Antioxidant Activity/Capacity Measurement. 2. Hydrogen Atom Transfer (HAT)-Based, Mixed-Mode (Electron Transfer (ET)/HAT), and Lipid Peroxidation Assays

Abstract

Measuring the antioxidant activity/capacity levels of food extracts and biological fluids is useful for determining the nutritional value of foodstuffs and for the diagnosis, treatment, and follow-up of numerous oxidative stress-related diseases. Biologically, antioxidants play their health-beneficial roles via transferring a hydrogen (H) atom or an electron (e(-)) to reactive species, thereby deactivating them. Antioxidant activity assays imitate this action; that is, antioxidants are measured by their H atom transfer (HAT) or e(-) transfer (ET) to probe molecules. Antioxidant activity/capacity can be monitored by a wide variety of assays with different mechanisms, including HAT, ET, and mixed-mode (ET/HAT) assays, generally without distinct boundaries between them. Understanding the principal mechanisms, advantages, and disadvantages of the measurement assays is important for proper selection of method for valid evaluation of antioxidant properties in desired applications. This work provides a general and up-to-date overview of HAT-based, mixed-mode (ET/HAT), and lipid peroxidation assays available for measuring antioxidant activity/capacity and the chemistry behind them, including a critical evaluation of their advantages and drawbacks.

Antioxidant Capacity of Anthocyanin Pigments

“…Antioxidant activity/capacity measurement: classification, physicochemical principles, mechanisms and electron transfer-based assays [154] Antioxidant activity/capacity measurement: hydrogen atom transfer-based, mixed-mode and lipid peroxidation assays [155] Antioxidant activity/capacity measurement: reactive oxygen and nitrogen species scavenging assays, oxidative stress biomarkers and chromatographic/chemometric assays [156] Recent applications for in vitro antioxidant activity assay [157] Evaluation of procedures for assessing anti-and pro-oxidants in plant samples [158] Capacity of antioxidants to scavenge multiple reactive oxidants and to inhibit plasma lipid oxidation induced by different biological oxidants [159] Analytical methods applied to antioxidant and antioxidant capacity assessment in plant-derived products [160] Advantages and limitations of commons testing methods for antioxidants [161] A comprehensive overview on the biology behind some reactive molecules and the means for their detection [162] Potentiometric study of antioxidant activity: development and prospects [163] Methods for determining the efficacy of radical-trapping antioxidants [164] Electrochemical methods for total antioxidant capacity [165] The role of consumption of dietary bioactives on the prevention of adverse health [166] Synthetic and natural phenolic antioxidants: mode of action, health effects, degradation products and toxicology [167] Up-to-date overview of methods available for measuring antioxidant activity [168] Use of metallic nanoparticles and quantum dots as novel tools for reliable assessment of antioxidant activity in food and biological samples [169] Review on in vivo and in vitro methods evaluation of antioxidant activity [170] IUPAC technical report: methods of measurement and evaluation of natural antioxidant capacity/activity [171] Evaluating the antioxidant capacity of natural products: a review on chemical and cellular-based assays [172] Application of free radical diphenylpicrylhydrazyl to estimate the antioxidant capacity of food samples [173] Application of both stationary and flow electrochemical methods for analysis of antioxidant properties of plant and clinical samples [174] Phenol-based antioxidants and the in vitro methods used for their assessment [175] Main components in the foodstuffs and beverages: antioxidant methods, chemical and kinetic basis …”

Genotype by Environment Interaction Unravels Influence on Secondary Metabolite Quality in Cassava Infested by Bemisia tabaci

“…The sample was centrifuged at 10,000 rpm for 10 minutes and 5 ml of supernatant was transferred into a fresh tube and 5ml of distilled water was added, followed by 1 ml of 0.1% ferric chloride. The sample was mixed well and absorbance read at 700 nm (Apak et al, 2016). In this assay, the presence of reducers (i.e., antioxidants) causes the reduction of the Fe 3+ /ferricyanide complex to the ferrous form.…”

“…In this assay, the presence of reducers (i.e., antioxidants) causes the reduction of the Fe 3+ /ferricyanide complex to the ferrous form. The formation of blue-colored ferrous tripyridyltriazine complex (Fe 2+ -TPTZ) was measured at pH 3.6 spectrophotometrically (Apak et al, 2016).…”

“…Temperature and moisture stress also not only affect cell water potential (V m ) as a result of xylem pressure (Ncube et al, 2012) but alter antioxidative properties of plants (Lemoine, Burkepile, & Parker, 2014;Ncube et al, 2012). This occurs through chelating transition metal ions, direct scavenging of molecular species of active oxygen, trapping the lipid alkoxyl radical and lipid peroxidation (Apak, Özyürek, Güçlü, & Çapanoʇlu, 2016). The changes that occur in the amounts of phenolic, tannin, flavonoid and antioxidative capacity reduce plant palatability and defense to insect pests (Stevens et al, 2007).…”

Applicability of a Voltammetric Assay Based on the Electroreduction of Oxygen to Evaluate the Antioxidant Capacity of Pequi (Caryocar brasiliense Camb.) Pulp

“…1 However, these colorimetric methods have some limitations. 2,3 For example, the samples must undergo a pretreatment to eliminate interfering agents, such as reducing sugars and organic acids. 4 In fact, each method has its own characteristics, such as the reaction mechanism, types of oxidation substrates, reaction medium (basic, acid or neutral), compound proof of reaction and expression of results.…”