Citation

García-Arredondo A, Rojas-Molina A, Bah M, Ibarra-Alvarado C, Gallegos-Corona MA, García-Servín M. Comp. Biochem. Physiol. C Toxicol. Pharmacol. 2015; 169: 55-64.

Affiliation

Instituto de Neurobiología, Universidad Nacional Autónoma de México, Campus Juriquilla, Querétaro 76201, México.

Copyright

(Copyright © 2015, Elsevier Publishing)

DOI

10.1016/j.cbpc.2014.12.004

PMID

25572857

Abstract

Millepora complanata is a cnidarian widely distributed in the coral reefs of the Mexican Caribbean. This species is popularly known as "fire coral", since contact with it causes severe pain, skin eruptions and blisters. In the present study, the systemic toxicity of M. complanata aqueous extract was assessed in mice. The results indicated that intravenous administration of the extract induces violent convulsions and death in mice within 1min (LD50=4.62μgprotein/g of body weight). Doses less than the LD50 (1.33, 2.67 and 4.00μgprotein/g) produced histopathological damage in kidneys and lungs attributed to the presence of cytolysins. Such histopathological damage was completely eliminated after incubation of the extract in heat denaturing conditions. Unexpectedly, the denatured extract conserved its lethal effect. These findings demonstrated that the extract contained hemolytic and phospholipase activities that might be responsible for the histopathological damage, and additionally it contained other unidentified thermostable toxins, likely secondary metabolites with lethal effects in mice. Chromatographic analysis of the crude extract led to the isolation of a 61kDa vasoconstrictor protein. Furthermore, several non-peptidic vasoconstrictor fractions were separated. Particularly interesting was the fraction MC1-IIA obtained as a result of three-step chromatography processes (ion exchange, gel filtration and reverse phase). Like the original crude extract, this fraction induced vasoconstriction and delayed hemolysis and lethal effects in mice. A subsequent chromatographic analysis of MC1-IIA showed that this fraction contained at least four non-peptidic compounds. MS and NMR spectroscopic data analyses indicated that these metabolites were poly-oxygenated alkylbenzenes. The present study constitutes the first report of the presence of non-peptidic lethal toxins in an organism of the class Hydrozoa, and evidences the great structural diversity of the toxins produced by the Millepora species.

Language: en