Extraction of polysaccharide from Ganoderma lucidum and its immune enhancement activity

In the present study, in order to maximize the yield of polysaccharides from Ganoderma lucidum, response surface methodology was employed to optimize the ultrasonic/microwave-assisted extraction (UMAE) conditions. The results indicated that the optimal extraction conditions were ultrasonic power of 50 W, microwave power of 284 W, extraction time of 701 s and water/solid ratio of 11.6:1, respectively. Using UMAE, the yield of polysaccharides was 115.56% above that of classical hot water extraction (HWE) and increased by 27.7% as against ultrasound-assisted extraction (UAE), which confirmed the great potential application of UMAE technology in the extraction of polysaccharides. The immunological assays results demonstrated that polysaccharides of G. lucidum extracted by ultrasonic/microwave (UMP) could improve the weight of immune organ of immunocompromised mice, restore delayed-type hypersensitivity (DTH) reaction to DFNB, improve hemolysis antibody level and natural killer cell activity at high-dose. However, UMP had no noticeable effects on phagocytosis of monocyte at the tested dosage range. (C) 2010 Published by Elsevier B.V.