Amphimedon compressa

The biosynthesis of pregnenelone (112) in mammals has been well documented [1] it is known to be produced from cholesterol (1) via its 20,22-dihydroxy derivative (121) (Scheme 19A). The origin of 112 has been investigated in the sponge Amphimedon compressa. At the present time it is not known whether cholesterol and its 20,22-dihydroxy derivative serve as precursors for this pregnane in A. compressa however a new pathway (Scheme 19B) has been found to operate [89]. This involves the conversion of 22-dehydro sterols (e.g. stigmasterol, 122) to pregnenelone. The mechanism is believed to... 

Alkylpyridines supposedly lie also along another biosynthetic route, affording pofymeric pyridinium compounds in marine haliclonid sponges the Indo-Pacific Callyspongia fibrosa (Davies-Coleman 1993), the Caribbean Amphimedon compressa (Albrizio 1995), and the Mediterranean Reniera sarai (Sep5i6 1997). 

Kerr, R., KeUy, K. and Schulman, A. (1995) A novel biosynthetic route to pregnanes in the marine sponge Amphimedon compressa.. Nat. Prod., 58,1077-80. 

Another high molecular weight pyridinium salt, amphitoxin (75) Fig. (20), isolated from the sponge Amphimedon compressa, is a polymer based on randomly sequenced 3-alkyl and 3-alkenyl pyridinium units in an overall ratio of 1 1 [31]. It was purified to the stage of two If actions with molecular weight ranges of 1000-3000 (38%) and 3000-10000 Da (62%). In 2001, a mixture of two closely related polymeric 3-AP homologues, identified as halitoxin (74) and amphitoxin (75), was isolated f ova. Amphimedon viridis [32]. 

The marine sponge Amphimedon compressa (= Haliclona rubens) is one of a number of marine invertebrates which has been shown to produce pregnane steroids [4, 65], The biosynthetic origin of pregnanes in higher animals has been studied extensively, and in such systems, pregnane... 

FIGURE 18 New acetamidoglucosylceramide (68) from the sponge Amphimedon compressa. 

Amphimedon compressa. Exhibits antifeedant activity. Albrizio, S. et al, J. Nat. Prod., 1995, 58, 647. 

OMe-16 0 Amphimedon compressa 0.5 Carballeira, Shalabi, and Negron, 1989b... 

Albrizio, S., Ciminiello, P Fattomsso, E., Magno, S., and Pawlik, J.R. (1995) Amphitoxin, a new high molecular weight antifeedant pyridinium salt from the Caribbean sponge Amphimedon compressa. J. Nat. Prod., 58, 647-652. 

Costantino, V, Fattorusso, E., Imperatore, C Mangoni, A., and Teta, R. (2009a) Amphiceramides A and B, novel glycosphingolipids from the marine sponge Amphimedon compressa. Eur. J. Org. Chem., 2112-2119. 

Carballeira, N.M. and Lopez, M.R. (1989) On the isolation of 2-hydroxydocosanoic and 2-hydroxy-tricosanoic acids from the marine sponge Amphimedon compressa. Lipids, 24, 89-91. 

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