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.