Phyllospongianes A-E, Dinorscalarane Sesterterpenes from the Marine Sponge Phyllospongia foliascens .

Phyllospongianes A-E ( 1 - 5 ), five new scalarane derivatives featuring an unprecedented 6/6/6/5 tetracyclic dinorscalarane scaffold, along with the known probable biogenetic precursor, 12-deacetylscalaradial ( 6 ), were isolated from the marine sponge Phyllospongia foliascens . The structures of the isolated compounds were determined by analysis of spectroscopic data and electronic circular dichroism experiments. Compounds 1 - 5 are the first 6/6/6/5 tetracyclic scalarane derivatives to be reported within the scalarane family. Compounds 1 , 2 , and 4 exhibited antibacterial activity against Vibrio vulnificus , Vibrio parahemolyticus , Escherichia coli , Staphylococcus aureus , Enterococcus faecalis , Bacillus subtilis , and Pseudomonas aeruginosa with MIC values ranging from 1 to 8 μg/mL. Furthermore, compound 3 exhibited significant cytotoxic activity on MDA-MB-231, HepG2, C4-2-ENZ, MCF-7, H460, and HT-29 cancer cell lines with IC 50 values in the range between 0.7 and 13.2 μM.