Free Radical-mediated Oxidative Stress Research Articles

Anti-aging chitosan/gelatin film crosslinked by α-Arbutin for bone regeneration by free radical scavenging to prevent osteoblast senescence.

Osteoblasts play a critical role in maintaining bone homeostasis. Senescence causes by free radical-mediated oxidative stress may affect the viability and osteogenic differentiation potential of osteoblast during bone formation. To eliminate the impacts of senescent cells by free radical scavenging is an optimal option for bone regeneration in age-related bone disease, such as osteoporosis (OP) and periodontitis. In this study, we fabricated an antioxidant film (CG-ARB) by crosslinking chitosan (C) and gelatin (G) using α-Arbutin (ARB) as a crosslinker. The morphological, physicochemical, and radical scavenging characteristics of the films were investigated. Its antioxidative ability to prevent osteoblast senescence for restoration of osteogenic differentiation was analyzed in vitro. A Sprague- Dawley (SD) rat model with critical size calvarial defect was used to evaluate the bone regeneration and biosafety in vivo. The results demonstrated that CG-ARB formed a dense fiber membrane, allowing for the gradual and sustained release of ARB for at least 10 days. ARB exerted antioxidant effect that prevented osteoblast senescence in vitro and promote bone healing in vivo. Furthermore, CG-ARB did not cause hemolysis or organ toxicity, and was therefore, considered biosafe. These results indicated that CG-ARB film could be an ideal drug delivery system (DDS) for sustained released of ARB in bone defect repair.

HPTLC-Bioautography-MS-Guided Strategy for the Detection of Phthalides With Antimicrobial and Antioxidant Activities From Ligusticum chuanxiong Essential Oil.

Antimicrobial resistance and free radical-mediated oxidative stress and inflammation involved in many pathological processes have become treatment challenges. One strategy is to search for antimicrobial and antioxidant ingredients from natural aromatic plants. This study established a rapid and high-throughput effect-component analysis method to screen active ingredients from Ligusticum chuanxiong essential oil (CXEO). The study aims to screen phthalides with antimicrobial and antioxidant activities from CXEO by high-performance thin-layer chromatography (HPTLC)-bioautography combined with HPLC-TOF/MS method. Antimicrobial activity was evaluated by disc diffusion and micro broth dilution methods. Antioxidant capacity was performed by DPPH scavenging test. Phthalides in CXEO were identified using HPLC-TOF/MS method. HPTLC-bioautography technique was established to screen phthalides of antifungal and antioxidant activities. CXEO had significant inhibitory activity against Candida albicans, weak or undetected inhibitory activity against Staphylococcus aureus, Escherichia coli, and Pseudomonas aeruginosa. For tested strains of C. albicans, inhibition zone diameters ranged from 13 to 17 mm, and MICs were from 0.5 to 2 mg mL-1. CXEO also had strong antioxidant activity, IC50 value for scavenging DPPH free radicals was 1.014 ± 0.014 mg mL-1. Nine phthalides in CXEO were tentatively identified. Ligustilide and senkyunolide A were screened to have both antimicrobial activity against C. albicans and strong DPPH scavenging property. HPTLC-bioautography-MS-guided strategy is very practical for high-throughput screening of antifungal and antioxidant phthalides from CXEO. Invitro experiments have shown that phthalides and CXEO have good biological activities, which may be used to the treatment of C. albicans infection or oxidative stress damage caused by various diseases. The therapeutic potential should be validated invivo in the future.

