NO Scavenging Activity Research Articles

Antioxidant Potential and Toxicity Study of the Cerium Oxide Nanoparticles Synthesized by Microwave-Mediated Synthesis.

Monodispersed cerium oxide nanoparticle has been synthesized by microwave-mediated hydrothermal as well as microwave-mediated solvothermal synthesis. X-ray diffraction (XRD) data shows that the synthesized particles are single phase. SEM and TEM analysis suggest that particle synthesized by microwave-mediated solvothermal method are less agglomerated. In vitro toxicology study of the synthesized nanoceria particles has shown good free radical scavenging activity for NO and 1,1-diphenyl-2-picrylhydrazyl (DPPH) radical assayed except superoxide radical within a concentration range of 25 to 75 ng ml(-1). Nanoceria particle also showed inhibition of Fe-ascorbate-induced lipid peroxidation (LPx) in chick liver mitochondrial fractions. Solvothermally synthesized nanoceria showed better protection against Fe-ascorbate-induced LPx than the hydrothermal one while the hydrothermally synthesized nanoceria showed better DPPH and NO scavenging activity. The ceria nanoparticles also prevented Fe-ascorbate-H2O2-induced carbonylation of bovine serum albumin in a dose-dependent manner. At higher concentration, i.e., 100 ng ml(-1), the synthesized nanoparticles showed a reverse trend in all the parameters measured indicating its toxicity at higher doses.

Effects of methanolic extracts of edible plants on RAGE in high-glucose-induced human endothelial cells.

Advanced glycation end products' (AGEs) engagement of a cell-surface receptor for AGEs (RAGE) has been causally implicated in the pathogenesis of vascular complications in diabetic patients. Methanolic extracts from edible plants (MEEP) are naturally occurring phenolic compounds. The phenolic compounds have been reported to possess potent radical-scavenging properties. We investigated whether MEEP could inhibit high glucose-induced RAGE production through interference with reactive oxygen species generation in endothelial cells (ECs). ECs were incubated with 4.5g/l of glucose in culture medium treated with 21 MEEP. Determination of RAGE production in the culture supernatants was performed by colorimetric ELISA. DNA damage was determined by using the 8-hydroxydeoxyguanosine ELISA kit. Because peroxynitrite radicals with stronger toxicity were produced by nitric oxide radical (NO), the NO scavenging activity of MEEP was assessed as nitrite generation. Peroxynitrite radical-dependent oxidation inhibition by MEEP was estimated by the Crow method. The results showed that four extracts reduced RAGE production. The extract from onion peel showed the highest RAGE production inhibition activity, followed by that of onion rhizome, cow pea and burdock. The results showed that RAGE production is correlated with the above-mentioned indicators. This study supports the utilization of four extracts for improved treatment of diabetic complications.

Glutathione S-transferase pi (GST-pi) inhibition and anti-inflammation activity of the ethyl acetate extract of Streptomyces sp. strain MJM 8637

To investigate the anti-cancer properties of soil-borne actinobacteria, MJM 8637, the glutathione S-transferase pi (GST-pi) assay, anti-tumor necrosis factor (TNF)-α assay, the level of antioxidant potential by DPPH radical scavenging activity, NO scavenging activity, and ABTS radical scavenging activity in ethyl acetate extract were determined. The 16S rDNA sequencing analysis revealed that Streptomyces sp. strain MJM 8637, which was isolated from Hambak Mountain, Korea, has 99.5% similarity to Streptomyces atratus strain NBRC 3897. The physiological and the morphological characteristics of the strain MJM 8637 were also identified. The ethyl acetate extract of MJM 8637 inhibited TNF-α production approximately 61.8% at concentration 100μg/ml. The IC50 value of the strain MJM 8637 extract on GST-pi was identified to be 120.2±1.6μg/ml. In DPPH, NO, and ABTS radical scavenging assays, the IC50 values of the strain MJM 8637 extract were found to be 977.2μg/ml, 1143.7μg/ml, and 454.4μg/ml, respectively. The ethyl acetate extract of the strain MJM 8637 showed 97.2±1.3% of cell viability at 100μg/ml in RAW 264.7 cell viability assay. The results obtained from this study suggest that the ethyl acetate extract of Streptomyces sp. strain MJM 8637 could be considered as a potential source of drug for the cancers that have multidrug resistance with its GST-pi inhibition and anti-inflammation activities, and low cytotoxicity.

