Secoiridoid glycosides from the rhizomes of Gentiana scabra and their anti-inflammatory activities through inactivation of MAPK/ERK/p38 and NF-κB pathways

Two new secoiridoid glycosides, gentscaside A (1) and gentscaside B (2), were isolated along with three known compounds gentiopicroside (3), rindoside (4), gentiotrifloroside (5), from the Rhizomes of Gentiana scabra. The structures of the new compounds were determined by comprehensive NMR analysis, and their absolute configurations were determined on the basis of detailed spectroscopic analyses and acidic hydrolysis. The five compounds were evaluated for their anti-inflammatory activity (NO inhibitory activity in LPS-stimulated macrophages). Compounds 1, 4 and 5 showed significant inhibitory effects on LPS-induced NO release in RAW 264.7 cells. The IC₅₀ values are 2.15 μM, 3.02 μM and 6.87 μM, respectively. Additionally, the potential anti-inflammatory mechanism of the active new compound 1 was explored.