Serum oxidative stressors levels and association of mtDNA variants with type 2 diabetes mellitus in the Central India population

BackgroundThe mitochondrial genome has a high rate of mutability which plays a major role in pathogenic mutations. These mutations are implicated with mitochondrial dysfunction increasing the vulnerability to Diabetes Mellitus (DM). AimThe study aimed to evaluate the changes in oxidative markers and analyse the specific mitochondrial DNA variants that contributed to DM in the central Indian population. MethodTo assess mitogenomic alteration, Sanger sequencing was used to identify the single nucleotide polymorphisms (SNPs) or variants, while ELISA kits were used to evaluate oxidative stress. ResultsThe levels of 8-Hydroxy-2-deoxyguanosine (8-OHdG) and Malondialdehyde (MDA) in type 2 diabetes mellitus (T2DM) were significantly higher than in healthy individual (HI). In T2DM (3371.80 ± 1110.7 pg/ml) the levels of 8-OHdG were significantly greater and were found to be nine times higher compared to the control group (P < 0.001). Additionally, MDA level which is indicative of lipid peroxidation, in the diabetic groups (39.34 ± 23.05 ng/ml) contributed to 18 times higher than the control groups (2.16 ± 2 ng/ml). Moreover, 52 variants were found in our population, among which C10400T variants were significantly prevalent and clustered with the A10398G. These variants confirmed a strong association, on analysis for linkage disequilibrium (r2), with a slightly higher r2 value in the T2DM group (0.92) compared to controls (0.85), indicating a stronger link with diabetes. According to multivariate regression analysis, variants associated with the mitogenome such as C16192T (CI: 0.004 to 1.30, p = 0.028) were found to play a protective role against T2DM. Furthermore, A3384G and G16129A may contribute to the protective role against the risk of developing diabetes. ConclusionThe study demonstrates that diabetic patients are more vulnerable to certain mtDNA variants, directly linked to increased hyperglycemia. Elevated free radical-mediated oxidative stress likely affects these mtDNA variants.

Influence of green tea on alcohol aggravated neurodegeneration of cortex, cerebellum and hippocampus of STZ-induced diabetic rats

The main aim of this study was to evaluate the cytotoxic effects of chronic alcohol consumption on various regions of diabetic brain and preventive role of GTE. Clinical, experimental and histopathological observations indicate chronic, excessive alcohol consumption aggravates the free radical-mediated oxidative and nitrosative stress in several tissues including brain. Treatment with Epigallocatechin gallate (EGCG) significantly reduced the levels of oxidative/nitrosative stress paradigms, increased glutathione (GSH) levels and enhanced the activities of antioxidant enzymes. Histopathology evaluation revealed the possible influence of EGCG in reversing alcohol exacerbated diabetes-induced damage in cortex, cerebellum and hippocampus of brain. Furthermore, these studies have provided evidence to show how EGCG can exactly occupy the position in functional sites of nNOS (neuronal nitric oxide synthase) and induce a conformational change, inhibition of enzymatic activity and prevention of neurodegeneration/necrotic changes of tissue, in comparison with the rosiglitazone and glibenclamide. To summarise, this research has offered useful information on the action of EGCG that would provide potential protection against ethanol exacerbated diabetic brain damageand additional evidence for the use of EGCG as a lead compound for drug discovery.

Bioactive Tryptophan-Based Copper Complex with Auxiliary β-Carboline Spectacle Potential on Human Breast Cancer Cells: In Vitro and In Vivo Studies.

Biocompatible tryptophan-derived copper (1) and zinc (2) complexes with norharmane (β-carboline) were designed, synthesized, characterized, and evaluated for the potential anticancer activity in vitro and in vivo. The in vitro cytotoxicity of both complexes 1 and 2 were assessed against two cancerous cells: (human breast cancer) MCF7 and (liver hepatocellular cancer) HepG2 cells with a non-tumorigenic: (human embryonic kidney) HEK293 cells. The results exhibited a potentially decent selectivity of 1 against MCF7 cells with an IC50 value of 7.8 ± 0.4 μM compared to 2 (less active, IC50 ~ 20 μM). Furthermore, we analyzed the level of glutathione, lipid peroxidation, and visualized ROS generation to get an insight into the mechanistic pathway and witnessed oxidative stress. These in vitro results were ascertained by in vivo experiments, which also supported the free radical-mediated oxidative stress. The comet assay confirmed the oxidative stress that leads to DNA damage. The histopathology of the liver also ascertained the low toxicity of 1.

Protective effect of quercetin in combination with caloric restriction against oxidative stress-induced cell death of Saccharomyces cerevisiae cells.