Electron Paramagnetic Resonance Study of the Free Radical Scavenging Capacity of Curcumin and Its Demethoxy and Hydrogenated Derivatives.

The quantitative free radical scavenging capacity of curcumin and its demethoxy derivatives (demethoxycurcumin (Dmc) and bisdemethoxycurcumin (Bdmc)) and hydrogenated derivatives (tetrahydrocurcumin (THC), hexahydrocurcumin (HHC) and octahydrocurcumin (OHC)) towards 1,1-diphenyl-2-picryl hydrazyl (DPPH), nitric oxide radical (NO), hydroxyl radical (HO(·)) and superoxide anion radical (O2(·)) were investigated by electron paramagnetic resonance (EPR) spectroscopy. One mole of the hydrogenated derivatives scavenged about 4 mol of the DPPH radical, while curcumin and Dmc scavenged about 3 mol of the DPPH radical. Curcumin and THC showed moderate scavenging activity towards NO, yielding 200 mmol of NO scavenged per 1 mol of the scavenger. In contrast, curcumin and its derivatives showed very low scavenging activity towards HO(·) and O2(·), yielding approximately only 3-12 mmol scavenged per 1 mol of the tested compounds. Our results suggest that curcumin and its derivatives principally act as chain breaking antioxidants rather than as direct free radical scavengers. Furthermore, we showed that the ortho-methoxyphenolic group and the heptadione linkage of these molecules greatly contributed to their DPPH and NO scavenging activity.

A convenient method for the synthesis of (prop-2-ynyloxy)benzene derivatives via reaction with propargyl bromide, their optimization, scope and biological evaluation.

A highly convenient method has been developed for the synthesis of (prop-2-ynyloxy) benzene and its derivatives. Differently substituted phenol and aniline derivatives were allowed to react with propargyl bromide in the presence of K2CO3 base and acetone as solvent. The compounds were synthesized in good yields (53–85%). Low cost, high yields and easy availability of compounds helped in the synthesis. Electron withdrawing groups favor the formation of stable phenoxide ion thus in turn favors the formation of product while electron donating groups do not favor the reaction. Phenol derivatives gave good yields as compared to that of aniline. As aprotic polar solvents favor SN2 type reactions so acetone provided best solvation for the reactions. K2CO3 was proved to be good for the synthesis. Antibacterial, Antiurease and NO scavenging activity of synthesized compounds were also examined. 4-bromo-2-chloro-1-(prop-2-ynyloxy)benzene 2a was found most active compound against urease enzyme with a percentage inhibition of 82.00±0.09 at 100 µg/mL with IC50 value of 60.2. 2-bromo-4-methyl-1-(prop-2-ynyloxy)benzene 2d was found potent antibacterial against Bacillus subtillus showing excellent inhibitory action with percentage inhibition of 55.67±0.26 at 100 µg/ml wih IC50 value of 79.9. Based on results, it can be concluded that some of the synthesized compounds may have potential antiurease and antibacterial effects against several harmful substances.

Cymbopogon citratus industrial waste as a potential source of bioactive compounds.

Cymbopogon citratus (Cc), commonly known as lemongrass, is a very important crop worldwide, being grown in tropical countries. It is widely used in the food, pharmaceutical, cosmetic and perfumery industries for its essential oil. Cc aqueous extracts are also used in traditional medicine. They contain high levels of polyphenols, which are known for their antioxidant and anti-inflammatory properties. Hydrodistillation of lemongrass essential oil produces an aqueous waste (CcHD) which is discarded. Therefore a comparative study between CcHD and Cc infusion (CcI) was performed to characterize its phytochemical profile and to research its antioxidant and anti-inflammatory potential. HPLC-PDA/ESI-MS(n) analysis showed that CcI and CcHD have similar phenolic profiles, with CcHD presenting a higher amount of polyphenols. Additionally, both CcI and CcHD showed antioxidant activity against DPPH (EC50 of 41.72 ± 0.05 and 42.29 ± 0.05 µg mL(-1) respectively) and strong anti-inflammatory properties, by reducing NO production and iNOS expression in macrophages and through their NO-scavenging activity, in a dose-dependent manner. Furthermore, no cytotoxicity was observed. The data of this study encourage considering the aqueous solution from Cc leaf hydrodistillation as a source of bioactive compounds, which may add great industrial value to this crop.

