Diterpenoids from Excoecaria agallocha and their cytotoxic activity

A phytochemical investigation on the twigs and leaves of Excoecaria agallocha led to the discovery of eight undescribed diterpenoids, along with 21 known analogues. Their structures were elucidated based on comprehensive HRESIMS, HREIMS, and NMR spectroscopic analyses. The cytotoxicity of some isolates was tested against human lung cancer cells (A549) and human promyelocytic leukemia cells (HL-60). Compounds 2 and 4 showed moderate cytotoxic effect against HL-60 with IC₅₀ values of 7.60 ± 2.67 μM and 12.64 ± 0.13 μM, respectively. However, other tested compounds displayed little or weak inhibitory effects against A549 and HL-60 with inhibition rate less than 50% at the concentration of 20 μM.