Impairment of antioxidant enzymes activities has been well reported in several human diseases. Effective anti-ageing strategies involving antioxidant supplementation and/or caloric restriction (CR) are receiving a great attention to mitigate free radical-mediated oxidative damage in several disease conditions to improve active longevity. Therefore, in this work, we have evaluated the protective effect of quercetin under non restriction (NR) and CR conditions on the sensitivity of Saccharomyces cerevisiae mutant strains (sod1∆, sod2∆, cta1∆, ctt1∆, tsa1∆ and glr1∆) deficient in antioxidant defence systems (superoxide dismutase, catalase, thioredoxin peroxidase and glutathione reductase) against H2 O2 -induced oxidative stress. Our results demonstrate that quercetin in combination with CR has strongly reduced the H2 O2 -mediated stress in the yeast mutant cells compared to NR conditions. Furthermore, we show that quercetin in combination with CR enhanced the percentage viability of yeast cells during chronological ageing. Our research findings suggest that antioxidant supplementation in combination with CR might have potent beneficial effects than individual therapies against free radical-mediated oxidative stress. SIGNIFICANCE AND IMPACT OF THE STUDY: Oxidative stress results from an imbalance between free radicals and antioxidant defense systems in our body. Supplementation with exogenous antioxidants is necessary to neutralize the free radical mediated damage. Polyphenols are a group of naturally occurring plant compounds with strong free radical-scavenging activity and exhibits potent anti-aging property by mitigating oxidative stress. On the other hand, caloric restriction (CR) has been reported to be a popular leading anti-aging approach to ameliorate age-associate macromolecular damages in various chronic human diseases. Evaluation of protective effects of antioxidant supplementation in combination with CR against free radical mediated oxidative stress is pivotal for the development of novel anti-aging strategies to improve active longevity.

Assessment of Plasma Malondialdehyde in Acne Patients on Isotretinoin Therapy

Abstract Background Acne vulgaris is a chronic inflammatory disorder of the pilosebaceous unit that affects predominantly adolescents and young adults. Oral isotretinoin is a highly effective treatment agent for patients with nodulocystic acne and moderate to severe acne resistant to conventional therapy, isotretinoin might have side effects of oxidative stress and lipid peroxidation. . Malondialdehyde is the end product of lipid peroxidation and is a good marker of free radical-mediated damage and oxidative stress. Objective The purpose of this study to estimate malondialdehyde level in patients on Isotretinoin treatment for moderate to severe acne and compare them with healthy control group. Patients and Methods The case-control study was conducted at Ain. Shams University Faculty of Medicine, Egypt, from October 2017 to April 2017, and comprised male or non-pregnant female patients more than 18 years of age. 88 participants were included in the study; 44 cases, categorized by the Global Evaluation Acne (GEA) into 22 patients with moderate acne vulgaris and 22 patients with severe acne in comparison to equal healthy matching group. Isotretinoin was started in a dosage of 0.5mg/kg/day, and1.0mg/kg/day in patients with moderate and severe acne vulgaris respectively. Malondialdehyde, liver function tests, lipid profile and CBC were tested at the baseline for all participants and after 3 months for the patients who started isotretnoin therapy. Results In the current study, the mean baseline level malondialdehyde among all cases was 141.39 µmo1/m1±88.90, (range: 34.5 -360) and in controls it was 40 [µmo1/m1 ±11.3, (range: 9.5-90.4) this difference was statistically highly significant (P = 0.001). There was highly significant difference in malondialdehyde serum level (p = 0.0001) among all cases after 3 months of isotretnoin therapy, also there was a significant increase in MDA serum level among moderate cases (p = 0.021) and highly significant increase of MDA in severe cases (p=.001).ALP, ALT, serum cholesterol and triglyceride significant increases were seen in all cases. Conclusion low dose isotretinoin seems to have less side effects on basic laboratory data such as CBC, liver function tests, lipid profile and Malondialdehyde serum levels than high dose.

Dietary supplementation of Pleurotus tuber regium in rat feed ameliorates metabolic and hematotoxicity induced by carbon tetrachloride.

