Isolation of a polysaccharide with antiproliferative, hypoglycemic, antioxidant and HIV-1 reverse transcriptase inhibitory activities from the fruiting bodies of the abalone mushroom Pleurotus abalonus

Objective The intent of this study was to purify and characterize a polysaccharide named LA from the fruiting bodies of the edible mushroom Pleurotus abalones. Methods The 120-kDa polysaccharide was obtained by extraction with boiling water, ethanol precipitation, ion exchange chromatography on Diethylaminoethyl-cellulose and gel filtration on Sephadex G-200. Key findings The LA was composed of glucose, rhamnose, glucuronic acid, xylose, galactose and arabinose in the molar ratio of 26.3 : 2.7 : 1 : 1.4 : 1.8 : 1.2. The FITR and 1H-NMR spectrum of LA disclosed that it was a saccharide with an alpha-configuration. Its 13C-NMR spectrum revealed that its main chain was [-> 6)-alpha-d-Gly(1 ->](n). The LA exhibited antioxidant activities, especially in scavenging 1,1- diphenyl-2-picryl-hydrazyl radicals and hydroxyl radicals. It manifested antiproliferative activity towards breast cancer MCF7 cells with an IC50 of 3.7 mu m, and also exerted some antiproliferative activity against HepG2 cells. It manifested a hypoglycemic action on diabetic mice. It inhibited HIV-1 reverse transcriptase with an IC50 of 8.7 x 10-2 mu m. Conclusions The polysaccharide from the abalone mushroom.