Two new guaianolide-type sesquiterpenoids with NO inhibitory activity from Chrysanthemum indicum

Two new guaianolide-type sesquiterpenoids chrysanthemulides K and L (1 and 2), together with six known analogues (3-8), were isolated from an CH₂Cl₂ extract of the aerial parts of Chrysanthemum indicum. The structures of new compounds 1 and 2 were established by extensive spectroscopic analysis, including UV, IR, MS, NMR and computational electronic circular dichroism (ECD) methods. Inhibitory effects of all compounds on nitric oxide production were investigated in lipopolysaccharide (LPS)-induced RAW 264.7 cells. Results showed that compounds 1-8 displayed NO production inhibitory activity with IC50 values ranged from 3.5 to 34.3 µM.