Pleurotus tuber regium, a wild edible mushroom can reduce free radical-mediated injury and oxidative stress induced by carbon tetrachloride (CCl4) via improvement of antioxidant capacity. This work evaluates the protective effects of this mushroom against the metabolic and hematological toxicity induced by CCl4. Sixty male Sprague Dawley rats were divided into six groups (n = 10). Group I received olive oil (3 mL/kg) i.p. twice weekly for 13 weeks, while maintaining free access to food and water ad libitum (negative control). Group II received 3 mL/kg (30% CCl4 in olive oil) injected i.p. twice weekly, while Groups III, IV, and V received 100, 200, and 500 mg wild edible P. tuber regium (33.3% in feed) daily in addition to 3 mL/kg CCl4 in olive oil injected twice weekly i.p. Group VI received olive oil (3 mL/kg) i.p. twice weekly for 13 weeks in addition to 500 mg P. tuber regium (33.3% in feed) daily. The body weight (b.w.), feed intake (FI), and water intake (WI) were obtained weekly, while the hematological indices and oxidative stress parameters were carried out shortly after necropsy on days 30, 60, and 90. Treatment with CCl4 significantly (p < 0.05) decreased the b.w., FI and WI, feed efficiency, ascorbic acid, α-tocopherol, and antioxidant enzymes, superoxide dismutase, catalase, total glutathione, and peroxidase, while increasing the oxidative stress as measured by malondialdehyde in CCl4 only group when compared with control. Supplementation of feed with P. tuber regium reversed the effects of CCl4. Pleurotus tuber regium ameliorated the CCl4-induced metabolic and hematotoxicity by improving the antioxidant capacity.

In Vitro and In Vivo Antioxidant Properties of Taraxacum officinale in Nω-Nitro-l-Arginine Methyl Ester (L-NAME)-Induced Hypertensive Rats

Oxidative stress has gained attention as one of the fundamental mechanisms responsible for the development of hypertension. The present study investigated in vitro and in vivo antioxidant effects of 70% ethanol-water (v/v) leaf and root extracts of T. officinale (TOL and TOR, respectively). Total phenolic and flavonoid content of plant extracts were assessed using Folin Ciocalteau and aluminium chloride colorimetric methods; while, 2,2-diphenyl-1-picrlhydrazyl (DPPH), 2,2-azinobis (3-ethylbenzothiazoline-6-sulfonic acid (ABTS) and ferric reducing antioxidant power (FRAP) protocols were used to determine the free radical scavenging and total antioxidant capacities (TAC), respectively. The in vivo total antioxidant capacity and malondialdehyde acid (MDA) levels for lipid peroxidation tests were performed on organ homogenate samples from Nω-nitro-L-arginine methyl ester (L-NAME)-induced hypertensive rats treated with leaf extract, TOL (500 mg/kg/day) and TOR (500 mg/kg/day) for 21 days. Results showed that compared to TOR, TOL possessed significantly higher (p < 0.01) polyphenol (4.35 ± 0.15 compared to 1.14 ± 0.01) and flavonoid (23.17 ± 0.14 compared to 3 ± 0.05) content; free radical scavenging activity (EC50 0.37 compared to 1.34 mg/mL) and total antioxidant capacities (82.56% compared to 61.54% ABTS, and 156 ± 5.28 compared to 40 ± 0.31 FRAP) and both extracts showed no toxicity (LD50 > 5000 mg/kg). TOL and TOR significantly (p < 0.01) elevated TAC and reduced MDA levels in targets organs. In conclusion, T. officinale leaf extract possesses significant anti-oxidant effects which conferred significant in vivo antioxidant protection against free radical-mediated oxidative stress in L-NAME-induced hypertensive rats.

Reductive Reprogramming: A Not-So-Radical Hypothesis of Neurodegeneration Linking Redox Perturbations to Neuroinflammation and Excitotoxicity.

