Free radicals in chemical antioxidant assays

Free radicals in chemical antioxidant assays are synthetic or naturally occurring reactive species employed in in vitro experiments to quantify the antioxidant potential of substances. These assays, such as the DPPH (2,2-diphenyl-1-picrylhydrazyl) or ABTS (2,2'-azino-bis(3-ethylbenzothiazoline-6-sulfonic acid)) tests, rely on the ability of a test compound to donate electrons or hydrogen atoms to neutralize the radical, typically resulting in a measurable color change (PMID: 23769221). While these specific chemical radicals are not therapeutic targets, they serve as models for endogenous reactive oxygen species (ROS) like superoxide and hydroxyl radicals that cause oxidative stress in vivo (PMID: 28249118). In biological systems, excessive free radical production is linked to cellular damage and the progression of diseases such as cancer, neurodegeneration, and cardiovascular disorders (PMID: 24511325). Antioxidant drugs and supplements interact with these species by scavenging them directly or by inducing protective enzymatic pathways to maintain redox homeostasis (PMID: 11327322). The use of these assays allows researchers to screen for potential therapeutic agents that can mitigate oxidative damage in clinical settings, although the correlation between in vitro capacity and in vivo efficacy remains a significant challenge.

Other names

DPPH (2,2-diphenyl-1-picrylhydrazyl)ABTS (2,2'-azino-bis(3-ethylbenzothiazoline-6-sulfonic acid))Reactive oxygen speciesROSReactive nitrogen speciesRNSOxidantsAntioxidant capacity assays

Neutralization of reactive species through electron transfer (SET) or hydrogen atom transfer (HAT) mechanisms (PMID: 23769221).