Phlorotannins of the edible brown seaweed Ecklonia cava Kjellman induce sleep via positive allosteric modulation of gamma-aminobutyric acid type A-benzodiazepine receptor: A novel neurological activity of seaweed polyphenols

► Phlorotannins of Ecklonia cava Kjellman (ECK) induce sleep via positive allosteric modulation of GABAA-BZD receptors. ► Eckol, eckstolonol, dieckol, and triphlorethol-A were for the first time characterised as a GABAA-BZD receptor ligand. ► Hypnotic effects of ECK were fully inhibited by flumazenil, a specific GABAA-BZD receptor antagonist.