Free radical-mediated oxidative stress, neuroinflammation, and excitotoxicity have long been considered insults relevant to the progression of Alzheimer's disease and other aging-related neurodegenerative disorders (NDD). Among these phenomena, the significance of oxidative stress and, more generally, redox perturbations, for NDD remain ill-defined and unsubstantiated. Here, I argue that (i) free radical-mediated oxidations of biomolecules can be dissociated from the progression of NDD, (ii) oxidative stress fails as a descriptor of cellular redox states under conditions relevant to disease, and (iii) aberrant upregulation of compensatory reducing activities in neural cells, resulting in reductive shifts in thiol-based redox potentials, may be an overlooked and paradoxical contributor to disease progression. In particular, I summarize evidence which supports the view that reductive shifts in the extracellular space can occur in response to oxidant and inflammatory signals and that these have the potential to reduce putative regulatory disulfide bonds in exofacial domains of the N-methyl-D-aspartate receptor, leading potentially to aberrant increases in neuronal excitability and, if sustained, excitotoxicity. The novel reductive reprogramming hypothesis of neurodegeneration presented here provides an alternative view of redox perturbations in NDD and links these to both neuroinflammation and excitotoxicity.

In vitro Antiproliferative and inhibition of oxidative DNA damage activities of n-butanol extract of Limonium bonduelli from Algeria

Abstract Plants are the main sources of natural antioxidants in the form of phenolic compounds, which help human beings to deal with oxidative stress, caused by free radical damage. For this reason, the present study was carried out to evaluate the antiproliferative, antioxidant and inhibition of oxidative DNA damage activities of n-butanol extract obtained from aerial parts of Limonium bonduelli. The antioxidant potential was determined using 1,1-diphenyl-2-picrylhydrazyl (DPPH) radical scavenging and inhibition of lipid peroxidation assay. Antiproliferative activity was evaluated using xCELLigence RTCA instrument on two tumor cell lines; HT-29 (human colon adenocarcinoma) and HeLa (human cervix carcinoma). DNA damage inhibition was evaluated using photolyzing 46966 plasmid. Also, total phenolic and total flavonoid contents were determined using a spectrophotometric method. Total phenolic (343 ± 0.05 µg/mg) and flavonoid (220.5 ± 0.04 µg/mg) were indicated as gallic acid and quercetin equivalents respectively. The extract exhibited significant IC50 values in lipid peroxidation (IC50= 181.18 ± 0.65 µg/mL) and DPPH radical scavenging assays (IC50= 14.92 ± 0.032 µg/mL). The extract also partially protected 46966 plasmid DNA from free radical-mediated oxidative stress in a DNA damage inhibition assay and showed concentration-dependent antiproliferative effects. n-butanol extract of L. bonduelli is a rich source of natural antioxidants and anticancer agents.

508: Free radical-mediated oxidative stress in patients exposed to oxygen in labor

Laboring patients often receive oxygen (O2) supplementation in an attempt to reverse perceived fetal hypoxia. Excess O2 exposure generates free radicals that have the potential to accumulate and cause oxidative stress. Malondialdehyde (MDA), is a product of free radical-mediated lipid peroxidation and marker of oxidative stress that is associated with adult and neonatal morbidity. We compared maternal MDA levels between laboring patients exposed to room air (RA) and O2, and investigated the relationship between duration of exposure and MDA. This was a pilot study performed in a subset of patients in a randomized controlled trial comparing O2 to RA in patients with intrapartum Category II electronic fetal monitoring (EFM). Patients randomized to O2 received 10L/min O2 by facemask until delivery. The RA group did not receive a facemask or O2. Because patients were randomized when they had Category II EFM at any point after 6cm cervical dilation, durations of exposure varied within groups. Maternal blood was drawn within an hour of delivery, immediately centrifuged, and resultant plasma stored at -80°C. The Thiobarbituric Acid Reactive Substances assay was used to quantify MDA. Nonparametric tests were used to compare median MDA concentrations between RA and O2 groups and between patients exposed for: <30 min, 30-60 min, and >60 min. Maternal samples were obtained in 27 O2 and 32 RA patients. There was no difference in overall median MDA concentrations between O2 and RA groups (Median [IQR] 6.3 [6.0,6.6] vs 6.6 [6.2,6.7] P=0.40) (Table). Among patients receiving O2, MDA was significantly higher in those exposed for 30-60 min than those exposed for <30 min. MDA levels after >60 min exposure were not different than levels after exposure for <30min or 30-60 min in either group. Among patients in the RA group, median MDA concentrations were unchanged across all three durations of exposure (Figure). MDA concentrations were overall similar between RA and O2 groups. However, there is an increase in MDA within 60 min of O2 exposure that is not present in RA-exposed patients. This increase in MDA within the first 60 min of O2 exposure highlights the need for future studies with a larger sample size to identify a safe duration of O2 exposure that limits oxidative stress.View Large Image Figure ViewerDownload Hi-res image Download (PPT)

