sydowinin b

Sydowinin B is a xanthone polyketide that has been found inA. sydowiiand has immunosuppressant activity.1It inhibits LPS- or concanavalin A-induced proliferation of isolated mouse splenic lymphocytes (IC50s = 19.2 and 20.8 μg ml, respectively).2Sydowinin B inhibits superoxide generation in, and elastase release from, isolated human neutrophils induced by cytochalasin B and N-Formyl-Met-Leu-Phe with IC50values of 21.2 and 12.62 μM, respectively.3

MS 347a is a myosin light chain kinase (MLCK) inhibitor; an epoxide analog of sydowinin B (MS-347b).