Eudistoma fragum

Eudistomin K (155) (135) and its sulfoxide (171) (136) were isolated from the New Zealand ascidian Ritterella sigillinoides. The sulfoxide (171) also shows antiviral activity. The structure of 155 was determined by X-ray analysis (137) and that of 171 by semisynthesis from 155. Three other /3-carbolines, named eudistomins R, S, and T (172-174) were obtained from a Bermudian tunicate (E. olivaceum) by using an amino-bonded HPLC column (138). A 2-methyl-1,2,3,4-tetrahydro- -carboline with an /V-methylpyrrolidine at C-l, named woodinine (175), was isolated from a New Caledonian ascidian (Eudistoma fragum) (139), extracts of which exhibit antimicrobial activity. 

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]. 

Eudistoma fragum Debitus etal., 1988 Mahboobi etal., 1997... 

Several P-carboHne alkaloids related to eudistomins were isolated from Eudistoma glaucus and other species of Eudistoma, such as E. album, E.fragum, and E. gUboverde. Generally, these derivatives have antiviral and antitumor activities similar to those of eudistomins, but eudistomi-din A is also an antagonist of calmodulin (Kobayashi, Nakamura, and Ohizumi, 1986). Some members of this series are presented in Figure 28.21. 

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