Polycitor

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]. 

Four simple sulfates (158-161) were identified as antimicrobial constituents of Halocynthia roretzi from Japan [160]. Sodium (or potassium) 2,6-dimethyIheptyl sulfate (161) was also found in Polycitor adriaticus from Croatia [161]. The absolute configuration of 2,6-dimethylheptyl sulfate (161), which has also been found in other Mediterranean ascidians, has been determined using Mosher s method [162],... 

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>. 

Decatromicins A (1218) and B (1219) are produced by an Actinomadura sp. and are active against Gram-positive bacteria including methicillin-resistant Staphylococcus aureus (1229,1230). These compounds are closely related to pyrrolosporin A (1220) from Micromonospora sp. (1231,1232). The ascidian Polycitor africanus from Madagascar has afforded the new polycitone B (1221) (1233), which is related to the known polycitone A (1), a potent inhibitor of retroviral reverse transcriptases and cellular DNA polymerases (1234). The known polycitrin B was synthesized for the first time (1235). 

Rudi A, Evan T, Aknin M, Kashman Y (2000) Polycitone B and Prepolycitrin A Two Novel Alkaloids from the Marine Ascidian Polycitor africanus. J Nat Prod 63 832... 

As part of their ongoing investigation of bioactive natural products from tropical marine invertebrates collected in Sodwana Bay (situated in northern Kwazulu-Natal, South Africa), Kashman and co-workers isolated three novel alkaloids, polycitone A (89) and polycitrins A and B (90 and 91) from an ascidian Polycitor sp. [86]. The structure of 89 was established from X-ray data while the structures of 90 and its mono-O-methyl ether analogue, 91, followed from analysis of the NMR data of these two compounds. Two possible biosynthetic precursors of 89-91,... 

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... 

Lukianols A and B (49 and 50) were isolated from an unidentified ascidian collected at Palmyra atoll (N.E. of the Solomon Islands) [43]. Lukianol A exhibited moderate cytotoxicity (ICsoof 1 pg/mL against KB cell cultures), but lukianol B was 100 times less active [43]. The lukianols are closely related to polycitrins A and B (51 and 52), which were isolated from a Polycitor sp. [44]. Polycitrin A has been synthesised [45] by a proposed biomimetic route (based on known slime mould metabolites), but no activity data for the polycitrins has been published. These metabolites are some of the simplest of a group of highly substituted pyrrole derivatives... 

Among the most highly substituted of the pyrrole derivatives reported from ascidians to date, is polycitone-A (84), which was isolated along with polycitrins A and B from a tunicate of the genus Polycitor [44]. The biosynthetic processes which lead to (substituted) phenacyl substituents... 

In 1994, Francisco et al. isolated ascididemin as a major alkaloid from the grey morphs of the ascidian Cystodytes delle chiajei (Polycitor idae) collected near Punta de la Crev in the Balearic Isles, Spain 150). The CHCls/MeOH extract of the ascidian was first solvent partitioned and then subjected to chromatographic purification, which afforded ascididemin (323) (0.43% dry weight). 

Rudi, A., Evan, T., Aknin, M., Kaslunan, Y., (2000). Polycitone B and Prepolycitrin A Two novel alkaloids from the marine ascidian Polycitor africanus. J. Nat. Prod. 63, 832-833. 

Polycitor Pyrrole alkaloids, sulfur aromatic derivatives... 

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... 

Polydtone B and prepolycitrin A, which is regarded as a biological precursor of the series, were extracted from Polycitor afiicanus harvested in the north-west of Madagascar and Mayotte (Comoros). 

Polycitone A (280) and B (281), polycitrin A (282) and B (283), and prepolycitrin A (284) were reported from the Indo-Pacific ascidians Polycitor sp. and P. africanus by Kashman s group (167,168). Their structures were established by spectroscopic and chemical methods. The structure of polycitone A (280) was confirmed by X-ray crystallography (167). 

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