Inhibitory effects of phloroglucinol derivatives isolated from Ecklonia stolonifera on Fc(epsilon)RI expression

Two bioactive phloroglucinol derivatives, dioxinodehydroeckol (DHE) and phlorofucofuroeckol A (PFF-A) were isolated from edible marine brown alga, Ecklonia stolonifera, and evaluated for effects on cell surface Fc(epsilon)RI expression in KU812F cells. DHE and PFF-A were found to reduce the cell surface expression, and total cellular protein and mRNA levels for the Fc(epsilon)RI alpha chain. Moreover, both compounds exerted inhibitory effects against the elevation of intracellular calcium concentration [Ca(2+)](i) and histamine release from anti-Fc(epsilon)RI alpha chain antibody (CRA-1)-stimulated cells. These inhibitory effects were stronger for PFF-A than for DHE. These results show that two phloroglucinol derivatives, DHE and PFF-A, may exert anti-allergic effects via the inhibition of Fc(epsilon)RI expression, calcium influx, and degranulation in basophils, and contributes to the pharmacological activities of marine brown alga, including E. stolonifera.