Interactions of the flavonols quercetin, fisetin, kaempferol, and myricetin with liposomal membranes

Flavonols, belonging to a subgroup of secondary plant metabolites, have a high therapeutic potential. To compare molecular parameters of the flavonols and their interactions with membranes, we performed quantum chemical modeling of structure and electronic characteristics of some flavonols such as quercetin, fisetin, kaempferol, and myricetin and considered the effects of the flavonols on liposomal membranes, using fluorescence spectroscopy, an electric-kinetical method and differential scanning calorimetry. Quercetin was more effective in increasing liposomal membrane stiffness and hydration, while fisetin increased zeta potential and destabilized the membrane to a greater extent. We hypothesize that a modification of the biological membrane structure, stability, reduction of fluidity and enhancement of bilayer hydration by the flavonols underlie their biochemical and pharmacological effects.