Ambroxol inhibits peroxynitrite-induced damage of alpha1-antiproteinase and free radical production in activated phagocytic cells

Ambroxol for neuropathic pain: hiding in plain sight?

ABSTRACT

Ambroxol is a multifaceted drug with primarily mucoactive and secretolytic actions, along with anti-inflammatory, antioxidant, and local anaesthetic properties. It has a long history of use in the treatment of respiratory tract diseases and has shown to be efficacious in relieving sore throat. In more recent years, ambroxol has gained interest for its potential usefulness in treating neuropathic pain. Research into this area has been slow, despite clear preclinical evidence to support its primary analgesic mechanism of action-blockade of voltage-gated sodium (Na v ) channels in sensory neurons. Ambroxol is a commercially available inhibitor of Na v 1.8, a crucial player in the pathophysiology of neuropathic pain, and Na v 1.7, a particularly exciting target for the treatment of chronic pain. In this review, we discuss the analgesic mechanisms of action of ambroxol, as well as proposed synergistic properties, followed by the preclinical and clinical results of its use in the treatment of persistent pain and neuropathic pain symptoms, including trigeminal neuralgia, fibromyalgia, and complex regional pain syndrome. With its well-established safety profile, extensive preclinical and clinical drug data, and early evidence of clinical effectiveness, ambroxol is an old drug worthy of further investigation for repurposing. As a patent-expired drug, a push is needed to progress the drug to clinical trials for neuropathic pain. We encourage the pharmaceutical industry to look at patented drug formulations and take an active role in bringing an optimized version for neuropathic pain to market.

Ambroxol, a mucolytic agent, boosts HO-1, suppresses NF-κB, and decreases the susceptibility of the inflamed rat colon to apoptosis: A new treatment option for treating ulcerative colitis

Ulcerative colitis (UC) is a chronic inflammatory bowel disease of unknown etiology that increases the risk of developing colorectal cancer and imposes a lifelong healthcare burden on millions of patients worldwide. Current treatment strategies are associated with significant risks and have been shown to be fairly effective. Hence, discovering new therapies that have better efficacy and safety profiles than currently exploited therapeutic strategies is challenging. It has been well delineated that NF-κB/Nrf2 crosstalk is a chief player in the interplay between oxidative stress and inflammation. Ambroxol hydrochloride, a mucolytic agent, has shown antioxidant and anti-inflammatory activity in humans and animals and has not yet been examined for the management of UC. Therefore, our approach was to investigate whether ambroxol could be effective to combat UC using the common acetic acid rat model. Interestingly, a high dose of oral ambroxol (200 mg/kg/day) reasonably improved the microscopic and macroscopic features of the injured colon. This was linked to low disease activity and a reduction in the colonic weight/length ratio. In the context of that, ambroxol boosted Nrf2 activity and upregulated HO-1 and catalase to augment the antioxidant defense against oxidative damage. Besides, ambroxol inactivated NF-κB signaling and its consequent target pro-inflammatory mediators, IL-6 and TNF-α. In contrast, IL-10 is upregulated. Consistent with these results, myeloperoxidase activity is suppressed. Moreover, ambroxol decreased the susceptibility of the injured colon to apoptosis. To conclude, our findings highlight the potential application of ambroxol to modify the progression of UC by its anti-inflammatory, antioxidant, and antiapoptotic properties.

Drug repositioning in neurodegeneration: An overview of the use of ambroxol in neurodegenerative diseases

Amyotrophic lateral sclerosis (ALS) is the most common motor neuron disease in adults. While it is primarily characterized by the death of upper and lower motor neurons, there is a significant metabolic component involved in the progression of the disease. Two-thirds of ALS patients have metabolic alterations that are associated with the severity of symptoms. In ALS, as in other neurodegenerative diseases, the metabolism of glycosphingolipids, a class of complex lipids, is strongly dysregulated. We therefore assume that this pathway constitutes an interesting avenue for therapeutic approaches. We have shown that the glucosylceramide degrading enzyme, glucocerebrosidase (GBA) 2 is abnormally increased in the spinal cord of the SOD1^G86R mouse model of ALS. Ambroxol, a chaperone molecule that inhibits GBA2, has been shown to have beneficial effects by slowing the development of the disease in SOD1^G86R mice. Currently used in clinical trials for Parkinson's and Gaucher disease, ambroxol could be considered as a promising therapeutic treatment for ALS.

