNOS uncoupling, genistein elevated the expression of sirtuin-1; furthermore, the effects of genistein on eNOS uncoupling were blunted with sirtuin-1 siRNA. The present study indicated that genistein ameliorated eNOS uncoupling was concerned with sirtuin-1 pathway in ox-LDL-injured HUVECs.

Lipoicmethylenedioxyphenol Reduces Experimental Atherosclerosis through Activation of Nrf2 Signaling

Objective

Oxidative stress is implicated in the pathogenesis of atherosclerosis, and Nrf2 is the transcriptional factor central in cellular antioxidant responses. In the present study, we investigate the effect of a dihydrolipoic acid derivative lipoicmethylenedioxyphenol (LMDP) on the progression of atherosclerosis and test whether its effect on atherosclerosis is mediated by Nrf2.

Methods and Results

Both magnetic resonance imaging (MRI) scanning and en face analysis reveal that 14 weeks of treatment with LMDP markedly reduced atherosclerotic burden in a rabbit balloon vascular injury model. Myograph analyses show decreased aortic contractile response to phenylephrine and increased aortic response to acetylcholine and insulin in LMDP-treated animals, suggesting that LMDP inhibits atherosclerosis through improving vascular function. A role of Nrf2 signaling in mediating the amelioration of vascular function by LMDP was supported by increased Nrf2 translocation into nuclear and increased expression of Nrf2 target genes. Furthermore, chemotaxis analysis with Boydem chamber shows that leukocytes isolated from LMDP-treated rabbits had reduced chemotaxis, and knock-down of Nrf2 significantly reduced the effect of LMDP on the chemotaxis of mouse macrophages.

Conclusion

Our results support that LMDP has an anti-atherosclerotic effect likely through activation of Nrf2 signaling and subsequent inhibition of macrophage chemotaxis.

The Functions of Antioxidants and Heat Shock Proteins Are Altered in the Immune Organs of Selenium-Deficient Broiler Chickens

Despite increasing evidence indicating the essential involvement of selenium (Se) in the immune system, the effect of Se deficiency on the regulation of oxidative stress and heat shock proteins (Hsps) in broiler chickens is still unclear. In the present study, we established an exudative diathesis (ED) broiler chicken model caused by Se deficiency. We then analyzed histological observations and detected the expression levels of Hsps and antioxidant indexes in immune tissues. The antioxidant function declined remarkably, and most of the Hsp expression levels increased significantly in the spleen, thymus, and bursa of Fabricius of the broiler chicks with ED (except the messenger RNA (mRNA) levels of Hsp27, Hsp40, and Hsp70, which decreased in thymus tissues from the treatment groups); therefore, constitutive oxidation resistance and higher Hsps in broiler chicks with ED caused defects in immune organ morphology and function, as evidenced by abnormal histological structures: red pulp broadening and lymphocytes in the cortex and medulla of the thymic lobule decreased distinctly and distributed loosely. These results underscore the importance of Se in establishing an immune organ microenvironment conducive to normal function.

Cardiovascular and Hepatic Toxicity of Cocaine: Potential Beneficial Effects of Modulators of Oxidative Stress

Oxidative stress (OS) is thought to play an important role in the pharmacological and toxic effects of various drugs of abuse. Herein we review the literature on the mechanisms responsible for the cardiovascular and hepatic toxicity of cocaine with special focus on OS-related mechanisms. We also review the preclinical and clinical literature concerning the putative therapeutic effects of OS modulators (such as N-acetylcysteine, superoxide dismutase mimetics, nitroxides and nitrones, NADPH oxidase inhibitors, xanthine oxidase inhibitors, and mitochondriotropic antioxidants) for the treatment of cocaine toxicity. We conclude that available OS modulators do not appear to have clinical efficacy.

Beneficial effect of pentoxifylline into the testis of rats in an experimental model of unilateral hindlimb ischemia/reperfusion injury

Objective

The objective of the present study was to investigate the role of pentoxifylline (PTX) on remote testicular injury caused by unilateral hind limb ischemia/reperfusion of rats.

Materials and Methods

Twenty healthy male Wistar rats were allocated randomly into two groups: ischemia/reperfusion (IR group) and ischemia/reperfusion + pentoxifylline (IR+PTX group). Ischemia was induced by placement of a rubber tourniquet at the greater trochanter for 2h. Rats in IR+PTX group received PTX (40 mg/kg IP) before the reperfusion period. At 24h after reperfusion, testes were removed and levels of superoxide dismutase (SOD), malondialdehyde (MDA), catalase (CAT) and myeloperoxidase (MPO) activity were determined in testicular tissues. Three rats of each group were used for wet/ dry weight ratio measurement. Testicular tissues were also examined histopathologically under light microscopy.