Photoprotective Potential of Glycolic Acid by Reducing NLRC4 and AIM2 Inflammasome Complex Proteins in UVB Radiation-Induced Normal Human Epidermal Keratinocytes and Mice

Exposure to UVB radiation induces inflammation and free radical-mediated oxidative stress through reactive oxygen species (ROS) that play a crucial role in the induction of skin cancer. Glycolic acid (GA) is frequently used in cosmetics and dermatology. The aim of the study was to analyze the photoprotective mechanisms through which GA retards UVB-induced ROS accumulation and inflammation in normal human epidermal keratinocytes (NHEKs) and mice skin, respectively. NHEK cell line and C57BL/6J mice were treated with GA (0.1 or 5 mM) for 24 h followed by UVB irradiation. ROS accumulation, DNA damage, and expression of inflammasome complexes (NLRP3, NLRC4, ASC, and AIM2) were measured in vitro. Epidermal thickness and inflammasome complex proteins were analyzed in vivo. GA significantly prevented UVB-induced loss of skin cell viability, ROS formation, and DNA damage (single and double strands DNA break). GA suppressed the mRNA expression levels of NLRC4 and AIM2 among the inflammasome complexes. GA also blocked interleukin (IL)-1β by reducing the activity of caspase-1 in the NHEKs. Treatment with GA (2%) inhibited UVB-induced inflammation marker NLRC4 protein levels in mouse dorsal skin. The photoprotective activity of GA was ascribed to the inhibition of ROS formation and DNA damage, as well as a reduction in the activities of inflammasome complexes and IL-1β. We propose that GA has anti-inflammatory and photoprotective effects against UVB irradiation. GA is potentially beneficial to the protection of human skin from UV damage.

Protective role of green tea on diabetic nephropathy—A review

AbstractNowadays, diabetes and diabetes-mediated dysfunctions are overwhelming at every nook and corner of the world which has been a sober concern to the current health care professionals. However, chronic hyperglycemic subjects often suffer from hypertension, atherosclerosis, insulin resistance, brain injury, and other dysfunctions due to high glucose level which lead to kidney failure. Altogether, diabetic nephritis, fibrosis, stenosis, iron overload, and hypertrophy may often escort towards diabetic nephropathy. Furthermore, hyperglycemia-generated free radical-mediated oxidative stress plays the central role to aggravate the condition. Oxidative stress also inhibits production of several natural antioxidant genes like Nrf2, Sirt1, PGC-1α, superoxide desmutase, and catalase. Similarly, production of pro-inflammatory cytokines such as IL, TNF-α, MIP, α-SMA, and NF-κβ has been observed high in the diabetic subjects. High glucose inside the body also activates mitogen-activated protein kinase family and ...

Gender and chronological age affect erythrocyte membrane oxidative indices in citrate phosphate dextrose adenine-formula 1 (CPDA-1) blood bank storage condition.