Anti-inflammatory and antioxidant properties of jervine, a sterodial alkaloid from rhizomes of Veratrum album

BACKGROUND

Veratrum, hellebore is an important plant species of the Liliaceae family and jervine is the characteristic steroidal alkaloid constituent of Veratrum album.

PURPOSE

In the current study, anti-inflammatory and antioxidant effects of jervine isolated from NH₄OH-benzene extract of V. album rhizomes were investigated on CAR induced paw edema in rats.

METHODS/STUDY DESIGN

In inflammatory study, 50, 100, 200 and 400  mg/kg doses of jervine, 25  mg/kg doses of DIC and IND were orally administered, and the volume of the foots were measured up to their knee arthrosis by plethismometer. After one hour of the oral administration of the all treatments, 0.1 ml of CAR solution (1%) was injected into the foot of the all rat groups and the volume of the foots were measured during 5 h after CAR injection. GPx, SOD, GR, MPO, CAT enzymes activities and GSH, LPO levels of the supernatants of paw homogenates and inflammation biomarkers such as TNF-α and IL-1β in the rats serums were also estimated.

RESULTS

According to the present results, jervine exerted 50.4-73.5% anti-inflammatory effects in carrageenan induced paw edema. Inflammation biomarkers such as TNF-α, IL-1β and MPO that increased by CAR injection were suppressed by the administrations of all doses of jervine, IND and DIC. In all paw tissues, LPO levels as indicator of oxidative tissue damage were found to be high in CAR-treated group and it was found to be decreased in all doses of jervine.

CONCLUSION

Jervine, DIC and IND reduced the negative effects of CAR due to increasing effects on the SOD, CAT, GSH, GPx and GR antioxidants.

Ambroxol for the treatment of fibromyalgia: science or fiction?

Fibromyalgia appears to present in subgroups with regard to biological pain induction, with primarily inflammatory, neuropathic/neurodegenerative, sympathetic, oxidative, nitrosative, or muscular factors and/or central sensitization. Recent research has also discussed glial activation or interrupted dopaminergic neurotransmission, as well as increased skin mast cells and mitochondrial dysfunction. Therapy is difficult, and the treatment options used so far mostly just have the potential to address only one of these aspects. As ambroxol addresses all of them in a single substance and furthermore also reduces visceral hypersensitivity, in fibromyalgia existing as irritable bowel syndrome or chronic bladder pain, it should be systematically investigated for this purpose. Encouraged by first clinical observations of two working groups using topical or oral ambroxol for fibromyalgia treatments, the present paper outlines the scientific argument for this approach by looking at each of the aforementioned aspects of this complex disease and summarizes putative modes of action of ambroxol. Nevertheless, at this point the evidence basis for ambroxol is not strong enough for clinical recommendation.

Kinetics and Mechanism of Oxidation of d-Penicillamine in Acidified Bromate and Aqueous Bromine

The oxidation of the biologically active compound d-penicillamine (Depen) by acidic bromate has been studied. The stoichiometry of the reaction is strictly 1 : 1, in which Depen is oxidized only as far as the sulfonic acid with no cleavage of the C–S bond to yield sulfate. Electrospray ionization spectroscopy shows that Depen is oxidized through addition of oxygen atoms on the sulfur centre to successively yield sulfenic and sulfinic acids before the product sulfonic acid. In conditions of excess Depen over the oxidant, sulfenic acid was not observed. Instead, nearly quantitative formation of the dimer was obtained. The dimer, which is the d-penicillamine disulfide species, was formed from a reaction of the putative highly electrophilic sulfenic acid with unreacted Depen in a condensation-type reaction and not through a radical-mediated pathway. Further oxidation of the dimer is slow because it is the most stable intermediate in the oxidation of Depen. In excess oxidant conditions, negligible dimer formation is observed. The reaction of bromine with Depen gives a stoichiometry of 3 : 1 with the same sulfonic acid product. This reaction is so fast that it is essentially diffusion controlled. Our stopped-flow instrument could not capture the oxidation by the first 2 moles of bromine, only the section of the reaction in which the sulfinic acid is oxidized to sulfonic acid.

