Showing papers on "DPPH published in 1991"

The possible involvement of free radical scavenging properties in the actions of cytokines.

Abstract: Among the cytokines which show an antiproliferative effect on certain tumor cells, we investigated the free radical scavenging properties of tumor necrosis factor-alpha, interferon-alpha, and interferon-gamma. The scavenging properties were determined in vitro by the ability to reduce DPPH free radicals. All of these cytokines exhibited marked DPPH free radical scavenging ability.

The Studies of Composition of Fatty Acids and Antioxidant Activities in Parts of Omija (Schizandra chinensis Baillon)

Abstract: We have studies fatty acid composition of water extracts of parts of omija (Schizandra chinensis Baillon) and antioxidant activities of fractionated omija parts (fruits, endocarps, seeds) were determined by DPPH methods and by in vitro hepatic microsomal lipid peroxidation system. Fatty acid composition was not different by parts of omija and major fatty acids are linoleic, oleic, and palimitic acids, among fatty acids is water extracts of parts of omija, linoleic acid was highest in content. Methanol and buthanol fractions of seeds and ethyl acetate fraction of endocarps showed stronger antioxidant activities by DPPH methods. Methanol and buthanol fractions of seeds also showed on inhibitory effect on in vitro liver microsomal lipid peroxidation.

Preparation of pyrazoles using hydrazyl radicals initiated by dpph

Abstract: Hydrazyl radicals, initiated by DPPH, reacted with α,β-unsaturated ketones without any good leaving group on their β-positions to yield pyrazoles regio-selectively.

Stimulation by copper(ii) of reactivity of various sulfhydryl-containing compounds with 2,2-diphenyl-1-picrylhydrazyl

Abstract: The reaction of 2,2-diphenyl-1-picrylhydrazyl (DPPH) with various sulfhydryl-containing compounds including ergothioneine, glutathione, 1-methyl-2-mercaptoimidazole (methimazole), and 2-mercaptoimidazole was stimulated 7-14 fold by the addition of copper (II) sulfate. The reaction of DPPH with other 2-imidazolethiones substituted at both the 4 and 5 positions was not stimulated by Cu(II). The stimulation may result from the formation of a complex between Cu(II) and the sulfhydryl-containing compounds.

Intercalation of free radical, dpph, into montmorillonite

Abstract: The adosorption of DPPH in the interlayer of sodium montmorillonite and sodium saponite have been investigated by ESR. As the results, DPPH molecules dimerize to form diamagnetic species in montmorillonite, whereas DPPH molecules in saponite exist as isolated stable free radical species at room temperature.

Preparation of Pyrazoles Using Hydrazyl Radicals Initiated by DPPH.

Abstract: Hydrazyl radicals, initiated by DPPH, reacted with α,β-unsaturated ketones without any good leaving group on their β-positions to yield pyrazoles regio-selectively.