From Topsentia

Halistanol sulfate (532) from Halichondria cf. moorei is a tris-sodium sulfate salt, which possesses antimicrobial, hemolytic, and ichthyotoxic activity [444]. It was later isolated from two sponges of the genus Topsentia as the free sterol and found to inhibit pp60v-src protein tyrosine kinase activity [445]. The tris(2-aminoimidazolium) salt of halistanol sulfate (533) was isolated from Topsentia sp. from Japan and is also antimicrobial [446]. 

Additional unusual steroid derivatives have been isolated from marine sponges, eg., polymastiamides, steroid/aminoacid conjugates isolated from Polymastia boletiformis, a Norwegian marine sponge [180], and an aminoimidazolium salt of steroid trisulfate from Topsentia sp. [181], Some of these marine sterols are being reproduced by chemical synthesis in the laboratory [182],... 

A new C31 sterol was isolated from Topsentia ophiraphi-dites harvested on the Colombian coast of the Caribbean Sea (Calderon et ah, 2004). In this species, it has been shown that the stereochemistry at C-24 is R for (22E)-24-... 

Ibisterol sulfate (550) is a sulfated sterol from a deepwater Topsentia sp. that was cytoprotective against HIV-1 in the NCI primary screen [457]. 

A Topsentia sp. from Okinawa contained five antimicrobial 14-methyl sterol sulfates, topsentiasterol sulfates A-E (551-555) [458]. 

Ophirapstanol trisulfate (556) from deepwater Topsentia ophiraphidites showed inhibition in the guanosine diphosphate/G-protein RAS exchange assay [459]. 

Recently, bromodeoxytopsentin (76) and isobromodeoxytopsentin (77) have been isolated from the Korean sponge Topsentia genitrix. They exhibit cytotoxicity against the human leukemic cell line K-562 (LC50 0.6 and 2.1 pg/ml, respectively) [69]. 

Topsentinols A through J, ten new 7-hydroxy sterols with unusual polyalkylated side chains, have been isolated from the Okinawan marine sponge Topsentia sp. 

Tsukamoto, S., Kato, H., Hirota, H., and Fusetani, N., Isolation of an unusual 2-aminoimidazolium salt of steroid trisulfate from a marine sponge Topsentia sp., Fish. Sci., 63, 310, 1997. 

The topsentins are a series of bis(indole) alkaloids first reported from a specimen of Topsentia genetrix. The parent compounds topsentin (13) and bromotopsentin (14) were isolated simultaneously from a specimen of Spongosorites ruetzleri collected in deep water... 

This compound also occurs in a number of related Haplosclerid sponges, such as Topsentia spp., Monanthus ciocalyptoides, Foliolina sp., mdiXestospongia spp., as well as from Aaptos sp., Trachyopsis sp., and two species of Pseudaxynissa... 

G., and Ottinger, R. (1987) Topsentins, new toxic bis-indole alkaloids from the marine sponge Topsentia genitrix. Can. J. Ghent. 65,2118-2121. 

McKee, T., Cardellina, J. H., Tischler, M., Snader, K. M., Boyd, M. R. (1993) Ibisterol sulfate, a novel HIV-inhibitory sulfated sterol from the deep water sponge Topsentia sp. J. Nat. Prod. 34, 389-392. 

The cytotoxic T. and nortopsentins are isolated from the Mediterranean sponge Topsentia genitrix as well as from deep-sea sponges of the genus Spongosorites. The T. are active against P388 leukemia cells and B16 melanoma cells. 

The A-nor-sterols are common among Axinelhdae but rarer among Halichondriidae the opposite is observed for sterols with polymethylated side chains and sulfated sterols. Among the branched side-chain sterols, topsentinols A-L, which have an isopropyl or isopropylidene at position 24, with or without an additional methyl at 25, were isolated from a Japanese Topsentia (Ishibashi, Yamagishi, and Kobayashi, 1997 Dai et ah, 2010a) all currently known topsentinols are displayed on Figure 19.50, and topsenti-nol K trisulfate is shown in Figure 19.34. 

Topsentolide Ai is the first of a series of oxylipins isolated from an imdetermined spedes of genus Topsentia of Korean origin. This derivative has structural similarities with halicholactone, first isolated from the Japanese spedes Halichondria okadai and subsequently found in the brown alga Laminaria sinclairii, but does not include cydopropane (see Chapter 14). The presence of an epoxy may explain the anti-tumor properties of topsentolide Ai (Luo et al., 2006b). The absolute configuration of topsentolide Al was determined by synthesis (Kobayashi, Ishigami, and Watanabe, 2010). 

Calderon, G.J., Castellanos, L, Duque, C., Echigo, S Hara, N and Fujimoto, Y. (2004) OphirasteroL a new C31 sterol from the marine sponge Topsentia ophiraphidites. Steroids, 69,93-100. 

J, new sterols with highly branched side chains from marine sponge Topsentia sp. Chem. Pharm. Bull., 45,1435-1438. 

Fusetani, N., Takahashi, M., and Matsunaga, S. (1994a) Biochemical marine metabolites. 61. Topsentiatriol sulfates, antimicrobial sterol sulfates possessing novel side chains, from a marine sponge, Topsentia sp. Tetrahedron, 50, 7765-7770. 

Gunasekera, S.P., Sennett, S.H., Kelly-Borges, M., and Bryant, R.W. (1994a) Ophirapstanol trisulfate, a new biologically active steroid sulfate from the deep water marine sponge Topsentia ophiraphidites. J. Nat. Prod., 57,1751-1754. 

Guzii, A.G., Makarieva, T.N., Denisenko, VA., Dmitrenok, P.S., Burtseva, Y.V., Krasokhm, V.B., and Stonik, VA (2008) Topsentiasterol sulfates with novel iodinated and chlorinated side chains from the marine sponge Topsentia sp. Tetrahedron Lett., 49, 7191-7193. 

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