Effect of Ambroxol and Beclomethasone on Lipopolysaccharide-Induced Nitrosative Stress in Bronchial Epithelial Cells

BACKGROUND

Nitrosative stress is involved in different airway diseases. Lipopolysaccharide (LPS) induces neutrophil-related cytokine release and nitrosative stress in human bronchial epithelial (BEAS-2B) cells alone or with human polymorphonuclear neutrophils (PMNs). Ambroxol protects against oxidative stress, and beclomethasone dipropionate is an anti-inflammatory drug.

OBJECTIVES

We evaluated the ability of ambroxol and/or beclomethasone dipropionate to inhibit LPS-induced expression/release of RANTES, IL-8, inducible NO synthase (iNOS), myeloperoxidase (MPO) and 3-nitrotyrosine (3-NT: nitrosative stress biomarker) in BEAS-2B ± PMNs stimulated with LPS (1 μg/ml).

METHODS

The effect of ambroxol and/or beclomethasone dipropionate on IL-8, RANTES and iNOS levels was assessed by Western blot analysis; IL-8, MPO and 3-NT levels were measured by ELISA. Cell viability was assessed by the trypan blue exclusion test.

RESULTS

In BEAS-2B alone, LPS (at 12 h) increased RANTES/iNOS expression and IL-8 levels (p < 0.001). Ambroxol suppressed LPS-induced RANTES expression and IL-8 release (p < 0.001), whilst inhibiting iNOS expression (p < 0.05). Beclomethasone dipropionate had no effect on RANTES but halved iNOS expression and IL-8 release. Coculture of BEAS-2B with PMNs stimulated IL-8, MPO and 3-NT production (p < 0.001), potentiated by LPS (p < 0.001). Ambroxol and beclomethasone dipropionate inhibited LPS-stimulated IL-8, MPO and 3-NT release (p < 0.05). Ambroxol/beclomethasone dipropionate combination potentiated the inhibition of IL-8 and 3-NT production in BEAS-2B with PMNs (p < 0.05 and p < 0.01, respectively). Ambroxol and/or beclomethasone dipropionate inhibited nitrosative stress and the release of neutrophilic inflammatory products in vitro.

CONCLUSION

The additive effect of ambroxol and beclomethasone dipropionate on IL-8 and 3-NT inhibition suggests new therapeutic options in the treatment of neutrophil-related respiratory diseases such as chronic obstructive pulmonary disease and respiratory infections.

Ambroxol hydrochloride in the management of idiopathic pulmonary fibrosis: Clinical trials are the need of the hour

Idiopathic pulmonary fibrosis (IPF) is a debilitating lung disease of unknown etiology. Its pathogenesis remains poorly elucidated but aberrant wound healing is central to its pathology. It has a median survival time of 3 to 5 years. None of the treatment modality or drugs tried in its management has so far changed the overall outcome. Recent in vitro and experimental studies have shown that ambroxol hydrochloride exerts several newer actions, namely the surfactant stimulatory, anti-imflammatory and anti-oxidant actions, in addition to its being a secrrtolytic and mucokinetic agent. The anti inflammatory and anti-fibrotic properties of the drug are due to its ability to block the release of oxidant stress markers, cytokines, leukotrienes, MPO activity, hydroxyproline content, nitic oxide and/or collagen I & III mRNA in the local milieu while preserving the SOD and GSH-PX activities. In human studies also, the agent was able to block the expression of TGF-beta and TNF-alpha in plasma and preserving the carbon monoxide diffusion capacity of the lungs in lung cancer patients on radiation therapy. Thus, ambroxol may have the potential to check the dysregulated healing process that is typical of IPF. This, coupled with its safety profile for human use, warrants clinical trials of the drug in the management of IPF.

