Anti-oxidant therapy: does it have a role in the treatment of human disease?

Impact of Thermo-Responsive N-Acetylcysteine Hydrogel on Dermal Wound Healing and Oral Ulcer Regeneration

This study investigates the efficacy of a thermo-responsive N-acetylcysteine (NAC) hydrogel on wound healing and oral ulcer recovery. Formulated by combining NAC with methylcellulose, the hydrogel's properties were assessed for temperature-induced gelation and cell viability using human fibroblast cells. In vivo experiments on Sprague Dawley rats compared the hydrogel's effects against saline, NAC solution, and a commercial NAC product. Results show that a 5% NAC and 1% methylcellulose solution exhibited optimal outcomes. While modest improvements in wound healing were observed, significant enhancements were noted in oral ulcer recovery, with histological analyses indicating fully regenerated mucosal tissue. The study concludes that modifying viscosity enhances NAC retention, facilitating tissue regeneration. These findings support previous research on the beneficial effects of antioxidant application on damaged tissues, suggesting the potential of NAC hydrogels in improving wound care and oral ulcer treatment.

Vitamin C as Scavenger of Reactive Oxygen Species during Healing after Myocardial Infarction

Currently, coronary artery bypass and reperfusion therapies are considered the gold standard in long-term treatments to restore heart function after acute myocardial infarction. As a drawback of these restoring strategies, reperfusion after an ischemic insult and sudden oxygen exposure lead to the exacerbated synthesis of additional reactive oxidative species and the persistence of increased oxidation levels. Attempts based on antioxidant treatment have failed to achieve an effective therapy for cardiovascular disease patients. The controversial use of vitamin C as an antioxidant in clinical practice is comprehensively systematized and discussed in this review. The dose-dependent adsorption and release kinetics mechanism of vitamin C is complex; however, this review may provide a holistic perspective on its potential as a preventive supplement and/or for combined precise and targeted therapeutics in cardiovascular management therapy.

Gallic acid protects against isoproterenol-induced cardiotoxicity in rats

BACKGROUND

Gallic acid (GA) is a polyphenolic agent with interesting pharmacological impacts on the cardiovascular system.

OBJECTIVE

The present study purposed to study the protective effects of GA at 25 and 50 mg/kg against isoproterenol (ISO)-induced cardiac damage in ischemia/reperfusion (I/R) in rats.

METHODS

Male Wistar rats were randomly assigned into six groups: Control, Control treated with GA at 25 mg/kg (GA25), Control treated with GA at 50 mg/kg (GA50), Hypertrophic rats induced by ISO (ISO), Hypertrophic rats treated with GA at 25 mg/kg (ISO+GA25), and Hypertrophic rats treated with GA at 50 mg/kg (ISO+GA50). Heart isolation was performed to induce a cardiac I/R injury model. Cardiac hemodynamic parameters were recorded. Serum Lactate Dehydrogenase (LDH) and Creatine Kinase-MB (CK-MB) and cardiac Superoxide dismutases (SOD) levels were evaluated. The gene expression of Sarcoplasmic reticulum Ca²⁺-ATPase (SERCA2a) was assessed.

RESULTS

We found that GA at 50 mg/kg was significantly increased cardiac function at post I/R period in ISO-induced hypertrophic hearts. Moreover, it suppressed cardiac hypertrophy, the serum LDH and CK-MB levels in ISO injected rats. Administration of GA at 50 mg/kg was significantly increased SOD level and SERCA2a gene expression in the hypertrophic hearts.

CONCLUSION

GA at 50 mg/kg could improve cardiac performance possibly by increasing antioxidant defense enzymes, reducing cell damage, and enhancing SERCA2a gene expression in hypertrophic heart induced by ISO in I/R injury conditions.

