Synthesis and proapoptotic activity of oleanolic acid derived amides
作者:Lucie Heller、Anja Knorrscheidt、Franziska Flemming、Jana Wiemann、Sven Sommerwerk、Ioana Z. Pavel、Ahmed Al-Harrasi、René Csuk
DOI:10.1016/j.bioorg.2016.08.004
日期:2016.10
Thirty-one different 3-O-acetyl-OA derived amides have been prepared and screened for their cytotoxic activity. In the SRB assays nearly all the carboxamides displayed good cytotoxicity in the low μM range for several human tumor cell lines. Low EC50 values were obtained especially for the picolinylamides 14-16, for a N-[2-(dimethylamino)-ethyl] derivative 27 and a N-[2-(pyrrolinyl)-ethyl] carboxamide
Several oligo-methylene diamine derived carboxamides of oleanolic and maslinic acid have been prepared, and substitutions of the terminal primary amine as well as variations of the length of alkyl chain of the diamine moiety were made. Biological evaluation of their cytotoxic activity was performed using photometric sulfor-hodamin B assays employing a panel of different human cancer cell lines. These experiments showed most of the carboxamides to be cytotoxic with EC50 values below 10 mu M. Prolongation of the alkyl chain length initially reduced EC50 values to a minimum, but a decrease in cytotoxicity was observed for longer alkyl chains. Variation of substituents at the terminal nitrogen atom, however, did not influence EC50 values at all. Noteworthy results were obtained particularly for compounds 4, 6 and 23 as indicated by EC50 values lower than 2 mu M, and in case of a maslinic derivative 23 even an increased tumor/non-tumor cell selectivity was observed. These compounds were further investigated using fluorescence microscopy and flow cytometry analysis, which revealed 6 to show indications of apoptosis.