Lupeol-3-carbamate Derivatives: Synthesis and Biological Evaluation as Potential Antitumor Agents

In the following study, a series of new lupeol-3-carbamate derivatives were synthesized, and the structures of all the newly derived compounds were characterized. The new compounds were screened to determine their anti-proliferative activity against human lung cancer cell line A549, human liver cancer cell line HepG2, and human breast cancer cell line MCF-7. Most of the compounds were found to show better anti-proliferative activity in vitro than lupeol. Among them, obvious anti-proliferation activity (IC₅₀ = 5.39~9.43 μM) was exhibited by compound <b>3i</b> against all three tumor cell lines. In addition, a salt reaction was performed on compound <b>3k</b> (IC₅₀ = 13.98 μM) and it was observed that the anti-proliferative activity and water solubility of compound <b>3k·CH₃I</b> (IC₅₀ = 3.13 μM), were significantly enhanced subsequent to the salt formation process. The preliminary mechanistic studies demonstrated that apoptosis in HepG2 cells was induced by compound <b>3k·CH₃I</b> through the inhibition of the PI3K/AKT/mTOR pathway. In conclusion, a series of new lupeol-3-carbamate derivatives were synthesized via the structural modification of the C-3 site of lupeol, thus laying a theoretical foundation for the design of this new anticancer drug.