Ambroxol inhibits neutrophil respiratory burst activated by alpha chain integrin adhesion

The purpose of the present study was to investigate the possible anti-oxidant effect(s) of Ambroxol on neutrophils activated by ligand-binding of the drug with membrane-associated adhesion integrin CD11a and to estimate dose-response changes in oxygen free radical production. The amount of free radical production by anti-CD11a- and anti-CD4-coated neutrophils stimulated with N-formyl-methionyl-leucyl-phenylalanine (FMLP) and challenged with increasing concentration of Ambroxol, was evaluated within a time frame of 90 minutes. A significant dose-dependent effect response of Ambroxol on O2&#8254; production by cells coated with anti-CD11a antibody was observed. This preliminary study opens a new perspective on the therapeutic role of Ambroxol as an antioxidant drug and for its potential use in controlling oxidative stress, particularly in leukocyte-dependent inflammation.

Biofilm-dependent airway infections: a role for ambroxol?

Biofilms are a key factor in the development of both acute and chronic airway infections. Their relevance is well established in ventilator associated pneumonia, one of the most severe complications in critically ill patients, and in cystic fibrosis, the most common lethal genetic disease in Caucasians. Accumulating evidence suggests that biofilms could have also a role in chronic obstructive pulmonary disease and their involvement in bronchiectasis has been proposed as well. When they grow in biofilms, microorganisms become multidrug-resistant. Therefore the treatment of biofilm-dependent airway infections is problematic. Indeed, it still largely based on measures aiming to prevent the formation of biofilms or remove them once that they are formed. Here we review recent evidence suggesting that the mucokinetic drug ambroxol has specific anti-biofilm properties. We also discuss how additional pharmacological properties of this drug could be beneficial in biofilm-dependent airway infections. Specifically, we review the evidence showing that: 1-ambroxol exerts anti-inflammatory effects by inhibiting at multiple levels the activity of neutrophils, and 2-it improves mucociliary clearance by interfering with the activity of airway epithelium ion channels and transporters including sodium/bicarbonate and sodium/potassium/chloride cotransporters, cystic fibrosis transmembrane conductance regulator and aquaporins. As a whole, the data that we review here suggest that ambroxol could be helpful in biofilm-dependent airway infections. However, considering the limited clinical evidence available up to date, further clinical studies are required to support the use of ambroxol in these diseases.

Anti-inflammatory and antinociceptive effects of salbutamol on acute and chronic models of inflammation in rats: involvement of an antioxidant mechanism

The possible role of β-2 adrenergic receptors in modulation of inflammatory and nociceptive conditions suggests that the β-2 adrenergic receptor agonist, salbutamol, may have beneficial anti-inflammatory and analgesic effects. Therefore, in this study, we induced inflammatory and nociceptive responses with carrageenan-induced paw edema or cotton-pellet-induced granuloma models, both of which result in oxidative stress. We hypothesized that salbutamol would prevent inflammatory and nociceptive responses by stimulating β-2 adrenergic receptors and the prevention of generation of ROS during the acute inflammation process in rats. Both doses of salbutamol used in the study (1 and 2 mg/kg) effectively blocked the acute inflammation and inflammatory nociception induced by carrageenan. In the cotton-pellet-induced granuloma test, both doses of salbutamol also significantly decreased the weight of granuloma tissue on the cotton pellets when compared to the control. Anti-inflammatory and analgesic effects of salbutamol were found to be comparable with those of indomethacin. Salbutamol decreased myeloperoxidase (MPO) activity and lipid peroxidation (LPO) level and increased the activity of superoxide dismutase (SOD) and level of glutathione (GSH) during the acute phase of inflammation. In conclusion, salbutamol can decrease acute and chronic inflammation, possibly through the stimulation of β-2 adrenergic receptors. This anti-inflammatory effect may be of significance in asthma treatment, where inflammation also takes part in the etiopathology. This study reveals that salbutamol has significant antioxidative effects, which at least partially explain its anti-inflammatory capabilities. These findings presented here may also shed light on the roles of β-2 adrenergic receptors in inflammatory and hyperalgesic conditions.

