Manuel Norte

Dinoflagellate polyether within the yessotoxin, pectenotoxin and okadaic acid toxin groups: Characterization, analysis and human health implications

Diarrhetic Shellfish Poisoning (DSP) is a specific type of food poisoning, characterized by severe gastrointestinal illness due to the ingestion of filter feeding bivalves contaminated with a specific suite of toxins. It is known that the problem is worldwide and three chemically different groups of toxins have been historically associated with DSP syndrome: okadaic acid (OA) and dinophysistoxins (DTXs), pectenotoxins (PTXs) and yessotoxins (YTXs). PTXs and YTXs have been considered as DSP toxins because they can be detected with the bioassays used for the toxins of the okadaic acid group, but diarrhegenic effects have only been proven for OA and DTXs. Whereas, some PTXs causes liver necrosis and YTXs damages cardiac muscle after intraperitoneal injection into mice. On the other hand, azaspiracids (AZAs) have never been included in the DSP group, but they cause diarrhoea in humans. This review summarizes the origin, characterization, structure, activity, mechanism of action, clinical symptoms, method for analysis, potential risk, regulation and perspectives of DSP and associated toxins produced by marine dinoflagellates.

Yessotoxins, a Group of Marine Polyether Toxins: an Overview

Yessotoxin (YTX) is a marine polyether toxin that was first isolated in 1986 from the scallop Patinopecten yessoensis. Subsequently, it was reported that YTX is produced by the dinoflagellates Protoceratium reticulatum, Lingulodinium polyedrum and Gonyaulax spinifera. YTXs have been associated with diarrhetic shellfish poisoning (DSP) because they are often simultaneously extracted with DSP toxins, and give positive results when tested in the conventional mouse bioassay for DSP toxins. However, recent evidence suggests that YTXs should be excluded from the DSP toxins group, because unlike okadaic acid (OA) and dinophyisistoxin-1 (DTX-1), YTXs do not cause either diarrhea or inhibition of protein phosphatases. In spite of the increasing number of molecular studies focused on the toxicity of YTX, the precise mechanism of action is currently unknown. Since the discovery of YTX, almost forty new analogues isolated from both mussels and dinoflagellates have been characterized by NMR or LC-MS/MS techniques. These studies indicate a wide variability in the profile and the relative abundance of YTXs in both, bivalves and dinoflagellates. This review covers current knowledge on the origin, producer organisms and vectors, chemical structures, metabolism, biosynthetic origin, toxicological properties, potential risks to human health and advances in detection methods of YTXs.

Non-terpenoid C-15 metabolites from the red seaweed Laurencia pinnatifida☆

Abstract The structures of absolute configurations of the halogenated vinyl acetylenes which are natural products from the red alga Laurencia pinnatifica (Gmal. Lamour) are described. The structure of trans - pinnatifidenyne 2 was determined by spectral, chemical and X-ray diffraction analyses. The structure of cis -pinnatifidenyne 1 is based on spectral comparison and chemical interconversion with the trans -isomer 2 . The structure of the acyclic trienyne 8 was secured as: (6 R ,7 R )-3- cis , 9- cis ,12- cis ,6-acetoxy,7-chloropentadeca-3,9,12-trien-1-yne by synthesis from cis -pinnatifidenyne 1 . The reactivity of these compounds to various conditions of catalytic hydrogenation has been examined in detail.

Okadaic acid : a proton and carbon NMR study

Abstract Okadaic acid is an extremely interesting toxin responsible for diarrhetic shellfish poisoning (DSP). This interest is due not only to its fascinating structure but also to its unknown biosynthetic origin. In this paper we report on the full NMR study of this molecule including the appropriate 2D homo and heteronuclear NMR experiments neccesary to carried out its biosynthetic study. Okadaic acid is an extremely interesting toxin responsible for diarrhetic shellfish poisoning (DSP). This interest is due not only to its fascinating structure but also to its unknown biosynthetic origin. In this paper we report on the full NMR study of this molecule, including the appropriate 2D homo and heteronuclear NMR experiments, necessary to carried out its biosynthetic study.

Studies on the biosynthesis of the polyether marine toxin dinophysistoxin-1 (DTX-1)

Abstract The biosynthetic origin of DTX-1 is establish on the basis of the NMR spectral data of samples obtained by addition of labelled [1- 13 C 1 ], [2- 13 C 1 ] and [1,2- 13 C 2 ] sodium acetate to artificial cultures of the dinoflagellate Prorocentrum lima.

Structural determination and biosynthetic origin of two ester derivatives of okadaic acid isolated from Prorocentrum lima

Abstract The dinoflagellate Prorocentrum lima is responsible for the production of the toxins involved in the red tide phenomenon known as diarrhetic shellfish poisoning (DSP). In this paper we report on the isolation, structural elucidation and biosynthetic origin of two ester derivatives of okadaic acid on the basis of their spectroscopical data. Its biosynthetic origin was indicated by addition of labelled sodium [1- 13 C 1 ], [2- 13 C 2 ] and [1,2- 13 C 2 ] acetate to artificial cultures of the dinoflagellate.

New alkaloids from a marine zoanthid

Abstract Five new alkaloids zoanthenol 7,3-hydroxynorzoanthamine 8, 30-hydroxynorzoanthamine 9,11-hydroxynorzoanthamine 10 and 11-hydroxyzoanthamine 11 have been isolated from a marine zoanthid. Their structures were determined through the interpretation of 2D-NMR spectral data. Their relative stereochemistries were proposed on the basis of ROESY data.

New metabolites from the marine mollusc Siphonaria grisea

Abstract Four new metabolites 6, 7, 8and 9 possessing a polypropionate carbon skeleton, have been isolated from the marine gastropod mollusc S. grisea. Their structures and absolute configurations have been determined by spectroscopical and chemical methods. The absolute configuration of pectinatone 5, is reassigned on the basis of its chemical degradation and X-ray analysis.

Terpenoids of the red alga laurencia pinnatifida

Abstract The structures of three brominated terpenoids which are natural products from the red alga Laurencia pinnatifida (Gmal. Lamour) are described. The structures of the sesquiterpenes 4 and 5 were determined by spectral comparison and chemical interconversion. The structure of the squalene-derived terpenoid 8 was secured by chemical transformation into thyrsiferol, a brominated triterpene previously isolated from the red alga Laurencia thyrsifera.

Thyrsenols A and B, two unusual polyether squalene derivatives

Abstract Two new polyether squalene derivatives, thyrsenol A 2 and thyrsenol B 3, have been isolated from the red alga Laurencia viridis. Their structures, which possess an unusual enol-ether moiety, were determined through the interpretation of 2D-NMR spectral data. The relative stereochemistry is proposed on the basis of ROESY and NOEDIFF data. Their cytotoxic activities were evaluated.