2.2.1. Preparation of Resveratrol Solution

A stock solution of *Trans*-resveratrol (Res, M.W. 228.25) was prepared by dissolving resveratrol powder (16 mg) in 1000 µL of dimethyl sulfoxide (DMSO), stirring for 3 min to obtain a concentration of 70 mM. From this solution, 143 µL were withdrawn and diluted in 857 µL of bidistilled sterile water under stirring for 3 min to obtain a concentration of 10 mM. Both solutions were stored in dark glass vials at −20 ◦C until use, and 4 or 8 µL of the second solution was added to the *cis*-side of the membrane, to obtain the final concentration of 10 or 20 µM, respectively.
