Differential scanning calorimetry evidence of the enhancement of beta-sitosterol absorption across biological membranes mediated by beta-cyclodextrins.

beta-Sitosterol is a plant sterol that has received much attention because of its effectiveness in reducing
the absorption of dietary cholesterol, as well as in offering protection from cardiovascular diseases
and cancer development. Thus, the knowledge of the interaction of beta-sitosterol with biological
membranes can help in understanding its mechanism of action. In the present paper, the differential
scanning calorimetry technique has been used to study the interaction of beta-sitosterol with a
biomembrane model constituted by dimyristoylphosphatidylcholine multilamellar vesicles. Furthermore,
kinetic experiments have been carried out to follow the uptake of beta-sitosterol by biomembranes and
the effect of beta-cyclodextrins on such a process. Our results indicate that opportune concentrations of
beta-cyclodextrins improve the uptake of beta-sitosterol by phospholipid membranes.