Antitumor and immunomodulatory activity of polysaccharides from the root of Limonium sinense Kuntze

Limonium sinense (Girard) Kuntze is a traditional Chinese folk medicine used for the treatment of fever, hemorrhage, hepatitis and other disorders. The study focused on the antitumor and immunomodulatory activities of L. sinense polysaccharides (LSP) which was obtained from the root of the plant. The antitumor effects of only LSP and LSP in combination with 5-fluorouracil (5-FU) were both evaluated with Heps-bearing tumor mice models. In addition, the macrophage phagocytosis assay, splenocyte proliferation and cytokines production tests were used to assess the immunomodulatory activities of LSP. The results revealed that the LSP (at the dose of 200 and 400 mg/kg) had an obvious inhibition on the growth of transplanted mouse tumor. It also exhibited a significant synergistic effect of antitumor activity when combined with 5-FU (p < 0.05). Furthermore, the LSP (at the dose of 100 and 200 mg/kg) remarkably improved macrophage phagocytosis function in immune suppressed mice. In addition, LSP (at the dose of 50-200 μg/ml) showed significant synergistic effects on ConA-stimulated proliferation and IFN-γ and IL-2 production of splenocyte in vitro (p < 0.05). These findings suggest that LSP had clear antitumor activity which might be related to its regulation of immune function in mice.