Palythoa toxica Palytoxin

Another zoanthid-derived polyketide that is likely produced by a dinoflagellate is palytoxin (125), an extremely potent neurotoxin from Palythoa toxica and several other unrelated animals. The closely related ostreocins, for example, ostreocin D (126), have been reported from a free-living dinoflagellate Ostreopsis siamensis, indicating a similar source in the animal. ... 

Palytoxin has been isolated to date in numerous areas of the world both from zoanthids belonging to the genus Palythoa and in other species. Moore and Scheuer [3] first reported the isolation of palytoxin from the Hawaiian zoanthid Palythoa toxica, while 1 year later, it was also isolated from Palythoa tuberculosa in tropical Pacific waters of Okinawa, Japan [8]. Since then, palytoxin and its congeners have been found in P. vestitus from Hawaii [9], P. mammilosa [10] and P. caribaeorum... 

Figure 5.1. Proposed structure of palytoxin from a Tahitian Palythoa sp. (1A). The two paiytoxins from Hawaiian P toxica are the related C-55 hemiketais (partiai structures 1B and 1C). Reproduced with permission from Moore and Bartolini 1981, American Chemical Society.

Palytoxin from the Tahitian Palythoa has a molecular form of Cj29H22iN30j4 (Mj. 2659). On the other hand, palytoxin from P. toxica has a molecular form of C,29H223N3054 (M. 2611), with two possible structures (Fig. 5.1) that differ from the former in the C-55 hemiketal ring. Palytoxin from the Hawaiian P. tuberculosa is a mixture of the three palytoxins from the Tahitian Palythoa and P. toxica (Mooie and Bartolini 1981). The two components in palytoxin from the Okinawan P. tuberculosa (Mj. 2681 Macfarlane et al. 1980) may be the related C-54 ketal and hemiketal (Moore and Bartolini 1981). The palytoxin from P. caribaoreum has a molecnlar mass of 2680, while the palytoxin-like substance isolated from Lophozozymus pictor crab, which showed a very similar positive ion MS profile, was estimated to possess a molecular mass of 2681.0 Da (Lau et al. 1995). 

This spectmm is similar for all palytoxins, regardless of subtle differences present in their proton magnetic resonance (PMR H-NMR) and caibon magnetic resonance (CMR C-NMR) spectra, as in the case of palytoxins from P. toxica from Hawaii, P. mammilosa from Jamaica, and Palythoa sp. from Tahiti (Moore et al. 1975 Beress et al. 1983). This characteristic UV absorption profile of palytoxin is another parameter that could verify the presence of this toxin and its analogues (Tan and Lau 2000). 

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