Substituted phenols as pollutants that affect membrane fluidity

In a toxicological context, the cellular effects of a variety of molecular compounds interacting with membranes may be understood in terms of their ability to affect and modulate lipid-membrane physical properties and even slight changes in membrane fluidity may cause aberrant function and pathological processes. Different model systems (mice splenocytes and liposomes) have been used in modelling studies of the physical effects on lipid bilayers underlying the action of membrane active phenolic compounds, considered by EPA (Environmental Protection Agency) as priority pollutants (phenol; 2-chlorophenol; 2,4-dichlorophenol; 2,4,6-trichlorophenol; pentachlorophenol; 2-nitrophenol; 2,4-dinitrophenol; 2-methyl-4,6-dinitrophenol). Membrane fluidity was assessed by fluorescence steady-state anisotropy of a fluorescent probe 1,6-diphenil-1,3,5-hexatriene (DPH). The substituted phenols increased the fluidity of cells and liposome membranes in a concentration dependent manner and the nitro substituted phenols were the most efficient perturbing the biophysical properties of the membrane. A good parallelism has been established between the results obtained with cell models and artificial liposome model systems, implying that liposomes are useful alternative systems in membrane modification studies and can be conveniently used in order to evaluate the potential toxic effect of phenol derivatives that are common environmental pollutants.