The role and mechanism of citrus flavonoids in cardiovascular diseases prevention and treatment

Cardiovascular diseases (CVDs) have been ranked as the leading cause of death in the world, whose global incidence is increasing year by year. Citrus, one of the most popular fruits in the world, is rich in flavonoids. Citrus flavonoids attract special attention due to a variety of biological activities, especially in the prevention and treatment of CVDs. The research progress of citrus flavonoids on CVDs have been constantly updated, but relatively fragmented, which needed to be systematically summarized. Hence, the recent research about citrus flavonoids and CVDs were reviewed, including the types and in vivo processes of citrus flavonoids, epidemiology study and mechanism on prevention and treatment of CVDs by citrus flavonoids. This review would provide a theoretical basis for the citrus flavonoids research and a new idea in the citrus industry development and application.

Cyclooxygenase-2 inhibition improves antioxidative defense during experimental hypercholesterolemia

Scientific literature shows that inflammation and oxidative stress contribute in the pathogenesis of atherosclerosis. The oxidative stress is the consequence of an imbalance between the free radical generation and elimination. One source of free oxygen radicals is cyclooxygenase (COX)-2 and, therefore, inhibiting the activity of this enzyme is likely to reduce oxidative stress. In the present study an experimental rabbit model of hypercholesterolemia was developed and the effects of COX-2 inhibitors, nimesulide and celecoxib were observed on the activities of antioxidant enzymes, superoxide dismutase (SOD), glutathione peroxidase (GPx) and total antioxidant status (TAS). Rabbits were divided into four groups- control, saline, nimesulide and celecoxib, with all groups fed a high cholesterol diet, which only received saline. Low activities of SOD, GPx and TAS were measured in the hypercholesterolemic rabbits pretreated with saline. In the same group, a reciprocal relationship was observed between the LDL-cholesterol concentration and the plasma activities of GPx, SOD and TAS. Rabbits in nimesulide and celecoxib group showed significantly higher activities of SOD, GPx and TAS in hypercholesterolemic rabbits compared to saline group (p<0.05). Our study shows that selective and timely use of COX-2 inhibitors would be useful in preventing the onset and development of atherosclerosis by enhancing antioxidant defence system.

Oxidative stress-related biomarkers in essential hypertension and ischemia-reperfusion myocardial damage

Cardiovascular diseases are a leading cause of mortality and morbidity worldwide, with hypertension being a major risk factor. Numerous studies support the contribution of reactive oxygen and nitrogen species in the pathogenesis of hypertension, as well as other pathologies associated with ischemia/reperfusion. However, the validation of oxidative stress-related biomarkers in these settings is still lacking and novel association of these biomarkers and other biomarkers such as endothelial progenitor cells, endothelial microparticles, and ischemia modified albumin, is just emerging. Oxidative stress has been suggested as a pathogenic factor and therapeutic target in early stages of essential hypertension. Systolic and diastolic blood pressure correlated positively with plasma F2-isoprostane levels and negatively with total antioxidant capacity of plasma in hypertensive and normotensive patients. Cardiac surgery with extracorporeal circulation causes an ischemia/reperfusion event associated with increased lipid peroxidation and protein carbonylation, two biomarkers associated with oxidative damage of cardiac tissue. An enhancement of the antioxidant defense system should contribute to ameliorating functional and structural abnormalities derived from this metabolic impairment. However, data have to be validated with the analysis of the appropriate oxidative stress and/or nitrosative stress biomarkers.

Molecular basis of cardioprotective effect of antioxidant vitamins in myocardial infarction

Acute myocardial infarction (AMI) is the leading cause of mortality worldwide. Major advances in the treatment of acute coronary syndromes and myocardial infarction, using cardiologic interventions, such as thrombolysis or percutaneous coronary angioplasty (PCA) have improved the clinical outcome of patients. Nevertheless, as a consequence of these procedures, the ischemic zone is reperfused, giving rise to a lethal reperfusion event accompanied by increased production of reactive oxygen species (oxidative stress). These reactive species attack biomolecules such as lipids, DNA, and proteins enhancing the previously established tissue damage, as well as triggering cell death pathways. Studies on animal models of AMI suggest that lethal reperfusion accounts for up to 50% of the final size of a myocardial infarct, a part of the damage likely to be prevented. Although a number of strategies have been aimed at to ameliorate lethal reperfusion injury, up to date the beneficial effects in clinical settings have been disappointing. The use of antioxidant vitamins could be a suitable strategy with this purpose. In this review, we propose a systematic approach to the molecular basis of the cardioprotective effect of antioxidant vitamins in myocardial ischemia-reperfusion injury that could offer a novel therapeutic opportunity against this oxidative tissue damage.

