Diversified ent -kaurane diterpenoids from leucosceptrum canum

A systematic phytochemical study on the aerial parts of Leucosceptrum canum collected in Sichuan Liangshan was conducted. Fourteen ent-kaurane diterpenoids (1-14) including two new compounds (4β,11β,15β)-11,15-dihydroxy-20 (10→9)-kaur-5,16-dien-18-oic acid (1) and (4β,11β,12β)-11,12-dihydroxykaur-16-en-18-oic acid (2) were identified using comprehensive chromatographic techniques. Their structures were unambiguously established by various spectroscopic experiments (including 1D, 2D-NMR and HRMS), and single crystal X-ray diffraction. The anti-inflammatory and in vitro tumour growth inhibitory activities of selected compounds were evaluated.