No abstract

The chemistry of the burrowing sponge Aka coralliphagum was investigated to identify chemically labile secondary metabolites. The HPLC-MS analysis of the two growth forms typica and incrustans revealed different metabolites. The previously unknown sulfated compounds siphonodictyals B1 to B3 (6-8), corallidictyals C (9) and D (10), and siphonodictyal G (11) were isolated, and their structures were elucidated by NMR and MS experiments. The compounds were tested in a DPPH assay, in antimicrobial assays against bacteria, yeasts, and fungi, and in antiproliferation assays using cultures of mouse fibroblasts. The biological activity was linked to the presence of the ortho-hydroquinone moiety.The burrowing sponge Aka coralliphagum ()Siphonodictyon coralliphagum) is a bright yellow colored sponge that burrows into corals. Four distinct morphological growth forms have been described for Aka coralliphagum from the Caribbean: forma typica, f. tubulosa, f. obruta, and f. incrustans. 1 Several bioactive sesquiterpene hydroquinones, such as the siphonodictyals (B, 1) and siphonodictyols, 2 were obtained from the forms tubulosa and typica. Although the isolation of labile compounds such as siphonodictyols G (2) and H (3) suggested the existence of additional sulfated phenolic compounds in A. coralliphagum, compounds such as the siphonodictyals were isolated without respect to the occurrence of sulfated metabolites. Past isolation and purification methods did not account for the problem of compound hydrolysis. 2a,b This paper describes the isolation, structure elucidation, and biological testing of the new, labile metabolites siphonodictyals B1 to B3 (6-8), corallidictyals C (9) and D (10), and siphonodictyal G (11) from the Aka growth form incrustans. In order to compare the secondary metabolites of the two growth forms incrustans and typica, an HPLC analysis of their crude extracts was performed. These two forms of Aka occur in different habitats, with typica predominating on shallow water reefs (10-15 m) while incrustans occurs on deep water vertical slopes (20-25 m). It was deemed important to isolate the labile natural products of these two growth forms in their naturally occurring forms in order to understand more about their biological and ecological function. Results and DiscussionExtracts of sponge samples were investigated by an HPLC-MS screening. The two growth forms of Aka coralliphagum (typica and incrustans) showed differences in HPLC fingerprints and their major metabolites (Figure 1). While forma typica contained more polar compounds (shorter retention times), forma incrustans contained three main compounds with a less polar character. Further characterization by HPLC-API-CID-MS/MS showed a single or double sulfation of compounds with shorter retention times. This was deduced by loss of m/z 80 under MS/MS conditions and detection of a [SO 3 ] -ion at m/z 80 (see Supporting Information) 3 as well as a sulfur-specific isotopic pattern. These results indicate that the two growth forms have considerable differences...

SummaryThe chemical investigation of the Caribbean sponge Agelas citrina revealed four new pyrrole–imidazole alkaloids (PIAs), the citrinamines A–D (1–4) and the bromopyrrole alkaloid N-methylagelongine (5). All citrinamines are dimers of hymenidin (6) which was also isolated from this sponge as the major metabolite. Citrinamines A (1) and B (2) are derivatives of the PIA dimer mauritiamine (7), whereas citrinamine C (3) is derived from the PIA dimer nagelamide B (8). Citrinamine D (4) shows an uncommon linkage between the imidazole rings of both monomeric units as it is only observed in the benzocyclobutane ring moiety of benzosceptrins A–C (9–11). Compound 5 is the N-methyl derivative of agelongine (12) which consist of a pyridinium ring and an ester linkage instead of the aminoimidazole moiety and the common amide bond in PIAs.

Two new bromopyrrole alkaloids were isolated from the Caribbean sponge Stylissa caribica. The new natural products, 4-bromopyrrole-2-carboxyarginine (1) and 4-bromopyrrole-2-carboxy-N(epsilon)-lysine (2), are derivatives of amino acids linked with a 4-bromopyrrole-2-carboxylic acid. The structures were elucidated on the basis of NMR and MS/MS data and their absolute configurations assigned via synthesis.

No abstract

A detailed analysis of the chemical constituents of a specimen of Agelas wiedenmayeri (Alcolado, 1984) was performed. Four brominated alkaloids (1−4) were isolated and one was identified as a new bromopyrrole metabolite. The structure of the new compound, 1, was assigned using spectroscopic methods. Compounds 2 and 3, which are the major brominated metabolites, have been previously described from other Agelas sponges. The new compound, 1, may be a biosynthetic precursor for oroidin-like derivatives.Bromopyrrole-derived alkaloids are well-known in marine sponges of the genus Agelas. 1 In our search for bioactive substances from marine organisms, a series of brominated pyrrole alkaloids have been isolated from a specimen of the sponge Agelas wiedenmayeri (Alcolado, 1984) collected off the coast of the Florida Keys, FL. Examination of the methanol/dichloromethane extract of this sponge resulted in isolation of the known alkaloids 4,5-dibromopyrrole-2-carboxylic acid 2, oroidin 3, and bromoageliferin 4 as well as of the new bromopyrrole-derived alkaloid, 4-bromopyrrole-2-carboxyhomoarginine 1 (5 mg, 0.005% of dry weight) (Figure 1). In this communication we describe the isolation and structural elucidation of the new bromopyrrole alkaloid 1. To the best of our knowledge, this is the first report on the chemistry of Agelas wiedenmayeri.The marine sponge Agelas wiedenmayeri (Alcolado, 1984)

There are a large number of studies on sponges from warm or tropical waters, whereas little is known about the chemistry of sponges from Arctic waters. Here, we describe the isolation and structure elucidation of two new 3-alkyltetrahydropyridine alkaloids (haliclamines C and D) from the Arctic sponge Haliclona viscosa. MS and 2D NMR spectroscopy

ChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 100 leading journals. To access a ChemInform Abstract of an article which was published elsewhere, please select a “Full Text” option. The original article is trackable via the “References” option.