Planta Med 1996; 62(4): 289-292
DOI: 10.1055/s-2006-957886
Papers

© Georg Thieme Verlag Stuttgart · New York

Radical Scavenger Activity of Three Flavonoid Metabolites Studied by Inhibition of Chemiluminescence in Human PMNs1

Irmgard Merfort2 , 6 , Jörg Heilmann2 , [1] , Manfred Weiss3 , Piergiorgio Pietta4 , Claudio Gardana5
  • 2Institute for Pharmaceutical Biology, University of Düsseldorf, Universitätsstr. 1, D-40225 Düsseldorf, Germany
  • 3Department of Anaesthesiology, University of Düsseldorf, Moorenstr. 5, D-40225 Düsseldorf, Germany
  • 4Università degli Studi di Milano, Dipartimento di Scienze e Tecnologie Alimentari e Microbiologiche, Via G. Celoria, 2, I-20133 Milano, Italy
  • 5ITBA-CNR, V. le F. ili Cervi, 96, I-20090 Segrate, Milano, Italy
  • 6Institute for Pharmaceutical Biology, Albert-Ludwigs-University of Freiburg, Schänzlestr. 1, D-79104 Freiburg, Germany
1 Lecture, ALPAC, QSFNE, Helsinki, Finland, August 1995
Further Information

Publication History

1995

1996

Publication Date:
04 January 2007 (online)

Abstract

3,4-Dihydroxyphenylacetic acid, 3-hydroxyphenylacetic acid, and 3-(4-hydroxyphenyl)-propionic acid, metabolites which arise from quercetin glycosides, respectively, from flavones and probably from procyanidins by the human intestinal microflora, have been tested for their effects on oxygen radical production by human PMNs stimulated with FMLP or opsonized zymosan. Oxygen radicals were detected by luminol-augmented chemiluminescence measurements. Furthermore free radical scavenging activity of these metabolites was investigated in a cell-free system in which oxygen radicals were generated by horseradish peroxidase with H2O2 as substrate. 3,4-Dihydroxyphenylacetic acid reduced considerably chemiluminescence in PMNs in an amount which was much more pronounced than those of the other two metabolites. Concentrations of 1 µmol/l showed an inhibition by 84 % with FMLP as stimulant and by 15 % with opsonized zymosan, indicating that different signal transduction pathways are influenced in PMNs. Using the same conditions the unmetabolized quercetin showed an inhibition of chemiluminescence by 74% (FMLP), resp. 20% (opsonized zymosan). In the cell free system 3,4-dihydroxyphenylacetic acid suppressed much more effectively chemiluminescence than 3-hydroxyphenylacetic acid. In contrast, 3-(4-hydroxyphenyl)-propionic acid led to an increase of chemiluminescence generated in the cell-free system (FMLP and zymosan), i.e. by 30% and by 25%, at the highest concentration of 4 µmol/l. In conclusion, flavonoid metabolites differ in their effects on free radical production of PMNs and their radical scavenging potencies.

1 Part of the thesis of J. Heilmann