Abstract

Three water-soluble polysaccharides (DDP1-1, DDP2-1 and DDP3-1) were obtained from the aqueous extracts of the stems of Dendrobium denneanum by hot water extraction, ethanol precipitation, and fractionated by DEAE-cellulose ion exchange chromatography and Sephadex G-200 gel filtration chromatography. The main structure characterizations and anti-tumor activities of three fractions were evaluated in this paper. The results showed DDP1-1 with 12.50 mg/kg could significant inhibit the increment of the tumor, increase immune index of S180 mice, and also strongly promote the secretion of IL-2, TNF-α and IFN-γ. Therefore, results of these studies demonstrated the polysaccharide DDP1-1 has strong anti-tumor and immunomodulation abilities.

Key words: Immunomodulating, Dendrobium denneanum, polysaccharide, anti-tumor.