Myriocin (35891-70-4) is a fungal metabolite with potent immunosuppressant activity.¹ It inhibits serine palmitoyltransferase (Ki = 0.28 nM) blocking the synthesis of ceramide.² Myriocin was found to suppress melanoma cell proliferation by cell cycle arrest at the G ₂/M phase through decreased sphingolipid levels and increased p53 and p21 (waf1/cip1) expression.³

References/Citations
1) Fujita et al.(1994) Fungal metabolites. Part 11. A potent immunosuppressive activity found in Isaria sinclairii metabolite; J. Antibiot. 47 208
2) Miyake et al. (1995) Serine palmitoyltransferase is the primary target of a sphingosine-like immunosuppressant ISP-1/myriocin; Biochem. Biophys. Res. Commun. 211 396
3) Lee et al. (2012) Myriocin, a serine palmitoyltransferase inhibitor, suppresses tumor growth in a murine melanoma model by inhibiting de novo sphingolipid synthesis; Cancer Biol Ther. 13 92