Ambroxol: a multifaceted molecule with additional therapeutic potentials in respiratory disorders of childhood

INTRODUCTION

Mucoactive drugs are currently used to cleanse the respiratory tract following disturbance of the normal mucociliary clearance due to mucous hyperproduction and/or modification of its physicochemical characteristics. However, in addition to possessing the ability to perform specific actions on airway secretion, these compounds have the capability to modulate the mechanisms involved in abnormal secretions. Indeed, over the years, in the postmarketing phase, a large number of studies have been published showing interesting pharmacological activities in addition to their secretagogue activity.

AREAS COVERED

This article collates available data on ambroxol (2-amino-3,5-dibromo-N-[trans-4-hydroxycyclohexyl]benzylamine), a metabolite of bromhexine, used as a secretagogue in the treatment of childhood airway diseases. This article goes beyond the mucoactive aspects of the drug covering its multiple pharmacological properties.

EXPERT OPINION

The non-mucoactive functions exhibited by the compound may provide beneficial effects on airway structure and function in health and disease. Beyond the mucokinetic and secretagogue effects, ambroxol showed great antioxidant, anti-inflammatory, local anesthetic and surfactant synthesis stimulatory activities. Moreover, some antiviral and antibacterial activities were shown. These findings may better explain the clinical results observed in a variety of airway disorders and suggest additional therapeutic potential. Further studies are needed to better define the clinical relevance of these non-mucolytic activities.

Post-translational protein modification by carotenoid cleavage products

Carotenoids are known to generate various aldehydes, known as carotenoid-derived aldehydes (CDAs), which could efficiently react with protein or DNA. In this in vitro model study, interaction between CDA and protein has been studied. Various proteins were incubated with CDA, and protein modification and adduct formation were confirmed by using matrix-assisted laser desorption and ionization time-of-flight, amino acid analysis, and measuring enzyme activity on modification with CDA. Using radiolabeled NaB((3) H)H(4) and Raney nickel as well as sulfhydryl assay (Ellman's reagent), we confirmed that CDA could conjugate with cysteine through a thioether linkage. The carbonyl assay using 2,4-dinitrophenylhydrazine revealed the possible involvement of Schiff's base reaction between CDA and lysine. The adducts formed between β-apo-8-carotenal (BA8C) and N-acetylcysteine and BA8C and N-acetyllysine were confirmed by HPLC and ESI-MS. Our results suggest that CDA could alter protein function by post-translational interaction with cysteine and lysine by thioether linkage and by schiff's based bonds, respectively. Thus, the formation of CDA adducts with proteins could alter functional properties of proteins responsible for maintaining cell homeostasis and thereby cause cellular toxicity. In view of these observations, further studies are required to understand the delicate balance between beneficial and/or harmful effects of carotenoids as a dietary supplement to slow age-related macular degeneration progression.

Genotoxic effects of carotenoid breakdown products in human retinal pigment epithelial cells

PURPOSE

To investigate the genotoxic effects of lutein (LBP) and beta -carotene breakdown products (beta -apo-8-carotenal, BA8C) and the preventive role of GSH in human retinal pigment epithelial cells (ARPE-19).

METHODS

LBP- and BA8C-induced DNA damage in human retinal pigment epithelial cells (ARPE-19) was determined by comet assay. The DNA damage was quantified by the image analysis system using Comet Score software. ARPE-19 cell viability was determined by CellTiter 96 AQ(ueous) one-solution cell proliferation assay kit. Intracellular GSH levels were measured by Ellman's reagent.

RESULTS

Incubation of serum-starved ARPE-19 cells with LBP and BA8C caused significant DNA damage in a dose- and time-dependent manner. The DNA damage and cell death incurred by LBP and BA8C were significantly prevented by N-acetylcysteine (NAC) but not by alpha -tocopherol + ascorbic acid (T + AA). Furthermore, BSO-induced GSH depletion in ARPE-19 cells caused a significant elevation in LBP- and BA8C-induced DNA damage, whereas increased GSH levels in ARPE-19 cells prevented it.

