Triterpenes from Euphorbia spinidens with immunomodulatory activity

Dried aceton-chloroform extract of aerial parts of Euphorbia spinidens Bornm. ex Prokh. endemic to Iran, yielded two new triterpenoids, lup-20(29)-ene-33, 28 diol commonly known as betulin and (3β,23E)Cycloarta-23-ene-3,25-diol. The structures of the isolated compounds were elucidated by 13 C- and 1 H-NMR as well as 2D-NMR, IR and by the aid of mass fragmentation pattern. In phagocyte chemiluminescence assay, different concentrations of compounds were incubated with the human whole blood in triplicate and the chemiluminescence activity of phagocytic cells were measured by using serum opsonized zymosan and luminol. For lymphocyte proliferation assay, peripheral human blood lymphocytes were incubated with different concentrations of the test compound in supplemented Roswell Park Memorial Institute (RPMI) 1640 medium along with 5.0 µg/ml phytohemagglutinin (PHA) at 37oC in CO2 environment for 72 h and proliferation level was determined by Beta-scintillation counter. In phagocyte chemiluminescence assay, betulin showed moderate inhibitory effect on the oxidative burst in the neutrophils, while addition of betulin triterpene was able to stimulate the proliferation of the phytohemagglutinin (PHA) treated human peripheral blood lymphocytes (hPBLs).