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 α-lipoic acid (α-LA) to obtain a copolymer, α-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 note, 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 ₂ in the food and pharmaceutical fields.