It is well known that in vitro storage lesions lead to membrane dysfunction and decreased number of functional erythrocytes. As erythrocytes get older, in storage media as well as in peripheral circulation, they undergo a variety of biochemical changes. In our study, the erythrocytes with different age groups in citrate phosphate dextrose adenine-formula 1 (CPDA-1) storage solution were used in order to investigate the possible effect of gender factor on oxidative damage. Oxidative damage biomarkers in erythrocyte membranes such as ferric reducing antioxidant power, pro-oxidant-antioxidant balance, protein-bound advance glycation end products, and sialic acid were analyzed. Current study reveals that change in membrane redox status during blood-bank storage condition also depends on both gender depended homeostatic factors and the presence of CPDA-1. During the storage period in CPDA-1, erythrocytes from the male donors are mostly affected by free radical-mediated oxidative stress but erythrocytes obtained from females are severely affected by glyoxidative stress.

Enhancement of lipid peroxidation and its amelioration by vitamin E in a subject with mutations in the SBP2 gene

Selenocysteine (Sec) insertion sequence-binding protein 2 (SBP2) is essential for the biosynthesis of Sec-containing proteins, termed selenoproteins. Subjects with mutations in the SBP2 gene have decreased levels of several selenoproteins, resulting in a complex phenotype. Selenoproteins play a significant role in antioxidative defense, and deficiencies in these proteins can lead to increased oxidative stress. However, lipid peroxidation and the effects of antioxidants in subjects with SBP2 gene mutations have not been studied. In the present study, we evaluated the lipid peroxidation products in the blood of a subject (the proband) with mutations in the SBP2 gene. We found that the proband had higher levels of free radical-mediated lipid peroxidation products, such as 7β-hydroxycholesterol, than the control subjects. Treatment of the proband with vitamin E (α-tocopherol acetate, 100 mg/day), a lipid-soluble antioxidant, for 2 years reduced lipid peroxidation product levels to those of control subjects. Withdrawal of vitamin E treatment for 7 months resulted in an increase in lipid peroxidation products. Collectively, these results clearly indicate that free radical-mediated oxidative stress is increased in the subject with SBP2 gene mutations and that vitamin E treatment effectively inhibits the generation of lipid peroxidation products.

Ischemia-modified albumin levels in overt and subclinical hypothyroidism.

Free radical-mediated oxidative stress (OS) has been implicated in the pathogenesis of thyroid disorders. The ischemia-modified albumin (IMA) has been proposed as a marker of protein oxidative damage, which has been found to reflect hypoxic stress. Our aim was to evaluate IMA, malondialdehyde (MDA), and reduced glutathione (GSH) levels in patients with overt hypothyroidism (OHT) and subclinical hypothyroidism (SHT) in comparison to euthyroid controls. Albumin, IMA, IMA/albumin ratio, MDA, GSH, total cholesterol (TC), triglycerides (TG), HDL-Cholesterol were assessed in 105 subjects grouped into OHT, SHT patients, and euthyroid controls with 35 subjects in each group. MDA and IMA levels were significantly elevated while the GSH concentrations were significantly lower in OHT and SHT patients compared to controls (p < 0.01). When IMA values were normalized for albumin concentrations, the IMA/albumin ratio was also significantly elevated in both patient groups compared to controls (p < 0.01). These changes were more pronounced in the OHT group when compared to SHT group. In OHT group, thyroid-stimulating hormone (TSH) levels showed significant positive correlation with MDA (r = 0.470, p = 0.004), IMA (r = 0.530, p = 0.001), and IMA/albumin ratio (r = 0.525, p = 0.001). Both IMA (r = -0.342, p = 0.041), IMA/albumin ratio (r = -0.378, p = 0.023) showed significant negative correlation with GSH in OHT patients. No significant correlation between variables was, however, observed in SHT group. Increase of MDA and IMA levels with decreased antioxidant status indicate the presence of OS in hypothyroid patients, which was more pronounced in OHT patients. Elevated levels of IMA can be a clinically useful marker of protein oxidative damage and OS in hypothyroidism.

