Using a kinase screen to investigate the constituents of the sponge Stelletta clavosa obtained from diverse habitats.

Abstract Fourteen collections of the marine sponge Stelletta clavosa have been obtained from diverse Indo-Pacific locations in order to conduct a comparison of their major constituents. The dichloromethane extract of one collection (no. 00369) exhibited activity in a c-Raf-1 kinase assay. Bioactivity-directed isolation resulted in the known porphyrin analogs pyropheophorbide a ( 2 ) and purpurin 18 methyl ester ( 3 ). Further spectroscopic screening of the various sponge extracts resulted in the isolation of four swinholide polyketides, a carotenoid, and three diketopiperazines. Pyropheophorbide a ( 2 ) exhibited the best IC 50 among the porphyrin type compounds (IC 50 2 against a panel of 85 kinases.