A Modification of the ABTS• Decolorization Method and an Insight into Its Mechanism

Abstract

A modification of the ABTS• decolorization assay for plate readers is presented. In our modification, 200 µL of ABTS solution of absorbance 1.0 at 734 nm was added with an antioxidant and decreased absorbance resulted. For comparison of antioxidant activities in the kinetic assay of absorbance decrease, concentration dependence of absorbance decrease and of area under curve are recommended. “Fast” and “slow” antioxidants were distinguished: while the reactions of “fast” antioxidants ABTS• were completed within seconds, the reactions of “slow” antioxidants were not finished after 6 min. We recommend reaction time of 60 min for assays of such antioxidants, blood plasma and plant extracts. Sub-additive interactions between some antioxidants (ascorbate and Trolox, hispidulin and Trolox, and glutathione and ascorbate) were found in the ABTS• decolorization; possible reasons for such interactions are discussed.

Comparisons of Physicochemical Properties, Bacterial Diversities, Isoflavone Profiles and Antioxidant Activities on Household and Commercial doenjang

“…This was observed because DPPH reacts with free radicals, but ABTS reacts with different free radicals, including peroxyl, hydroxyl, alkoxyl, and inorganic radicals, to form stable ABTS + type cationic radicals; due to having these differences, a difference in binding capacity to antioxidants occurred [41]. Therefore, ABTS + measured the antioxidant power of hydrophilic and hydrophobic substances, so it was judged to exhibit higher scavenging activity compared to DPPH [42]. The hydroxyl radical scavenging activity of fermented soybean yogurt and fermented soybean solid was estimated at 39% (500 µg/mL) and 49% (200 µg/mL) [43,44], which indicated higher amount compared to doenjang used in the study.…”

Colour characteristics, phenolic content and antioxidant activity of Spirulina platensis soaked in basil (Ocimum basilicum) leaves extract

“…ABTS and DPPH are radical scavenging‐based methods which generally have three mechanisms of antioxidants effect of phenolic compounds including hydrogen atom transfer, single electron transfer followed by proton transfer and sequential proton loss electron transfer (Munteanu & Apetrei, 2021; Gulcin & Alwasel, 2023). Usually, ABTS slow reactions with antioxidant were ascribed to hydrogen atom transfer, while fast ones were ascribed to single electron transfer reactions (Kut et al ., 2022). Gulcin & Alwasel (2023) reported that the reaction between DPPH and antioxidant depends on the difference in the ratio of mixed hydrogen atom transfer and single electron transfer mechanisms.…”

Comparison of Antioxidant and Antiproliferative Effects of Various Forms of Garlic and Ramsons

“…A modified [ 86 ] assay of Re et al [ 87 ] was used. Briefly, 200-μL aliquots of ABTS ● solution diluted with PBS to a concentration providing absorbance of 1.0 at 734 nm were pipetted to wells of a 96-well plate and added with 0–10 μL of the extracts or 0.5 mM Trolox, shaken, and left for 30 min at room temperature (21 ± 1 °C).…”

“…The antioxidant capacity of garlic and ramson extracts was calculated by comparing the slopes of dependencies of absorbance changes on the concentrations of Trolox and extracts as described previously [ 86 ] using the formula:…”