Evaluating the antiallergic effects of polyphenols extracted from Ecklonia cava subsp. stolonifera at each step of a powder-manufacturing process

Abstract

We investigated the antiallergic effects of 80 % methanol (80M) extracts obtained from Ecklonia cava subsp. stolonifera, harvested along the coast of Nishinoshima Town, Oki Islands, Shimane Prefecture, Japan, at different stages of algal powder manufacturing (involving heating operations). The radical-scavenging activity of the extracts increased during the manufacturing process. The extracts could mitigate allergic inflammation in mice and degranulation in rat basophilic leukemia-2H3 cells. The contents of typical algal polyphenols, such as phlorotannins (eckol, 6,6′-bieckol, 8,8′-bieckol, dieckol, and phlorofucofuroeckol-A), in the 80M extracts were analyzed via high-performance liquid chromatography and liquid chromatography-mass spectrometry, which revealed that eckol and dieckol were more abundant than the other three phlorotannins throughout the manufacturing process, while an increasing trend in the contents of all five phlorotannins was observed in later stages of the manufacturing process. Furthermore, measurement of the total polyphenol content revealed the probability of polyphenol polymerization during manufacture.