Synthesis, biological evaluation and molecular docking of podophyllotoxin-conjugated pentacyclic triterpenoids as novel anticancer agents

The pentacyclic triterpenoids (PTs) compounds including glycyrrhetinic acid (GA), oleanolic acid (OA), ursolic acid (UA) and betulinic acid (BA) were modified via azide-alkyne click synthesis of triazole moiety with podophyllotoxin resulted in thirty-two conjugated derivatives (19-50) and tested theirs in vitro anticancer activity using MTT (3-(4,5-dimethylthiazole-2-yl)-2,5-diphenyltetraz-olium bromide) assay against four cancer cell lines, including human cervical carcinoma (HeLa), human lung adenocarcinoma (A549), human hepatoma carcinoma (HepG2), and human colon carcinoma (HCT-116). NMR and HRMS techniques were utilized to identify the structure for the newly synthesized compounds. Among all derivatives, compound 19 showed promising anticancer activity against HCT116 (IC50=0.31 μM) and HeLa (IC50=0.85 μM) cell lines, compound 20 exhibited astonishing anticancer activity against HCT116 (IC50=0.27 μM) and HeLa (IC50=1.03 μM), compound 35 sowed potent inhibitory activity against HCT116 (IC50=0.31 μM) and A549 (IC50=0.85 μM) cell lines. To better understand their molecular interactions, these compounds were subjected to in silico studies, including molecular docking and molecular dynamics simulations, using the corresponding protein structures (PDB IDs: 8EXU, 6GUE, and 1M17). The computational results confirmed the potential of compounds 19, 20, and 35, highlighting that their anticancer activities are driven by stable hydrogen bonding and hydrophobic interactions within the binding sites. These compounds demonstrated significant inhibitory activity comparable to the positive controls Cisplatin and Etoposide, thereby positioning them as promising lead candidates for further optimization and development as potential anticancer agents.