Optimization for the extraction of polysaccharides from Ganoderma lucidum and their antioxidant and antiproliferative activities

Response surface methodology was used to optimize the ultrasonic extraction parameters for polysaccharides from Ganoderma lucidum. The optimal extraction conditions were as follows: ultrasonic power 320 W, temperature 70 degrees C and time 34 min. Using these parameters, the experimental yield was 2.78%, and the oxygen radical absorbance capacity (ORAC) value was 1956 mu mol Trolox/g, both of which were not significantly different from their predicted values. Then G. lucidum polysaccharides (GLP) were separated into four fractions: GLP1 (>10 kDa), GLP2 (8-10 kDa), GLP3 (2.5-8 kDa) and GLP4 (<2.5 kDa) using ultrafiltration membranes. All the polysaccharide fractions were rich in glucose and galactose. In vitro antioxidant activities (including 2,2-diphenyl-1-picrylhydrazyl (DPPH) radical scavenging activities, reducing power, ferrous ion chelating abilities and ORAC values) and antiproliferative activities against PC12 cells of all of the polysaccharide fractions were evaluated. Results indicated that GLP1 and GLP2 had stronger antioxidant and antiproliferative activities than the other fractions, which may be related to their molecular weight profiles. (C) 2013 Taiwan Institute of Chemical Engineers. Published by Elsevier B.V. All rights reserved.