ABSTRACT
@#In order to search for new anti-inflammatory agents with strong activity and less toxicity relative to CDDO-Me, the ester prodrugs 2-8 of CDDO-Me were synthesized by treatment of oleanolic acid(OA)with DMF/K2CO3 to generate 1, followed by esterification of 1 with various aliphatic and aromatic carboxylic acids, respectively. All the target compounds showed strong inhibitory effects on LPS-induced NO production in RAW 264. 7 cells. Among them, compounds 2 and 7 possessed the most potent inhibitory effects with IC50=(2. 34±0. 67)and(3. 83±0. 97)nmol/L, respectively. Moreover, MTT assay indicated that all the target compounds(2-8)displayed much weaker anti-proliferative activity against RAW 264. 7 cell lines than CDDO-Me, suggesting that they may be less toxic than CDDO-Me.
ABSTRACT
@#The novel oleanolic acid derivatives 2a-2e were synthesized by introducing an α, β-unsaturated ketone moiety to C-ring of oleanolic acid(OA)via a nine-step reaction sequence, yielding an active CDDO-Me analogue(1), followed by coupling of C3-OH of 1 with various aliphatic and aromatic carboxylic acids, respectively. Derivatives 3a-3e were synthesized by substituting C-1 of compounds 2a-2e with bromine. The target compounds were characterized by IR, MS and 1H NMR spectra. All the target compounds showed strong inhibitory effects against two tumor cell lines(HepG2 and A549)to a varying extent. The anti-proliferative activities of active compounds 3b and 3c(IC50=6. 13±1. 16 μmol/L and IC50=5. 49±1. 03 μmol/L, respectively)against HepG2 and A549 were more potent than compound 1 and comparable to the positive control CDDO-Me. In addition, all the target compounds displayed much weaker anti-proliferative activity against the two tumor cell lines than that against normal BEAS-2B cells. Compound 3c showed ten-fold selective inhibition against HepG2 relative to BEAS-2B cells, and is thus worthy of further study.