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. (C) 2018 Published by Elsevier B.V.