New and Biologically Active Imidazole Alkaloids from Two Sponges of the Genus Leucetta

Abstract

Chemical investigation of two sponges, Leucetta chagosensis and Leucetta cf chagosensis, collected from the Great Barrier Reef and the Fiji Islands, respectively, has led to the isolation of three new imidazole alkaloids (1-3), along with the known compounds isonaamine B (4) and naamine A (5). The structures of the new compounds (1-3) were elucidated by employing spectroscopic techniques (NMR, MS, UV, and IR). The structures of the known compounds 4 and 5 were determined by comparison of their (1)H and (13)C NMR spectroscopic data with published values. Compounds 1 and 2 were found to be cytotoxic toward several tumor cell lines (GI(50) values ranged from 1.3 to 7.0 microg/mL).

Two new imidazole alkaloids from Leucetta chagosensis sponge

“…A groups of imidazole alkaloids have been isolated from genus Leucetta (Carmely and Kashman, 1987;Carmely et al, 1989;Gross et al, 2002;Fu et al, 1997;Dunbar et al, 2000;Plubrukarn et al, 1997;Akee et al, 1990;Carroll et al, 1993;Mancini et al, 1995;Crews et al, 2003;Alvi et al, 1993;He et al, 1992) included among these are naamines (Carmely and Kashman, 1987;Carmely et al, 1989;Gross et al, 2002;Fu et al, 1997;Dunbar et al, 2000), isonaamines (Carmely and Kashman, 1987;Carmely et al, 1989), naamidines (Carmely and Kashman, 1987;Alvi et al, 1993;He et al, 1992) and isonaamidines Alvi et al, 1993). The compounds were named after the Bay of Naama where the sponge was first collected (Carmely et al, 1989), in addition to kealiiquinone (Fu et al, 1997;Akee et al, 1990), leucettamine (Carmely et al, 1989;Crews et al, 2003), preclathridine (Alvi et al, 1993;He et al, 1992), leucosolenamines A and B (Ralifo et al, 2007), (2E, 6Z, 9Z)-2-methyl-2, 6,9-icosatrienal (Watanabe et al, 2000), dorimidazole A, leucettamol , calcaridine A (Edrada et al, 2003), leucettamide , and halogenated natural products (Tsukamoto et al, 2008).…”

“…The compounds were named after the Bay of Naama where the sponge was first collected (Carmely et al, 1989), in addition to kealiiquinone (Fu et al, 1997;Akee et al, 1990), leucettamine (Carmely et al, 1989;Crews et al, 2003), preclathridine (Alvi et al, 1993;He et al, 1992), leucosolenamines A and B (Ralifo et al, 2007), (2E, 6Z, 9Z)-2-methyl-2, 6,9-icosatrienal (Watanabe et al, 2000), dorimidazole A, leucettamol , calcaridine A (Edrada et al, 2003), leucettamide , and halogenated natural products (Tsukamoto et al, 2008). Some of these alkaloids show very important biological activities as cytotoxic (Gross et al, 2002;Tsukamoto et al, 2007), antimicrobial (Carmely and Kashman, 1987;Carmely et al, 1989;Gross et al, 2002;Mancini et al, 1995), inhibition of Ubc13-Uev1A interaction and anticancer activities (Tsukamoto et al, 2008). Previous investigation of the current sample Leucetta chagosensis, has led to isolation of naamines F, and G in addition to series of kealiinine A, B and C compounds (Hassan et al, 2004).…”

Spongian Diterpenes from the Sponge <i>Hyattella</i> aff. <i>intestinalis</i>

“…Spongian diterpenes were first reported in 1979 as unique metabolites of a sponge, 8) and since then a number of spongians have been reported. [9][10][11][12][13][14] Recent reports include new cyototoxic spongians 15) and rediscovery of spongiatriol (1) as a moderate apoptosis inducer and an inhibitor of nuclear factor-kappaB (NF-κB) activation. 16,17) In this report we describe the structures of three new spongians and their biological activities.…”

Marine biodiversity: exploring bioactive chemical space

“…[29][30][31][32][33][34][35][36][37][38] Haplosclerida) collected at Indented Head Reef (Port Phillip Bay). 73 D and E. 121 A new purine derivative, microxine (142), was isolated from marine sponge Microxina sp. collected in Cape Jaffa (South Australia).…”

“…Chemical investigations of Leucetta chagosensis (Great Barrier Reef) yielded cytotoxic imidazole alkaloids, isonaamidine E (154) and isonaamine C. 142 Ianthellamide A, a selective kynurenine-3-hydroxylase inhibitor (IC 50 1.5 µM), was isolated from Ianthella quadrangulata (Harrier Point, Orpheus Island). 143 Investigation of an Australian (Curacao Island, Queensland) marine sponge …”