What is spin trap?
Spin trapping is an analytical technique employed in chemistry and biology for the detection and identification of short-lived free radicals through the use of electron paramagnetic resonance (EPR) spectroscopy. EPR spectroscopy detects paramagnetic species such as the unpaired electrons of free radicals.
How do radical traps work?
The technique they developed was the use of an unsaturated compound (C-nitroso or nitrone) to react with the radical(s) to be detected via a free radical addition reaction to give a new radical with a longer lifetime, known as a spin adduct. The unsaturated compound used to trap the radicals is known as the spin trap.
What is a free radical trap?
Listen to pronunciation. (free RA-dih-kul SKA-ven-jer) A substance, such as an antioxidant, that helps protect cells from the damage caused by free radicals.
Is Dpph a spin trap?
2,2-Diphenyl- 1-picrylhydrazyl (DPPH) was purchased from Tokyo Kasei Kogyo and recrystallized from a chloroform-ethanol mixture. The following compounds were used as spin-trapping reagents (Scheme 1). The seven kinds of spin trap were obtained from Aldrich and used as received.
What is radical clock experiment?
In chemistry, a radical clock is a chemical compound that assists in the indirect methodology to determine the kinetics of a free-radical reaction. The radical-clock compound itself reacts at a known rate, which provides a calibration for determining the rate of another reaction.
What is radical quenching?
Free radical quenching can be defined as any reaction in which the free radical forms products that are not free radicals. The intervention of free radical chemistry can occur either early or late in the sequence of chain reactions.
What does Dpph stand for?
DPPH is a common abbreviation for the organic chemical compound 2,2-diphenyl-1-picrylhydrazyl. It is a dark-colored crystalline powder composed of stable free radical molecules.
What is DPPH used for?
The DPPH assay is used to predict antioxidant activities by mechanism in which antioxidants act to inhibit lipid oxidation, so scavenging of DPPH radical and therefore determinate free radical scavenging capacity. The method is widely used due to relatively short time required for the analysis.
Why Methanol is used in DPPH assay?
The standard DPPH assay uses methanol or ethanol as solvents, or buffered alcoholic solutions in a ratio of 40%/60% (buffer/alcohol, v/v) to keep the hydrophobic hydrazyl radical and phenolic test compounds soluble while offering sufficient buffering capacity at different pHs tested.
What is radical reaction in chemistry?
A radical substitution reaction is a reaction which occurs by a free radical mechanism and results in the substitution of one or more of the atoms or groups present in the substrate by different atoms or groups. The initiation step in a radical chain reaction is the step in which a free radical is first produced.
What are scavenging enzymes?
The amounts and activities of ROS scavenging enzymes, including catalase (CAT), ascorbate peroxidase, and superoxide dismutase are strongly down-regulated in aleurone layers treated with GA. CAT activity, protein, and Cat2 mRNA decline rapidly following exposure of aleurone layers to GA.
How do antioxidants quench free radicals?
Enzymatic antioxidants work by breaking down and removing free radicals. The antioxidant enzymes convert dangerous oxidative products to hydrogen peroxide (H2O2) and then to water, in a multi-step process in presence of cofactors such as copper, zinc, manganese, and iron.