Safingol is the L-threo diastereomer of D-erythro-sphinganine Both forms of sphinganine inhibit PKC by binding at the regulatory phorbol-binding domain (IC50s = 7 and 24 μM for erythro-sphinganine and safingol, respectively). Safingol also inhibits sphingosine kinases (Ki = 3-5 μM). Safingol, alone or in combination with chemotherapeutic agents, is cytotoxic against cancer cell lines.