Bioactive Diterpene Derivatives from the Marine Sponge Spongionella sp.

Three new compounds of the rare classes trisnorditerpenes, bisnorditerpenes, and norditerpenes, gracilins J−L (1, 2, 6), and a new diterpene, 3′-norspongiolactone (8), were isolated from the extract of the marine sponge Spongionella sp. using NMR- and bioassay-guided fractionation, in addition to three known gracilins (3−5) as well as the known diterpenoid tetrahydroaplysulphurin-1 (7). The structures were elucidated using NMR spectroscopic...