Semisynthesis of novel magnolol-based Mannich base derivatives that suppress cancer cells via inducing autophagy

Magnolol , a natural bioactive neolignan , was found in the bark of a traditional Chinese medicine Magnoliae officinalis (“Hou Po” in Chinese). In this study, thrity-two magnolol-based Mannich base derivatives 3a – p and 4a – p were synthesized, and evaluated for their anti-proliferative activities against a panel of human tumor cell lines (T47D, MCF-7, Hela and A549). Among all derivatives, compound 3p displayed the most potent antiproliferative activity against T47D, MCF-7 and Hela cell lines with IC 50 values of 0.91, 3.32 and 1.71 μM, respectively. Compared with the parental magnolol and the positive drug cisplatin , 3p exhibited up to 76.1-fold and 10.3-fold enhancement of cytotoxic effect on T47D cancer cells, respectively. Mechanism study revealed that the most potent derivative 3p suppressed cancer cells via inducing autophagy. Moreover, 3p also possessed suppressive effects on migration of T47D and Hela cancer cells. In addition, some interesting structure-activity relationships (SARs) were also summarized.