Antioxidant effect of 4-nerolidylcatechol and α-tocopherol in erythrocyte ghost membranes and phospholipid bilayers.

Abstract

4-Nerolidylcatechol (4-NC) is found in Pothomorphe umbellata root extracts and is reported to have a topical protective effect against UVB radiation-induced skin damage, toxicity in melanoma cell lines, and antimalarial activity. We report a comparative study of the antioxidant activity of 4-NC and α-tocopherol against lipid peroxidation initiated by two free radical-generating systems: 2,2'-azobis(2-aminopropane) hydrochloride (AAPH) and FeSO4/H2O2, in red blood cell ghost membranes and in egg phosphatidylcholine (PC) vesicles. Lipid peroxidation was monitored by membrane fluidity changes assessed by electron paramagnetic resonance spectroscopy of a spin-labeled lipid and by the formation of thiobarbituric acid-reactive substances. When lipoperoxidation was initiated by the hydroxyl radical in erythrocyte ghost membranes, both 4-NC and α-tocopherol acted in a very efficient manner. However, lower activities were observed when lipoperoxidation was initiated by the peroxyl radical; and, in this case, the protective effect of α-tocopherol was lower than that of 4-NC. In egg PC vesicles, malondialdehyde formation indicated that 4-NC was effective against lipoperoxidation initiated by both AAPH and FeSO4/H2O2, whereas α-tocopherol was less efficient in protecting against lipoperoxidation by AAPH, and behaved as a pro-oxidant for FeSO4/H2O2. The DPPH (2,2-diphenyl-1-picrylhydrazyl) free-radical assay indicated that two free radicals were scavenged per 4-NC molecule, and one free radical was scavenged per α-tocopherol molecule. These data provide new insights into the antioxidant capacity of 4-NC, which may have therapeutic applications for formulations designed to protect the skin from sunlight irradiation.

• Authors: K S Fernandes, A H M Silva, S A Mendanha, K R Rezende, A Alonso
• Journal: Brazilian journal of medical and biological research = Revista brasileira de pesquisas medicas e biologicas (Braz J Med Biol Res) Vol. 46 Issue 9 Pg. 780-8 (Sep 2013) ISSN: 1414-431X [Electronic] Brazil
• PMID: 24068194 (Publication Type: Journal Article, Research Support, Non-U.S. Gov't)

Chemical References

• 4-nerolidylcatechol
• Amidines
• Antioxidants
• Catechols
• Free Radicals
• Peroxides
• Phosphatidylcholines
• Phospholipids
• Plant Extracts
• perhydroxyl radical
• Malondialdehyde
• 2,2'-azobis(2-amidinopropane)
• alpha-Tocopherol

Topics

• Amidines (administration & dosage, pharmacology)
• Antioxidants (pharmacology)
• Catechols (pharmacology)
• Electron Spin Resonance Spectroscopy
• Erythrocyte Membrane (drug effects)
• Free Radicals (analysis)
• Humans
• Lipid Peroxidation (drug effects)
• Malondialdehyde (analysis)
• Peroxides (analysis)
• Phosphatidylcholines (pharmacology)
• Phospholipids (pharmacology)
• Plant Extracts (chemistry, pharmacology)
• Plant Roots (chemistry)
• alpha-Tocopherol (pharmacology)