AUTHOR=Policastro Debora , Giorno Eugenia , Scarpelli Francesca , Godbert Nicolas , Ricciardi Loredana , Crispini Alessandra , Candreva Angela , Marchetti Fabio , Xhafa Sonila , De Rose Renata , Nucera Antonello , Barberi Riccardo C. , Castriota Marco , De Bartolo Loredana , Aiello Iolinda 

TITLE=New Zinc-Based Active Chitosan Films: Physicochemical Characterization, Antioxidant, and Antimicrobial Properties

JOURNAL=Frontiers in Chemistry

VOLUME=Volume 10 - 2022

YEAR=2022

URL=https://www.frontiersin.org/journals/chemistry/articles/10.3389/fchem.2022.884059

DOI=10.3389/fchem.2022.884059

ISSN=2296-2646

ABSTRACT=The improvement of the antioxidant and antimicrobial activities of chitosan (CS) films can be realized by incorporating transition metal complexes as active components. In this context, bio-active films were prepared by embedding a newly synthesized acylpyrazolonate Zn(II) complex, [Zn(QPhtBu)2(MeOH)2], into the eco-friendly biopolymer chitosan matrix. Homogeneous, amorphous, flexible and transparent CS@Znn films were obtained through the solvent casting method in dilute acidic solution, using different weight ratios of the Zn(II) complex to chitosan and characterized by PXRD, TGA, DSC, FTIR, Raman, and SEM techniques. The X ray single crystal analysis of [Zn(QPhtBu)2(MeOH)2] and the evaluation of its intermolecular interactions with a protonated glucosamine fragment through Hydrogen Bond Propensity (HBP) calculations are reported. The effects of the different content of the [Zn(QPhtBu)2(MeOH)2] complex on the CS biological proprieties have been evaluated, proving that the new CS@Znn films show improved antioxidant activity, tested according to DPPH method, with respect to pure CS, related to the concentration of the incorporated Zn(II) complex. Finally, the CS@Znn films were tried out as antimicrobial agents, showing an increase in antimicrobial activity against Gram-positive bacteria (Staphylococcus Aureus) with respect to pure CS, when detected by the Agar Disk-Diffusion Method.