An in vitro, ex vivo, and in vivo demonstration of the lipolytic effect of slimming liposomes: An unexpected alpha(2)-adrenergic antagonism.

Most of the slimming products already developed for cosmetic applications did not result from strategies that integrate whole lipolysis-regulating mechanisms. We thus focused our attention on a more complete integration of these mechanisms and we developed slimming liposomes (SLC) containing two micro-circulation activators, i.e., esculoside and Centella asiatica extracts, one phosphodiesterase inhibitor, i.e., caffeine, and one fatty acid-beta oxidation activator, i.e., L-carnitine. The validity of our approach was assessed through (a) in vitro tests demonstrating that SLC induced a dramatic increase in the cyclic adenosine monophosphate (cAMP) content in human adipocytes, with a subsequent rise in the nonesterified fatty acids (NEFA) content of human adipocyte incubation medium, and (b) in vivo studies showing that SLC could provide an actual potent slimming effect on human volunteers. Moreover, we give here, through binding experiments, the unambiguous demonstration that SLC is able to antagonize the alpha(2)-adrenergic receptor that is known to reduce intracellular AMPc content and, subsequently, to down-regulate lipolysis. This alpha(2)-adrenergic antagonism has never been reported for any component of SLC, and this work is the first demonstration of the alpha(2)-adrenergic antagonism of such a combination of active liposome compounds.