Synthesis and biological activity of halophenols as potent antioxidant and cytoprotective agents

A variety of halophenols were prepared by a practical route. The halophenols all displayed promising DPPH radical-scavenging activity, and two bromophenols exhibited high protective activity against H2O2-induced injury in HUVEC. A series of new bromophenols and chlorophenols were prepared by a practical route. The in vitro antioxidative activity of the halophenols was evaluated by the 1,1-diphenyl-2-picrylhydrazyl (DPPH) radical-scavenging assay, and their cytoprotective activity was also tested on hydrogen peroxide (H2O2)-induced injury in human umbilical vein endothelial cells (HUVEC). All halophenols tested displayed moderate to good DPPH radical-scavenging activity, and two bromophenols, 2,3′-dibromo-4,5,6′-trihydroxydiphenylmethanone (16c) and 2,3-dibromo-4,5-dihydroxydiphenylmethanone (17c) exhibited high protective activity against H2O2-induced injury in HUVEC with EC50 values of 0.4 and 0.8μM, respectively. The preliminary structure–activity relationships of these compounds were also investigated in order to determine the essential structures required for their bioactivities.