Preparation of Prunella vulgaris polysaccharide-zinc complex and its antiproliferative activity in HepG2 cells

Prunella vulgaris polysaccharides have been reported to have antioxidant, antitumor and immunomodulatory activities. In this study, P. vulgaris polysaccharide (P1)-zinc complex (P1-Zn) was first prepared by a facile method and its antiproliferative effect on HepG2 human hepatocellular carcinoma cells was also investigated. Results showed that P1-Zn could effectively inhibit the proliferation (98.4% inhibition rate at 500 μg/mL) of HepG2 cells through induction of apoptosis, evidenced by morphological changes, chromatin condensation and G0/G1 phase cell cycle arrest. The intracellular mechanism of P1-Zn induced apoptosis was found to be the involvement of the activation of caspase-3 and -9, reactive oxygen species (ROS) overproduction and mitochondrial dysfunction. Our findings suggest that P1-Zn may be a potent candidate for human hepatocellular carcinoma treatment and prevention in functional foods and pharmacological fields.