Rubellawus A-D, Four New Diterpenoids Isolated from Callicarpa rubella and Their Anti-NLRP3 Inflammasome Effects

Four new diterpenoids, rubellawus A-D (1-4), along with three known compounds, were isolated and identified from the flowers of Callicarpa rubella. Their structures were elucidated by various spectroscopic analysis. All the compounds were screened for their anti-inflammatory activity and 14 alpha-hydroxyisopimaric acid and isopimaric acid showed significant NLRP3 inflammasome inhibitory activity with IC50 values of 7.02 and 3.99 mu M.