New tigliane-type diterpenoids from Euphorbia aellenii Rech. f. with immunomodulatory activity

The cytotoxic chloroform fraction of Euphorbia aellenii Rech. F. (Euphorbiaceae) afforded two new phorbol diterpenoids: 4-deoxy-4 alpha-phorbol-12-(2,3-dimethyl) butyrate-13-isobutyrate and 17-hydroxy-4-deoxy-4 alpha-phorbol-12-(2,3-dimethyl) butyrate-13-isobutyrate. Their structures were elucidated by NMR and other spectroscopic methods. The immunomodulating potentials of the isolated compounds were tested using standard proliferation and chemiluminescence assays. Compound 2 showed moderate inhibitory activity against both T-cell proliferation and reactive oxygen species (ROS) production in whole blood with IC50 of 14.0 +/- 0.57 and 44.1 +/- 3.8 mu g/ml, respectively, while compound 1 was relatively inactive with IC50 >50 mu g/mL for T-cell proliferation, and >100 mu g/mL for ROS.