Stereoselective effects of monoterpenes on the microviscosity and curvature of model membranes assessed by fluorescence anisotropy and light scattering analysis.

ZUNINO M. P.; TURINA, A. V; ZIGADLO J.A.; PERILLO M. A.

CHIRALITY

WILEY-LISS, DIV JOHN WILEY & SONS INC

Año: 2011 vol. 23 p. 867 - 877

0899-0042

Here we evaluated stereoselectivity in monoterpenes (MTs) ability to disturbmembrane dynamics. Correlations between molecular structure and physicochemicalproperties of pinenes, menthols and carvones enantiomers were investigated through clusterand principal component analysis. So, MTs´ concentration-dependent changes in lightscatteringand DPH-fluorescence polarization induced by MTs were measured on largeunilamellar vesicles (LUVs) of dipalmitoylphosphatidylcholine.The behavior of the less polar compounds (hydrocarbons) were characterized by amembrane expansion (increase in light-scattering), detectable within the low-concentrationrange. They remained in the membrane up to the highest concentrations tested exhibiting aconcentration-dependent anisotropy decrease. Within the more polar terpenes (alcohols)prevailed a budding phenomenon with the production of small LUVs with roughly constantcurvature (more evident at medium and high concentrations) which explains the slight changein microviscosity (DPH fluorescence anisotropy). These behaviors were compatible with thedeeper localization within the membrane core of the formers compared with the latters aspredicted from the corresponding polar charge distribution in their molecular structures.The enantioselectivity was expressed by neomenthol at low concentration and carvoneat medium concentration. Inhibition and potentiation was evidenced, within the lowconcentrationrange, by the racemic mixtures in neomenthol and beta-pinenes, respectively.