The enzyme Δ6 desaturase mediates the conversion of linoleic acid to γ-linolenic acid (GLA), which can then be elongated to dihomo-γ-linolenic acid (DGLA). DGLA can then be used as a substrate for Δ5 desaturase to produce arachidonic acid (AA), the fatty acid that is used to generate eicosanoids. SC 26196 is an inhibitor of Δ6 desaturase (IC50 = 0.2 μM in a rat liver microsomal assay) that completely blocks the conversion of linoleic acid to arachidonic acid (AA). It is selective for Δ6 desaturase, as IC50 values for Δ5 and Δ9 desaturases exceed 200 μM and it has no effect on the conversion of dihomo-γ-linolenic acid to AA. SC 26196 is orally active in vivo, decreasing edema in the carrageenan paw edema model in mice. It also blocks aging-related increases in AA in myocardial cardiolipin in mice, attenuating contractile dysfunction without impacting mitochondrial oxidative stress.
SC-26196 is a Delta6 fatty acid desaturase (Delta6D) inhibitor. It specifically inhibited Delta6D activity with an IC(50) value of 100 nM. The rate-limiting step in arachidonic acid synthesis is the desaturation of dietary linoleic acid by Delta6D. SC-26196 completely prevented this conversion of linoleic acid to arachidonic acid.