Design, synthesis and biological evaluation of novel diosgenin–benzoic acid mustard hybrids with potential anti-proliferative activities in human hepatoma HepG2 cells

To discover new lead compounds with anti-tumour activities, in the present study, natural diosgenin was hybridised with the reported benzoic acid mustard pharmacophore. The in vitro cytotoxicity of the resulting newly synthesised hybrids (8–10, 14a–14f, and 15a–15f) was then evaluated in three tumour cells (HepG2, MCF-7, and HeLa) as well as normal GES-1 cells. Among them, 14f possessed the most potential anti-proliferative activity against HepG2 cells, with an IC(50) value of 2.26 µM, which was 14.4-fold higher than that of diosgenin (IC(50) = 32.63 µM). Furthermore, it showed weak cytotoxicity against GES-1 cells (IC(50) > 100 µM), thus exhibiting good antiproliferative selectivity between normal and tumour cells. Moreover, 14f could induce G0/G1 arrest and apoptosis of HepG2 cells. From a mechanistic perspective, 14f regulated cell cycle-related proteins (CDK2, CDK4, CDK6, cyclin D1 and cyclin E1) as well mitochondrial apoptosis pathway-related proteins (Bax, Bcl-2, caspase 9, and caspase 3). These findings suggested that hybrid 14f serves as a promising anti-hepatoma lead compound that deserves further research.