Secondary metabolites from Gentiana cruciata L. and their anti-inflammatory and analgesic activities

A previously unreported secoiridoid glycoside, cruciatoside (1) was isolated from the aerial parts of Gentiana cruciata L. along with ten known compounds eustomoside (2), eustomorusside (3), gentiopicroside (4), 6'-O-β-D-glucopyranosyl gentiopicroside (5), loganic acid (6), isoorientin (7), isovitexin (8), isovitexin 2''-(E)-ferulate (9), mangiferin (10), and 2-methyl-inositol (11). The chemical structures of the isolates were elucidated based on extensive 1 D and 2 D NMR experiments as well as HRMS analysis. All isolates were evaluated for their in vitro anti-inflammatory and analgesic activities. Compounds 9, 4, and 7 (200 µM) showed moderate anti-inflammatory activity by inhibiting nitrite production from LPS-induced RAW 264.7 macrophage cells, with the inhibition rates of 39.5%, 25.8% and 22.9% respectively without exhibiting substantial cytotoxicity. Besides, 1, 2, 4, and 7 exerted the highest decrease in IL-6 levels. Moreover, compound 4 showed in vitro analgesic activity by decreasing the PGE₂ level comparable to the reference drugs.