Preparation, characterization, and antitumor immunity activity of polysaccharide fractions from Radix Tinosporae in vivo

To investigate the preliminary structural characteristics and functions of polysaccharides from Radix Tinosporae, a neutral α-glucan polysaccharide, RTP-W with a molecular weight of 14.248 kDa was obtained. The potential therapeutic effect of RTP-W on hepatocellular carcinoma was investigated in vivo. Structural analysis revealed that RTP-W comprises a backbone of (1 → 4)-linked α-D-Glcp units with the occasional occupancy of α-Glcp-(1 → at the O-6 position for every nine α (1 → 4)-D-Glcp unit. Studies showed that RTP-W significantly protects the liver against cancer, extends the survival of mice with liver cancer, and lowers ALT, AST, and GGT levels in their blood. Further investigation revealed that RTP-W reversed the exhaustion of CD8⁺ T cells by reducing PD-1 expression and promoting cell proliferation and cytokine expression, primarily through the activation of the Akt signaling pathway. These findings indicate that RTP-W has promising potential as an immunomodulatory agent with antitumor effects.