Blapsimidazolium A: A new imidazolium carboxylate derivative with anti-inflammatory activity from medicinal insect Blaps rynchopetera

Blaps rynchopetera Fairmaire is a medicinal insect of Yi-nationality medicine used for a long time in Yunnan, China. In the present study, a new blapsimidazolium A (1), together with twelve known N-containing compounds (2-13), were isolated from this insect. The structures were elucidated by extensive spectroscopic analyses (1D and 2D NMR, HR-MS) and comparisons with the reported literature. Blapsimidazolium A was identified as racemic mixture by optical rotation and chiral analysis. Blapsimidazolium A (1) has a unique architecture containing an imidazolium carboxylate moiety. The results of molecular docking showed that blapsimidazolium A bound well to IL-1β, IL-6 and iNOS. The racemates of (±)-blapsimidazolium A (1) exerted anti-inflammatory activity in LPS-stimulated THP-1 cells by significantly decreasing the production of the proinflammatory cytokines IL-1β, IL-6 and iNOS. This is the first report describing the anti-inflammatory activity of this type imidazolium carboxylate derivative.