Villagorgia rubra

The indoloquinolizidine alkaloid Villagorgin B (360) was isolated from the Gorgonian Villagorgia rubra collected in New Caledonia (Scheme 108). The positive charge of the molecule was deduced from the chemical shifts of the C-6 and C-5 ethylene bridge. However, only one NH group was detectable in NMR in DMSO-Jg (93TL7773). Additional heteroaromatic... 

The manzamine alkaloids are characterized by a complex pentacyclic diamine linked to C-l of a B-carboline moiety. The first B-carboline compound (norharman and harman) was reported from a bioluminiscent marine dino-flagellate Noctiluca miliaris [31], followed by the discovery of the eudistomins from Eudistoma olivaceum [32, 33, 34], Their occurrence has been reported not only from sponges and tunicates, but also from the Bryozoan Costaticella hastata [35], and Cribricellina cribraria [36] and lately from the Cnidaria (Villagorgia rubra) exemplified by the Villagorgins [37]. 

Espada, A., Jimenez, C Debitus, C and Riguera, R. (1993) Villagorgin A and B. New type of indole alkaloids with acetylcholine antagonist activity from the gorgonian Villagorgia rubra. Tetrahedron Lett., 34, 7773-7776. 

Clavulazine is an alkaloid of pyrazine that has been identified in the stoloniferan Clavularia viridis, and the gorgonaceans Villagorgia rubra and Eunicdla granulata from Madeleine Islands, Senegal, yielded some rare examples of indole alkaloids. Among them, villagorgins A and B are acetylcholine inhibitors. 

Few purine bases and nucleosides have been isolated from Octocorallia, but recall the historical significance of the discovery of arabinosyladenine (Ara-A) in the gorgo-nian Eunicella cavolini (see Chapter 4) and the identification of caffeine in the two gorgonians Paramuricea chamaleon (Imre et al., 1987) and Villagorgia rubra (Espada et al., 1993). 

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