Penthorum chinense Pursh polysaccharide induces a mitochondrial-dependent apoptosis of H22 cells and activation of immunoregulation in H22 tumor-bearing mice

Penthorum chinense Pursh has been widely used as a Chinese traditional functional food for liver disease prevention and therapy. A novel cold-water soluble polysaccharide (PCP-4) has been prepared from Penthorum chinense Pursh at 4 °C. PCP-4 contained both α and β configurations and mainly consisted of galactose, arabinose, galacturonic acid, rhamnose, and glucose (molar ratio: 6.38:5.26:1.69:1:0.87) with an average molecular weight of 1.83 × 106 Da. In vitro experiments results demonstrated that PCP-4 effectively inhibits the proliferation of H22 cells and blocks cells at S phase in a dose-dependent manner. Otherwise, PCP-4-treated cells exhibited typical morphological features of apoptotic cells. Combined the results from western blot analysis, Annexin V-FITC/PI staining, Rhodamine 123 staining and DCFH-DA staining, PCP-4 was found to induce H22 cell apoptosis in vitro via the mitochondrial signaling pathway. The results of in vivo experiments suggested that PCP-4 significantly suppresses xenograft tumor growth by protecting immune organs, enhancing immune cells functionality, and inducing apoptosis. Overall, these results clearly show that Penthorum chinense Pursh polysaccharide serves as a valuable natural product for hepatocellular carcinoma therapy.