Reductive stress linked to small HSPs, G6PD, and Nrf2 pathways in heart disease

SIGNIFICANCE

Aerobic organisms must exist between the dueling biological metabolic processes for energy and respiration and the obligatory generation of reactive oxygen species (ROS) whose deleterious consequences can reduce survival. Wide fluctuations in harmful ROS generation are circumvented by endogenous countermeasures (i.e., enzymatic and nonenzymatic antioxidants systems) whose capacity decline with aging and are enhanced by disease states.

RECENT ADVANCES

Substantial efforts on the cellular and molecular underpinnings of oxidative stress has been complemented recently by the discovery that reductive stress similarly predisposes to inheritable cardiomyopathy, firmly establishing that the biological extremes of the redox spectrum play essential roles in disease pathogenesis.

CRITICAL ISSUES

Because antioxidants by nutritional or pharmacological supplement to prevent or mitigate disease states have been largely disappointing, we hypothesize that lack of efficacy of antioxidants might be related to adverse outcomes in responders at the reductive end of the redox spectrum. As emerging concepts, such as reductive, as opposed, oxidative stress are further explored, there is an urgent and critical gap for biochemical phenotyping to guide the targeted clinical applications of therapeutic interventions.

FUTURE DIRECTIONS

New approaches are vitally needed for characterizing redox states with the long-term goal to noninvasively assess distinct clinical states (e.g., presymptomatic, end-stage) with the diagnostic accuracy to guide personalized medicine.

Thiol antioxidants in combination with vitamin B12 induce apoptotic death of human lymphocytic leukemia cells by destabilization of lysosomes with the involvement of iron ions

The extensively used thiol antioxidants (dithiothreitol, glutathione, and N-acetylcysteine) in combination with hydroxycobalamine (vitamin B12) gain toxic activity in relation to human lymphocytic leukemia cell line HL60. Combined treatment with thiol and vitamin B12 was followed by early destabilization of lysosomes and apoptotic death of cells. The cytotoxic effect was abolished by caspase inhibitors. An iron-chelating agent deferoxamine partly prevented cell death, while lysosomal protease inhibitor pepstatin produced no protective effect.

Ruthenium(II) carbonyl complexes containing pyridine carboxamide ligands and PPh₃/AsPh₃/Py coligands: synthesis, spectral characterization, catalytic and antioxidant studies

New ruthenium(II) carbonyl complexes bearing pyridine carboxamide and triphenylphosphine/triphenylarsine/pyridine have been prepared by direct reaction of ruthenium(II) precursors with some pyridine carboxamide ligands, N,N-bis(2-pyridinecarboxamide)-1,2-ethane (H(2)L(1)), N,N-bis(2-pyridinecarboxamide)-1,2-benzene (H(2)L(2)) and N,N-bis(2-pyridinecarboxamide)-trans-1,2-cyclohexane (H(2)L(3)). The organic ligands offering two N(amide) and two N(pyridine) donor sites to the metal centre. They have been characterized by elemental analyses, FT-IR, UV-Visible, NMR ((1)H, (13)C and (31)P) and ESI-MS techniques. Based on the above data, an octahedral structure has been assigned for all the complexes. The catalytic efficiency of the complexes in transfer hydrogenation of ketones in the presence of iPrOH/KOH and N-alkylation of amine in the presence of tBuOK was examined. Furthermore, the antioxidant activity of the ligands and its ruthenium(II) complexes were determined by DPPH radical, nitric oxide radical, hydroxyl radical and hydrogen peroxide scavenging methods, which indicates that the ruthenium(II) complexes exhibit more effective antioxidant activity than the ligands alone.

