New Alkaloids from the Indopacific Sponge Stylissa carteri

Abstract

Two samples of the marine sponge Stylissa carteri collected in Indonesia yielded two new bromopyrrole alkaloids: debromostevensine (1) and debromohymenin (2), as well as nine other known congeners (3-11). The structures of the new compounds were unambiguously established on the basis of their NMR and mass spectra.

Biosynthesis, asymmetric synthesis, and pharmacology, including cellular targets, of the pyrrole-2-aminoimidazole marine alkaloids

“…Sceptrin, ageliferin, and bromoageliferin were also found to have antibacterial activity against E. coli at 10 μg/disk. 142,130 along with a previously observed antibiotic effect of sceptrin and ageliferin against B. subtilis , S. aureus , and E. coli . at a concentration of 0.2 μmol/disk.…”

“…Nakamuric acid ( 176 ) and its corresponding methyl ester ( 177 ) from Agelas nakamurai only exhibited antibacterial activity against B. subtilis , with 9 mm zones of inhibition. These P-2-AIs exhibit lower antibiotic activity compared to sceptrin ( 52 ) and ageliferin ( 157a ) 130 and these preliminary SAR studies suggested that structural changes in the guanidine moiety of the dimer can alter bioactivity. The presence of the oxoguanidine in oxysceptrins and absence of the guanidine in nakamuric acid and its methyl ester leads to a substantial decrease in activity or complete loss of antibiotic activity.…”

“…( Z )-debromohymenialdisine and ( Z )-hymenialdisine also proved to be active against human monocytic leukemia cells (MONOMAC- 6) with IC 50 values of 2.4 and 0.2 μg/mL, respectively. 130 The synthesis and utility of hymenialdisines as potential medicinal agents has been recently reviewed. 131 …”

High resolution spatial mapping of brominated pyrrole-2-aminoimidazole alkaloids distributions in the marine sponge Stylissa flabellata via MALDI-mass spectrometry imaging

“…The pseudomolecular ion cluster for the compound at m/z 825/ 827/829/831/333/835 was indicative of a chlorotetrabrominated compound. There are at least two B-P-2-AI compounds published with this molecular weight: konbu'acidin B 3 (8) and tetrabromostyloguanidine (9). 33 MS-MS analysis of this ion cluster obtained directly from the tissue slice yielded fragments 18, 251 and 269 amu smaller than the parent indicating loss of water, a dibromopyrrole carboxylate and water and dibromopyrrole carboxylate respectively.…”

Sponges (Porifera)

“…The frequent occurrence of biologically active natural products in sessile or slow moving marine invertebrates such as sponges, tunicates or shell-less mollusks that usually lack morphological defense structures such as protective shells or thorns is not a mere coincidence, but reflects an ecological adaptation that has been shaped during evolution allowing these delicate organisms to survive and flourish in spite of usually heavy predation by fish and other predators (Proksch and Ebel1998;Proksch 1999;McClintock and Baker 2001). In the marine, as in the terrestrial environment, the accumulation of toxic and/or distasteful natural products is also an effective strategy to repulse potential predators or to force back neighbors competing for space.…”