Effect of extraction methods on the properties and antioxidant activities of Chuanminshen violaceum polysaccharides

The yields, properties and antioxidant activities of polysaccharides extracted from Chuanminshen violaceum (CVPs) by various methods including heated reflux extraction (HRE), ultrasound-assisted extraction (UAE), and microwave-assisted extraction (MAE), were evaluated. The results indicated that the yield of the polysaccharides (34.59%) obtained by MAE was higher than those obtained by other methods. Polysaccharides extracted by all three methods had similar physicochemical characteristics and FT-IR spectra. However, SEM images of particles of Chuanminshen violaceum treated by the three different methods were significantly different. Compared with HRE, UAE and MAE resulted in CVPs with lower molecular weight distributions and higher reducing power and scavenging abilities for ABTS(+center dot) and DPPH center dot. CVPs obtained by UAE had reduced scavenging abilities for DPPH center dot compared to those obtained by MAE. These data indicated that MAE resulted in better extraction yields for CVPs and also resulted in CVPs with higher bioactivity. (C) 2016 Elsevier B.V. All rights reserved.