Mangifera indica (mango)

Mangifera indica, commonly used herb in ayurvedic medicine. Although review articles on this plant are already published, but this review article is presented to compile all the updated information on its phytochemical and pharmacological activities, which were performed widely by different methods. Studies indicate mango possesses antidiabetic, anti-oxidant, anti-viral, cardiotonic, hypotensive, anti-inflammatory properties. Various effects like antibacterial, anti fungal, anthelmintic, anti parasitic, anti tumor, anti HIV, antibone resorption, antispasmodic, antipyretic, antidiarrhoeal, antiallergic, immunomodulation, hypolipidemic, anti microbial, hepatoprotective, gastroprotective have also been studied. These studies are very encouraging and indicate this herb should be studied more extensively to confirm these results and reveal other potential therapeutic effects. Clinical trials using mango for a variety of conditions should also be conducted.

Evaluation of antioxidative activity of Croatian propolis samples using DPPH* and ABTS*+ stable free radical assays

Propolis is one of the richest sources of plant phenolics (flavonoids and phenolic acids), which are widely recognized as rather strong antioxidants. The aim of our work was to use colored stable free radical (DPPH* and ABTS*+) spectrophotometric and thin-layer chromatographic (TLC) assays to study the antioxidative behavior of the phenolics (caffeic acid, galangin and pinocembrin) most commonly present in Croatian propolis samples obtained from different Croatian regions. We propose a mathematical model providing a more sophisticated interpretation of the obtained results and a new parameter named antioxidative efficiency (AOE) is introduced. The kinetic behaviour of chosen standards determined by spectrophotometric assays follows the exponential decrease of the absorption curve. Explained numerically, AOE represents the absolute value of the first derivative of an absorbance curve in the point A0/e (where A0 is the absorbance measured at t = 0 and e is the natural logarithm base). The advantage of this newly introduced parameter is that it provides an easy and accurate mutual comparison between the rates of antioxidative efficiency of different propolis samples. A TLC assay was only applicable in the case of the DPPH* radical. Dose-response curves were described using a linear function with AOE expressed as a coefficient of the slope. The chromatographic method was shown to be very rapid, reliable and easy-to-perform.

Inhibition of Gap Junctional Intercellular Communication and Activation of Mitogen-Activated Protein Kinase by Tumor-Promoting Organic Peroxides and Protection by Resveratrol

Dicumyl peroxide (di-CuOOH) and benzoyl peroxide (BzOOH) act as tumor promoters in SENCAR mice, whereas di-tert-butylhydroperoxide does not. Tumor promotion requires the removal of growth suppression by inhibition of gap junctional intercellular communication (GJIC) and the induction of mitogenic intracellular pathways. We showed that di-CuOOH and BzOOH both reversibly inhibited GJIC and transiently activated mitogen-activated protein kinase, specifically, the extracellular receptor kinase at noncytotoxic conditions in WB-F344 rat liver epithelial cells, whereas the non-tumor-promoting di-tert-butylhydroperoxide did not inhibit GJIC or activate extracellular receptor kinase. di-CuOOH but not BzOOH inhibited GJIC through a phosphatidylcholine-specific phospholipase C-dependent mechanism. N-acetylcysteine (NAC) was needed to prevent a cytotoxic, glutathione-depleting effect of BzOOH, whereas di-CuOOH was noncytotoxic and did not alter glutathione levels at all doses and times tested. Pretreatment of WB-F344 cells with resveratrol, a polyphenolic antioxidant present in red wine, prevented at physiological doses the inhibition of GJIC by di-CuOOH but not from BzOOH and was effective in significantly preventing extracellular receptor kinase activation by both peroxides. NAC did not prevent any of the peroxide effects on either GJIC or extracellular receptor kinase, suggesting a specific antioxidant effect of resveratrol.

