Sulfated modification of longan polysaccharide and its immunomodulatory and antitumor activity in vitro.

A water-soluble polysaccharide fraction (LP1) was prepared from Dimocarpus longan Lour. by hot water extraction, DEAE-cellulose and Sephadex G-100 chromatography. Its sulfated derivative (LP1-S) was prepared by the sulfuric acid method. Preliminary tests in vitro showed LP1 and LP1-S could stimulate murine lymphocytes proliferation, increase pinocytic activity of murine macrophages and production of nitric oxide (NO), interleukin 6 (IL-6), IL-1β and tumor necrosis factor-alpha (TNF-α) in macrophages. Furthermore, LP1-S exhibited higher antiproliferative activity against human nasopharyngeal carcinoma HONE1 cells in vitro than LP1, which might be caused by the sulfate group in its structures. These results indicated that the LP1-S might be useful for developing safe antitumor drugs or health food.