Anti-Inflammatory Properties of Longifuran A, a New Benzofuran from the Stems of Amomum longiligulare.

In this study, the following compounds were isolated from the dichloromethane fraction of the stems of Amomum longiligulare and then characterized: a new benzofuran, namely, longifuran A ( 1 ); five other phenolic compounds, namely, 4-methoxycinnamic acid ( 2 ), 2,5-dimethoxyphenol ( 3 ), eudesmic acid ( 4 ), 1,7-bis(4-hydroxyphenyl)-1,4,6-heptatrien-3-one ( 5 ), and 4,4'-dihydroxychalcone ( 6 ); and two triterpenoids, namely, 24-methylcycloartan-3β-ol ( 7 ) and 24-methylencycloartan-3β-ol ( 8 ). They were evaluated in terms of their inhibitory effects on NO production in LPS-stimulated RAW 264.7 macrophages. Results indicated that 1 and 5 exhibited promising inhibitory activities against NO generation with IC 50 of 10.47 ± 1.02 μM and 8.51 ± 1.14 μM, respectively. Enzymatic assays demonstrated that they remarkably suppressed the secretion of two pro-inflammatory cytokines (i.e., IL-6 and TNF-α). They also dose-dependently inhibited the expression of inducible nitric oxide synthase and cyclooxygenase-2, two important enzymes modulating inflammation. Therefore, 1 and 5 could be targets for the development of new anti-inflammatory therapeutics.