Zahraa Mokhtar¹ , Athraa Jameel Ali², Sana Hitur Awad³, Mohammed Bashar Al-Qazzan⁴, Muhanned A Mahmoud⁵

¹College of Pharmacy, Uruk University; ²College of Veterinary Medicine, University of Baghdad; ³Department of Chemistry, College of Science for Women, University of Baghdad; ⁴College of Pharmacy, Bilad Alrafidain University; ⁵College of Veterinary Medicine, University of Baghdad, Baghdad, Iraq.

For correspondence:-  Zahraa Mokhtar   Email: Zahraa.Sahar2305m@csw.uobaghdad.edu.iq

Received: 15 February 2025        Accepted: 20 June 2025        Published: 31 July 2025

Citation: Mokhtar Z, Ali AJ, Awad SH, Al-Qazzan MB, Mahmoud MA. Preparation of new Schiff base derivatives from chitosan grafted with polyvinylpyrrolidone and study of their antimicrobial activity. Trop J Pharm Res 2025; 24(7):935-948 doi: https://dx.doi.org/10.4314/tjpr.v24i7.10

© 2025 The authors.
This is an Open Access article that uses a funding model which does not charge readers or their institutions for access and distributed under the terms of the Creative Commons Attribution License (http://creativecommons.org/licenses/by/4.0) and the Budapest Open Access Initiative (http://www.budapestopenaccessinitiative.org/read), which permit unrestricted use, distribution, and reproduction in any medium, provided the original work is properly credited..

Abstract

Purpose: To synthesize and characterize novel Schiff base-chitosan composites and determine their antimicrobial activity. Methods: Novel Schiff-base chitosan composites were synthesized by grafting polyvinylpyrrolidone and then replacing it with different aldehydes. The resulting composites were characterized using advanced analytical techniques, including thermogravimetric analysis (TGA), x-ray diffraction (XRD) studies and Fourier transform infrared spectroscopy (FT-IR). Results: The FT-IR results revealed that the Schiff-base chitosan was successfully produced during mixing and the crystallinity change of the samples was explained by the XRD patterns. Thermogravimetric analysis (TGA) of compounds A1, A3 and A4 showed weight loss of the compounds with the most significant weight loss observed in the fourth and final steps of the reaction. Analysis of the surface morphology of compounds A3, A5, and A6 by scanning electron microscopy (SEM), revealed multiple layers of sheets in the dark gray sections, as well as kinked and wrinkled portions. Compounds A2 – A6 exhibited biological activities against Gram-positive and Gram-negative bacteria as well as fungal species. Docking studies indicate that compound A6, with a binding affinity of -3.09, demonstrates antibacterial properties. Conversely, compound A2, with a binding affinity of -9.102, exhibited antifungal activity. Conclusion: The synthesized compounds possess higher antifungal potential due to the presence of benzene ring which enhances the binding affinity for antifungal activity while diminishing their antibacterial activity.

Keywords: Chitosan, Molecular docking, Polymer, Polyvinylpyrrolidone, Scanning electron microscopy (SEM), Thermogravimetry

Impact Factor
Thompson Reuters (ISI): 0.6 (2023)
H-5 index (Google Scholar): 49 (2023)