Peroxynitrite (ONOO-), formed by the reaction of superoxide (?O2
-) and nitric oxide (?
NO), is a cytotoxic species that can oxidize several cellular components such as
proteins, lipids, and DNA. It has been implicated in diseases such as cancer,
Alzheimer's disease, rheumatoid arthritis, and atherosclerosis. Due to the lack of
endogenous enzymes responsible for ONOO- inactivation, developing a specific ONOO-
scavenger is considerably important. The aim of this study was to evaluate the ability
of phloroglucinol isolated from E. stolonifera to scavenge ONOO- and to protect cells
against ONOO-. Phloroglucinol was found to be as a potent ONOO- scavenger. The data
demonstrated that phloroglucinol led to decrease ONOO--mediated nitration of tyrosine
through electron donation. Phloroglucinol provided cytoprotection from cell damage
induced by ONOO-.

Keywords: Peroxynitrite, scavenging activity, Phloroglucinol, Nitrotyrosine, Cytoprotection,
Smooth muscle cells