Toxicity Bioassay and Cytotoxic Effects of the Benthic Marine Dinoflagellate Amphidinium operculatum.

Ana Luisa Mejía-Camacho,Allan Douglas Cembella,Lorena María Durán-Riveroll

doi:10.3390/jox11020003

Abstract

Benthic dinoflagellates produce a wide array of bioactive compounds, primarily polyketides, that cause toxic effects on human consumers of seafood and perhaps mediate species interactions in the benthic microenvironment. This study assesses toxic and other bioactive effects of the benthic dinoflagellate Amphidinium operculatum (strain AA60) in two targeted bioassays. The brine shrimp (Artemia salina) bioassay revealed lethal effects of direct exposure to live dinoflagellate cells (Treatment A) and even higher potency with ethanolic extracts of lysed cells (Treatment D). There were no inimical bioactive effects of components released to the aqueous growth medium (Treatment B) or from aqueous cell lysates (Treatment C). The hypothesis that released bioactive compounds provide a chemical defense against metazoan grazers is therefore not supported by these results. The cytotoxic effect of ethanolic crude extracts of this dinoflagellate exhibited mild to high growth reduction effects on six human cancer cell lines. In particular, crude cell-free extracts proved highly growth-inhibitory activity towards breast and lung cancer cell lines MCF-7 and SKLU-1, respectively. Preliminary anti-cancer results indicate that natural bioactive compounds from Amphidinium are worthy of structural characterization and further toxicological investigation as potential therapeutants.

Highlights

Benthic marine dinoflagellates are key primary producers and a critical component of trophic webs, in tropical and sub-tropical ecosystems, such as coral reefs [1]
Benthic dinoflagellates produce a wide array of bioactive compounds, which act as toxins for human consumers of seafood when accumulated via the marine food chain and may have toxic or allelochemical effects on other benthic organisms [2]
Benthic dinoflagellates are notorious as causative agents of seafood poisoning syndromes, most prominently ciguatera fish poisoning (CFP) and diarrheic shellfish poisoning (DSP)

Summary

Introduction

Benthic marine dinoflagellates are key primary producers and a critical component of trophic webs, in tropical and sub-tropical ecosystems, such as coral reefs [1]. Benthic dinoflagellates produce a wide array of bioactive compounds, which act as toxins for human consumers of seafood when accumulated via the marine food chain and may have toxic or allelochemical effects on other benthic organisms [2]. Known toxigenic benthic dinoflagellates are represented among more than a dozen species that produce polyketide-derived bioactive compounds [2,3,4]. These polyether compounds pose a known or potential risk to human health, and include okadaic acid and dinophysistoxins, ciguatoxins, maitotoxins, cooliatoxins, palytoxins, etc., as well as other macrolides of uncertain toxicity [5,6,7,8]

Methods

Results

Conclusion