A fungal metabolite with potent immunosuppressant activity that is 10-100 fold more compared to Cyclosporin A (Cat. No. 1522). It inhibits serine palmitoyltransferase (Ki = 0.28 nM) blocking the synthesis of ceramide. It 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.