Antitumor activity of polysaccharides from Lepista sordida against laryngocarcinoma in vitro and in vivo

Four water-soluble polysaccharides (LSPa1, LSPb1, LSPb2 and LSPc1) extracted from the fruiting bodies of Lepista sordida were prepared by DEAE cellulose-52 anion-exchange and Sepharose 6 Fast Flow gel-permeation chromatography. LSPa1 was composed of Glc, Man and Gal with a molar ratio of 3.2: 1.3: 0.6. LSPb1, LSPb2 and LSPc1 were composed of Glc, Man, Gal, Rha and Ara in the proportions of 2.6: 2.1: 0.9: 0.6: 0.3, 1.2: 1.0: 2.3: 0.6: 0.5, 0.2: 0.3: 2.3: 0.3: 2.0, respectively. The high-performance gel-permeation chromatography (HPGPC) analysis showed that the average molecular weight (Mw) of four polysaccharides were approximately 156, 134, 96 and 57 kDa, respectively. MTT and lactate dehydrogenase (LDH) assays indicated that three acidic polysaccharides, namely LSPb1, LSPb2 and LSPc1, possessed more potent antiproliferative effect on human laryngocarcinoma Hep-2 cells than neutral polysaccharide LSPa1 in a dose- and time-dependent manner and the effect increased in the order of LSPa1 < LSPb2 < LSPb1 < LSPc1, which is the same as their uronic acid content. Furthermore the tumor volume and tumor weight were also obviously suppressed after two weeks' treatment of LSPc1 to mice engrafted with Hep-2 cancer cells. Results of these studies demonstrated that the polysaccharide LSPc1 had a potential application as natural antitumor drugs.