Antioxidant activity and free radical scavenging activities of Streptomyces sp. strain MJM 10778.

To investigate the antioxidant activity of soil-borne actinobacteria. The total phenolic contents, the level of antioxidant potential by DPPH radical scavenging activity, NO scavenging activity, and ABTS radical scavenging activity in ethyl acetate extract were determined. The 16S rDNA sequencing analysis revealed that Streptomyces sp. strain MJM 10778, which was isolated from Hambak Mountain, Korea, has 99.9% similarity to Streptomyces misionensis (S. misionensis) NBRC 13063. The physiological and the morphological test revealed that the strain MJM 10778 has different characteristics from the strain NBRC 13063. The entire antioxidant assay with the ethyl acetate extract displayed good radical scavenging activity. The IC50 values of the strain MJM 10778 extract on DPPH, NO, and ABTS radicals were identified to be 92.8 μg/mL, 0.02 μg/mL, and 134.9 μg/mL, respectively. The ethyl acetate extract of the strain MJM 10778 showed an 81.50% of cell viability at 100 μg/mL in Raw264.7 cell viability assay. The results obtained suggest that the ethyl acetate extract of Streptomyces sp. strain MJM 10778 could be considered as a potential source of drug for the diseases that is caused by free radicals with its anti-oxidant activities and low cytotoxicity.

Phytochemical-capped biogenic gold nanocrystals with chemocatalytic and radical scavenging potential

A refined phytosynthetic protocol for the synthesis of gold nanoparticles has been presented in the paper. Nanogold is synthesized using essential oil of leaves of Myristica fragrans. The synthesized nanoparticles have been characterized using UV–vis spectroscopy, TEM, XRD and FTIR. The morphology and dispersity of the particles are found to depend on the quantity of diluted oil used in the synthesis. The gold nanoparticles formed are polydisperse varying in morphology (spheres, pentagons, hexagons), at lower oil concentrations and spherical, monodisperse gold nanoparticles are obtained on increasing the quantity of oil added at 373K. XRD analysis revealed the fcc crystalline structure of the synthesized gold nanoparticles. Detailed analysis of FTIR data leads to the result that tertiary alcohols are responsible for the reduction of gold nanoparticles, and in synergism with other groups they bring about the stabilisation of these metallic nanoparticles. FTIR spectral analysis reports are in accordance with GC–MS analysis results. The synthesized gold nanoparticles are efficient nanocatalysts. The activation energy for the reduction of methylene blue, methyl orange and para-nitrophenol is lowered and their degradation is completed in 10, 7 and 20min, respectively, on the addition of 0.7mL of the synthesized gold colloid. The synthesized gold colloid with homogenous, monodisperse particles is used for catalytic and antioxidation studies. The biogenic gold nanoparticles are found to be potential antioxidants as revealed through their superoxide radical scavenging activity, hydroxyl radical scavenging activity, hydrogen peroxide scavenging activity, NO scavenging activity, DPPH scavenging activity and reducing power activity.

Fermentation characteristics of tofu with kimchi seasoning

Tofu (T) was fermented with kimchi seasoning (K) at a ratio of 1:0.5 and 1:1 (w/w) without and with a starter (L) (designated 1:0.5 TK, 1:0.5 TK-L, 1:1 TK and 1:1 TK-L) to utilize as a new type of lactic acid fermented food. A starter strain KL-12 was isolated from kimchi and identified to belong to the Lactobacillus plantarum group. During fermentation of four TK groups for 16 weeks at 20 °C, pH decreased from initial 6.4–6.5 to 4.1–4.6 after 16 weeks, with a remarkable decrease after 1 week. A reversible trend was observed with LAB viable cells. Antioxidant activities of four TK groups increased with fermentation time. After 16 weeks, the 1:1 TK-L group showed higher antioxidant activities (total phenolic content, DPPH and NO scavenging activity) and free amino acids than other three groups. These results indicate the potential use of lactic acid fermented food as a valuable resource for development of functional foods.

