Antitumor effect of a polysaccharide isolated from Phellinus pullus as an immunostimulant.

The antitumor function of fungal polysaccharides is a popular area of interest in the research field due to their high efficiency and low side effects. The main mechanism of fungal polysaccharides is immune enhancement. The polysaccharose (APS-3) was extracted from the fruit body of Phellinus pullus. The proliferation inhibition to mouse sarcoma 180 (S180) tumor cells was studied by the MTT method. Mice models of transplanted S180 tumor were established and treated with APS-3 to verify the antitumor activity in vivo. Natural killer (NK) and lymphokine-activated killer (LAK) cytotoxicities of the mice were evaluated by the lactate dehydrogenase method. APS-3 can significantly inhibit the proliferation of the S180 cells. Cells could be completely inhibited by 1.6 mg/ml APS-3 after 24 h treatment. After 18 days of treatment, the antitumor rate of the high-dose group was 85.47%. Histopathology detection showed that for the APS-3-treated mice, the tumor cells dissolved, and exhibited a large range of structureless necrotic areas. NK and LAK cytotoxicities of the APS-3 treated mice increased by 61.85 and 56.16%, respectively, compared with the normal control mice. APS-3 can be used as an antitumor agent by way of immune enhancement.