title: Composition and biological activities of the aqueous extracts of three scleractinian corals from the Mexican Caribbean:Pseudodiploria strigosa,Porites astreoidesandSiderastrea siderea.
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 ofPseudodiploria strigosa,Porites astreoidesandSiderastrea 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 A2and 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.
  
  
  CONCLUSIONS
  This study suggests that scleractinian corals produce low-molecular-weight peptides that are lethal to crickets and induce vasoconstriction.
authors.affiliation: Departamento de Investigación Química y Farmacológica de Productos Naturales, Facultad de Química, Universidad Autónoma de Querétaro, Querétaro, 76010 Mexico.
authors.forename: Alejandro
authors.initials: A
authors.lastname: García-Arredondo
authors.affiliation: Departamento de Investigación Química y Farmacológica de Productos Naturales, Facultad de Química, Universidad Autónoma de Querétaro, Querétaro, 76010 Mexico.
authors.forename: Alejandra
authors.initials: A
authors.lastname: Rojas-Molina
authors.affiliation: Departamento de Investigación Química y Farmacológica de Productos Naturales, Facultad de Química, Universidad Autónoma de Querétaro, Querétaro, 76010 Mexico.
authors.forename: César
authors.initials: C
authors.lastname: Ibarra-Alvarado
authors.affiliation: Departamento de Ciencias de la Salud, Universidad Autónoma Metropolitana, Campus Iztapalapa, Mexico City, 09340 Mexico ; Instituto de Química, Universidad Nacional Autónoma de México, Mexico City, 04510 Mexico.
authors.forename: Fernando
authors.initials: F
authors.lastname: Lazcano-Pérez
authors.affiliation: Instituto de Química, Universidad Nacional Autónoma de México, Mexico City, 04510 Mexico.
authors.forename: Roberto
authors.initials: R
authors.lastname: Arreguín-Espinosa
authors.affiliation: Unidad Académica de Sistemas Arrecifales, Instituto de Ciencias del Mar y Limnología, Universidad Nacional Autónoma de México, Puerto Morelos, Quintana Roo 77500 Mexico.
authors.forename: Judith
authors.initials: J
authors.lastname: Sánchez-Rodríguez
keywords: Hemolysis; Nociceptive response; Porites astreoides; Pseudodiploria strigosa; Scleractinia; Siderastrea siderea; Toxicity; Vasoconstriction