Phytochemical Screening, In-vitro Evaluation of Antioxidant and Free Radical Scavenging Activity of Leaves, Stems and Roots of Xanthium strumarium L., (Compositae)

Introduction: Many diseases are associated with oxidative stress caused by free radicals. Current research is directed towards finding naturally occurring antioxidants of plant origin. Xanthium strumarium L. a cocklebur or bur weed is a reputed medicine in Europe, China, Indo-china, Malaysia and America. It is used in treatment of common disease such as hemicrania, leucoderma, biliousness, poisonous bites of insects, epilepsy, long standing malaria, relieving constipation, diarrhoea, vomiting etc. The present research deals with phytochemical screening and in-vitro evaluation of antioxidant activities of the various extracts of leaves, stems and roots of X. strumarium L. Method: Successive extracts of leaves, stems and roots was subjected for phytochemical screening. Various extracts of leaves, stems and roots were screened in-vitro for total antioxidant potential. Inhibition of oxygen derived free radicals, viz., assay for free radical scavenging of nitric oxide, hydrogen peroxide, the antioxidant capacity by phosphomolybdenum, reducing power ability and determination of phenolic and flavonoids content in the extracts of leaves, stems and roots were performed. DPPH scavenging activity or the Hydrogen donating capacity was quantified in presence of stable DPPH radical on the basis of Blois method. NO scavenging activity was performed in the presence of nitric oxide generated from sodium nitroprusside using ascorbic acid as standard in both methods. The phenolic content was determined by using Folin-Ciocalteu reagent and flavonoid content was determined by aluminium chloride. Result: The preliminary phytochemical screening revealed the presence of saponins, sterols, flavonoids, alkaloids and phenolic compounds in the extracts. The scavenging activity was found to be dose dependent. The reducing capacity serves as significant indicator of antioxidant activity. The reducing power increased with the increasing concentration of sample. The 100mg powder of leaves yielded 0.069, 0.523, 1.620 mg/g phenolic content and 0.17, 0.45, 0.95 mg/g flavonoid content with solvents such as petroleum ether (60o-80oc), chloroform, and ethanol respectively. Similarly, in case of stems and roots the phenolic content yielded 0.063, 0.324, 1.324 mg/g and 0.040, 0.159, 0.41 mg/g and flavonoids content 0.00, 0.11, 0.23 mg/g and 0.00, 0.05, 0.18 mg/g respectively, using quercetin as standard. Conclusion: The present study provides evidence that X. strumarium L., is a potential source of antioxidants and the extracts have constituents which were capable of showing antioxidant activity and the said in-vitro antioxidant activity may also be due to the presence of antioxidant principles present in the extracts like flavonoid and phenolic compounds. So the folklore use of X. strumarium L. has been proved in present research work. These findings confirm the great interest of the herb whose phytochemistry and phytopharmacology should be investigated further in order to detect possible phytotherapeutic uses in the prevention of ageing related diseases, cardiovascular disorders and Alzheimer disease.

Morusin from Morus Australis Roots Inhibits 12-O-tetradecanoylphorbol-13-Acetate Induced Transformation of Epidermal JB6 Cells

The roots of Morus australis have been used as a traditional Chinese medicine for the treatment of diabetes, arthritis, and rheumatism. Recently, it was also evaluated as skin-whitening cosmetics. Other biological activity is not well known. In our preliminary study, it showed ethanol extract of Morus australis roots (MRE) contained polyphenolic compositions such as morusin and oxyresveratrol which may possess chemoprevention properties. Chemoprevention has been acknowledged as an important and practical strategy for the management of cancer. In the present study, whether roots of Morus australis are attributed to antitumor promotion potential are evaluated by the JB6 mouse epidermal cell model. First, MRE showed effective DPPH and NO scavenging activity in vitro. In mice skin assay, MRE inhibited 12-O-tetradecanoylphorbol-13 acetate (TPA) induced leukocyte infiltration, hyperkeratosis and hyperplasia. In JB6 cells, cytotoxicity of MRE, morusin and oxyresveratrol in JB6 cells were assessed by MTT assay, respectively. Noncytotoxic concentrations of MRE inhibited TPA induced tumorigenic anchorage-independent colonies in soft agar in a does dependent manner. In addition, MRE, morusin and oxyresveratrol inhibited TPA-induced ROS production, epithelial-mesenchymal transitions associated protein expression and inflammatory proteins expression including iNOS and COX-2. MRE also inhibited TPA-induced actin rearrangement, cell adhesion and cell migration in JB6 cells. Furthermore, it showed that MRE, morusin and oxyresveratrol inhibited TPA-induced up-regulation of vimentin, N-cadherin and down-regulation of E-cadhrin. Morusin and oxyresveratrol also inhibited TPA-induced nucler translcation of Snail and Twist which regulated epithelial-mesenchymal transitions proteins expression. In addition, morusin and oxyresveratrol may inhibit EMT through infibiting GSH depletion. In conclusion, our data presented that MRE has a potential of anti-transformation.

