Monolayer nanoarchitectonics at the air-water interface for molecular understanding of the interaction of isolinderanolide E with cholesterol

Isolinderanolide E, an alkylated butanolide isolated from Nectandra oppositifolia (Lauraceae), was incorporated in cholesterol Langmuir monolayers. The main insights obtained with the in situ characterizations was that isolinderanolide E fluidized the monolayers, which could not attain rigid states with compression and also decreased the trans/gauche ratio conformers, suggesting molecular disorder. Morphology analysis revealed the formation of typical aggregates upon drug incorporation. These data could be associated with the fact that the monolayers became unstable with isolinderanolide E incorporation, with pre-compressed films decreasing the surface pressure spontaneously with a higher rate than pure cholesterol monolayers. In conclusion, natural isolinderanolide E changed the thermodynamic, mechanical, structural, and morphological cholesterol monolayers, which may be essential to understand the action at the molecular level bioactives in selected membrane models.