This work proposes the application of batch-injection analysis with amperometric detection to determine the antioxidant capacity of real samples based on the measurement of DPPH radical consumption. The efficient concentration or EC50 value corresponds to the concentration of sample or standard required to scavenge 50% DPPH radicals. For the accurate determination of EC50, samples were incubate...

Semen Oroxyli, derived from the seed of Oroxylum indicum L., is a commonly used Traditional Chinese Medicine with beneficial effects against several respiratory disorders. Antioxidative flavonoids may be partly responsible for its medicinal functions. The aim of this study was to rapidly determine the antioxidants in Semen Oroxyli based on a HPLC-DPPH method. Four major flavonoids, baicalein-7-...

Radical scavenging and antioxidant activities of nine flavonoids previously isolated from the aerial parts of Chenopodium bonus-henricus L. were established using DPPH and ABTS free radicals as well as inhibition of lipid peroxidation in a linoleic acid system by the ferric thiocyanate method. Patuletin glycosides, compounds 1, 2 and 7 showed the highest DPPH (85.78%, 85.59%, 86.07%) and ABTS a...

Molyneux, P. The use of the stable free radical diphenylpicrylhydrazyl (DPPH) for estimating antioxidant activity Songklanakarin J. Sci. Technol., 2004, 26(2) : 211-219 The use of the stable free radical diphenylpicrylhydrazyl (DPPH) to estimate the activity of antioxidants is reviewed. Current applications of the method are examined, particularly the use of the parameter EC50 (substrate concen...

As plants produce a huge amount of antioxidants they can represent a source of new compounds with antioxidant activities. From this point of view, the main goal of this research was to study the antioxidant activities of the Ficus carica through the 1,1-diphenyl-2-picrylhydrazyl (DPPH) radicalscavenging method. Since DPPH assay has been largely used as a quick, reliable, and reproducible parame...

1,1-dipheny-2-picrylhydrazyl (DPPH) scavenging activities of the 80% methanolic leaf extracts of three cultivars (small leaf, SL; big leaf, BL; thin leaf, TL) of Mai-Men-Dong (Liriope spicata L.) are analyzed by spectrophotometry. The concentrations required for 50% inhibition (IC 50 ) of DPPH radicals were 81.08, 96.97, and 53.78 μg/mL, respectively. The methanolic extracts were further partit...

Optimization of phenolic extraction from Orthosiphon stamineus was carried out in present study by investigating the effects of ethanol concentration (0-100%, v/v), extraction time (60-300 min) and extraction temperature (25-65oC) on the phenolic recovery using single factor experiment. Total phenolic content (TPC), total flavonoid content (TFC) and condensed tannins content (CTC) were used for...

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 ...

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.