Radical scavenging activity of steviol glycosides, steviol glucuronide, hydroxytyrosol, metformin, aspirin and leaf extract of Stevia rebaudiana

Introduction: Reactive oxygen species (ROS), generated in many bioorganic redox processes, are the most dangerous by-products in the aerobic environment. The aim of this study was to compare the in vitro antioxidant activity of some chemical compounds and leaf extract of Stevia rebaudiana as natural antioxidant. Methods: The radical scavenging activity of ascorbic acid, quercetine, stevioside (ST), rebaudioside A (Reb A), steviol glucuronide (SVglu), glucose, sucrose, hydroxytyrosol, metformin and aspirin were measured and expressed as the inhibitory concentration in mM giving 50% reduction of radicals (IC50). Results: Ascorbic acid, quercetine, ST, Reb A, SVglu, glucose, sucrose, hydroxytyrosol, metformin and aspirin were active OH scavengers. Superoxide radicals were efficiently scavenged by ascorbic acid, SVglu, quercetine, hydroxytyrosol, ST, Reb A and aspirin. Quercetine, hydroxytyrosol, ascorbic acid and aspirin were active in limiting the amount of thiobarbituric acid (TBA) reactive material. Only ascorbic acid, quercetine and hydroxytyrosol showed DPPH and NO scavenging activity. Leaf extract of S. rebaudiana had an excellent ROS scavenging activity. Treatment of leaf extracts with PVPP and active charcoal removed a part of their scavenging activity. Results showed that sugars were not efficient ROS scavengers. Conclusion: Radical scavenging activity of steviol derivatives, aspirin, metformin and hydroxytyrosol might explain most of beneficial pharmacological effects on ROS related diseases, such as hypertension, type 2 diabetes, atherosclerosis, inflammation and certain forms of cancers. The results obtained in this study indicate that leaf extract of S. rebaudiana has a great potential to use as a natural antioxidant agent.

Evaluation of phytochemical constituents and antioxidant activity of selected actinorhizal fruits growing in the forests of Northeast India

Hippophae salicifolia, Elaeagnus pyriformis, Myrica esculenta and M. nagi are actinorhizal plants growing in the sacred forests of Northeast India with multipurpose uses. The present investigation was undertaken to determine the phenol, flavonoid and flavonol contents of the fresh fruit juice of these plant species including the antioxidant potential by means of DPPH, H2O2 and NO scavenging activity and FRP. The total phenolic, flavonoid and flavonol contents of fruit juice ranged from 321.68+/-0.06 to 76.67+/-0.01 mg/g GAE, 272.92+/-0.07 to 20.12+/-0.02 mg/g QE and 258.92+/-0.08 to 18.72+/-0.02 mg/g QE, respectively. At 2.0 mg/mL concentration, DPPH scavenging activity was found to be the highest in M. esculenta (89.62 percent) and the lowest in E. pyriformis (17.58 percent). The reducing power activity was found significantly higher in H. salicifolia juice, which increased with increase in concentration. The H2O2 scavenging activity of H. salicifolia juice was found to be as high as 98.78 percent, while Elaeagnus juice was found to be less effective with just 48.90 percent. Juice of H. salicifolia showed the greatest NO scavenging effect of 75.24 percent as compared to juice of E. pyriformis, where only 37.54 percent scavenging was observed at the same concentration. Taking into account all the experimental data, it can be said that the fruits of H. salicifolia and both M. nagi and M. esculenta have good antioxidant activity compared to fruits of E. pyriformis.

