Small structural changes of pentacyclic lupane type triterpenoid derivatives lead to significant differences in their anticancer properties.

In the present investigations five new derivatives of betulinic and betulonic acid were synthesized and the effect of this structural variations on anticancer activity was studied and discussed. The antiproliferative activity of betulinic and betulonic acid derivatives was studied against eight tumor cell lines of different histogenic origin. The derivatives exerted a dose dependent antiproliferative action at micromolar concentrations toward target tumor cell lines. The apoptotic mode of cell death on colon cancer cell line HT-29 was induced by the most active compounds 5, 2-amino-3-hydroxy-2-(hydroxymethyl)propyl (3-O-acetyl)betulinate, and 9, 2-amino-3-hydroxy-2-(hydroxymethyl)propyl betulonate. Treatment of HT-29 cells with 5 and 9 induced apoptosis, as observed by dye exclusion test (trypan blue) and by the appearance of a typical ladder pattern in the DNA fragmentation assay and FITC annexin V assay. Cell cycle perturbations caused by compound 5 are also presented. Copyright (c) 2010 Elsevier Masson SAS. All rights reserved.