Anticlastogenic activity of morin against whole body gamma irradiation in Swiss albino mice

Anticlastogenic activity of morin was explored against whole body gamma radiation, at a dose rate of 1.66 Gy/min in Swiss albino mice pretreated intraperitoneal or orally. Pretreatment with morin 10, 25, 50, 75, 100, 125, and 150 mg/kg, i.p. delayed and reduced percentage mortality and increased mean survival times in mice irradiated with 10 Gy gamma radiation. Intraperitoneal route was found superior to oral route. An i.p. dose of 100 mg/kg was found to be the most effective dose in preventing radiation-induced weight loss, increasing the mean survival times and reducing percentage mortality. Morin (100 mg/kg) pretreatment effectively maintained spleen index (spleen weight/body weight x 100) and stimulated endogenous spleen colony forming units. Pretreatment with morin (100 mg/kg) significantly reduced dead, inflammatory, and mitotic cells in irradiated mice jejunum along with a significant increase in goblet cells and rapidly multiplying crypt cells. Morin (100 mg/kg) also maintained the villus height close to normal, prevented mucosal erosion and basement membrane damage in irradiated jejunum. Nuclear enlargement in epithelial cells of jejunum was lower in morin treated mice compared to radiation control. Morin (100 mg/kg) also significantly elevated the endogenous antioxidant enzymes viz. glutathione S transferase (GST), superoxide dismutase (SOD) and reduced glutathione (GSH), in normal mice at 2, 4 and 8 h post treatment. Drastic decrease in endogenous enzymes (GSH, GST, catalase and SOD) and total thiols was observed in irradiated mice at 2, 4 and 8 h post irradiation, while pretreatment with morin (100 mg/kg) prevented this decrease. Morin (100 mg/kg) also elevated radiation LD(50) from 9.2 to 10.1 Gy, indicating a dose modifying factor (DMF) of 1.11.

Dysregulated Toll-like receptor expression and signaling in bone marrow-derived macrophages at the onset of diabetes in the non-obese diabetic mouse

The expression, responsiveness and regulation of mouse Toll-like receptors (TLRs) in bone marrow-derived macrophages (BM-Ø) were investigated prior to and following the development of diabetes. Expression of TLR3 and TLR5 was significantly higher in newly diabetic non-obese diabetic (NOD) mice when compared with pre-diabetic and control strains of mice. The TLR3 ligand poly(I)poly(C) triggered up-regulation of its own receptor in NOR and pre-diabetic NOD, but TLR3 was already highly expressed in diabetic NOD mice. Expression levels of TLR3 correlated with poly(I)poly(C)-triggered IFN activity. LPS triggered down-regulation of TLR4 in pre-diabetic NOD, NOR and BALB/c, while levels of TLR4 remained consistently elevated in type 1 diabetic NOD and type 2 diabetic NZL mice. Dysregulation of TLR4 expression in the diabetic state correlated with increased nuclear factor kappa B (NF-kappaB) activation in response to the TLR4 ligand LPS and higher expression of IL-12p40, tumor necrosis factor alpha (TNFalpha), IL-6 and inducible nitric oxide synthase but lowered expression of IL-10. Exposure of bone marrow precursor cells from NOD mice to a hyperglycemic environment during differentiation into macrophages resulted in elevated levels of TLR2 and TLR4 and the cytokine TNFalpha. The results indicate that macrophage precursors are influenced by systemic changes in diabetes favoring altered TLR expression and sensitivity that may influence susceptibility to macrophage-mediated diabetes complications and explain inappropriate responses to infection in diabetes.

