Digalactosyldiacylglycerols and phosphatidylcholines isolated from a brown alga as effective phagostimulants for a young abalone.

Abstract

The methanol extracts of a brown alga Undaria pinnatifida (“Wakame” in Japanese) showed marked feeding stimulation activity against a young abalone Haliotis discus REEVE on application of a new bioassay procedure developed by ourselves. Digalactosyldiacylglycerols (DGDGs) and phosphatidylcholines (PCs) have for the first time been isolated as the effective phagostimulants and identified by spectroscopic and chemical degradative studies. Small amounts of these lipids as 30 ?? 60μg/sample zone are effective for the abalone. This suggests that these lipids also play an important role in the feeding-behavior of the herbivorous gastropods.