| 1 | Author
| Purusotam Basnet3, TetsuyaM. Atsunob, Richard Neidlein3 | Requires cookie* | | Title
| Potent Free Radical Scavenging Activity of Propol Isolated from Brazilian Propolis  | | | Abstract
| We evaluated free radical scavenging activity of the water, methanol and chloroform ex tracts of propolis in l,l-diphenyl-2-picrylhydrazyl (DPPH) free radical and xanthine-xanthine oxidase (XO D) generated superoxide anion assay systems. The free radical scavenging activ ity guided fractionation and chemical analysis led to the isolation of a new compound, propol {3-[4-hydroxy-3-(3-oxo-but-l-enyl)-phenyl]-acrylic acid) from the water extract, which was more potent than most common antioxidants such as vitamin C and vitamin E (a-tocopherol) in these assay systems. | | |
Reference
| Z. Naturforsch. 52c, 828—833 (1997); received August 7/September 19 1997 | | |
Published
| 1997 | | |
Keywords
| Propol, Propolis, Free Radicals, Superoxide Anion, Antioxidative Activity | | |
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| default:Reihe_C/52/ZNC-1997-52c-0828.pdf | | | Identifier
| ZNC-1997-52c-0828 | | | Volume
| 52 | |
2 | Author
| E. F. Elstner, D. From, M. Eyer | Requires cookie* | | Title
| Analysis of Different Mechanisms of Photosynthetic Oxygen Reduction  | | | Abstract
| Three mechanisms of oxygen reduction by chloroplast lamellae in the presence of autoxidizable electron acceptors can be differentiated by product analyis in the presence or absence of either dibromothymoquinone (DBMIB) or superoxide dismutase (SOD) : 1) H20 2 is the product of two-electron oxygen reduction by 2,3-dimethyl-5,6-methylenedioxy-p-benzoquinone, involving only photosystem II. This reaction is not inhibited by either DBMIB or SOD. 2) Superoxide anion, and H20 2 as the product of its dismutation, are products of monovalent oxygen reduction following autoxidation of certain low potential electron acceptors (herbicides) of photosystem I. These reactions are not inhibited by SOD but are blocked by DBMIB. 3) H20 2 is the product of and "apparent" two-electron photoreduction of oxygen, mediated by certain o-diphenols (caffeic acid). These reactions are inhibited by both DBMIB and SOD in dicating the involvement of photosystem I and of 0 2-as an intermediate in the H20 2 producing reaction. | | |
Reference
| Z. Naturforsch. 33c, 276 (1978); received February 6 1978 | | |
Published
| 1978 | | |
Keywords
| Oxygen Reduction, Photosynthetic Electron Transport, Superoxide Anion, Peroxide Formation, Chloroplasts | | |
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| default:Reihe_C/33/ZNC-1978-33c-0276.pdf | | | Identifier
| ZNC-1978-33c-0276 | | | Volume
| 33 | |
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