Hemeoxygenase 1 partly mediates the anti-inflammatory effect of dieckol in lipopolysaccharide stimulated murine macrophages

Eisenia bicyclis is edible brown algae recognized as a rich source of bioactive derivatives mainly phlorotannins reported for their anti-oxidant properties. Of all phlorotannins identified so far, dieckol has shown the most potent effect in anti-inflammatory, radical scavenging and neuroprotective functions. However, whether dieckol up-regulates hemeoxygenase 1 (HO-1) and this mediates its anti-inflammatory effect in murine macrophages remains poorly understood. Dieckol (12.5-50 mu M) inhibited nitric oxide production and attenuated inducible nitric oxide synthase, phospho (p)-PI-3 K, p-Akt, p-IKK-alpha/beta, p-I kappa B-alpha and nuclear p-NF-kappa Bp65 protein expressions, and NF-kappa B transcriptional activity in LPS (0.1 mu g/ml) stimulated murine macrophages. On the other hand, dieckol up-regulated HO-1 which partly mediated its anti-inflammatory effect in murine macrophages. Thus, dieckol appeared to be a potential therapeutic agent against inflammation through HO-1 up-regulation. (C) 2014 Elsevier B.V. All rights reserved.