The anti-inflammatory secoiridoid glycosides from gentianae scabrae radix: the root and rhizome of Gentiana scabra.

Gentianae Scabrae Radix is a well-known traditional medicine that is used for the treatment of hepatitis, cholecystitis and inflammatory diseases. It consists mainly of secoiridoid glycosides, with representatives of gentiopicroside, sweroside and swertiamarin. In the present study, a chemical investigation of the CHCl3 extract of Gentianae Scabrae Radix derived from Gentiana scabra Bunge yielded seven new (1-7) and ten known (8-17) secoiridoid glycosides. Their structures were elucidated by extensive spectroscopic analyses and comparison with literature data. All 17 compounds were evaluated for their inhibitory effects against NO, IL-6 and TNF-α productions induced by lipopolysaccharide (LPS) in RAW264 cells. Among them, 8-epi-kingiside derivatives 1-3; kingiside derivatives 4, 5 and 10; and a sweroside derivative 6 showed inhibition activity against IL-6 production with IC50 values of 51.70-61.10 μM, whereas sweroside derivatives 12 and 15-17 and a swertiamarin derivative 13 showed inhibition effects on both NO and IL-6 productions with IC50 values of 64.74-94.95 and 48.91-75.45 μM, respectively. All the compounds exhibited weak inhibitory activity (IC50 > 100 μM) in a TNF-α bioassay. Finally, a primary structure-activity relationship of these secoiridoid glycosides is discussed.