Anti-inflammatory constituents from the root of Litsea cubeba in LPS-induced RAW 264.7 macrophages. (1st September 2016) - Lin, Bing
Abstract: Context Litsea cubeba (Lour.) Pers. (Lauraceae) has long been used as a folk remedy in Traditional Chinese Medicine (TCM) for the treatment of rheumatic diseases. Previous studies from our laboratory indicated that L. cubeba extract showed anti-arthritic activity in rats. Objective To study L. cubeba chemically and biologically and to find the potential constituents responsible for its anti-arthritic effect. Materials and methods The compounds were isolated from the root of L. cubeba by column chromatography which eluted with PE:EtOAc gradient system, and the structures were elucidated by detailed spectroscopic data analysis; the anti-inflammatory activity of the isolated compounds was evaluated by lipopolysaccharide (LPS)-induced RAW 264.7 cells and the TNF-α and NO level were measured by ELISA (commercial kit); The iNOS and COX-2 mRNA expression were measured by RT-PCR and the phosphorylation of IκBα, IKKβ, P38 and Akt were determined by western blots. Results A novel 9-fluorenone, 1-ethoxy-3, 7-dihydroxy-4, 6-dimethoxy-9-fluorenone (1 ), together with 4 known compounds, namely pinoresinol (2 ), syringaresinol (3 ), 9, 9′- O -di-( E )-feruloyl-meso-5, 5′-dimethoxysecoisolariciresinol (4 ) and lyoniresinol (5 ) were isolated from the root of L. cubeba for the first time. The IC50 for NO inhibition on compounds1 and4 were 56.1 ± 1.2 and 32.8 ± 2.3 μM, respectively. The IC50 for TNF-α inhibition were 28.2 ± 0.9 and 15.0 ± 1.0 μM, respectively. Both1 and4 suppress mRNA expression of iNOS, COX-2 and protein phosphorylation of IκBα, IKKβ in LPS-induced RAW 264.7 cells. Discussion and conclusion Compounds1 and4 isolated from L. cubeba exhibited potent anti-inflammatory activity through the NF-κB signal pathway.