Podocarpane trinorditerpenes from Celastrus angulatus and their biological activities.

Five new podocarpane trinorditerpenes (1-5) and a dimeric trinorditerpene with an unprecedented skeleton bearing a 1,4-benzodioxane moiety (6) along with seven known compounds (7-13) were isolated from the stems of Celastrus angulatus (Celastraceae). These compounds' structures were elucidated by comprehensive spectroscopic analysis. In addition, the absolute configuration of 1 was determined by single crystal X-ray diffraction analysis. Compounds 3, 4, 7, and 12 exhibited moderate inhibitory activity against LPS-induced NF-κB activation in murine macrophage RAW264.7 cells at IC50 values of 25.08, 18.64, 15.33 and 3.89 μM, respectively. However, compound 6 exhibited potent cytotoxicity against the A549 and MDA-MB-231 human tumour cell lines with IC50 values of 4.47 μM and 5.86 μM, respectively. Compound 9 exhibited potent cytotoxicity against the HCT116 and BEL7404 human tumour cell lines with IC50 values of 6.77 μM and 9.45 μM, respectively.