Didemnum candidum

Lindquist, N. and Fenical, W., Ascidiatrienolides A-C, novel lactonized eicosanoids from the marine ascidian Didemnum candidum, Tetrahedron Lett., 30, 2735, 1989. 

Crude extracts of the ascidian Didemnum candidum exhibit strong inhibitory effects against phospholipase A2 in vitro. A search for the active component led to the discovery of ascidiatrienolide A 33 (20), an eicosatetraene derivative that is closely related to the didemnilactones 34-36 derived from the tunicate Didemnum moseley (27). The latter are endowed with high affinity to the leukotriene B4 receptor of human polymorphonuclear leucocyte membrane fractions. These fatty acid derivatives of marine origin provided yet another opportunity to validate our strategy for ( ,Z)-control outlined in the previous chapter based upon proper matching of the reactivity of the metathesis catalyst with the conformational preferences of a constrained substrate (22). 

Bromotryptamine (107) has been reported [14] from a collection of a Lissoclinum sp. from the GBR, and from Didemnum candidum from the Gulf of Mexico [77], while 5-bromo-N,N-dimethyl tryptamine (108) was reported from a New Caledonian collection of Eudistoma fragum where it co-occurred with woodinine [78]. 5-Bromo-N,N-dimethyltryptamine exhibited antimicrobial activity (with 12 mm and 17 mm zones of inhibition reported at 100 pg per 6 mm disk against S. aureus and E coli resp. 17mm and 22 mm zones at 200 pg per disk against the same microorganisms). A synthesis of 5-bromo-N,N-dimethyltryptamine has been reported [79]. 

Bromotryptamine and two bis-indolic derivatives, one of which contains a piperazine, have been isolated from the species Didemnum candidum collected on the roots of mangrove trees in a mangrove swamp in the Gulf of California (Fahy, Potts, and Faulkner, 1991). 

Fahy, E., Potts, B.C.M., and Eaulkner, D.J. (1991) 6-Bromotryptamine derivatives from the Gulf of California tunicate Didemnum candidum. J. Nat. Prod., 54, 564-569. 

---