Chrysin enhances antioxidants and oxidative stress in L-NAME-induced hypertensive rats

Objectives: The study seeks to evaluate the effect of chrysin; a natural, biologically active compound extracted from plants, honey or propolis, on the tissues and circulatory antioxidant status and lipid peroxidation in Nω-nitro-l-arginine methyl ester (L-NAME) induced hypertensive rats. Materials and Methods: Male albino rats were divided into four groups. Control (Group I) and chrysin supplementation of the control (Group II) received normal diet. Groups III and IV received L-NAME (40 mg/kg B.W). Groups II and IV received chrysin (25 mg/kg B.W) dissolved in 0.2% dimethylsulfoxide solution after the 4 th week. Results and Discussion: The results showed significantly elevated levels of tissue and circulatory thiobarbituric acid reactive substances, conjugated dienes and lipid hydroperoxides, and significantly lowered enzymic and non-enzymic antioxidant activity of superoxide dismutase, catalase, glutathione peroxidase, reduced glutathione, vitamin C and vitamin E in L-NAME-induced hypertensive rats compared with those in control group. From chrysin administration to rats with L-NAME-induced hypertension leads to tissue damage which significantly decreases the levels of thiobarbituric acid reactive substances, lipid hydroperoxides and conjugated dienes, and significantly elevates the activity of superoxide dismutase, catalase, glutathione peroxidase, reduced glutathione, vitamin C and vitamin E in the tissues and circulation compared with those on the unsupplemented L-NAME induced hypertensive group. Conclusions: Chrysin offers protection against free radical-mediated oxidative stress in rats with L-NAME-induced hypertension.

Antioxidant activity and DNA damage inhibition in vitro by a methanolic extract of Carissa carandas (Apocynaceae) leaves

The aim of this study was to determine the antioxidant and DNA damage inhibition potential of a methanolic extract of Carissa carandas leaves. The extract had significant (p<0.05), dose-dependent DPPH radical scavenging activity (median inhibitory concentration, 73.1μg/ml), total antioxidant activity, H2O2 scavenging activity (median inhibitory concentration, 84.03μg/ml) and reducing power activity. The extract also completely protected pBR322 plasmid DNA from free radical-mediated oxidative stress in a DNA damage inhibition assay. The antioxidant and DNA damage inhibition properties of C. carandas can be attributed to a high content of phenolic compounds (84.0mg gallic acid equivalents/g dry weight of extract), estimated in the Folin–Ciocalteau assay. The high antioxidant and DNA damage inhibiting potential of C. carandas could be used to develop antioxidant compounds for therapeutic applications.

Vitamin D3 potentiates the antitumorigenic effects of arsenic trioxide in human leukemia (HL-60) cells

BackgroundArsenic trioxide (ATO) is a novel form of therapy that has been found to aid acute promyelocytic leukemia (APL) patients. Our laboratory has demonstrated that ATO-induced cytotoxicity in human leukemia (HL-60) cells is mediated by oxidative stress. Pro-oxidants have been known to play a role in free radical-mediated oxidative stress. Vitamin D3, (Vit D3) an active metabolite of vitamin D has been reported to inhibit the growth of number neoplasms such as prostate, breast, colorectal, leukemia, and skin cancers. The goal of the present research was to use (HL-60) cells as an in vitro test model to evaluate whether low doses of Vit D3 potentiate the toxicity of ATO and whether this toxic action is mediated via apoptotic mechanisms.MethodHL-60 cells were treated either with a pharmacologic dose of ATO alone and with several low doses of Vit D3. Cell survival was determined by MTT assay. Cell apoptosis was measured both by flow cytometry assessment, and DNA laddering assay.ResultsMTT assay indicated that Vit D3 co-treatment potentiates ATO toxicity in HL-60 cells in a dose dependent manner. A statistically significant and dose-dependent increase (p <0.05) was recorded in annexin V positive cells (apoptotic cells) with increasing doses of Vit D3 in ATO-treated cells. This finding was confirmed by the result of DNA laddering assay showing clear evidence of nucleosomal DNA fragmentation in vitamin and ATO co-treated cells.ConclusionThe present study indicates that Vit D3 potentiates the antitumor effects of ATO. This potentiation is mediated at least in part, through induction of phosphatidylserine externalization and nucleosomal DNA fragmentation. These findings highlight the potential impact of Vit D3 in promoting the pharmacological effect of ATO, suggesting a possible future role of Vit D3/ATO combination therapy in patients with acute promyelocytic leukemia (APL).