Dextran-immobilized curcumin: An efficient agent against food pathogens and cancer cells

Abstract

Curcumin–dextran conjugate was synthesized by free radical grafting reaction between curcumin and dextran. The chemical characterization of the conjugate was obtained by Fourier-transform infrared and 1H-NMR (proton nuclear magnetic resonance) spectroscopy analysis, while the functionalization degree was determined by the Folin–Ciocalteu assay, finding a 22.93 mg of curcumin/g of dextran conjugate. Antioxidant activity of curcumin and curcumin–dextran conjugate was investigated employing DPPH• radical method, and IC50 (the half maximal inhibitory concentration) values of curcumin and the curcumin–dextran conjugate (Cur equivalents) were 86.6 ± 0.1 and 17.4 ± 1 µM, respectively. The presence of dextran into the curcumin–dextran conjugate improved radical scavenging activities of the curcumin. In addition, antimicrobial effect of curcumin and curcumin–dextran conjugate was evaluated against gram-positive ( Listeria monocytogenes and Staphylococcus aureus) and gram-negative ( Escherichia coli O157:H7 and Salmonella typhimurium) bacteria. According to our experiments, gram-positive microorganisms are more sensitive to these compounds than gram-negative ones. Curcumin–dextran is a more potent bacteriostat ( S. aureus (minimum inhibitory concentration = 0.008 µg/mL), E. coli O157:H7 (minimum inhibitory concentration = 250 µg/mL), and S. typhimurium (minimum inhibitory concentration = 500 µg/mL)) and also a more potent bacteriosid against S. aureus and S. typhimurium than curcumin. The cytotoxic effects of the curcumin–dextran conjugate toward AGS, MCF-7, and normal fibroblast cell lines were determined at 48 and 72 h using an MTT assay. The results revealed the considerable antiproliferative effects of the curcumin–dextran conjugate in both AGS and MCF-7 cancer cells in comparison with fibroblast cells. This study shows that dextran as a versatile scaffold develops the biological activities of curcumin by covalent grafting and can be regarded in further bioapplications.

Alginate Bioconjugate and Graphene Oxide in Multifunctional Hydrogels for Versatile Biomedical Applications

“…To prove this hypothesis, the retainment of CF antioxidant potency upon conjugation to Alg and the further co-polymerization in the acrylate network were assessed by determining the available phenolic groups by the Folin–Ciocalteu tests [ 63 ], the Trolox (6-hydroxy-2,5,7,8-tetramethylchroman-2-carboxylic acid) equivalent antioxidant capacity (TEAC) [ 64 ], and the concentration needed for a 50% decay (IC 50 ) of DPPH (1,1-diphenyl-2-picrylhydrazyl) radical [ 65 ].…”

“…The amount of total phenolic equivalents, expressed as CF equivalent per g of sample was determined using Folin–Ciocalteu assay, as reported in [ 63 ], using the calibration curve of the free antioxidant. The TEAC values were determined according to a previously reported protocol with slight modifications [ 64 ].…”

Future and the past of polymeric antioxidants

“…Polymeric conjugates of polyethylene glycol and resveratrol, regardless of the polymer‐AO spacer structure, were able to secure resveratrol against metabolism in vitro and displayed an enhanced pharmacokinetic profile of the products 44 . Some researchers suggested introducing AO by free radical grafting to the polymer 45‐48 …”

“…Thus, it has been established that due to the presence of quercetin fragments in the starch chain, the latter acquires not only AO properties but also the resistance to the degradation of the polymer chain 47 . In the case of using another polysaccharide dextran, the conjugation of easily oxidized gallate increases the stability of the antioxidant itself, which significantly increases the antioxidant potential of the entire system 48 …”

Dextran-Curcumin Nanoparticles as a Methotrexate Delivery Vehicle: A Step Forward in Breast Cancer Combination Therapy

“…We chose curcumin (CUR) as polyphenol moiety because of its well-known biological properties and ability to be used in combination chemotherapy protocols for the treatment of a wide number of cancer diseases with high efficiency [17,18]. In the literature, different CUR-polymer conjugates (e.g., xylan [19], hyaluronic acid [20], chitosan [21], Dextran [22], PEG [23], and albumin [24]) were reported with the purpose to improve the anticancer performance of the polyphenol and to synergize conventional chemotherapeutics such as methotrexate (MTX), doxorubicin, and paclitaxel. Herein, we propose the enzymatic conjugation of CUR to Dextran (DEX-CUR), a glucose homopolysaccharide showing high biocompatibility and chemical versatility [25], in order to transfer the biological activity of CUR to a macromolecular systems able to self-assembly (DC), encapsulate, and control the release of MTX.…”