Diterpenoid glycosides from the flower of Trollius chinensis Bunge and their nitric oxide inhibitory activities

Trolliusditerpenosides A-Q (1-17), seventeen new labdane-diterpenoid glycosides, were isolated from the dried flowers of Trollius chinensis Bunge, a plant that has been commonly used as both an anti-inflammatory folk medicine and a healthcare tea for its therapeutic and anti-viral and antibacterial properties. Their structures were corroborated via comprehensive spectroscopic analysis, ECD calculations, and single-crystal X-ray diffraction analysis. Furthermore, the inhibitory activities on lipopolysaccharide (LPS)-induced NO production in RAW 264.7 macrophages of all compounds (1-17) were evaluated in vitro. Compounds 3, 6, 7, and 11 displayed significant inhibitory activities against NO production, with IC50 values ranging from 1.6 +/- 0.1 to 14.4 +/- 0.2 mu M. In addition, compounds 3, 6, 7, and 11 all down-regulated the mRNA expression of iNOS, COX-2, and IL-1 beta in RAW 264.7 cells mediated by LPS. These findings not only support the chemical context of genus Trollius but also the exploration of new chemical entities with pharmacological significance from this genus.