Effect of Carbon Source on Properties and Bioactivities of Exopolysaccharide Produced by Trametes ochracea (Agaricomycetes).

The effects of carbon source on properties and bioactivities of exopolysaccharide (EPS) produced by Trametes ochracea were investigated in this study. The results indicated that EPS production varied with five different carbon sources. After a fermentation period of 8 days, sucrose was the most suitable carbon source for biomass and EPS production. The predominant carbohydrate compositions in EPSs identified were glucose and mannose. The EPS fermented by sucrose has the highest glucose content. Then, FT-IR spectral analysis revealed prominent characteristic groups in EPSs. Each particular EPS possessed the specific bands at 808-809 cm-1 and 914-922 cm-1, indicating both α- and ß-configurations of the sugar units. Furthermore, thermogravimetric analysis (TGA) indicated the EPS with sucrose and glucose as carbon source showed different degradation behavior compared with the other three EPSs. The variation also affects antioxidant and antihyperlipemia activities investigated using hydroxyl and DPPH radical scavenging assay, and in hyperlipemia mice. Sucrose was the best carbon source from the viewpoint of OH and DPPH radical scavenging activities, and antihyperlipemia activity, probably due to the relatively high glucose content in EPS.

Pectin-decorated selenium nanoparticles as a nanocarrier of curcumin to achieve enhanced physicochemical and biological properties.

In this study, the authors developed pectin-stabilised selenium nanoparticles (pectin-SeNPs) for curcumin (Cur) encapsulation and evaluated their physicochemical properties and biological activities. Results showed that pectin-SeNPs and Cur-loaded pectin-SeNPs (pectin-SeNPs@Cur) exhibited monodisperse and homogeneous spherical structures in aqueous solutions with mean particle sizes of ∼61 and ∼119 nm, respectively. Cur was successfully encapsulated into pectin-SeNPs through hydrogen bonding interactions with an encapsulation efficiency of ∼60.6%, a loading content of ∼7.4%, and a pH-dependent and controlled drug release in vitro. After encapsulation was completed, pectin-SeNPs@Cur showed enhanced water solubility (∼500-fold), dispersibility, and storage stability compared with those of free Cur. Moreover, pectin-SeNPs@Cur possessed significant free radical scavenging ability and antioxidant capacity in vitro, which were stronger than those of pectin-SeNPs. Antitumour activity assay in vitro demonstrated that pectin-SeNPs@Cur could inhibit the growth of HepG2 cells in a concentration-dependent manner, and the nanocarrier pectin-SeNPs exhibited a low cytotoxic activity against HepG2 cells. Therefore, the results suggested that pectin-SeNPs could function as effective nanovectors for the enhancement of the water solubility, stability, and in vitro bioactivities of hydrophobic Cur.