Optimization of ultrasonic/microwave assisted extraction (UMAE) of polysaccharides from Inonotus obliquus and evaluation of its anti-tumor activities

Recently, the use of ultrasonic and microwave has attracted considerable interest as an alternative approach to the traditional extraction methods. In this paper, in order to maximize the yield and purity of polysaccharides from Inonotus obliquus, response surface methodology (RSM) was employed to optimize the ultrasonic/microwave assisted extraction (UMAE) conditions. The results indicated that the optimal conditions for UMAE were 90 W microwave power, 50 W ultrasonic power together with 40 kHz ultrasonic frequency, solid/water ratio was 1:20 (W/V) and the extracting time was 19 min, respectively. Under the optimal conditions, the yield and purity of polysaccharides were 3.25% and 73.16%, respectively, which are above that of traditional hot water extraction and close to the predicted value (3.07% and 72.54%, respectively). These results confirmed that ultrasonic/microwave assisted extraction (UMAE) of polysaccharides had great potential and efficiency compared with traditional hot water extraction. At the same time, the anti-tumor activities of the polysaccharides from I. obliquus with UMAE were evaluated. The results suggested that polysaccharides from I. obliquus exhibited obvious anti-tumor activities.