Chitosan–Quercetin Bioconjugate as Multi‐Functional Component of Antioxidants and Dual‐Responsive Hydrogel Networks

Abstract

Multifunctional hydrogels based on chitosan–quercetin (CHITQ) conjugate are prepared by a thermo‐induced radical procedure in the presence of N‐isopropylacrylamide (NIPAAm), acrylamide (AAm), and N,N′‐methylenebis(acrylamide) (MEBA). At first, quercetin (Q) is grafted onto chitosan backbone with a functionalization degree of 275 mg of Q per gram of conjugate, as calculated by 1H‐NMR analyses to impart antioxidant properties to the polysaccharide. Then, a pH and temperature sensitive hydrogel was obtained by involving CHITQ and NIPAAm in the polymerization reaction. The accessibility of phenolic moieties is modified in response to the hydrogel swelling/deswelling, as confirmed by antioxidant tests performed at different temperatures. Dual stimuli‐responsive hydrogels are proposed for the delivery of caffeine as model drug. The release profiles of caffeine depict a system particularly performing as on/off device at acidic pH with excellent applicability prospects.

Sangiovese cv Pomace Seeds Extract-Fortified Kefir Exerts Anti-Inflammatory Activity in an In Vitro Model of Intestinal Epithelium Using Caco-2 Cells

“…The amount of total phenolic equivalents (TPE) in the extracts and fortified and unfortified kefir was determined using Folin-Ciocalteu reagent procedure [27]. Total phenolic compounds was expressed as milliequivalents of gallic acid (GA) per grams of extract.…”

A Tara Gum/Olive Mill Wastewaters Phytochemicals Conjugate as a New Ingredient for the Formulation of an Antioxidant-Enriched Pudding

“…Our scientific experience suggests that antioxidant features of biomolecules in the olive mill wastewaters (OMW), as well as leaves, pomace and pits discharged from the EVOO production process, are partially recycled and usefully employed in the nutraceutical and pharmaceutical fields [ 4 , 5 ]. To this regard, literature data highlighted that the employment of macromolecular antioxidants displayed some undoubted advantages such as increased stability and slower degradation rate, compared to the compounds with low molecular weight [ 6 ]. In particular, polysaccharides are involved in the preparation of different foodstuffs specifically in a wide variety of milk-based desserts such as pudding due to their ability to influence the rheological and texture characteristics of the final product [ 7 ].…”

Nanotechnologies: An Innovative Tool to Release Natural Extracts with Antimicrobial Properties

“…Biomedical devices based on chitosan (CT) were exploited for developing nanofibrous wound dressing materials [164]. Additionally, CT is also known for its strong antibacterial activity against different fungi, bacteria, and viruses [165][166][167]. However, CT viscosity, as well as the high charge of the polysaccharide chains, made difficult the electrospinning process, and the application of highly acidic and toxic solvents was required [168].…”