Results

Activities of SOD and CAT in testicular tissues were decreased by ischemia/ reperfusion (P<0.05). Significantly increased MDA levels in testicular tissues were decreased by PTX treatment (P<0.05). MPO activity in testicular tissues in the IR group was significantly higher than in the IR+PTX group (P<0.05). The wet/dry weight ratio of testicular tissues in the IR group was significantly higher than in the IR+PTX group (P<0.05). Histopathologically, there was a statistically significant difference between two groups (P<0.05).

Conclusions

According to histological and biochemical findings, we conclude that PTX has preventive effects in the testicular injury induced by hind limb ischemia/reperfusion.

N-acetylcysteine inhibits in vivo oxidation of native low-density lipoprotein

Low-density lipoprotein (LDL) is non-atherogenic, while oxidized LDL (ox-LDL) is critical to atherosclerosis. N-acetylcysteine (NAC) has anti-atherosclerotic effect with largely unknown mechanisms. The present study aimed to determine if NAC could attenuate in vivo LDL oxidation and inhibit atherosclerosis. A single dose of human native LDL was injected intravenously into male C57BL/6 mice with and without NAC treatment. Serum human ox-LDL was detected 30 min after injection, reached the peak in 3 hours, and became undetectable in 12 hours. NAC treatment significantly reduced serum ox-LDL level without detectable serum ox-LDL 6 hours after LDL injection. No difference in ox-LDL clearance was observed in NAC-treated animals. NAC treatment also significantly decreased serum ox-LDL level in patients with coronary artery diseases and hyperlipidemia without effect on LDL level. Intracellular and extracellular reactive oxidative species (ROS) production was significantly increased in the animals treated with native LDL, or ox-LDL and in hyperlipidemic LDL receptor knockout (LDLR(-/-)) mice that was effectively prevented with NAC treatment. NAC also significantly reduced atherosclerotic plaque formation in hyperlipidemic LDLR(-/-) mice. NAC attenuated in vivo oxidation of native LDL and ROS formation from ox-LDL associated with decreased atherosclerotic plaque formation in hyperlipidemia.

Targeting metabolic disorders by natural products

The most prevalent metabolic disorders are diabetes mellitus, obesity, dyslipidemia, osteoporosis and metabolic syndrome, which are developed when normal metabolic processes are disturbed. The most common pathophysiologies of the above disorders are oxidative stress, Nrf2 pathways, epigenetic, and change in miRNA expression. There is a challenge in the prevention and treatment of metabolic disorders due to severe adverse effects of some synthetic drugs, their high cost, lack of safety and poverty in some conditions, and insufficient accessibility for the general population in the world. With increasing interest in shifting from synthetic drugs to phytotherapy as an alternative treatment, there is still a gap in scientific evidences of plant-derived therapeutic benefits. One reason may be slow rate of translation of animal studies' findings into human clinical trials. Since metabolic disorders are multifactorial, it seems that poly-herbal medications, or drug-herbal combination are needed for their treatment. However, further researches to determine the most effective plant-derived metabolites, and their cellular mechanism in order to set priorities for well-designed animal and clinical trials, and also more studies with strong scientific evidences such as systematic review and meta-analysis of controlled studies are needed.

Sesquiterpenoids and lignans from the roots of Syringa pinnatifolia

Two new sesquiterpenoids, pinnatifone A (1) and pinnatifone B (2), and two new lignans, pinnatifolin (3) and isopinnatifolin (4), along with six known lignans (5-10), were isolated from the roots of Syringa pinnatifolia. The structures of the new compounds were elucidated by extensive spectroscopic methods, including NMR, MS, UV, and IR spectra. The lignans were screened for their anti-oxidant activity (2,2-diphenyl-1-picrylhydrazyl (DPPH) assay). Most of them showed potent anti-oxidant activity, especially compound 5, whose potent anti-oxidant activity had an SC50 value higher than that of the positive control vitamin C.

C-reactive protein stimulates RAGE expression in human coronary artery endothelial cells in vitro via ROS generation and ERK/NF-κB activation

AIM

The receptor for advanced glycation end-products (RAGE) plays an important role in development of atherosclerosis, and C-reactive protein (CRP) has been found to stimulate its expression in endothelial cells. In this study we investigated how CRP regulated the expression of RAGE in human coronary artery endothelial cells (HCAECs).

