Extraction optimization of antioxidant polysaccharides from the fruiting bodies of Chroogomphis rutilus (Schaeff.: Fr.) OK Miller by Box-Behnken statistical design

Response surface methodology (RSm) was used to optimize the extraction conditions of polysaccharides (CRP) from the fruiting bodies of Chroogomphis rutilus with a Box-Behnken design (BBD). Three independent variables such as extraction temperature (degrees C), extraction time (h) and ratio of water to raw material were investigated. The experimental data obtained were fitted to a second-order polynomial equation using multiple regression analysis. The 3-D response surface plot and the contour plot derived from the mathematical models were applied to determine the optimal conditions. The optimum extraction conditions were as follows: extraction temperature 96.6 degrees C, extraction time 2.7h and ratio of water to raw material 22. Under these conditions, the experimental value of 57.7 +/- 0.77 was well in close agreement with value predicted by the model. Preliminary in vitro antioxidant activity test showed CRP could scavenge hydroxyl radicals in a dose-dependent manner. (C) 2010 Elsevier Ltd. All rights reserved.