No abstract

[structure: see text] Bioassay-guided fractionation of the sponge Psammocinia sp. afforded psymberin (1) possessing 5S,8S,9S,11R,13R,15S,16R,17R stereochemistry. Psymberin exhibits structural similarities to the pederin family metabolites. The potent cytotoxicty and unique structural features of 1 make it a promising lead for therapeutic development.

No abstract

The marine sponge Diacarnus cf. spinopoculum has provided a series of norterpenes, including five new compounds (7-11), two new ent-compounds [(-)-1a and (+)-1b], and three known compounds (2a, 2b, and 12). Eight of these compounds represent additional examples of the muqubilin/sigmosceptrellin classes (norsesterterpene peroxides) or the nuapapuin class (norditerpene peroxides). Also isolated were dinorditerpenones 11 and 12, which are biosynthetically related to the muqubilin/sigmosceptrellin structure classes. In all, 11 compounds were evaluated for their cytotoxic properties using a soft agar assay system and the NCI's 60 cell-line screen. Compounds without peroxide functionality were inactive. Overall, the norsesterterpene peroxides were less selective as cytotoxins than norditerpene peroxide analogues. Two compounds, nuapapuin A methyl ester (3) and nuapapuin B (7), which were somewhat selective in their cytotoxic behavior, were selected for further in vivo evaluation.