Synthesis, and anti-inflammatory activities of gentiopicroside derivatives

A series of 26 novel derivatives have been synthesized through structural modification of gentiopicroside, a lead COX-2 inhibitor. And their in vivo and in vitro anti-inflammatory activities have been investigated. The in vitro anti-inflammatory activities were evaluated against NO, PGE₂, and IL-6 production in the mouse macrophage cell line RAW264.7 stimulated by LPS. Results showed that most compounds had good inhibitory activity. The in vivo inhibitory activities were further tested against xylene-induced mouse ear swelling. Results demonstrated that several compounds were more active than the parent compound gentiopicroside. The inhibition rate of the most active compound P23 (57.26%) was higher than positive control drug celecoxib (46.05%) at dose 0.28 mmol·kg^-1. Molecular docking suggested that these compounds might bind to COX-2 and iNOS. Some of them, e.g P7, P14, P16, P21, P23, and P24, had high docking scores in accordance with their potency of the anti-inflammatory activitiy, that downregulation of the inflammatory factors, NO, PGE₂, and IL-6, was possibly associated with the suppression of iNOS and COX-2. Therefore, these gentiopicroside derivatives may represent a novel class of COX-2 and iNOS inhibitors.