Biological activities and wound healing potential of a water-soluble polysaccharide isolated from Glycyrrhiza glabra in Wistar rat.

The present study aimed to evaluate the in vitro antibacterial and antioxidant activities and the in vivo wound healing performance of a polysaccharide isolated from Glycyrrhiza glabra named PSG. It was structurally characterized by Fourier transformed infrared (FT-IR) spectroscopy, which confirmed the presence of different polysaccharides functional bands. The antioxidant capacity of PSG was determined in vitro and evaluated in vivo through the examination of wound healing capacity. Thirty two rats were randomly divided into four groups: group I was treated with physiological serum (negative control); group II was treated with "CYTOL CENTELLA®"; group III was treated with glycerol and group IV was treated with polysaccharide. The response to treatments was assessed by macroscopic, histologic, and biochemical parameters. Data revealed that our sample exhibited potential antioxidant activities and accelerated significantly the wound healing process, after ten days of treatment, proved by the higher wound appearance scores and a higher content of collagen confirmed by histological examination, when compared with control and "CYTOL CENTELLA®". Overall, these findings proved that this polysaccharide isolated from Glycyrrhiza glabra could be considered as a natural bioactive polymer for therapeutic process in wound healing applications.

Dielectric environment and/or random disorder effects on free, charged and localized excitonic states in monolayer WS2.

Excitonic effects play an important role on the optoelectronic behavior of atomically thin two-dimensional (2D) crystals of the WS2 transition metal dichalcogenide. In this paper, neutral and charged exciton behaviors in monolayer WS2 are handled within effective-mass approximation for which the critical parameters are ensured from our ab initio calculations. Firstly, we reveal an exciton series with a novel energy dependence on the orbital angular momentum. Considerable control of the dielectric environment on neutral and charged excitons binding energies is elucidated. We demonstrate that for accepted values of effective masses, the negative and positive trion binding energies should be identical. Secondly, localization of neutral exciton center of mass motion by random potential arising from monolayer defects is also studied. The results obtained are in agreement with available experimental work.