Polycitor Varacin

Polycitor sp., Ascid, Tunicata varacin (aomatic polysulfide)/antimiaobial Makaieva 1995A... 

Varacin (114), a cytotoxic compound closely related to lissoclinotoxin A (106), was isolated from a Fijian sample of L vareau and a benzopentathiepin structure was proposed on the basis of spectral data [131]. Two total syntheses of varacin (114) have been carried out [132,133] and later, further syntheses were described [134-135]. N,N-dimethyl-5-(methylthio)varacin (115) and the corresponding trithiane (116) were obtained from L. japonicum from Palau and 3,4-desmethylvaracin (117) was isolated from a Eudistoma sp. from Pohnpei [136], An inseparable mixture of 5-(methylthio)varacin (118) and the corresponding trithiane (119) was obtained from a Pohnpeian Lissoclinum sp. [136]. Three additional antimicrobial polysulfides of the varacin family (120-122) were isolated from Polycitor sp., collected by dredging in the Sea of Japan [137]. 

The ascidian Lissoclinum japonicum from Palau contained the antimicrobial and antifungal metabolites N,N-dimethyl-5-(methylthio)varacin and 3,4-dimethoxy-6-(2 -iV,./V-dimethylaminoethyl)-5-(methylthio)benzotrithiane, both of which were isolated as the trifluoroacetate salts <1994T12785>. They selectively inhibit protein kinase. Also, varacin and three new antimicrobial marine polysulfides, varacins A-C, were isolated from the Far Eastern ascidian Polycitor sp. <1995JNP254>, extracted from the New Zealand ascidian Lissoclinum notti <2002T9779>. 

Varacin (13), the methyl ether of Lissoclinotoxin A, has been reported from Lissoclinum vareau [24], and from a Far Eastern Polycitor sp. (where it was also isolated as its N-acetyl derivative after acetylation of the crude extract to facilitate separation) [22]. A number of syntheses of varacin have been reported [20,25,26,27]. Desmethylvaracin (14) was... 

Varacin (see above) and three other related derivatives, varacins A-C, were re-isolated from an undetermined species of the genus Polycitor harvested at 90 m in the Sea of Japan (Makarieva et al, 1995). These authors revealed the existence of an equilibrimn between a... 

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