Comparison on structure, chain conformation, and antioxidant activity of polysaccharides extracted from Liriopes radix with hot water and ultrasound

The structures and chain conformations of two polysaccharides from Liriopes radix, WPRL-DS and UPRL-DS, isolated with hot water and ultrasound, respectively, were investigated by a combination of IR, GC, GC-MS, periodate oxidation, Smith degradation, NMR, AFM, and Congo red test. The results proved that the yield of ultrasonic extraction (UPRL-DS) was higher than that of hot water extraction (WPRL-DS). UPRL-DS had the same primary structure as WPRL-DS. However, UPRL-DS was spirally shaped whereas WPRL-DS was not. Both WPRL-DS and UPRL-DS were proved to have significant antioxidant activities as evidenced by their hydroxyl radical, superoxide anion, and 1,1-diphenyl-2-picryl-hydrazyl radical scavenging activities. UPRL-DS exhibited more effective antioxidant activity than WPRL-DS in a concentration-dependent manner.