Construction of Ginsenoside Nanoparticles with pH/Reduction Dual Response for Enhancement of Their Cytotoxicity Toward HepG2 Cells

The aim of this study is to construct a pH- and reduction-responsive nanodrug delivery system to effectively deliver a ginsenoside (Rh-2) and enhance its cytotoxicity against human hepatocarcinoma cells (HepG2). Here, pullulan polysaccharide was grafted by urocanic acid and alpha-lipoic acid (alpha-LA) to obtain a copolymer, alpha-LA-conjugated N-urocanyl pullulan (LA-URPA), which was expected to have pH and redox dual response. Then, the copolymer LA-URPA was used to encapsulate ginsenoside Rh-2 to form Rh-2 nanoparticles (Rh-2 NPs). The results showed that Rh-2 NPs exhibited an average size of 119.87 nm with a uniform spherical morphology. Of not; Rh 2 NPs showed a high encapsulation efficiency of 86.00%. Moreover, Rh-2 NPs possessed excellent pH/ reduction dual-responsive drug release under acidic conditions (pH 5.5) and glutathione (GSH) stimulation with a low drug leakage of 14.8% within 96 h. Furthermore, Rh-2 NPs with pH/reduction dual response had higher cytotoxicity than Rh-2 after incubation with HepG2 cells for 72 h, indicating that Rh 2 NPs had a longer circulation time. After the treatment with Rh-2 NPs, the excessive increase of reactive oxygen species and the decrease of superoxide dismutase, glutathione (GSH), and mitochondrial membrane potential suggested that the mitochondrial pathway mediated by oxidative stress played a role in this Rh-2 NP-induced apoptosis. In conclusion, this study provides a new strategy for improving the application of ginsenoside Rh, in the food and pharmaceutical fields.