Ethyl 6-Bromo-3-indolcarboxylate and 3-Hydroxyacetal-6-bromoindole, Novel Bromoindoles from the Sponge Pleroma menoui of the Coral Sea

Abstract

The demosponge Pleroma menoui (order Lithistida, suborder Trienosina (= Desmophorina), family Pleromidae), collected in the Coral Sea south-east of Noum ea at a depth of 500 m, is proven here to contain the novel alkaloids ethyl 6-brom o-3-indolcarboxylate and 3-hydroxyacetyl-6-brom oindole.

Chemical and Biological Aspects of Marine Sponges from the Family Mycalidae

“…Brominated indoles have been reported widely in the sponge class Demospongiae [10] in the orders Dictyoceratida, Poecilosclerida, Tetractinellida, and Suberitida. In particular from the genera Dysidea [11], Iotrochota [12,13], Tedania (Tedania) [14], Corallistes [15], Pleroma [16], Hymeniacidon [17], Pseudosuberites [18], and Spongosorites [19]. Brominated indoles have also been reported in other non-sponge marine taxa, for example, 12 from the ascidian Leptoclinides durus [20] and 14 from bacteria isolated from marine sediment [21].…”

“…In 1999, compounds 16 and 17 were reisolated from a Venezuelan M. (Carmia) microsigmatosa specimen together with ten new 5-alkylpyrrole-2-carboxaldehydes (33-42) and one new 5-alkylpyrrole-2-carboxaldehyde containing a terminal nitrile (43) [25]. In the same paper, the six compounds 16,17,35,36,40, and 41 were co-isolated from the sponge Desmapsamma anchorata (order Poecilosclerida). An Indian specimen of M. (Carmia) mytilorum yielded two new 5-alkylpyrrole-2-carboxaldehydes (44 and 45) [26], and another Indian species, M. (Carmia) tenuispiculata, was the source of three new compounds including the pyrrole derivative 46, mycaleoxime (47), and the nitrile terminate pyrrole 48 [8].…”

“…Mycaleoxime (47) differs from the other pyrrole derivatives by the presence of a carbonyl group adjacent to the pyrrole nucleus and a terminal aldoxime group. The new compounds mycalazals 3-13 (49-59) and mycalenitriles 1-3 (60-62) (distinguished by a terminal nitrile group) were found in M. (Carmia) cecilia from Mexico [27], with the eight known pyrrole derivatives 16,18,35,36,41,43,63, and 64 [23,25]. In 2009, 16 and 46 were reisolated from an Indonesian M. (Carmia) phyllophila [28].…”

“…In 2009, 16 and 46 were reisolated from an Indonesian M. (Carmia) phyllophila [28]. The 5-alkylpyrrole-2-carboxaldehydes 16,17,35,36,43,49,60, and 61 were again reisolated from a member of the Mycalidae family, this time from an unidentified M. (Carmia) sp. from Palau together with twelve new mycalenitriles 4-14 (65)(66)(67)(68)(69)(70)(71)(72)(73)(74)(75), and seven new mycalazals 14-20 (76-82) [29].…”

“…The nitrile 43 was an active inhibitor of the proliferation of the parasite Leishmania mexicana with an LD 50 value of 12 µg/mL [25]. A library of 22 pyrrole-2-carboxaldehydes including the mycalazals 3-13 (49)(50)(51)(52)(53)(54)(55)(56)(57)(58)(59), the mycalenitriles 1-3 (60)(61)(62), and the known pyrrole-2-carboxaldehydes 16,18,35,36,41,43,63, and 64 were screened against a panel of cell lines (LN-caP, IGROV, SK-BR3, SK-MEL-28, A-549, K-562, PANCI, LOVO, and HeLa cell lines), which resulted in some interesting structure activity observations (see [27] for specific GI 50 values). The authors compared the LN-caP cell line inhibition with the structures of the compounds and found that activity was associated with the presence of a single double bond, activity decreased with three double bonds, and was lost completely with two double bonds or saturated alkyl chains [27].…”