Antioxidant activities of an exopolysaccharide isolated and purified from marine Pseudomonas PF-6

An acidic exopolysaccharide (EPS) was isolated and purified from marine Pseudomonas PF-6. The test of physical properties indicated that the EPS was odorless, soluble in water, insoluble in organic solvents, and had a molecular weight of 8.83 x 10(5) Da. The test of chemical properties of the EPS showed that the EPS could be oxidized into uronic acid. Infrared spectrometry analysis exhibited absorption bands at 927.49 cm(-1) and 811.76 cm(-1), suggesting that the EPS belonged to a beta-type heteropolysaccharide with a pyran group. Several in vitro assays were applied to evaluate the antioxidant potential of the EPS. Results showed that the acidic EPS had scavenging actions on DPPH., center dot OH and O-2(-)center dot and the antioxidant activities increased with increases in its concentration. The scavenging action of the EPS on center dot OH was stronger than that of V-c, and its activity on O-2(-)center dot was almost the same as that of V-c. Crown Copyright (C) 2011 Published by Elsevier Ltd. All rights reserved.