Chemical defenses of tunicates of the genus Aplidium from the Weddell Sea (Antarctica)

• Published in: Polar Biology
• Main Authors: Núñez Pons, Laura, Forestieri, R., Nieto, Rosa María, Varela Díaz de Tuesta, María Mercedes, Nappo, Michela, Rodriguez, Jaime, Jimánez, Carlos, Castelluccio, Francesco, Carbone, Marianna, Ramos-Esplá, Alfonso A., Gavagnin, Margherita, Ávila Escartín, Conxita
• Other Authors: Universidad de Alicante. Departamento de Ciencias del Mar y Biología Aplicada, Biología Marina
• Format: Article in Journal/Newspaper
• Language: English
• Published: Springer Nature 2010
• Subjects: Chemical defense; Antarctic tunicates; Indole alkaloids; Deterrent activity; Aplidium species; Odontaster validus; Zoología; Antarctic; The Antarctic; Weddell; Weddell Sea; Antarc*; Antarctica; Polar Biology
• Online Access: http://hdl.handle.net/10045/108061; https://doi.org/10.1007/s00300-010-0819-7

Predation and competition are important factors structuring Antarctic benthic communities and are expected to promote the production of chemical defenses. Tunicates are subject to little predation, and this is often attributed to chemical compounds, although their defensive activity has been poorly demonstrated against sympatric predators. In fact, these animals, particularly the genus Aplidium, are rich sources of bioactive metabolites. In this study, we report the natural products, distribution and ecological activity of two Aplidium ascidian species from the Weddell Sea (Antarctica). In our investigation, organic extracts obtained from external and internal tissues of specimens of A. falklandicum demonstrated to contain deterrent agents that caused repellency against the Antarctic omnivorous predator, the sea star Odontaster validus. Chemical analysis performed with Antarctic colonial ascidians Aplidium meridianum and Aplidium falklandicum allowed the purification of a group of known bioactive indole alkaloids, meridianins A-G. These isolated compounds proved to be responsible for the deterrent activity. Funding was provided by the Ministry of Science and Education of Spain through the ECOQUIM Projects (REN2003-00545, REN2002-12006E ANT and CGL2004-03356/ANT).