Scavenging of reactive oxygen species by a novel glucurinated flavonoid antioxidant isolated and purified from spinach

Margalit Bergman, Alexander Perelman, Zvy Dubinsky, Shlomo Grossman

Research output: Contribution to journalArticlepeer-review

64 Scopus citations

Abstract

NAO is a natural water soluble antioxidant that was isolated and purified from spinach leaves. Using HPLC, NMR, and CMR spectroscopy, the main components were identified as flavonoids and p-coumaric acid derivatives. The NAO was found to be a very effective antioxidant in several in vivo and in vitro biological systems. In the present study, the antioxidant activity of the novel antioxidant glucurinated flavonoid (GF) isolated and characterized from NAO, is compared to well-known antioxidants. In addition, the direct free radical scavenging properties of the purified component GF were studied using the electron spin resonance (ESR) technique. GF and NAO were found to be superior to EGCG and NAC and to the Vitamin E homologue Trolox in inhibiting reactive oxygen species (ROS) formation in the autooxidation system of linoleic acid and in fibroblasts exposed to metal oxidation. GF and NAO were found to inhibit the ESR signal intensity of DMPO-O2 radical formation during the riboflavin photodynamic reaction. 10 mM GF caused approximately 90% inhibition in the intensity of the ESR signal, while NAO at a concentration of 60 μg/ml caused an inhibition of about 50%. Using the Fenton reaction, GF and NAO were found to inhibit DMPO-OH radical formation. A concentration of 2 mM GF caused a 70% inhibition in the intensity of the DMPO-OH radical ESR signal, while propyl gallate at the same concentration caused only 50% inhibition. Furthermore, both GF and NAO also inhibited the 1O2 dependent TEMPO radical generated in the photoradiation TPPS4 system. About 80% inhibition was obtained by 4 mM GF. The results obtained indicate that the natural antioxidants derived from spinach may directly affect the scavenging of ROS and, as a consequence, may be considered as effective sources for combating oxidative damage.

Original languageEnglish
Pages (from-to)753-762
Number of pages10
JournalPhytochemistry
Volume62
Issue number5
DOIs
StatePublished - Mar 2003

Bibliographical note

Funding Information:
This research was supported by the Lewitt-Schwartz Chair for Heart and Lung Disease Research of the Faculty of Life Sciences, Bar-Ilan University.

Keywords

  • ESR
  • GF
  • Natural antioxidant (NAO)
  • ROS
  • Spinach

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