Comparative Evaluation of Intestinal Nitric Oxide in Embryonic Zebrafish Exposed to Metal Oxide Nanoparticles

Nanoparticle (NP) exposure may induce oxidative stress through generation of reactive oxygen and nitrogen species, which can lead to cellular and tissue damage. The digestive system is one of the initial organs affected by NP exposure. Here, it is demonstrated that exposure to metal oxide NPs induces differential changes in zebrafish intestinal NO concentrations. Intestinal NO concentrations are quantified electrochemically with a carbon fiber microelectrode inserted in the intestine of live embryos. Specificity of the electrochemical signals is demonstrated by NO-specific pharmacological manipulations and the results are correlated with the 4,5-diaminofluorescein-diacetate (DAF-FM-DA). NPs are demonstrated to either induce or reduce physiological NO levels depending on their redox reactivity, type and dose. NO level is altered following exposure of zebrafish embryos to CuO and CeO2 NPs at various stages and concentrations. CuO NPs increase NO concentration, suggesting an intestinal oxidative damage. In contrast, low CeO2 NP concentration exposure significantly reduces NO levels, suggesting NO scavenging activity. However, high concentration exposure results in increased NO. Alterations in NO concentration suggest changes in intestinal physiology and oxidative stress, which will ultimately correspond to NPs toxicity. This work also demonstrates the use of electrochemistry to monitor in vivo changes of NO within zebrafish organs.

국내 자생 민들레 5종의 항산화 활성 및 Nitric Oxide 생성억제 활성

The effect on the antioxidant activity and Nitric Oxide activity production inhibitory activity of Taraxacum has not been known. Therefore, phenolics and flavonoid contents were investigated from the ethanol extracts of five differ-ent Taraxacum species. The results showed that, among the five Taraxacum, T. hallaisanensis contains the highest total phe-nolic and flavonoid contents. When the antioxidant activity was measured by DPPH, ABTS and reducing power activity, the free radical scavenging activity of T. hallaisanensis was also the highest among five Taraxacum species. However, mea-surement by CCK-8 assay in Raw264.7 cells indicated that the extracts of Taraxacum species have no effect on cell viability. Moreover, we also investigated the effect of Taraxacum species on NO scavenging activity in lipopolysaccharide (LPS)-stim-ulated Raw264.7 cells. The results clearly showed that Taraxacum species inhibited NO production, and the inhibitory effect of T. hallaisanensis was the strongest. The above results suggested that Taraxacum species affected the antioxidant and NO scavenging activity, and among the five species, antioxidant and NO scavenging activity assay of T. hallaisanensis was signif-icantly higher than those of other four Taraxacum species. Therefore, T. hallaisanensis could be used as a potential drug with anti-oxidant and anti-inflammatory effect.

Antioxidant activity of newly discovered lineage of marine actinobacteria

ObjectiveTo investigate the antioxidant activity of marine actinobacteria. MethodsThe content of total phenolics, the level of antioxidant potential by DPPH radical scavenging activity, metal chelating activity, FRAP method, β carotene assay and NO scavenging activity in extract were determined. ResultsIn all the methods the extract exhibited good scavenging activity except NO scavenging activity. The IC50 values of marine actinobacteria extract on DPPH radical were found to be 41.09 μg/mL. The zone of color retention was 12 mm in β-carotene bleaching assay. DNA protective efficiency of the extracts was also studied using UV-photolysed H2O2-driven oxidative damage to pBR322. HPLC analysis identified some of the major phenolic compounds in extracts, which might be responsible for the antioxidant potential and cyto-protection. It showed a 100% cytotoxic effect in brine shrimp lethality assay within 10 mins. The novel actinobacteria was identified as Streptomyces LK-3 (JF710608) through 16S rDNA Sequencing. ConclusionsThe results obtained suggest that the extracts bear anti-cancer metabolites and could be considered as a potential source for anti-cancer drug development.

Antarctic bacterial haemoglobin and its role in the protection against nitrogen reactive species

In a cold and oxygen-rich environment such as Antarctica, mechanisms for the defence against reactive oxygen and nitrogen species are needed and represent important components in the evolutionary adaptations. In the Antarctic bacterium Pseudoalteromonas haloplanktis TAC125, the presence of multiple genes encoding 2/2 haemoglobins and a flavohaemoglobin strongly suggests that these proteins fulfil important physiological roles, perhaps associated to the peculiar features of the Antarctic habitat. In this work, the putative role of Ph-2/2HbO, encoded by the PSHAa0030 gene, was investigated by in vivo and in vitro experiments in order to highlight its involvement in NO detoxification mechanisms. The PSHAa0030 gene was cloned and then over-expressed in a flavohaemoglobin-deficient mutant of Escherichia coli, unable to metabolise NO, and the resulting strain was studied analysing its growth properties and oxygen uptake in the presence of NO. We here demonstrate that Ph-2/2HbO protects growth and cellular respiration of the heterologous host from the toxic effect of NO-donors. Unlike in Mycobacterium tuberculosis 2/2 HbN, the deletion of the N-terminal extension of Ph-2/2HbO does not seem to reduce the NO scavenging activity, showing that the N-terminal extension is not a requirement for efficient NO detoxification. Moreover, the ferric form of Ph-2/2HbO was shown to catalyse peroxynitrite isomerisation in vitro, confirming its potential role in the scavenging of reactive nitrogen species. This article is part of a Special Issue entitled: Oxygen Binding and Sensing Proteins.

