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Showing papers on "DPPH published in 1990"


Journal ArticleDOI
TL;DR: The free radical scavenging ability of an ethanolic extract of propolis (EEP) was demonstrated by electron spin resonance spectroscopy, when 2,2-diphenyl-1-picrylhydrazyl (DPPH) was treated with increasing concentrations of EEP.
Abstract: The free radical scavenging ability of an ethanolic extract of propolis (EEP) was demonstrated by electron spin resonance spectroscopy, when 2,2-diphenyl-1-picrylhydrazyl (DPPH) was treated with increasing concentrations of EEP. It was shown that the DPPH signal intensity was inversely related to the EEP concentration and to the reaction time. It is assumed that the ability of components in EEP to donate a hydrogen atom is responsible for the lowering of the DPPH-EEP signal, and reflect the anti-oxidative nature of EEP.

117 citations


Journal Article
TL;DR: A number of medicinal species of the Apiaceae, Borraginaceae and Lamiaceae families present high rosmarinic acid and total hydroxycinnamic derivative contents.
Abstract: A number of medicinal species of the Apiaceae, Borraginaceae and Lamiaceae families present high rosmarinic acid and total hydroxycinnamic derivative contents. Species of genera Sanicula (Apiaceae), Lycopus, Melissa, Mentha, Origanum and Salvia (Lamiaceae) contain rosmarinic acid in large amount, more than 3%, based on dry weight. The antioxidant activity of hydroalcoholic extracts, on DPPH, is partly in relation with the hydroxycinnamic derivative content.

60 citations


Journal ArticleDOI
TL;DR: The hepatoprotective activities of 1, 2, 3 and 4 in vitro and in vivo are apparently due to their antioxidative effects, which were exhibited by further studies using 1,1-diphenyl-2-picrylhydrazyl (DPPH) radicals and CCl4-induced lipid peroxidation systems.
Abstract: Successive purification of the extract from Canarium album and Euphorbia nematocypha, guided by antihepatotoxic activity in primary cultured rat hepatocytes, led to the isolation of brevifolin (1), hyperin (2), ellagic acid (3) and 3,3'-di-O-methylellagic acid (4) as hepatoprotective compounds. Compounds 1,3 and 4 also reduced carbon tetrachloride (CCl4)-induced liver damage in mice. The hepatoprotective activities of 1, 2, 3 and 4 in vitro and in vivo are apparently due to their antioxidative effects, which were exhibited by further studies using 1,1-diphenyl-2-picrylhydrazyl (DPPH) radicals and CCl4-induced lipid peroxidation systems.

41 citations


Journal ArticleDOI
TL;DR: It appears that antioxidant activity and reduction of DPPH both require the presence of a free OH group on the ellipticine ring, and a good correlation is observed between cytotoxicity and antioxidant activity of the hydroxylated derivatives.

20 citations