Cytotoxic 8,9-seco-ent-kaurane diterpenoids from Croton kongensis.

Chemical study on the ethanolic extract generated from the aerial parts of Croton kongensis led to the isolation of three new 8,9-seco-ent-kaurane diterpenoids, kongeniods A‒C (1‒3), together with seven known analogs (4-10). The structures of these compounds were assigned by spectroscopic data analysis. The vitro cytotoxic tests showed that compounds 1-3 exhibited strong activities against HL-60 cell lines with IC50 values of 0.47, 0.58, and 1.27 μM, respectively.