Factors affecting in vitro and in vivo antioxidant effects. Experimental conditions and nature of oxidants determine antioxidant efficacy

Reactive oxygen and nitrogen species have been implicated in the onset and progression of various diseases and the role of antioxidants in the maintenance of health and prevention of diseases has received much attention. The action and effect of antioxidants have been studied extensively under different reaction conditions in multiple media. The antioxidant effects are determined by many factors. This review aims to discuss several important issues that should be considered for determination of experimental conditions and interpretation of experimental results in order to understand the beneficial effects and limit of antioxidants against detrimental oxidation of biological molecules. Emphasis was laid on cell culture experiments and effects of diversity of multiple oxidants on antioxidant efficacy.

Sorbus domestica Leaf Extracts and Their Activity Markers: Antioxidant Potential and Synergy Effects in Scavenging Assays of Multiple Oxidants

Sorbus domestica leaves are a traditionally used herbal medicine recommended for the treatment of oxidative stress-related diseases. Dry leaf extracts (standardized by LC-MS/MS and LC-PDA) and nine model activity markers (polyphenols), were tested in scavenging assays towards six in vivo-relevant oxidants (O2•−, OH•, NO•, H2O2, ONOO−, HClO). Ascorbic acid (AA) and Trolox (TX) were used as positive standards. The most active extracts were the diethyl ether and ethyl acetate fractions with activities in the range of 3.61–20.03 µmol AA equivalents/mg, depending on the assay. Among the model compounds, flavonoids were especially effective in OH• scavenging, while flavan-3-ols were superior in O2•− quenching. The most active constituents were quercetin, (−)-epicatechin, procyanidins B2 and C1 (3.94–24.16 µmol AA/mg), but considering their content in the extracts, isoquercitrin, (−)-epicatechin and chlorogenic acid were indicated as having the greatest influence on extract activity. The analysis of the synergistic effects between those three compounds in an O2•− scavenging assay demonstrated that the combination of chlorogenic acid and isoquercitrin exerts the greatest influence. The results indicate that the extracts possess a strong and broad spectrum of antioxidant capacity and that their complex composition plays a key role, with various constituents acting complementarily and synergistically.

Feasibility study for the production of multi-oxidants from the desalination of seawater brine

The primary goals of this study are to compare the efficiency of multiple oxidants that are produced using different commercially available anodes and separators and to optimize the reaction conditions for the recovery of multiple oxidants from brine. The brine produced in the desalination plants in Taiwan is the concentrated seawater that is recovered after the reverse osmosis process. The main component in the solution is NaCl. On average, chlorine concentration is approximately 3–5% by weight, which is slightly higher than the concentration for normal seawater. This concentrated brine can be used as raw material for the electrolyte to extract mixed disinfectant solutions. This study uses different catalytic electrolyzers to compare the efficiency with which multiple oxidants are produced using anodes that are coated in precious metal. A ruthenium-coated titanium anode generates the largest amount of active chlorine (chlorine dioxide). In terms of the diaphragms that are tested, the DuPont Nafion NE-2030 ion film produces active chlorine most efficiently. If no other chemicals are added to the brine (salinity 11.3%), Cl2 (302–376 mg L−1) is the primary oxidant generated from the original brine, and ClO2 (3.7–7.2 mg L−1) is the minor product in batch electrolysis. This article has been made Open Access thanks to the kind support of CAWQ/ACQE (https://www.cawq.ca).

Antioxidant capacity of foods for scavenging reactive oxidants and inhibition of plasma lipid oxidation induced by multiple oxidants

Antioxidant capacity is assessed by the rate and amount of scavenging oxidants and inhibition of lipid oxidation induced by multiple oxidants.

Predicting Internal Oxidation: Building on the Wagner Model

Wagner’s 1959 diffusion model of the internal oxidation process provided a method of predicting the rate at which a binary alloy was penetrated by dissolved oxygen as it precipitated the more reactive (but dilute) alloy component. Parabolic kinetics were predicted to depend on oxygen permeability in the unreacted alloy solvent and also, in cases where the reactive component was sufficiently mobile, the diffusion coefficient of the latter. The model has proven very successful, but is restricted to single oxidant-binary alloy systems, in which the precipitated oxide has extremely low solubility. This paper reviews recent results on a number of internal precipitation processes which cannot be described with the Wagner theory. These include formation of low stability carbides and nitrades; internal precipitation driven by multiple oxidants; the templating effects of prior precipitates on subsequently formed corrosion products; cellular precipitation morphologies; internal interface diffusion effects; volume changes in the reaction zone and the effects upon them of simultaneous external scaling.

Using Catalyst and Electrolysis Diaphragm Method to Produce Multiple Oxidants to Remove the Scaling and Slime in Cooling System

Increasing cycle of water circulation in industrial cooling water system caused accumulation of dissolving materials in circulating water. Subsequently, the problems including scaling, fouling, corrosion and slime occurred. The multiple oxidants including chlorine dioxide, ozone, peroxide hydrogen, and chlorine were prepared using diaphragm electrolysis method to alleviate the problems above in the cooling system. Meanwhile multiple oxidants can also inhibit the accumulation of biological dirt and erosion effectively. The efficiency of multiple oxidants to inhibit precipitation of magnesium carbonate and calcium carbonate can be increased by adjustment of pH value in the whole pipeline system to reduce corrosion rate of the pipeline and to achieve energy-water saving goal. The results showed that the high efficiency of chlorine dioxide mixture was an excellent bio-corrosion inhibitor and bio-accumulation bactericide. The residue concentration of mixture oxidants are at the range of 0.05 ~ 0.25 mg ClO2/L that is high enough to restrain the growth of micro-organisms.