The Influence of Phlorotannins and Bromophenols on the Feeding Behavior of Marine Herbivorous Gastropod <i>Turbo cornutus</i>

Abstract

The influence of phlorotannins and bromophenols on the feeding behavior of marine herbivores was determined using bioassay of Turbo cornutus . It was found that phloroglucinol and its oligomers isolated from the brown alga Eisenia bicyclis (eckol, fucofuroeckol A, phlorofucofuroeckol A, dieckol, and 8,8’-bieckol) had a deterrent effect against feeding behavior of T . cornutus in the concentration of algal body, respectively. In the case of the examination of 0.1 mM concentration, although fucofuroeckol A and phlorofucofuroeckol A significantly reduced feeding by T . cornutus , phloroglucinol and 8,8’-bieckol did not show any significant influence on feeding behavior , and eckol and dieckol had stimulating activity. 2,4-Dibromophenol and 2,4,6-tribromophenol, which are major components of extracellular secretions from Eisenia and Ecklonia species, caused the death, the torpidity, and the decreased appetite of T . cornutus at the concentration of 0.1 mM. In addition, 2,4-dibromophenol had strong feeding deterrent activity at the concentration of 1 μM. These results indicate that phlorotannins and bromophenols act as chemical defense agents of brown algae against environmental stresses such as the herbi vore attack.