In Vivo Evaluation of the Chronic Oral Toxicity of the Marine Toxin Palytoxin.

Andrea Boente-Juncal,Paz Otero,M Carmen Louzao,Carmen Vale,Sandra Raposo-García,Luis M Botana

doi:10.3390/toxins12080489

Abstract

Palytoxin (PLTX) is one of the most poisonous substances known to date and considered as an emergent toxin in Europe. Palytoxin binds to the Na+-K+ ATPase, converting the enzyme in a permeant cation channel. This toxin is known for causing human fatal intoxications associated with the consumption of contaminated fish and crustaceans such as crabs, groupers, mackerel, and parrotfish. Human intoxications by PLTX after consumption of contaminated fishery products are a serious health issue and can be fatal. Different reports have previously explored the acute oral toxicity of PLTX in mice. Although the presence of palytoxin in marine products is currently not regulated in Europe, the European Food Safety Authority expressed its opinion on PLTX and demanded assessment for chronic toxicity studies of this potent marine toxin. In this study, the chronic toxicity of palytoxin was evaluated after oral administration to mice by gavage during a 28-day period. After chronic exposure of mice to the toxin, a lethal dose 50 (LD50) of 0.44 µg/kg of PLTX and a No-Observed-Adverse-Effect Level (NOAEL) of 0.03 µg/kg for repeated daily oral administration of PLTX were determined. These results indicate a much higher chronic toxicity of PLTX and a lower NOAEL than that previously described in shorter treatment periods, pointing out the need to further reevaluate the levels of this compound in marine products.

Highlights

The marine toxin palytoxin (PLTX) is one of the most toxic marine phycotoxins known to date
A recent report described a massive bloom of the dinoflagellate Ostreopsis cf. ovata producer of 5.6 pg of PLTX per cell in the Adriatic Sea [5]
Based on the initial results for the acute toxicity of PLTX in mice [35], we further explored the chronic toxicity of this compound assessing its oral toxicity after a 28 daily exposure period

Summary

Introduction

The marine toxin palytoxin (PLTX) is one of the most toxic marine phycotoxins known to date.Since its first isolation, about 50 years ago, from marine corals of the genus Palythoa [1] and later on from algae of the genus Ostreopsis [2,3,4], the toxin was associated with high toxicity. A recent report described a massive bloom of the dinoflagellate Ostreopsis cf ovata producer of 5.6 pg of PLTX per cell in the Adriatic Sea [5]. This bloom was not an isolated case but rather massive Ostreopsis blooms have been reported in the Mediterranean Sea during the last 20 years as summarized in several reports [5] and increasingly reported in the literature [2,3,5,6,7,8,9,10], and are in expansion mainly due to environmental factors [11,12,13].

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