Antitumor and immunomodulating effects of polysaccharides isolated from Solanum nigrum Linne.

We have examined the effects of the crude polysaccharides isolated from Solanum nigrum Linne (SNL-P) in vitro and in vivo against U14 cervical cancer. SNL-P showed no antiproliferative effects in vitro at a dose up to 1 mg/ml. In vivo administration with SNL-P (90, 180, 360 mg/kg b.w., p.o.) decreased the number of ascites tumor cells and prolonged the survival time of U14 cervical-cancer-bearing mice. FACScan flow cytometer analysis showed that most of the ascites tumor cells were arrested in G2/M phase of cell cycle and the ratio of CD4+/CD8+ peripheral blood T-lymphocyte subpopulations were restored following treatment of SNL-P. Furthermore, the treatment with SNL-P also caused a significant increment in IFN-gamma (p < 0.01, 90, 180 and 360 mg/kg b.w.) and a remarkable decrease in Il-4 (p < 0.01, 90, 180 mg/kg b.w.; p < 0.05, 360 mg/kg b.w.) by the method of ELISA. These data showed that SNL-P possess potent antitumor activity and SNL-P might exert antitumor activity via activation of different immune responses in the host rather than by directly attacking cancer cells on the U14 cervical cancer bearing mice. Thus, SNL-P could be used as an immunomodulator and an anticancer agent.