Four New Sesquiterpenoids from the Roots of Incarvillea arguta and Their Inhibitory Activities against Lipopolysaccharide-Induced Nitric Oxide Production

Abstract

Four new sesquiterpenoids, argutosines A—D (1—4), together with two known ones (5, 6), were isolated from the roots of Incarvillea arguta. Their chemical structures were elucidated on the basis of MS, NMR spectroscopic analysis. All the sesquiterpenoids were tested for inhibitory activities against lipopolysaccharide (LPS)-induced nitric oxide (NO) production in RAW264.7 macrophages. Argutosines A, B and C (1—3) showed potent inhibitory activities with IC₅₀ values of 2.05, 0.55, and 9.87 μM, respectively.