Photochemical oxidation of municipal secondary effluents at low H2O2 dosage: Study of hydroxyl radical scavenging and process performance

2014 ◽  
Vol 237 ◽  
pp. 268-276 ◽  
Author(s):  
Bruno S. Souza ◽  
Renato F. Dantas ◽  
Angel Cruz ◽  
Carme Sans ◽  
Santiago Esplugas ◽  
...  
Keyword(s):  
Hydroxyl Radical ◽  
Radical Scavenging ◽  
Photochemical Oxidation ◽  
Process Performance ◽  
Secondary Effluents ◽  
Dosage Study

scholarly journals Real Time Normalization of Fast Photochemical Oxidation of Proteins Experiments by Inline Adenine Radical Dosimetry

2018 ◽  
Author(s):  
Joshua S. Sharp ◽  
Sandeep K. Misra ◽  
Jeffrey J. Persoff ◽  
Robert W. Egan ◽  
Scot R. Weinberger
Keyword(s):  
Hydroxyl Radical ◽  
Real Time ◽  
Hydroxyl Radicals ◽  
Conformational Changes ◽  
Radical Scavenging ◽  
Photochemical Oxidation ◽  
Major Step ◽  
Simple Method ◽  
Radical Concentration ◽  
High Concentrations

AbstractHydroxyl radical protein footprinting (HRPF) is a powerful method for measuring protein topography, allowing researchers to monitor events that alter the solvent accessible surface of a protein (e.g. ligand binding, aggregation, conformational changes, etc.) by measuring changes in the apparent rate of reaction of portions of the protein to hydroxyl radicals diffusing in solution. Fast Photochemical Oxidation of Proteins (FPOP) offers an ultra-fast benchtop method for performing HRPF, photolyzing hydrogen peroxide using a UV laser to generate high concentrations of hydroxyl radicals that are consumed on roughly a microsecond timescale. The broad reactivity of hydroxyl radicals means that almost anything added to the solution (e.g. ligands, buffers, excipients, etc.) will scavenge hydroxyl radicals, altering their half-life and changing the effective radical concentration experienced by the protein. Similarly, minute changes in peroxide concentration, laser fluence, and buffer composition can alter the effective radical concentration, making reproduction of data challenging. Here, we present a simple method for radical dosimetry that can be carried out as part of the FPOP workflow, allowing for measurement of effective radical concentration in real time. Additionally, by modulating the amount of radical generated, we demonstrate that FPOP HRPF experiments carried out in buffers with widely differing levels of hydroxyl radical scavenging capacity can be normalized on the fly, yielding statistically indistinguishable results for the same conformer. This method represents a major step in transforming FPOP into a robust and reproducible technology capable of probing protein structure in a wide variety of contexts.

scholarly journals Self-Organized Amphiphiles are Poor Hydroxyl Radical Scavengers in Fast Photochemical Oxidation of Proteins Experiments

2020 ◽  
Author(s):  
Zhi Cheng ◽  
Charles Mobley ◽  
Sandeep K. Misra ◽  
Joshua S. Sharp
Keyword(s):  
Critical Micelle Concentration ◽  
Hydroxyl Radical ◽  
Radical Scavenging Activity ◽  
Radical Scavenging ◽  
Photochemical Oxidation ◽  
Radical Scavenger ◽  
Cellular Membranes ◽  
Scavenging Effect ◽  
Significant Difference ◽  
Hydroxyl Radical Scavenger

ABSTRACTThe analysis of membrane protein topography using fast photochemical oxidation of protein (FPOP) has been reported in recent years, but still underrepresented in literature. Based on the hydroxyl radical reactivity of lipids and other amphiphiles, it is believed that the membrane environment acts as a hydroxyl radical scavenger decreasing effective hydroxyl radical doses and resulting in less observed oxidation of proteins. Here, we investigated the effect of bulk hydroxyl radical scavenging in FPOP using both isolated cellular membranes as well as detergent micelles. We found no significant change in radical scavenging activity upon the addition of disrupted cellular membranes with the membrane concentration in the range of 0-25600 cell/μL using an inline radical dosimeter. We confirmed the non-scavenging nature of the membrane with the FPOP results of a soluble model protein in the presence of cell membranes, which showed no significant difference in oxidation with or without membranes. The use of detergents revealed that, while soluble detergent below the critical micelle concentration acts as a potent hydroxyl radical scavenger as expected, additional detergent has little to no hydroxyl radical scavenging effect once the critical micelle concentration is reached. These results suggest that any scavenging effect of membranes or organized amphiphilic membrane mimetics in FPOP experiments are not due to bulk hydroxyl radical scavenging, but may be due to a localized scavenging phenomenon.

scholarly journals IN VITRO - ANTIOXIDANT AND PRELIMINARY PHYTOCHEMICAL ANALYSIS OF AEGLE MARMELOS (L.) CORREA. LEAF EXTRACT

