Anti-inflammatory effects of apo-9'-fucoxanthinone from the brown alga, Sargassum muticum.

Background: The marine environment is a unique source of bioactive natural products, of which Sargassum muticum (Yendo) Fensholt is an important brown algae distributed in Jeju Island, Korea. S. muticum is a traditional Korean food stuff and has pharmacological functions including anti-inflammatory effects. However, the active ingredients from S. muticum have not been characterized.
Methods: Bioguided fractionation of the ethanolic extract of S. muticum, collected from Jeju island, led to the isolation of a norisoprenoid. Its structure was determined by analysis of the spectroscopic data. In vitro anti-inflammatory activity and mechanisms of action of this compound were examined using lipopolysaccharide (LPS)-stimulated RAW 264.7 cells through ELISA assays and Western blot analysis.
Results: Apo-9'-fucoxanthinone, belonging to the norisoprenoid family were identified. Apo-9'-fucoxanthinone effectively suppressed LPS-induced nitric oxide (NO) and prostaglandin E2 (PGE2) production. This compound also exerted their anti-inflammatory actions by down-regulating of NF-κB activation via suppression of IκB-α in macrophages.
Conclusions: This is the first report describing effective anti-inflammatory activity for apo-9'-fucoxanthinone'-fucoxanthnone isolated from S. muticum. Apo-9'-fucoxanthinone may be a good candidate for delaying the progression of human inflammatory diseases and warrants further studies.