Sphingoid Bases

Sphingoid bases, also called “long-chain bases” are the backbone of all sphingolipids. The most important species is sphingosine ((2S,3R,4E)-2-amino-4-octadecen-1,3-diol), an aliphatic amine with 18 carbon atoms, an amine group at C2, two hydroxyl groups at C1 and C3, and a double bond in trans configuration at C4. Other prominent species are sphinganine (dihydrosphingosine, (2S,3R)-2-amino-octadecan-1,3-diol) that lacks the double bond and phytosphingosine ((2S,3R,4R)-2-amino-octadecan-1,3,4-triol) that has also a saturated aliphatic chain but an additional hydroxyl group at C4.

The term “sphingosin” was first used in 1884 by J.L.W. Thudichum when he isolated a mysterious substance from brain tissue and referred to the enigmatic sphinx. The structure of sphingosine and dihydrosphingosine was elucidated by H.E. Carter in 1947, who also named lipids containing a sphingoid base “sphingolipids.” Today, more than 60 structural variants of sphingoid bases are described.

For shorthand...