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Current Bioactive Compounds

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ISSN (Print): 1573-4072
ISSN (Online): 1875-6646

Research Article

Chitosan-grafted Cyclodextrin via Click Chemistry as an Encapsulating Agent to Enhance the Antibacterial Activity of Thymol

Author(s): Amine Ez-zoubi*, Naoufal El Hachlafi, Yassine Ez Zoubi, Hicham Zaroual, Wafae Moustaid, Riham Sghyar and Abdellah Farah

Volume 20, Issue 9, 2024

Published on: 25 January, 2024

Article ID: e250124226175 Pages: 9

DOI: 10.2174/0115734072283885231220071717

Price: $65

Abstract

Introduction: This paper aimed to investigate, for the first time, the possibility of increasing the antibacterial activities of thymol (TH) by developing an encapsulating agent based on chitosan-grafted cyclodextrin. For this purpose, β-cyclodextrin was monosubstituted at position 6 via propargyl bromide, and chitosan’s amine groups were converted to azide functions. After alkylation and diazotization reactions, the grafting of β-cyclodextrin onto the chitosan (CS- βCD) was realized via click chemistry alkyne–azide cycloaddition.

Methods: The incorporation of TH into chitosan-grafted β-cyclodextrin (TH/CS-βCD) was performed by the freeze-drying method, and the encapsulation efficiency was investigated based on various mass ratios (TH:CS-βCD). The optimized inclusion complex was then thoroughly examined by scanning electron microscopy (SEM), X-ray diffraction (XRD), thermogravimetric analysis (TGA), and differential scanning calorimetry (DSC).

Results: The antibacterial activity was assessed against Escherichia coli, Staphylococcus aureus, and Bacillus subtilis using broth-microdilution assay. Fourier transform infrared spectroscopy analysis demonstrated the successful grafting of β-cyclodextrin onto chitosan since the optimum mass ratio between TH and CS-βCD was 1:8 (w:w), corresponding to 78 ± 3.42% of encapsulation efficiency, while SEM, XRD, TGA and DSC confirmed the establishment of TH/CS-βCD inclusion complexes.

Conclusion: The in vitro investigation showed that TH/CS-βCD exhibited higher antibacterial properties compared to TH in free form.

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