Antioxidant Peptidomics Reveals Novel Skin Antioxidant System

It is generally agreed that reactive oxygen species (ROS) contribute to skin aging, skin disorders, and skin diseases. Skin possesses an extremely efficient antioxidant system. This antioxidant activity is conferred by two systems: antioxidant enzymes and

Hepatic Histopathological Characteristics and Antioxidant Response of Phytoplanktivorous Silver Carp Intraperitoneally Injected with Extracted Microcystins

Objective To investigate the hispathological characteristics and antioxidant responses in liver of silver carp after intraperitoneal administration of microcystins (MCs) for further understanding hepatic intoxication and antioxidation mechanism in fish. Methods Phytoplanktivorous silver carp was injected intraperitoneally (i.p.) with extracted hepatotoxic microcystins (mainly MC-RR and -LR) at a dose of 1000 mu g MC-LReq./kg body weight, and liver histopathological changes and antioxidant responses were studied at 1, 3, 12, 24, and 48 h, respectively, after injection. Results The damage to liver structure and the activities of hepatic antioxidant enzymes including catalase (CAT), superoxide dismutase (SOD), and glutathione peroxide (GPX) were increased in a time-dependent manner. Conclusion In terms of clinical and histological signs of intoxication and LD50 (i.p.) dose of MC-LR, silver carp appears rather resistant to MCs exposure than other fishes. Also, the significantly increased SOD activity in the liver of silver carp suggests a higher degree of response to MCs exposure than CAT and GPX.

Effect of beta-glucan on activity of antioxidant enzymes and Mx gene expression in virus infected grass carp

The effects of beta-glucan, an immunostimulatory agent, on the superoxide dismutase (SOD) and catalase (CAT) activities of erythrocytes and Mx gene expression were studied from grass carp that were challenged with grass carp hemorrhage virus (GCHV). The SOD and CAT activities in erythrocytes and Mx gene expression in spleen from the fish were detected by spectrophotometry and RT-PCR, respectively. Negative control fish were injected with PBS; positive control groups were injected with either P-glucan or GCHV only; and the experimental groups were pre-injected with beta-glucan 15 days prior to injection with GCHV. The results show that the SOD and CAT activities were higher in fish injected with beta-glucan for 15 days than the negative control group injected with PBS. The SOD and CATactivities significantly decreased when the fish were challenged with GCHV, but it was higher in the group pre-treated with beta-glucan than in infected fish not pre-treated, 15 days after GCHV infection. Mx gene expression levels increased during the early stages (at 12 h and 36 h) of GCHV infection, and it remained at higher levels from the 6th till the 10th day in the beta-glucan pre-treated group, but it was failing from the 6th day in the beta-glucan untreated group. The GCHV-infected group pre-treated with P-glucan had a higher survival rate (60%) than the group not pre-treated with P-glucan (20%), suggesting that beta-glucan possesses or enhances anti-viral responses. (C) 2009 Elsevier Ltd. All rights reserved.

Antioxidant capacity and lipophilic content of seaweeds collected from the Qingdao coastline

Lipophilic extracts from 16 species of seaweeds collected along the Qingdao coastline were screened and evaluated for their antioxidant activities (AA) using the beta-carotene-linoleate assay system. The diethyl ether soluble extracts of all selected seaweeds exhibited various degrees of antioxidative efficacy in each screen. The highest antioxidant capacities among the tested samples were observed for Rhodomela confervoides and Symphyocladia latiuscula and were comparable with that of the well-known antioxidant butylated hydroxytoluene and greater than that of propyl gallate. The lipophilic content of all 16 samples and the chemical composition of 4 selected seaweeds, R. confervoides and S. latiuscula, which had higher AA, Laminaria japonica, which had intermediate AA, and Plocamium telfairiae, which had lower AA, were analyzed by gas chromatography and gas chromatography-mass spectrometry, respectively. Fatty acids and alkanes were found. The present data indicated an increase in antioxidative property with increasing content of unsaturated fatty acid. The result of this study suggests that seaweeds can be considered as a potential source for the extraction of lipophilic antioxidants, which might be used as dietary supplements or in production in the food industry. This is the first report on the antioxidant activities of lipophilic extracts from seaweeds.

Natural bromophenols from the marine red alga Polysiphonia urceolata (Rhodomelaceae): Structural elucidation and DPPH radical-scavenging activity

Three new natural occurring bromophenols, 3-(3-bromo-4,5-dihydroxyphenyl)-2-(3,5-dibromo-4-hydroxyphenyl)propionic acid (1), (E)-4-(3-bromo-4,5-dihydroxyphenyl)-but-3-en-2-one (2), and (3,5-dibromo-4-hydroxyphenyl) acetic acid butyl ester (3), together with one known bromophenol, 1,2-bis(3-bromo-4,5-dihydroxyphenyl)ethane (4), were isolated and identified from the marine red alga Polysiphonia urceolata. The structures of these compounds were elucidated by extensive analysis of ID and 2D NMR and IR spectra and MS data. Each of the isolated compounds was evaluated for scavenging alpha,alpha-diphenyl-beta-picrylhydrazyl (DPPH) radical activity and all of them exhibited significant activity with IC50 values ranging from 9.67 to 21.90 mu M, compared to the positive control, a well-known antioxidant butylated hydroxytoluene (BHT), with IC50 83.84 mu M. (C) 2007 Elsevier Ltd. All rights reserved.

