Rhelogical, dermal wound healing and in vitro antioxidant properties of exopolysaccharide hydrogel from Pseudomonas stutzeri AS22

The in vitro antioxidant activity and the in vivo wound healing performance of the exopolysaccharide EPS22, produced by Pseudomonas stutzeri AS22, were investigated. Antioxidant activity was evaluated by three different tests. The scavenging effect on DPPH radicals at a concentration of I mg/ml was 80 +/- 1.41%. The reducing power reached a maximum of 1.26 +/- 0.02 at 2 mg/ml. Moreover, EPS22 showed good chelating ability and chelated almost 88.5 +/- 0.7% of ferrous ions at 0.75 mg/ml. The rheological characterization of EPS22 gel (0.5%) showed a pseudoplastic behavior, high elasticity, good mechanical strength and stability with high water-absorption ability. The application of the EPS22 gel on dermal full-thickness excision wounds in a rat model every two days, enhanced significantly wound healing activity and a total closure was achieved after 12 days of wound induction. Further, histological examination of biopsies showed advanced tissue regeneration, characterized by the presence of well-organized stratum of both derma and epidermis. (C) 2014 Elsevier B.V. All rights reserved.