Electron-transfer disproportionation of a 2,2-diphenyl-1-picrylhydrazyl radical (DPPH˙) occurred in the presence of Sc(3+) acting as a strong Lewis acid in deaerated acetonitrile. In contrast, in the case of weaker Lewis acids than Sc(3+), such as Mg(2+) and Li(+), external protons from acetic acid were required for the disproportionation of DPPH˙ to occur.

Strawberries can augment plasma antioxidant activity, but this may be confounded by selection of methods, time of blood sampling and concomitant dietary restrictions. We examined the effect of strawberry consumption on ferric reducing ability (FRAP) and 2,2-diphenyl-1-picrylhydrazyl (DPPH) radical scavenging activity (DPPH-test) of native and non-urate plasma in healthy subjects on their usual ...

In this article, a DPPH·-luminol chemiluminescence (CL) system was reported and the CL mechanism was discussed according to the CL kinetic properties after sequence injecting DPPH· into the DPPH·-luminol reaction mixture. It was observed that scutellarin could inhibit the CL response of the DPPH·-luminol system. Based on this observation, a simple and rapid flow injection CL method was develope...

We investigated the inhibition of advanced glycation endproduct (AGE) activity using the fluorescence characteristics of fractions and compounds from Corni Fructus. Corni Fructus extract and its iridoid glycoside components showed low inhibitory activities as well as the AGE inhibitor aminoguanidine. However, a low molecular weight polyphenol, 7-O-galloyl-D-sedoheptulose, and an antioxidant, tr...

Three hydroxycinnamic acid derivatives conjugated with glycine-containing oxazole were synthesized. The prepared compounds were tested for their antioxidant activity using the 1,1-diphenyl-2-picrylhydrazyl (DPPH) test. Among the tested hydroxycinnamic acid amides the highest DPPH scavenging activity has been found for the sinapic acid amide.

A 2,2-diphenyl-1-picrylhydrazyl radical (DPPH˙) was successfully solubilised in water by β-cyclodextrin (β-CD). DPPH˙/β-CD thus obtained was demonstrated to be a powerful tool to evaluate the antioxidative activity of water-soluble antioxidants, such as ascorbate and Trolox, in aqueous buffer solutions.

Stoichiometric evaluation of the radical scavenging activity of O-substituted derivatives at the C-2 position of ascorbic acid (AA) was conducted. Their reaction with a stable radical, 1,1-diphenyl-2-picrylhydrazyl (DPPH), under an acidic condition was assessed by the colorimetric method. 2-O-alpha-D-Glucopyranosyl-L-ascorbic acid (AA-2G) and a series of 6-O-acyl-2-O-alpha-D-glucopyranosyl-L-as...

A sensitive on-line DPPH-CE-DAD method was developed and validated for both screening and determining the concentration of seven antioxidants of Reduning injection. The pH and concentrations of buffer solution, SDS, β-CD and organic modifier were studied for the detection of DPPH and seven antioxidants. By on-line mixing DPPH and sample solution, a DPPH-CE method for testing the antioxidant act...

We deyeloped a simple screening method for antioxidant-producing strains using 1,1-diphenyl-2picrylhydrazyl (DPPH) and screened bacteria from 16 kinds of marine animals that lived in different enyironments in the sea to find 112 bacterial iso]ates producing antioxidants. Guided by decoloration of DPPH sprayed on silica gel TLC, uric acid, indole, 3,4-dimethoxyphenol, and 3-hydroxyindolin-2-one ...