beta-Cyclodextrins influence on E-3,5,4'-trimethoxystilbene absorption across biological membrane model: a differential scanning calorimetry evidence.

E-3,5,4'-trimethoxystilbene (TMS) is a naturally occurring analog of resveratrol. The anti-neoplastic, antiallergic and anti-angiogenic activities of TMS have been recently reported. From the viewpoint of metabolism, TMS may be more favourable than resveratrol because all of its hydroxyl groups, which are subjected to extensive glucuronide or sulphate conjugation in the metabolic pathways of resveratrol, are protected by methylation. Moreover, methylation increases lipophilicity and may enhance cell membrane permeability, but it decreases its solubility in aqueous media. A way to increase TMS solubility can be represented by complexation with beta-cyclodextrins. In the present paper, the differential scanning calorimetry technique has been used to study the interaction of TMS with a biomembrane model constituted by dimyristoylphosphatidylcholine multilamellar vesicles. Furthermore, kinetic experiments have been carried out to follow the uptake of TMS by biomembranes in the presence of beta-cyclodextrins to gain information on the effect of beta-cyclodextrins on the uptake process. Our results indicate that opportune concentrations of beta-cyclodextrins greatly improve the uptake of TMS by biomembrane models.