New immunosuppressive cyclomyrsinol diterpenes from Euphorbia kopetdaghi Prokh.

ABSTRACT

Aceton chloroform (12) extracts of the aerial parts of Euphorbia kopetdaghi Prokh. (Euphorbiaceae) were investigated for its diterpenoids and afforded three new five-membered ring, pentacyclic myrisinane polyester comprised of 3,5,10-O-triacetyl-8-O-isobutanoyl-14-O-benzoylcyclomyrsinol (1), 3,5,10,14-O-tetraacetyl-8-O-(2'-methyl butanoyl)-cyclomyrsinol (2) and 3,5,10,14-O-tetracetyl-8-O-isobutanoylcyclomyrsinol (3). The structures were elucidated based on (13)C- and (1)H-NMR as well as 2D-NMR, IR and different MS spectra and the immunomodulation activity for compound 1 was evaluated through lymphocyte proliferation assay, IL-2 assay, oxidative burst of phagocytic leukocytes and through their cytotoxicity on two cell lines. Compound 1 showed significant suppressive activity against phytohemagglutinin-activated T-cell proliferation with an IC(50) of 1.83 µg mL(-1), IL-2 suppressive activity with an IC(50) of 19.0 µg mL(-1) and oxidative burst suppressive activity with an IC(50) of 1.6 µg mL(-1) and ignorable cytotoxic effect on the CC-1 rat hepatocyte and 3T3-L1 mouse fibroblast cell-lines.