2017 ◽  
Vol 10 (6) ◽  
pp. 367
Author(s):  
Samidha M Pawaskar ◽  
Sasangan Kc
Keyword(s):  
Hydroxyl Radical ◽  
Leaf Extract ◽  
Radical Scavenging ◽  
Reducing Power ◽  
Total Phenolic ◽  
Phytochemical Analysis ◽  
Aegle Marmelos ◽  
Leaf Powder ◽  
Phenolic And Flavonoid

Objective: In this study, the leaf powder of Aegle marmelos (L.) Correa. was subjected to preliminary phytochemical and in vitro antioxidant analysis. Methods: The freshly prepared plant leaf extract was subjected to preliminary phytochemical screening, which revealed the presence of alkaloids, tannins, saponins, flavonoids, glycosides, phenolic compounds, terpenoids, and steroids. Reducing power, superoxide (SO) anion radical, nitric oxide (NO) radical, and hydroxyl radical scavenging assays were carried out to evaluate the antioxidant potential of the methanolic leaf extract of this plant. The amounts of total phenolic and flavonoid compounds were also determined. Results: This study has revealed that the A. marmelos (L.) Correa. leaf extract showed considerably high amounts of most of the phytochemicals, total antioxidant capacity, total phenolic, and flavonoid content. The study also indicated that the A. marmelos (L.) Correa. showed comparatively good scavenging activity, i.e., inhibition of hydroxyl radical, NO and SO anion scavenging and reducing power activities when compared with the respective standards. Conclusion: The leaf powder of A. marmelos (L.) Correa. can be used as easily accessible source of natural antioxidant and as a possible food supplement or in pharmaceutical industry.

scholarly journals Pharmacological studies of Mangifera indica leaf extract

2021 ◽  
Vol 7 (3) ◽  
pp. 073-079
Author(s):  
Agrawal RC
Keyword(s):  
Hydroxyl Radical ◽  
Radical Scavenging Activity ◽  
Mangifera Indica ◽  
Radical Scavenging ◽  
Antibacterial Activities ◽  
Positive Control ◽  
Screening Methods ◽  
Phytochemical Screening ◽  
Test Organisms ◽  
Almost All

The present study was undertaken to explore the phytochemical screening, anti-bacterial and anti-oxidant activities of the hydro-methanolic leaves extract of Mangifera indica using standard screening methods such as disc diffusion and DPPH methods. In phytochemical screening, Mangifera indicaextract showed presence of secondary metabolites such as carbohydrate, phenols, tanins and proteins whereas Saponins were absent. It also showed antibacterial activities against almost all the test organisms. The extracts possessed potent hydroxyl radical scavenging activity against the positive control standard Ascorbic acid. Results denote the presence of hydroxyl radical scavenging principles in the extracts.

scholarly journals Biological Properties of Silver Nanoparticles from β (1-3) Glucan Isolated from the Edible Mushroom Pleurotus florida

2020 ◽  
Vol 10 (2) ◽  
pp. 2096-2106
Keyword(s):  
Silver Nanoparticles ◽  
Drug Development ◽  
Hydroxyl Radical ◽  
Antioxidant Properties ◽  
Radical Scavenging ◽  
Edible Mushroom ◽  
Hot Water ◽  
Dependent Manner ◽  
Pleurotus Florida ◽  
Radical Scavenging Assay

Pleurotus florida of the genus Pleurotus is a delicious edible mushroom with high therapeutic potential. Silver nanoparticles (AgNPs) are gaining a lot of importance nowadays because of their wide industrial and biomedical applications. Capping of AgNPs with polysaccharides, the most potent mushroom derived metabolites, is promising towards natural drug development for free radical-induced ailments. In the present investigation, silver nanoparticles were synthesized using β-glucan isolated from P. florida, and their antioxidant properties were studied. Polysaccharide (PS) isolation was carried out by hot water extraction, alcohol precipitation, deproteinization, and dialysis. Preliminary characterization of PS by Anthrone, Lowry’s method, Paper Chromatography, and FT-IR showed that PS is protein-bound β-(1-3) - Glucan. Synthesis of Silver nanoparticle from PS (PS-AgNPs) was confirmed by UV spectroscopy. Antioxidant properties of PS and PS-AgNPs were evaluated by Total antioxidant capacity assay, DPPH assay, Total reducing power, and Hydroxyl radical scavenging assay. Both PS and PS-AgNPs showed profound antioxidant activity in a dose-dependent manner, and PS-AgNPs was more active than PS. The highest activity was shown in Hydroxyl radical scavenging assay in which PS and PS-AgNPs showed 81.8% and 89.4% activity, respectively, at the highest tested dose. The present study revealed the possible use of P. florida in antioxidant drug development.

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