Antitumor effects and immune regulation activities of a purified polysaccharide extracted from Juglan regia.

A water-soluble polysaccharide, named as JRP1, was extracted and fractioned from the epicarp of immature fruit of Juglans mandshurica Maxim. The determination of the monosaccharide composition in JRP1 with gas chromatography (GC) showed that JRP1 was composed of Gal (43.1%), Glu (23.6%), Ara (16.2%), Rha (9.8%) and Fru (7.3%). The results in vitro showed that 25, 50 and 100 μg/mL of JRP1 could present a significant inhibition on the growth of S180 cells, and furthermore, a significant improvement on the proliferation ability of lymphocytes and the phagocytic activity of macrophages. The results in vivo showed that compared with those in the control group, the inhibition rates of different doses of JRP1 on S180 cells in the tumor-bearing mice were 35.3%, 40.6% and 48.1%, respectively, and serum immune cytokine levels such as IL-2, TNF-α and IFN-γ were significantly improved. Our results confirm that JRP1 has the activities of effective antitumor and immunomodulatory function.