Many products are known to inhibit the biosynthesis of ceramides and glucosylcermides, but very few products stimulatethis process. In the literature, there is one report on ursonic acid as enhancer of sphingolipid biosynthesis (1). Sphingolipidsare ubiquitous components of all eukaryotic cell membranes that are involved in several major biological activities, such asgrowth regulation (2), differentiation and apoptosis (3). The modulation of these functions by sphingolipids seems to dependmainly on the constitutive sphingoid bases (4). During proliferation, differentiation and aging of keratinocytes, sphingolipidmetabolism is continuously changing (5). Whereas the most undifferentiated layers of the epidermis contain mostly membranelipids such as phospholipids, the differentiated keratinocytes contain ceramides, cholesterol and fatty acids predominantly.The lamellar bodies contain mostly glucosylceramides that are then hydrolyzed by a glucocerebrosidase into ceramides, themajor components of the intercellular matrix of corneocytes layers (6). The barrier function of the stratum corneum dependson the high proportion of protein-bound omega hydroxy ceramides along with free ceramides ...