Polyether toxin

YASUMOTO MURATA Polyether Toxins Involved in Seafood Poisoning... 

Diarrhetic shellfish poisoning is an illness caused by polyether toxins produced by dinoflagellates and accumulated in shellfish (31). Patients suffer from diarrhea, nausea, and stomach pain but recover within three days without serious aftereffects. Despite the relatively mild symptoms, careful attention should be paid to the... 

Scheme 2 Polyether toxins form red tide dinoflagellates...

Fig. 10.19. IDR-HSQC-TOCSY spectrum of the complex marine polyether toxin brevetoxin-2 (7). The data were recorded overnight using a 500 pg sample of the toxin (MW = 895) dissolved in 30 pi of d6-benzene. The data were recorded at 600 MHz using an instrument equipped with a Nalorac 1.7 mm SMIDG probe. Direct responses are inverted and identified by red contours relayed responses are plotted in black. The IDR-HSQC-TOCSY data shown allows large contiguous protonated segments of the brevetoxin-2 structure to be assembled, with ether linkages established from either long-range connectivities in the HMBC spectrum and/or a homonuclear ROESY spectrum.

The azaspiracids are another class of polyether toxins with unique spiro ring assemblies, a cyclic amine and a carboxylic acid. Five analogs have been described (Ofuji et al., 1999, 2001 Satake et al., 1998). Azaspiracids are produced by species of the dinoflagellate Protoperidinium, a phytoplankton genus historically thought to be benign (James et al., 2003a). 

Hokama, Y., An enzyme immunoassay for the detection of ciguatoxin and competive inhibition by related natural polyether toxins, in Seafood Toxins, Ragelis, E., ed., American Chemical Society, Washington, D.C., 1984. 

Pierce, R., et al.. Evaluation of solid sorbents for the recovery of polyether toxins (brevetoxins) in seawater. Bull. Env. Contam. Toxicol., 49, 479, 1992. 

Yasumoto, T., Polyether toxins produced by dinoflagellates, in Natori, S., Hashimoto, K. and Ueno, Y., eds., Mycotoxins and Phycotoxins 88, Elsevier, Amsterdam, 1989. 

And Competitive Inhibition by Related Natural Polyether Toxins... 

Physiological studies show that monensin is a sodium ionophore (15), that induces inotropic effect on guinea pig atria (17). The polyether toxins including ciguatoxin, okadaic acid, and the recently characterized brevetoxin (5, 16) also induce inotropic effect on guinea pig atrial tissue in vitro (17). Additionally, partially purified CTX has been implicated in the depolarization of nerve cells in vitro, which can be reversed by high concentrations of Ca tetrodotoxin and saxitoxin (18). 

The analysis of fish tissues for ciguatoxin by a newly developed enzyme-immunoassay procedure (26, 27) has been carried out in this study. Three areas of examinations have been attempted (1) the examination of clinically defined and documented and non-toxic consumed fish samples (2) the assessment of freshly caught fishes from the sites in the Leeward part of the island of Oahu where ciguatoxin is found and (3) competitive inhibition with suspension of purified ciguatoxin and closely related structurally similar polyether toxins. 

The formation of the six-membered ether ring via epoxy ester-ortho ester cyclic ether rearrangement supports the hypothesis that epoxy ester-ortho ester cyclic ether rearrangement may be involved in the biosynthesis of ladder-type marine polyether toxins. This reaction represents a biomimetic preparation of medium ring cyclic ethers. 

Yessotoxin and its analogues are disulfonated polyether toxins reported from shellfish from different countries, but a new derivative lacking a 1-sulfated substituent, 1-desulfoyessotoxin (YTX with R =H), has been isolated from mussels from Norway <1998MI235>. Its ESI-MS spectrum showed that this compound is 102 Da smaller than YTX 17, implying that one of the sulfate esters in YTX was desulfonated. The NMR data of 1-desulfoyessotoxin are similar to that of YTX 17 except for the 1-methylenic protons where desulfonation occurred they are shifted to upheld by 0.49ppm and their chemical shifts (3.72 and 3.78ppm) are typical of hydroxymethyl protons. 

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