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.