Protective effect of Mangifera indica L. extract (Vimang) on the injury associated with hepatic ischaemia reperfusion

The effect of Mangifera indica L. extract (Vimang) on treatment of injury associated with hepatic ischaemia/reperfusion was tested. Vimang protects from the oxidative damage induced by oxygen-based free radicals as shown in several in vitro test systems conducted. The ability of Vimang to reduce liver damage was investigated in rats undergoing right-lobe blood fl ow occlusion for 45 min followed by 45 min of reperfusion. The ischaemia/reperfusion model leads to an increase of transaminase (ALT and AST), membrane lipid peroxidation, tissue neutrophil in filtration, DNA fragmentation, loss of protein -SH groups, cytosolic Ca2+ overload and a decrease of catalase activity. Oral administration of Vimang (50, 110 and 250 mg/kg, b.w.) 7 days before reperfusion, reduced transaminase levels and DNA fragmentation in a dose dependent manner (p < 0.05). Vimang also restored the cytosolic Ca2+ levels and inhibited polymorphonuclear migration at a dose of 250 mg/kg b.w., improved the oxidation of total and non protein sulfhydryl groups and prevented modification in catalase activity, uric acid and lipid peroxidation markers (p < 0.05). These data suggest that Vimang could be a useful new natural drug for preventing oxidative damage during hepatic injury associated with free radical generation.

Impact of certain flavonoids on lipid profiles--potential action of Garcinia cambogia flavonoids

Flavonoids from Cocos nucifera, Myristica fragrance, Saraka asoka and Garcinia cambogia exerted hypolipidaemic activity in rats. Lipid lowering activity was maximum in rats administered flavonoids (10 mg/kg BW/day) from Garcinia cambogia. A dose response study revealed biphasic activity. Higher doses were less effective in reducing lipid levels in serum and tissues, although devoid of toxic effects.

Protective effects of Mangifera indica L. extract, mangiferin and selected antioxidants against TPA-induced biomolecules oxidation and peritoneal macrophage activation in mice

We compared the protective abilities of Mangifera indica L. stem bark extract (Vimang) 50-250 mgkg(-1), mangiferin 50 mgkg(-1), vitamin C 100 mgkg(-1), vitamin E 100 mgkg(-1)and beta -carotene 50 mgkg(-1)against the 12-O-tetradecanoylphorbol-13-acetate (TPA)-induced oxidative damage in serum, liver, brain as well as in the hyper-production of reactive oxygen species (ROS) by peritoneal macrophages. The treatment of mice with Vimang, vitamin E and mangiferin reduced the TPA-induced production of ROS by the peritoneal macrophages by 70, 17 and 44%, respectively. Similarly, the H(2)O(2)levels were reduced by 55-73, 37 and 40%, respectively, when compared to the control group. The TPA-induced sulfhydryl group loss in liver homogenates was attenuated by all the tested antioxidants. Vimang, mangiferin, vitamin C plus E and beta -carotene decreased TPA-induced DNA fragmentation by 46-52, 35, 42 and 17%, respectively, in hepatic tissues, and by 29-34, 22, 41 and 17%, in brain tissues. Similar results were observed in respect to lipid peroxidation in serum, in hepatic mitochondria and microsomes, and in brain homogenate supernatants. Vimang exhibited a dose-dependent inhibition of TPA-induced biomolecule oxidation and of H(2)O(2)production by peritoneal macrophages. Even if Vimang, as well as other antioxidants, provided significant protection against TPA-induced oxidative damage, the former lead to better protection when compared with the other antioxidants at the used doses. Furthermore, the results indicated that Vimang is bioavailable for some vital target organs, including liver and brain tissues, peritoneal exudate cells and serum. Therefore, we conclude that Vimang could be useful to prevent the production of ROS and the oxidative tissue damages in vivo.

Evaluation of the in vitro antioxidant activity of Mangifera indica L. extract (Vimang)

An extract of Mangifera indica L. (Vimang) was tested in vitro for its antioxidant activity using commonly accepted assays. It showed a powerful scavenger activity of hydroxyl radicals and hypochlorous acid and acted as an iron chelator. The extract also showed a significant inhibitory effect on the peroxidation of rat-brain phospholipid and inhibited DNA damage by bleomycin or copper-phenanthroline systems.