METHODS

HCAECs were treated in vitro with CRP (50 μg/mL) in combination with a variety of inhibitors. ROS generation was determined by immunocytochemistry and flow cytometry. The RAGE expression and phosphorylation of relevant signaling proteins were measured using Western blot analyses.

RESULTS

CRP stimulated the expression of RAGE in the cells, accompanied by markedly increased ROS generation, phosphorylation of ERK1/2 and NF-κB p65, as well as translocation of NF-κB p65 to the nuclei. CRP also stimulated phosphorylation of JNK and p38 MAPK. Pretreatment of the cells with the ROS scavenger N-acetyl-L-cysteine, ERK inhibitor PD98059 or NF-κB inhibitor PDTC blocked CRP-stimulated RAGE expression, but pretreatment with the NADPH oxidase inhibitor DPI, JNK inhibitor SP600125 or p38 MAPK inhibitor SB203580 did not significantly alter CRP-stimulated RAGE expression.

CONCLUSION

CRP stimulates RAGE expression in HCAECs in vitro via ROS generation and activation of the ERK/NF-κB signaling pathway.

Induction and functional significance of the heme oxygenase system in pathological shear stress in vivo

The present study examined the heme oxygenase (HO) system in an in vivo murine model of pathological shear stress induced by partial carotid artery ligation. In this model, along with upregulation of vasculopathic genes, HO-1 is induced in the endothelium and adventitia, whereas HO-2 is mainly upregulated in the endothelium. Within minutes of ligation, NF-κB, a transcription factor that upregulates vasculopathic genes and HO-1, is activated. Failure to express either HO-1 or HO-2 exaggerates the reduction in carotid blood flow and exacerbates vascular injury. After artery ligation, comparable induction of HO-2 occurred in HO-1(+/+) and HO-1(-/-) mice, whereas HO-1 induction was exaggerated in HO-2(-/-) mice compared with HO-2(+/+) mice. Upregulation of HO-1 by an adeno-associated viral vector increased vascular HO-1 expression and HO activity and augmented blood flow in both ligated and contralateral carotid arteries. Acute inhibition of HO activity decreased flow in the ligated carotid artery, whereas a product of HO, carbon monoxide (CO), delivered by CO-releasing molecule-3, increased carotid blood flow. In conclusion, in the partial carotid artery ligation model of pathological shear stress, this study provides the first demonstration of 1) upregulation and vasoprotective effects of HO-1 and HO-2 and the vasorelaxant effects of CO as well as 2) vascular upregulation of HO-1 in vivo by an adeno-associated viral vector that is attended by a salutary vascular response. Induction of HO-1 may reside in NF-κB activation, and, along with induced HO-2, such upregulation of HO-1 provides a countervailing vasoprotective response in pathological shear stress in vivo.

Glutathione prevents preterm parturition and fetal death by targeting macrophage-induced reactive oxygen species production in the myometrium

Preterm birth is an inflammatory process resulting from the massive infiltration of innate immune cells and the production of proinflammatory cytokines in the myometrium. However, proinflammatory cytokines, which induce labor in vivo, fail to induce labor-associated features in human myometrial cells (MCs). We thus aimed to investigate if reactive oxygen species (ROS) production could be the missing step between immune cell activation and MC response. Indeed, we found that ROS production is increased in the human preterm laboring myometrium (27% ROS producing cells, respectively, versus 2% in nonlaboring controls), with 90% ROS production in macrophages. Using LPS-stimulated myometrial samples and cell coculture experiments, we demonstrated that ROS production is required for labor onset. Furthermore, we showed that ROS are required first in the NADPH oxidase (NADPHox)-2/NF-κB-dependent macrophage response to inflammatory stimuli but, more importantly, to trigger macrophage-induced MCs transactivation. Remarkably, in a murine model of LPS-induced preterm labor (inducing delivery within 17 hours, with no pup survival), cotreatment with glutathione delayed labor onset up to 94 hours and prevented in utero fetal distress, allowing 46% pups to survive. These results suggest that targeting ROS production with the macrophage-permeable antioxidant glutathione could constitute a promising strategy to prevent preterm birth.