CONCLUSIONS

Our results suggest that breakdown products of dietary carotenoids could be genotoxic in ARPE-19 cells. LBP-induced genotoxic effects could worsen oxidative stress. The intracellular GSH pool in ARPE-19 cells might play a critical role in carotenoid breakdown products-induced genotoxicity.

Evaluation of anti-inflammatory and antioxidant activities of Peltigera rufescens lichen species in acute and chronic inflammation models

The anti-inflammatory effects of the methanol extract of the lichen species Peltigera rufescens (Weis.) Humb (MEPR) (Peltigeraceae) on acute (carrageenan-induced) and chronic (cotton pellet granule) phases of inflammation were investigated. The MEPR was capable of reducing carrageenan-induced inflammation and showed a potent antiproliferative effect (63.5%) in the chronic inflammation model. Inflammation is related to neutrophil infiltration and the production of neutrophil-derived mediators and free radicals. The MEPR reduced the myeloperoxidase and inducible nitric oxide synthase (NOS) activities, which were increased by carrageenan injection. Carrageenan injection also increased the lipid peroxidation (LPO) as compared with untreated paw tissues. The administration of MEPR, diclofenac, and indomethacin reduced the LPO in paw tissues through amelioration of the antioxidant defense systems. Neutrophil infiltration and neutrophil-derived free radicals in tissues therefore appeared to play an important role in the inflammation process induced by carrageenan. The anti-inflammatory effect of MEPR could be attributed to its reducing effect on the neutrophil-derived free radicals and its ameliorating effect on the antioxidant defense systems.

Ambroxol in the 21st century: pharmacological and clinical update

BACKGROUND

Belonging to the group of expectorants, ambroxol is an active substance with a long history that influences parameters considered to be the basis for the physiological production and the transport of the bronchial mucus. Therefore, ambroxol's indication is 'secretolytic therapy in acute and chronic bronchopulmonary diseases associated with abnormal mucus secretion and impaired mucus transport'.

OBJECTIVE

The aim of this review is to evaluate the pharmacological and clinical data on the mucokinetic compound ambroxol.

METHODS

The existing database that covers >40 years of pharmacological research and clinical development was analysed. Only studies with adequate study design were evaluated.

CONCLUSION

Ambroxol is shown to exert several activities: i) secretolytic activity (i.e., promotes mucus clearance, facilitates expectoration, and eases productive cough); ii) anti-inflammatory and antioxidant activity; and iii) a local anaesthetic effect through sodium channel blocking at the level of the cell membrane. The reduction on chronic obstructive pulmonary disease exacerbations is consistent and clinically relevant. The anaesthetic effect is a new pharmacological action that could be beneficial in the management of acute respiratory tract infections. The efficacy and safety of ambroxol is well established.

Modulation of acid-sensing ion channel activity by nitric oxide

Acid-sensing ion channels (ASICs) are a class of ion channels activated by extracellular protons and are believed to mediate the pain caused by tissue acidosis. Although ASICs have been widely studied, little is known about their regulation by inflammatory mediators. Here, we provide evidence that nitric oxide (NO) potentiates the activity of ASICs. Whole-cell patch-clamp recordings were performed on neonatal rat cultured dorsal root ganglion neurons and on ASIC isoforms expressed in CHO cells. The NO donor S-nitroso-N-acetylpenicillamine (SNAP) potentiates proton-gated currents in DRG neurons and proton-gated currents in CHO cells expressing each of the acid-sensitive ASIC subunits. Modulators of the cGMP/PKG pathway had no effect on the potentiation, but in excised patches from CHO cells expressing ASIC2a, the potentiation could be reversed by externally applied reducing agents. NO therefore has a direct external effect on the ASIC ion channel, probably through oxidization of cysteine residues. Complementary psychophysiological studies were performed using iontophoresis of acidic solutions through the skin of human volunteers. Topical application of the NO donor glyceryl trinitrate significantly increased acid-evoked pain but did not affect heat or mechanical pain thresholds. ASICs may therefore play an important role in the pain associated with metabolic stress and inflammation, where both tissue acidosis and a high level of NO are present.

