Comparison on characterization and antioxidant activity of polysaccharides from Ganoderma lucidum by ultrasound and conventional extraction

The polysaccharides of Ganoderma lucidum (GLP) extracted by the methods of ultrasound assisted extraction (UAE) and hot water extraction (HWE) were characterized and the antioxidant activities of GLP UAE and GLP HWE were compared. High performance gel permeation chromatography (HPGPC) showed that the average molecular weight of GLP UAE and GLP HWE were 465.65 kDa and 703.45 kDa, respectively. GLP UAE was composed of mannose , rhamnose , glucose, galactose and arabinose in the molar ratio of 2.58:1.25:11.17:2.5:1, while GLP HWE was composed of the same monosaccharide in the ratio of 3.11:1.11:19.44:2.33:1. GLP HWE showed a relatively higher antioxidant activity than GLP UAE by testing the reducing power, the scavenging ability on 1.1‑diphenyl‑2‑picryl‑hydrazyl (DPPH), hydroxyl radical and cellular protective effect on yeast cells from ultraviolet radiation (UV) damage. GLP UAE and GLP HWE were purified by chromatographic column of DEAE-52 cellulose . GLP UAE , GLP HWE and the purified components could be novel antioxidants for functional food.