16,17-dinor-abietane diterpenoids from Casearia kurzii.

Eleven undescribed 16,17-dinor-abietane diterpenoids, caseazins A-K (1 − 11), and ten known diterpenoids (12 − 21) were isolated from the twigs and leaves of Casearia kurzii (Flacourtiaceae). Caseazins A-K were the first abietane -type dinorditerpenoids to have been isolated from the plant of Casearia kurzii. Their chemical structures were elucidated using a combination of 1D and 2D NMR spectroscopy and mass spectrometry. The absolute configurations of 5 and 10 were established by electronic circular dichroism calculations. Moreover, compounds 2 , 3 , 13 , 14 , and 18 exhibited anti-inflammatory activity with IC 50 values of 0.17, 0.36, 6.55, 1.30, and 4.53 μM, respectively. IL-1β and caspase-1 analyses suggested that compound 14 inhibited NLRP3 inflammasome activation and blocked macrophage pyroptosis. Diterpenoids from Casearia kurzii with NLRP3 inflammasome inhibitory activity were reported in this research. [Display omitted] • Eleven undescribed dinorditerpenoids were isolated from Casearia kurzii. • The compound 14 showed potent inhibitory activity against pyroptosis by blocking NLRP3 inflammasome activation. Their structures were established by elucidated by NMR, HRESIMS and ECD analyses. [ABSTRACT FROM AUTHOR]