Enhancement of Antioxidant and Hydrophobic Properties of Alginate via Aromatic Derivatization: Preparation, Characterization, and Evaluation.

Smaher M Elbayomi,Yezi You,Tamer M Tamer,Haili Wang

doi:10.3390/polym13152575

Abstract

The preparation of bioactive polymeric molecules requires the attention of scientists as it has a potential function in biomedical applications. In the current study, functional substitution of alginate with a benzoyl group was prepared via coupling its hydroxyl group with benzoyl chloride. Fourier transform infrared spectroscopy indicated the characteristic peaks of aromatic C=C in alginate derivative at 1431 cm−1. HNMR analysis demonstrated the aromatic protons at 7.5 ppm assigned to benzoyl groups attached to alginate hydroxyl groups. Wetting analysis showed a decrease in hydrophilicity in the new alginate derivative. Differential scanning calorimetry and thermal gravimetric analysis showed that the designed aromatic alginate derivative demonstrated higher thermo-stability than alginates. The aromatic alginate derivative displayed high anti-inflammatory properties compared to alginate. Finally, the in vitro antioxidant evaluation of the aromatic alginate derivative showed a significant increase in free radical scavenging activity compared to neat alginate against DPPH (2,2-diphenyll-picrylhydrazyl) and ABTS free radicals. The obtained results proposed that the new alginate derivative could be employed for gene and drug delivery applications.

Highlights

Oxidative stress has attracted significant scientific attention as an intermediary in the etiology of many human diseases
To strengthen antioxidant and anti-inflammatory properties of alginate, an aromatic alginate derivative as a new derivative was prepared and characterized as demonstrated in Figure 1 hydroxyl groups of alginates were coupled with benzoyl chloride to develop the appropriate aromatic alginate derivative
In the 3600–1600 cm−1 region, three bands showed up: a broad band centered at 3374.5 cm−1 designated to hydrogen bonded O–H stretching vibrations and for the aromatic alginate derivative, the weak signal at 2928 cm−1 because of C-H stretching vibrations, and the asymmetric stretching of carboxylate O-C-O at 1735 cm−1

Summary

Introduction

Oxidative stress has attracted significant scientific attention as an intermediary in the etiology of many human diseases. The consequence of an imbalance between the production of oxidants and endogenous antioxidants to counteract is oxidative stress because of deficiency of antioxidants or growing reactive oxygen species (ROS), including superoxide anions, hydroxyl radicals (HO· ), hydrogen peroxide (H2 O2 ), singlet oxygen (1 O2 ), reactive nitrogen species (RNA), and reactive sulfur species (RSS) development [1,2]. Antioxidants are oxidation inhibitors, even at low concentrations; subsequently, antioxidants play a crucial role in the body. Antioxidants possess their activity in two basic ways, either by inhibiting the formation of ROS/RNS or neutralizing/scavenging

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Conclusion