Bioactive bromopyrrole metabolites from the Caribbean sponge Agelas conifera

Abstract

Biologically active extracts of the Caribbean sponge Agelas conifera have yielded, in exhaustive studies, the diacetate salts of seven new bromopyrroles (1,(3)(4)(5)(6)(7)(8), as well as that of the known debromooroidin dimer sceptrin (2). These compounds were found to be antiviral and antibacterial and were active in barnacle settlement and biochemical prophage induction assays. The structures assigned were based on spectroscopic comparisons to sceptrin and two-dimensional NMR data. Synthetic bromopyrroles were used to verify bromine substitution patterns. The oxysceptrins (4,5) are characterized by their aminoimidazolinone group, the ageliferins (6-8) by a unique cyclohexene-based skeleton.

Chemical defenses of the Caribbean sponges Agelas wiedenmayeri and Agelas conifera

“…Isolation of brominated alkaloids from a specimen of Agelas wiedenmayeri, which had been collected in May 1998 at North Dry Rocks, Key Largo, was performed using a previously described procedure (Assmann et al 1999). The isolated bromopyrrole alkaloids of both A. conifera and A. wiedenmayeri were identified by comparison of mass spectrometry and NMR data with those previously reported (Forenza et al 1971, Garcia et al 1973, Walker et al 1981, Kobayashi et al 1990, Keifer et al 1991 as well as on the basis of 2D NMR data (COSY, HSQC, HMBC).…”

“…Besides these 2 brominated alkaloids, a series of dimeric bromopyrrole alkaloids, the sceptrins and ageliferins, have been isolated from A. conifera, A. sceptrum and A. sp. (Walker et al 1981, Kobayashi et al 1990, Keifer et al 1991. Although it was surmised that the dimeric brominated alkaloids found in other species of Agelas from the Caribbean deterred feeding , purified compounds were never tested.…”

Structure of debromo-carteramine A, a novel bromopyrrole alkaloid from the Mediterranean sponge Axinella verrucosa

“…6,7,15 Furthermore, these compounds have a chemo-ecological interest due to their role in chemically mediated interactions such as in the chemical defense against predators 16,17 and fouling organisms. [18][19][20] The crude extracts of different Axinella species have also been reported to inhibit the growth of several environmental bacteria. 21 Using a bioassay-guided isolation approach, we have analyzed the butanol extract of a sample of A. verrucosa collected during the spring 2008 off Massa Lubrense, Bay of Naples.…”

MS-guided Fractionation as a Fast Way to the Identification of New Natural Products – MALDI-TOF-MS Screening of the Marine Sponge Stylissa caribica

“…3 shows the results of the MALDI-MS measurements of sponge powder. At m/z = 621.1, ageliferin (4) [22] was detected which was confirmed by NMR analysis after separation by chromatography. One of the oxidized dimeric pyrrole-imidazole alkaloids is tetrabromostyloguanidine (6) [24] which was recently isolated from this sponge.…”