ABTS/PP Decolorization Assay of Antioxidant Capacity Reaction Pathways

Abstract

The 2,2 -azino-bis(3-ethylbenzothiazoline-6-sulfonic acid) (ABTS •+ ) radical cation-based assays are among the most abundant antioxidant capacity assays, together with the 2,2-diphenyl-1picrylhydrazyl (DPPH) radical-based assays according to the Scopus citation rates. The main objective of this review was to elucidate the reaction pathways that underlie the ABTS/potassium persulfate decolorization assay of antioxidant capacity. Comparative analysis of the literature data showed that there are two principal reaction pathways. Some antioxidants, at least of phenolic nature, can form coupling adducts with ABTS •+ , whereas others can undergo oxidation without coupling, thus the coupling is a specific reaction for certain antioxidants. These coupling adducts can undergo further oxidative degradation, leading to hydrazindyilidene-like and/or imine-like adducts with 3-ethyl-2-oxo-1,3-benzothiazoline-6-sulfonate and 3-ethyl-2-imino-1,3-benzothiazoline-6-sulfonate as marker compounds, respectively. The extent to which the coupling reaction contributes to the total antioxidant capacity, as well as the specificity and relevance of oxidation products, requires further in-depth elucidation. Undoubtedly, there are questions as to the overall application of this assay and this review adds to them, as specific reactions such as coupling might bias a comparison between antioxidants. Nevertheless, ABTS-based assays can still be recommended with certain reservations, particularly for tracking changes in the same antioxidant system during storage and processing.

Flavonoids with Glutathione Antioxidant Synergy: Influence of Free Radicals Inflow

“…The lag-time durations for individual compounds and combinations were obtained from kinetic curves to calculate n -values and mixture effects, respectively ( Figure 2 ). The calculated n -values were as follows: 4.7, 3.3, 2.8, 2.7, and 0.8 for quercetin, morin, rutin, taxifolin, and glutathione, respectively [ 58 ]. Combinations of the tested flavonoids with glutathione were shown to have different mixture effects, from subadditive to a considerable synergy, which depended on both the flavonoid component structure and the ratio of components.…”

“…In this work, we tried to apply different approaches while utilizing the same antioxidants and—more importantly—the same model radicals. There are numerous methods to measure antioxidant activity/antioxidant capacity (AOA/AOC) [ 3 , 59 , 60 , 61 , 62 , 63 , 64 , 65 , 66 , 67 ]; of those, the ABTS-based methods are among the most widely used [ 58 ]. We applied two approaches based on the scavenging of ABTS •+ radical–cations to evaluate the antioxidant interaction of flavonoid–glutathione combinations.…”

“…In contrast, morin and glutathione were both tested in a wider range (10–60 inh%) and as a result showed a statistically significant inversely proportional decrease in n -value. Apparently, the higher the ABTS •+ :antioxidant ratio, the deeper the interaction; previously, it has been shown that the reaction of antioxidants with ABTS •+ can be deeper when the latter is in excess [ 58 ]. However, this effect was mostly negligible.…”

α-Bisabolol, a Dietary Bioactive Phytochemical Attenuates Dopaminergic Neurodegeneration through Modulation of Oxidative Stress, Neuroinflammation and Apoptosis in Rotenone-Induced Rat Model of Parkinson’s Disease

“…These beneficial effects of BSB against oxidative stress are ascribed to its strong antioxidant activity. Scavenging ABTS radical is one of the widely used spectrophotometric assay to detect the antioxidant potential of pure substances [ 55 ]. In our study, BSB scavenges ABTS radical in a concentration dependent manner.…”

Chicken Egg Proteins and Derived Peptides with Antioxidant Properties

“…Among the hydrogen atom transfer-based method most commonly used methods to measure the antioxidant capacity of egg-derived peptides is oxygen radical absorbance capacity (ORAC) which consist in a fluorescent compound, such as fluorescein, that is damaged by free radicals and subsequently loses its fluorescence, but when antioxidants are present the loss of fluorescence is inhibited [18]. The 2, 2-azinobis (3-ethyl benzothiazoline-6-sulfonic acid) diamonium salt (ABTS) radical scavenging method and lipid peroxidation inhibition assay are also included in this category, among others [17,19]. Despite the numerous in vitro studies performed to evaluate the antioxidant capacity of egg-derived hydrolysates or peptides, their commercial application is delayed due to the lack of scalable production processes, the few digestibility and bioavailability studies as well as animal studies available and the absence of clinical trials that probe their potential health benefits.…”