Carotenoid derived aldehydes-induced oxidative stress causes apoptotic cell death in human retinal pigment epithelial cells

Carotenoids have been advocated as potential therapeutic agents in treating age-related macular degeneration (AMD). In ocular tissues carotenoids may undergo oxidation and form carotenoid-derived aldehydes (CDA), which would be toxic to tissues. We have investigated the cytotoxic effects of CDA from beta-carotene, Lutein and Zeaxanthin on human retinal pigment epithelial cells (ARPE-19). The serum-starved ARPE-19 cells were treated with CDA without or with antioxidant, N-acetylcysteine (NAC) and cell viability, apoptosis, reactive oxygen species (ROS) levels, nuclear chromatin condensation as well as fragmentation, change in mitochondrial membrane potential (MMP) and activation of transcription factors NF-kappaB and AP-1 were determined. We observed a dose and time-dependent decline in cell viability upon incubation of ARPE-19 cells with CDA. The CDA treatment also led to elevation in ROS levels in a dose-dependent manner. Upon CDA treatment a significant number of apoptotic cells were observed. Also early apoptotic changes in ARPE-19 cells induced by CDA were associated with change in MMP. Increased nuclear chromatin condensation and fragmentation were also observed in cells treated with CDA. The cytotoxicity of CDA in ARPE-19 cells was significantly ameliorated by the antioxidant, NAC. Furthermore, CDA induced the activation of NF-kappaB and AP-1 which was significantly inhibited by NAC. Thus our results demonstrate that CDA could increase the oxidative stress in ARPE-19 cells by elevating ROS levels that would cause imbalance in cellular redox status, which could lead to cell death. This would suggest that high carotenoid supplementation for treatment of AMD should be used cautiously.

Amiodarone has anti-inflammatory and anti-oxidative properties: An experimental study in rats with carrageenan-induced paw edema

Amiodarone is a widely used anti-arrhythmic agent. We have investigated alterations in the glutathione (GSH) level and the activities of anti-oxidative enzymes (superoxide dismutase, catalase, glutathione s-transferase and glutathione reductase) and myeloperoxidase, as marker of acute inflammation, following oral administration of amiodarone and diclofenac in rats with carrageenan-induced paw edema. In the present study, we found that 1) Amiodarone reduced the development of carrageenan-induced paw edema, to a greater degree than diclofenac; 2) Amiodarone and diclofenac alleviated increases in the activities of catalase and glutathione s-transferase enzymes resulting from edema; 3) Amiodarone and diclofenac ameliorated depressions in the GSH level and the activities of superoxide dismutase and glutathione reductase enzymes caused by carrageenan injection; and 4) All doses of amiodarone and diclofenac caused an amplification in myeloperoxidase activity resulting from induced paw edema. These results suggest that the anti-inflammatory effect of amiodarone on carrageenan-induced acute inflammation can be attributed to its ameliorating effect on the oxidative damage.

Drugs modulating the biological effects of peroxynitrite and related nitrogen species

The term "reactive nitrogen species" includes nitrogen monoxide, commonly called nitric oxide, and some other remarkable chemical entities (peroxynitrite, nitrosoperoxycarbonate, etc.) formed mostly from nitrogen monoxide itself in biological environments. Regardless of the specific mechanisms implicated in their effects, however, it is clear that an integrated pharmacological approach to peroxynitrite and related species is only just beginning to take shape. The array of affected chemical and pathological processes is extremely broad. One of the most conspicuous mechanisms observed thus far has been the scavenging of the peroxynitrite anion by molecules endowed with antioxidant activity. This discovery has in turn lent great significance to several naturally occurring and synthetic antioxidants, which usually protect not only against oxidative reactions, but also from nitrating ones, both in vitro and in vivo. This has proven to be beneficial in different tissues, especially within the central nervous system. Taking these results and those of other biochemical investigations into account, many research lines are currently in progress to establish the true potential of reactive nitrogen species deactivators in the therapy of neurological diseases, ischemia-reperfusion damage, renal failure, and lung injury, among others.