Composition and biological activities of the aqueous extracts of three scleractinian corals from the Mexican Caribbean: Pseudodiploria strigosa, Porites astreoides and Siderastrea siderea

 

Alejandro García-Arredondo¹, Alejandra Rojas-Molina¹, César Ibarra-Alvarado¹, Fernando Lazcano-Pérez^2 3, Roberto Arreguín-Espinosa³, Judith Sánchez-Rodríguez⁴ 

 

1 Departamento de Investigación Química y Farmacológica de Productos Naturales, Facultad de Química, Universidad Autónoma de Querétaro, Querétaro 76010, Mexico

2 Departamento de Ciencias de la Salud, Universidad Autónoma Metropolitana, Campus Iztapalapa, Mexico City 09340, Mexico

3 Instituto de Química, Universidad Nacional Autónoma de México, Mexico City 04510, Mexico

4 Unidad Académica de Sistemas Arrecifales, Instituto de Ciencias del Mar y Limnología, Universidad Nacional Autónoma de México, Puerto Morelos, Quintana Roo 77500, Mexico

 

ABSTRACT

Background:

Scleractinian corals (stony corals) are the most abundant reef-forming cnidarians found in coral reefs throughout the world. Despite their abundance and ecological importance, information about the diversity of their toxins and their biological activities is very scarce. In this study, the chemical composition and the biological activities of the aqueous extracts of Pseudodiploria strigosa, Porites astreoides and Siderastrea siderea, three scleractinian corals from the Mexican Caribbean, have been assessed for the first time.

Methods:

Toxicity of the extracts was assessed in crickets; the presence of cytolysins was detected by the hemolysis assay; the vasoconstrictor activity was determined by the isolated rat aortic ring assay; the nociceptive activity was evaluated by the formalin test. The presence of phospholipases A₂ (PLA₂), serine proteases, and hyaluronidases was determined by enzymatic methods. Low-molecular-weight fractions were obtained by gel filtration chromatography and ultrafiltration.

Results:

Extracts from the three species were toxic to crickets, induced hemolysis in human and rat erythrocytes, produced vasoconstriction on isolated rat aortic rings, and presented phospholipase A₂ and serine-protease activity. Despite the fact that these corals are not considered to be harmless to humans, the extracts generated significant nociceptive responses. The matrix-assisted laser desorption/ionization time-of-flight (MALDI-TOF) mass spectrometry analysis of the low-molecular-weight fractions revealed the presence of peptides within a mass range of 3000 to 6000 Da. These fractions were toxic to crickets and two of them induced a transitory vasoconstrictor effect on isolated rat aortic rings.

Conclusion:

This study suggests that scleractinian corals produce low-molecular-weight peptides that are lethal to crickets and induce vasoconstriction.

 

Keywords: Scleractinia; Pseudodiploria strigosa; Porites astreoides; Siderastrea siderea; Toxicity; Hemolysis; Vasoconstriction; Nociceptive response

 

Received: August 08, 2016.

Accepted: November 12, 2016.

 

 

Authors' contributions

AGA performed the bioassays and the extracts fractionation. ARM and CIA supervised the pharmacological assays. JSR made substantial contributions to the specimen collection. FLP and RAE performed the chemical analysis of the fractions. AGA designed this project, coordinated all the activities, and wrote the manuscript. All authors read and approved the final manuscript.

 

Competing interests

The authors declare that they have no competing interests.