Mg(2+) enhanced the scavenging activity of (+)-catechin and quercetin against the 2,2-diphenyl-1-picrylhydrazyl radical (DPPH˙), while Al(3+) decreased their activity. Such effects of Mg(2+) and Al(3+) were not observed for kaempferol. Na(+) and Ca(2+) with large ionic radii showed little effect on the DPPH˙-scavenging activity of these three flavonoids.

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.

Phytochemical investigation of the aerial parts of Senecio desfontainei afforded one new benzoxepine derivative, senecioside (1) along with eleven known compounds (2-12). Their structures were assigned from H and C NMR spectra, DEPT and 2D COSY, NOE, HSQC and HMBC NMR experiments. All these compounds were tested for antioxidant activity in the 1,1-diphenyl-2-picrylhydrazyl (DPPH) radical scaven...

Methods: The antioxidant potential of pyrrolo [1, 2-A] pyrazine-1, 4-dione, hexahydro-3-(2-methylpropyl) (diketopiperazine) extracted from Streptomyces sp. VITMK1 was studied using reducing power assay. The scavenging of 2, 2-diphenyl-1-picrylhydrazyl (DPPH) radical and nitric oxide (NO) radical by the compound was also studied. The cytotoxic activity of the compound on RAW 264.7 macrophage cel...

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.

Pemanasan pada suhu dan waktu optimum dapat meningkatkan aktivitas antioksidan madu apis trigona karena meningkatnya total fenolik, flavonoid pigmen coklat. Kemampuan diukur melalui kemampuan menangkap radikal oleh DPPH (1,1-Diphenyl-2-picrylhydrazyl). Tujuan penelitian ini untuk membandingkan perubahan parameter penangkapan serta coklat 5 jenis dari kota Bogor, Kalimantan, Sulawesi, Lombok seb...

it has been investigated the in vitro antioxidant properties of ethanol extracts of the contained-allantoin plants in this study. contained-allantoined plant samples plantago lanceolata, plantago major, robinia pseudoacacia, platanus orientalis and aesculus hippocastanum were tested at different concentrations. the antioxidant activities of plant samples were analysed by 1,1- diphenyl-2-picrylh...