dihydrosphingoid

Dihydrosphingoid bases are saturated sphingoid bases, meaning they are long-chain amino alcohols that lack the trans double bond between carbons 4 and 5 found in sphingosine. They form the backbone of a subset of sphingolipids and are sometimes called dihydro bases or dihydrosphingoid bases. The best-known examples are sphinganine (also called dihydrosphingosine) and its hydroxylated derivatives, such as phytosphingosine, all of which have a saturated carbon chain.

Structurally, dihydrosphingoid bases typically feature an 18-carbon backbone with various hydroxyl groups and a primary amino group at the second carbon. They serve as the core components from which more complex sphingolipids are built. In many cells, the common form is sphinganine (d18:0), with additional hydroxylation producing phytosphingosine and related species.

Biosynthesis proceeds via the de novo sphingolipid pathway. Serine and palmitoyl-CoA are condensed by serine palmitoyltransferase to form 3-ketodihydrosphinganine, which is reduced to sphinganine. Dihydrosphingoid bases can be acylated by ceramide synthases to yield dihydroceramides, which in turn are desaturated by dihydroceramide desaturase to produce ceramides. Thus dihydrosphingoid bases are key intermediates and can be diverted into mature sphingolipids that participate in membrane structure and signaling.

Biological and clinical relevance is primarily as foundational sphingolipid units and as precursors to ceramides, sphingosine, and complex sphingolipids. Altered levels of dihydrosphingoid bases and related dihydroceramides have been observed in various metabolic states and diseases, making them useful targets in lipidomics studies and biomarker research. Analytical detection is commonly achieved through mass spectrometry-based lipid profiling.