Antioxidant activity of different sulfate content derivatives of polysaccharide extracted from Ulva pertusa (Chlorophyta) in vitro

Polysaccharide extracted from Ulva pertusa (Chlorophyta) is a group of sulfated heteropolysaccharide; for simplicity, the sulfated polysaccharide is referred to as ulvan in this paper. In this study, different sulfate content ulvans were prepared with sulfur trioxide/N,N-diinethylformamide (SO3-DMF) in formamide, and their antioxidant activities were investigated including scavenging activity of superoxide and hydroxyl radicals, reducing Power and metal chelating ability. As expected, we obtained several satisfying results, as follows: firstly, high sulfate content ulvans had more effective scavenging activity on hydroxyl radical than natural ulvan. Secondly, comparing with natural ulvan, high sulfate content ulvans exhibited stronger reducing power. Thirdly, HU4 (sulfate content, 30.8%) and HU5 (sulfate content, 32.8%) showed more pronounce chelating ability on ferrous ion at high concentration than other samples. (c) 2005 Elsevier B.V. All rights reserved.

Antioxidant activity of different molecular weight sulfated polysaccharides from Ulva pertusa Kjellm (Chlorophyta)

Polysaccharides extracted from Ulva pertusa Kjellm ( Chlorophyta) are a group of sulfated heteropolysaccharides, the ulvans. In this study, different molecular weight ulvans were prepared by H2O2 degradation and their antioxidant activities investigated including superoxide and hydroxyl radical scavenging activity, reducing power and metal chelating ability. The molecular weights of natural and degraded ulvans were 151.7, 64.5, 58.0, and 28.2 kDa, respectively, as determined by high performance gel permeation chromatography. Among the four samples, U-3 ( the lowest molecular weight sample) showed significant inhibitory effects on superoxide and hydroxyl radicals with IC50 values of 22.1 mu g mL(-1) and 2.8 mg mL(-1); its reducing power and metal chelating ability were also the strongest among the four samples. All the other samples also demonstrated strong activity against superoxide radicals. The results indicated that molecular weight had a significant effect on the antioxidant activity of ulvan with low molecular weight ulvan having stronger antioxidant activity.

In vitro antioxidant activity of acetylated and benzoylated derivatives of polysaccharide extracted from Ulva pertusa (Chlorophyta)

The antioxidant activity of natural ulvan and its derivatives (acetylated and benzoylated ulvans) in vitro was determined, including scavenging activity against superoxide and hydroxyl radicals, reducing power, and chelating ability. Obvious differences in antioxidant activity between natural ulvan and its derivatives were observed, moreover, the antioxidant activity of acetylated and benzoylated ulvans was stronger than that of natural ulvan. (C) 2006 Elsevier Ltd. All rights reserved.

Degradation of porphyran from Porphyra haitanensis and the antioxidant activities of the degraded porphyrans with different molecular weight

In the present paper, ascorbate and hydrogen peroxide (H2O2) were used to degrade porphyran. It was found that porphyran could be degraded by free radical that was generated by ascorbate and H2O2 in combination. It was possible to prepare desired porphyran products with different molecular weight by adjusting ascorbate to H,02 proportions and their concentrations. The molar ratio of I was demonstrated more effective than in other ratios. Higher concentrations accelerated the degradation. Moreover, results of chemical analysis and FT-IR spectra suggested that the main structure of degraded products still remained although some changes happened. The degraded and natural porphyrans possessed scavenging 1,1-diphenyl-2-picrylhydrazyl (DPPH)-radical activity and reducing power. Higher antioxidant activities were found in both systems when the molecular weight was reduced. The results indicated that the antioxidant activities were closely related to the molecular weight. The degraded porphyrans are potential antioxidant in vitro. (c) 2006 Elsevier B.V. All rights reserved.

Effects of heat-treatment processes on the electroless Ni-B coating and its natural aging mechanism

A Ni-B coating was prepared with EN using potassium borohydride reducing agent. The as-plated micro-structure of the coating was confirmed from XRD to be a mixture of amorphous and supersaturated solid solution. Three kinds of phase transformation were observed from the DSC curve. Different from the previous works, the formation of Ni4B3 and Ni2B was found during some transformation processes. The key factors which influence the variation of micro-hardness and micro-structure in deposits are the formation, the size and amount of Ni3B, Ni4B3 and Ni2B. Aging of the deposits treated under some heat treatment conditions occurred at room temperature. Changes of the micro-hardness indicated aging phenomena evidently. the natural aging phenomena are concerned with various kinds of decomposition of borides, especially with Ni4B3 phase. The extent of natural aging depends on the formation and the quantity of Ni(4)B3 and Ni2B.

Numerical Simulation of Nox Formation in Coal Combustion with Inlet Natural Gas Burning

A full two-fluid model of reacting gas-particle flows and coal combustion is used to simulate coal combustion with and without inlet natural gas added in the inlet. The simulation results for the case without natural gas burning is in fair agreement with the experimental results reported in references. The simulation results of different natural gas adding positions indicate that the natural gas burning can form lean oxygen combustion enviroment at the combustor inlet region and the NOz concentration is reduced. The same result can be obtained from chemical equilibrium analysis.

Experimental investigation on the chaotic phenomena in the wake of a natural thermal convection flow

Chaotic phenomena in the wake of thermal convection flow fields above a heating flat plate were investigated experimentally. A newly developed electron beam fluorescence technique (EBF) was used to simultaneously measure density fluctuation at 7 points in a cross section above the plate. Correlation dimensions, intermittence coefficients, Fourier spectrum have been obtained for different Grashof numbers. Spatial distribution of correlation dimensions are presented. The experimental result shows that there is a certain relationship between the density fluctuation and the Gr number. And time-spacial characteristic of chaos evolution is also given.