Determination of Paralytic Shellfish Poisoning (PSP) toxins in dietary supplements by application of a new HPLC/FD method
ABSTRACT Over the past years the importance of food additives and the development of so-called novel food increased permanently. Especially, the application of dietary supplements was on the rise. Then, more and more new products based on plants hitherto not used for human consumption were launched. Algae products containing valuable amounts of essential nutrients such as amino acids and trace elements play a decisive role. On the other hand, some algae including the blue-green algae (cyanobacteria) are capable of synthesizing harmful substances depending on species and provenience. Therefore, methods must be available to evaluate possible risks caused by toxins in algae-based dietary supplements. There are different groups of toxins related to marine algae and cyanobacteria. However, both marine algae and cyanobacteria are able to produce Paralytic Shellfish Poisoning (PSP) toxins which are potential neurotoxins. Hence, analytical methods for PSP determination have to be developed. The method for PSP toxin determination described below is based on ion-pair chromatography of the underivatized PSP toxins followed by post-column oxidation and fluorescence detection (FD). The determination of very low amounts of PSP toxins in different matrices of novel food is possible. In addition, the method allows to compare PSP profiles of various algae-based dietary supplements.
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ABSTRACT: The paralytic shellfish toxin (PST) profiles of Gymnodinium catenatum Graham have been reported for several isolates from the Pacific coast of Mexico cultured under different laboratory conditions, as well as from natural populations. Up to 15 saxitoxin analogues occurred and the quantity of each toxin depended on the growth phase and culture conditions. Previous analysis of toxin profiles of G. catenatum isolated from Mexico have been based upon post- column oxidation liquid chromatography with fluorescence detection (LC-FLD), a method prone to artifacts and non-specificity, leading to misinterpretation of toxin composition. We describe, for the first time, the complete toxin profile for several G. catenatum isolates from diverse locations of the Pacific coast of Mexico. Our new results confirmed previous reports on the dominance of the less potent sulfocarbamoyl toxins (C1/2); significant differences, however, in the composition (e.g., absence of saxitoxin, gonyautoxin 2/3, and neosaxitoxin) were revealed in our confirmatory analysis. The LC-MS/MS analyses also indicated at least seven putative benzoyl toxin analogues and provided support for their existence. This new toxin profile shows a high similarity (>80%) to the profiles reported from several regions around the world, suggesting low genetic variability among global populations.Food Additives and Contaminants - Part A Chemistry, Analysis, Control, Exposure and Risk Assessment 01/2015; DOI:10.1080/19440049.2014.1000978
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ABSTRACT: Aphantoxins induced zebrafish hepatic physiological and morphological changes.•AChE and MAO inhibition reflected abnormality of neurotransmitter inactivation.•ROS advance and T-AOC reduction suggested oxidative stress.•ALT, AST, histological and ultrastructural alterations indicated hepatic damageAquatic Toxicology 12/2014; 157:215-224. DOI:10.1016/j.aquatox.2014.10.016 · 3.51 Impact Factor
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ABSTRACT: Aphanizomenon flos-aquae secretes paralytic shellfish poisons (PSPs), termed aphantoxins, and endangers environmental and human health via eutrophication of water worldwide. Although the molecular mechanism of neuronal PSP toxicity has been well studied, several issues remain unresolved, notably the in vivo hepatic antioxidative responses to this neurotoxin. Aphantoxins extracted from a natural isolate of A. flos-aquae DC-1 were resolved by high performance liquid chromatography. The primary components were gonyautoxins 1 and 5 and neosaxitoxin. Zebrafish (Danio rerio) were treated intraperitoneally with either 5.3 or 7.61 (low and high doses, respectively) μg saxitoxin (STX) equivalents (eq)/kg of A. flos-aquae DC-1 aphantoxins. Antioxidative responses in zebrafish liver were examined at different timepoints 1-24h post-exposure. Aphantoxin administration significantly enhanced hepatic malondialdehyde (MDA) content 1-12h post-exposure, indicative of oxidative stress and lipid peroxidation. By contrast, levels of reduced glutathione (GSH) in zebrafish liver declined significantly after 3-24h exposure, suggesting that GSH participates in MDA metabolism. A significant upregulation of the activities of superoxide dismutase (SOD), catalase (CAT), and glutathione peroxidase (GPx) was observed, suggesting that aphantoxins induce lipid peroxidation in zebrafish liver and are likely to be hepatotoxic. Hepatic levels of MDA and GSH, and of the three enzymes (SOD, CAT, and GPx), therefore provide potential biomarkers for studying environmental exposure to aphantoxins/PSPs from cyanobacterial blooms. Copyright © 2014 Elsevier Inc. All rights reserved.Ecotoxicology and Environmental Safety 12/2014; 113C:425-432. DOI:10.1016/j.ecoenv.2014.12.029 · 2.48 Impact Factor