About the structure and biological function of AS
Structure. Alpha-hydroxy-fatty acid [A] sphingosine [S] ceramides (CER[AS], or AS) belong to the group of ceramide lipids within the sphingolipids. Their structure consists of a sphingoid base, specifically sphingosine, and a fatty acid, which is an α-hydroxy fatty acid. The fatty acid can be of variable length, hydroxylated, and contain double bonds.
Function. Alpha-hydroxy-sphingosines are mostly important for skin health where they serve structural and signaling roles. AS ceramides are involved in the formation of the epidermal barrier which protects against the environment and prevents trans-epidermal water loss. They are critical to barrier homeostasis. Skin ceramide imbalances can lead or contribute to the development of skin conditions. AS levels are reduced in psoriasis and dry skin. Further, AS ceramides are increased in Albino African skin.