Design, Synthesis and Biological Evaluation of Novel Oleanolic Acid Derivatives as Potential Anti-Leukemic Agents

Background: Chronic myeloid leukemia (CML) and other leukemia subtypes remain significant hematological malignancies that require the development of novel therapeutic agents with improved efficacy and selectivity. This study aimed to design, synthesize, and evaluate novel oleanolic acid (OA) derivatives as potential anti-leukemic agents. Methods: Structural modifications at the C-28 position afforded halogenated benzyl ester derivatives (MT-A-D), while aromatic acyl substitutions at the C-3 position generated derivatives NOA-1-16. The cytotoxic effects of the synthesized compounds were evaluated against K562, HL-60, Jurkat, and MT-2 leukemia cell lines and healthy PBMCs using the MTT assay. Apoptosis induction and ABL tyrosine kinase (TK) inhibition were also investigated. Molecular docking, MM/GBSA binding free energy calculations, and molecular dynamics (MD) simulations were performed to characterize ligand-enzyme interactions and binding stability. Results: MT-A exhibited the highest activity against HL-60 cells (IC₅₀ = 4.17 ± 0.65 μM), surpassing imatinib (IC₅₀ = 13.34 ± 1.92 μM). NOA-8 was the most potent compound against Jurkat and MT-2 cells, with IC₅₀ values of 6.81 ± 1.08 μM and 2.48 ± 0.88 μM, respectively. MT-A, MT-C, NOA-3, and NOA-8 displayed IC₅₀ values above 300 μM in PBMCs, indicating favorable selectivity. MT-A and MT-C induced significant apoptosis in K562 cells, while kinase assays revealed moderate ABL TK inhibition by these compounds. Docking, MM/GBSA, and MD analyses supported stable binding of MT-A and MT-C within the ABL ATP-binding pocket. Conclusions: MT-A, MT-C, NOA-3, and particularly NOA-8 emerged as promising anti-leukemic lead compounds with potent antiproliferative activity and favorable selectivity profiles, warranting further investigation for leukemia therapy.