Cardioprotective effect of rhizomes of Acorus gramineus against isoproterenol-induced cardiac damage in pigs

The present study was designed to evaluate the cardioprotective potential of water extract of rhizomes of Acorus gramineus (AGR) against isoproterenol (ISO)-induced myocardial infarction. Male pigs were orally administered with 250 or 500 mg/kg of AGR or with vehicle for 9 days, with concurrent subcutaneous injections of ISO on the 8th and 9th day. Administration of AGR significantly ameliorated ISO-induced cardiac dysfunctions as evidenced by the ventricular ST-segment interval and R-amplitude as well as the left ventricle fractional shortening and ejection fraction. Additionally, administration of AGR significantly attenuated increased cardiac injury markers, such as cardiac troponin T, tumor necrosis factor-α, and myeloperoxidase activity, and cardiac marker enzymes, and prevented the depletion of antioxidant parameters. Malondialdehyde formation was also inhibited by AGR. Based on the results, it is concluded that AGR possesses significant cardioprotective potential and may serve as an adjunct in the treatment and prophylaxis of myocardial infarction.

Selenium deficiency influences nitric oxide and selenoproteins in pancreas of chickens

Selenium (Se) deficiency induces pancreatic atrophy in chickens, but the molecular mechanism remains unclear. In this study, we investigated the effect of dietary Se deficiency on the expressions of 25 selenoproteins and the content of nitric oxide (NO) and examined the relationship between selenoproteins and NO. Chickens (180; 1 day old) were randomly divided into two groups, low (L) group (fed with Se deficient (Se 0.033 mg/kg) diet) and control (C) group (fed with normal (Se 0.2 mg/kg) diet). Then, pancreas was collected at 15, 25, 35, 45, and 55 days, and the content of NO, the activity of inducible NO synthase (iNOS), and the messenger RNA (mRNA) levels of 25 selenoproteins and iNOS were measured. The results showed that 25 selenoproteins were decreased (P < 0.05) by Se deficiency. Among them, thioredoxin reductase 1 (TXNRD1), selenoprotein S (SELS), selenoprotein U (SELU), selenoprotein X1 (SEPX1), and selenoprotein synthetase 2 (SPS2) were highly and extensively expressed than other types of selenoproteins in pancreas of chickens (P < 0.05). Thioredoxin reductase 2 (TXNRD2), glutathione peroxidase 1 (GPX1), glutathione peroxidase 3 (GPX3), selenoprotein I (SELI), iodothyronine deiodinase 1 (DIO1), selenoprotein P1 (SEPP1), selenoprotein W1 (SEPW1), selenoprotein O (SELO), selenoprotein T (SELT), selenoprotein M (SELM), selenoprotein X1 (SEPX1), and SPS2 were excessively decreased (P < 0.05). Meanwhile, NO content, iNOS activity, and mRNA level were increased strikingly compared with C group (P < 0.05). The correlation analysis suggested that NO had a strong negative correlation with GPX1, glutathione peroxidase 2 (GPX2), GPX3, DIO1, selenoprotein K (SELK), SELI, SEPX1, and SPS2. These results suggested that Se deficiency induced pancreatic injury by influencing NO and selenoproteins in pancreas of chickens. Thus, it offers some information on the mechanism of pancreatic injury induced by Se deficiency.

Antioxidant and anticancer aporphine alkaloids from the leaves of Nelumbo nucifera Gaertn. cv. Rosa-plena

Fifteen compounds were extracted and purified from the leaves of Nelumbo nucifera Gaertn. cv. Rosa-plena. These compounds include liriodenine (1), lysicamine (2), (-)-anonaine (3), (-)-asimilobine (4), (-)-caaverine (5), (-)-N-methylasimilobine (6), (-)-nuciferine (7), (-)-nornuciferine (8), (-)-roemerine (9), 7-hydroxydehydronuciferine (10) cepharadione B (11), β-sitostenone (12), stigmasta-4,22-dien-3-one (13) and two chlorophylls: pheophytin-a (14) and aristophyll-C (15). The anti-oxidation activity of the compounds was examined by antiradical scavenging, metal chelating and ferric reducing power assays. The results have shown that these compounds have antioxidative activity. The study has also examined the antiproliferation activity of the isolated compounds against human melanoma, prostate and gastric cancer cells. The results shown that 7-hydroxydehydronuciferine (10) significantly inhibited the proliferation of melanoma, prostate and gastric cancer cells. Together, these findings suggest that leaves of Nelumbo nucifera Gaertn. cv. Rosa-plena are a good resource for obtaining the biologically active substances with antioxidant properties.

Dietary non-enzymatic antioxidant capacity and the risk of myocardial infarction: a case-control study in Italy

BACKGROUND AND AIMS

Oxidative processes have been related to atherosclerosis, but there is scanty information on the role of dietary antioxidants in the prevention of acute myocardial infarction (AMI).

