Tumor promoters from marine natural

FUJIKIET AL. New Tumor Promoters from Marine Natural Products... 

Palytoxin isolated from zoanthids Palythoa spp. is known to be extremely lethal (0.5 fig/kgy mouse, i.p.) and to have the most complicated natural product structure (Figure 4) ever elucidated (13,14). The toxin was later revealed to be a potent tumor promoter (15). Yet, health risks due to the toxin have remained unclear, as the zoathids are the most unlikely organisms to be regarded as foodstuff. Recently, however, data are being compiled to indicate the wide distribution of this toxin among marine biota. 

Many environmental toxins interact with specific cellular receptors, including enzymes, ion channels and ion pumps, and thus provide natural tools for the study of cellular signalling pathways. Palytoxin, a compound isolated from the coelen-terate of genus Palythoa, is one such useful and intriguing compound. The structure of palytoxin was first determined in 1981 independently by Hirata (7) and Moore (2). As one of the most potent marine toxins known, palytoxin has been studied in a variety of systems ranging from erythrocytes to neurons. As a tumor promoter of the non 12-O-tetradecanoylphorbol-13-acetate (TPA) type, palytoxin can also be studied in the context of a growth control system. 

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