Synthesis, anticancer and antioxidant activities of 2,4,5-trimethoxy chalcones and analogues from asaronaldehyde: Structure–activity relationship

2,4,5-Trimethoxy chalcones and analogues were synthesized from asaronaldehyde derived from β-asarone. These novel compounds when tested against three human tumour cell lines (MCF-7, SW-982 and HeLa) using MTT assay, revealed that chalcones possessing electron donor groups in para position to carbonyl moiety of phenyl ring A, showed better inhibitory activity (2, 3, 4, 6, 7, 10, 17). When evaluated for antioxidant activities, compound 15 exhibited better free radical scavenging property in DPPH assay while compounds 2, 3, 5, 7, 9, 10, 11, 16, and 18 showed significant NO scavenging activity. All compounds exhibited very good phenyl hydrazine induced haemolysis of erythrocytes in phenylhydrazine assay. Structure–activity relationship (SAR) study using in-silico analysis matched well with in-vitro tumour cell inhibitory activity.

Production, Characterization and Antioxidant Potential of Protease fromStreptomycessp. MAB18 Using Poultry Wastes

Poultry waste is an abundant renewable source for the recovery of several value-added metabolites with potential industrial applications. This study describes the production of protease on poultry waste, with the subsequent use of the same poultry waste for the extraction of antioxidants. An extracellular protease-producing strain was isolated from Cuddalore coast, India, and identified as Streptomyces sp. MAB18. Its protease was purified 17.13-fold with 21.62% yield with a specific activity of 2398.36 U/mg and the molecular weight was estimated as 43 kDa. The enzyme was optimally active at pH 8–10 and temperature 50–60°C and it was most stable up to pH 12 and 6–12% of NaCl concentration. The enzyme activity was reduced when treated with Hg2+, Pb2+, and SDS and stimulated by Fe2+, Mg2+, Triton X-100, DMSO (dimethyl sulfoxide), sodium sulphite, and β-mercaptoethanol. Furthermore, the antioxidant activities of protease were evaluated using in vitro antioxidant assays, such as DPPH radical-scavenging activity, O2 scavenging activity, NO scavenging activity, Fe2+ chelating activity, and reducing power. The enzyme showed important antioxidant potential with an IC50 value of 78 ± 0.28 mg/mL. Results of the present study indicate that the poultry waste-derived protease may be useful as supplementary protein and antioxidant in the animal feed formulations.

In Vitro Antileishmanial Activity of Resveratrol Originates from its Cytotoxic Potential against Host Cells

In addition to a range of beneficial pharmacological activities, resveratrol is recently reported to have potential antileishmanial activities in vitro. The present study was conducted to evaluate the effect of resveratrol on promastigotes and amastigotes of transgenic Leishmania major expressing green fluorescent protein in comparison with its direct cytotoxic effects on host cells (bone marrow-derived and J774-G8 macrophages, respectively). As assessed by FACS analysis, resveratrol showed moderate antipromastigote activity at <35 µg/mL (153.2 µM) and promising effects at higher sample concentrations. In contrast, the green fluorescent protein signal as a measure of the intracellular parasites' viability was reduced in a concentration-dependent manner. Resveratrol strongly inhibited NO production, but did not display direct NO-scavenging activity in sodium nitroprusside solution. Western blotting indicated that resveratrol reduced recombinant interferon-γ/LPS-induced expression of iNOS protein. Microscopic studies, MTT evaluation, and FACS analysis showed significant cytotoxic effects on host cells in a concentration-dependent manner. This finding suggests that the in vitro antileishmanial activity of resveratrol is due to cytotoxic effects on host cells rather than attributable to a specific antiparasitic potential.