Immunopontentiating activities of the purified polysaccharide from evening primrose in H22 tumor-bearing mice.

A water-soluble polysaccharide named as EPP was isolated and purified from evening primrose by hot water extraction, alcohol-precipitation, anion exchange and gel permeation chromatography. EPP had a weight-average molecular weight of about 9.8 kDa and was composed of glucose (Glc), galactose (Gal), mannose (Man), arabinose (Ara) and rhamnose (Rha) in a molar ratio of 2.4:3.1:1.3:1.9:1.0. After 10 days of administration with EPP to H22 tumor-bearing mice, a significant increase in tumor growth inhibitory rate, body weight, relative spleen weight, lymphocytes proliferation, natural killer (NK) cell activity, macrophage phagocytosis, delayed type hypersensitivity (DTH), white blood cell and lymphocyte counts were observed at the dose of 25, 50 and 100 mg/kg. Meanwhile EPP treatment decreased the serum levels of alanine aminotransferase (ALT), aspartate aminotransferase (AST), alkalines phosphatases (ALP), creatinine and urea of tumor-bearing mice to normal levels. Thus, these data proved that EPP might be employed as effective therapeutic agents in the regulation of diverse immune reactions implicated in cancer.