METHODS AND RESULTS

The relationship between non-enzymatic antioxidant capacity (NEAC) and the risk of nonfatal AMI was investigated in a case-control study conducted in Milan, Italy, between 1995 and 2003. Cases were 760 patients below 75 years with a first episode of AMI and controls were 682 patients admitted to hospitals for acute conditions, who completed an interviewer-administered food frequency questionnaire, tested for validity and reproducibility. NEAC (excluding coffee) was measured using Italian food composition tables in terms of ferric reducing-antioxidant power (FRAP), Trolox equivalent antioxidant capacity (TEAC) and total radical-trapping antioxidant parameter (TRAP). The odds ratios (OR) of AMI, and the corresponding 95% confidence intervals (CI), were obtained by multiple logistic regression models including terms for main risk factors of AMI and total energy intake. NEAC was inversely related with the risk of AMI. The ORs for the highest quintile compared with the lowest one were 0.41 (95% CI, 0.27-0.63) for FRAP, 0.42 (95% CI, 0.27-0.65) for TEAC and 0.41 (95% CI, 0.27-0.62) for TRAP, with significant trends in risk. The inverse relationship was apparently stronger in women and in subjects aged ≥ 60 years.

CONCLUSIONS

Our results support a favorable role of dietary NEAC in the prevention of AMI, and encourage a high consumption of fruit and vegetables and a moderate consumption of wine and whole cereals.

A new lignan from the roots of Syringa pinnatifolia

Phytochemical investigation of the roots of Syringa pinnatifolia has resulted in the isolation of a new lignan, pinnatifolin A (1), together with seven known compounds (2-8). The structures were elucidated on the basis of extensive spectroscopic methods, including NMR, MS, UV and IR spectra. The seven lignans were screened for their antioxidant activity (DPPH assay), and most of them showed potent antioxidant activity.

Red ginseng (Panax ginseng) decreases isoproterenol-induced cardiac injury via antioxidant properties in porcine

Red ginseng (RG, Panax ginseng) has been shown to possess various ginsenosides. These ginsenosides are widely used for treating cardiovascular diseases in Asian communities. The present study was designed to evaluate the cardioprotective potential of RG against isoproterenol (ISO)-induced myocardial infarction (MI), by assessing electrocardiographic, hemodynamic, and biochemical parameters. Male porcines were orally administered with RG (250 and 500 mg/kg) or with vehicle for 9 days, with concurrent intraperitoneal injections of ISO (20 mg/kg) on the 8th and 9th day. RG significantly attenuated ISO-induced cardiac dysfunctions as evidenced by improved ventricular hemodynamic functions and reduced ST segment and QRS complex intervals. Also, RG significantly ameliorated myocardial injury parameters such as antioxidants. Malonaldialdehyde formation was also inhibited by RG. Based on the results, it is concluded that RG possesses significant cardioprotective potential through the inhibition of oxidative stress and may serve as an adjunct in the treatment and prophylaxis of MI.

Mitochondrial morphofunctional alterations in smooth muscle cells of aorta in rats

In an experimental model of atherogenesis induced by hyperfibrinogenemia (HF), the pharmacological response of vitamin E was studied in order to assess its antioxidant effect on the mitochondrial morphofunctional alterations in aortic smooth muscle cells. Three groups of male rats were used: (Ctr) control, (AI) atherogenesis induced for 120 days, and (AIE) atherogenesis induced for 120 days and treated with vitamin E. HF was induced by adrenalin injection (0.1 mg/day/rat) for 120 days. AIE group was treated with the administration of 3.42 mg/day/rat of vitamin E for 105 days after the first induction. Mitochondria morphology was analyzed by electronic microscopy (EM) and mitochondrial complexes (MC) by spectrophotometry. In group AI the total and mean number of mitochondria reduced significantly, the intermembranous matrix increased, and swelling was observed with respect to Ctr and AIE (P < 0.01). These damages were related to a significant decrease in the activity of citrate synthase and complexes I, II, III, and IV in group AI in comparison to Ctr (P < 0.001). Similar behavior was presented by group AI compared to AIE (P < 0.001). These results show that vitamin E produces a significative regression of inflammatory and oxidative stress process and it resolved the morphofunctional mitochondrial alterations in this experimental model of atherogenic disease.

Novel thermosensitive telechelic PEGs with antioxidant activity: synthesis, molecular properties and conformational behaviour

We report on the tailor-made polymer conjugates, which are highly compelling for biomedical applications due to their antioxidant activity and the adjustable thermosensitive properties.