ISSN print edition: 0366-6352 ISSN electronic edition: 1336-9075 Registr. No.: MK SR 9/7 Published monthly

Enhancement of antibacterial activity by a copper(II) and zinc(II) in chelation with ethylenediaminetetra-acetic acid and urea complex

Trong Nghia Nguyen, Quang Hoa Do, Thi Thuy Duong Vu, Thi Thuy Nguyen, Duc Toan Nguyen, Thi Bich Ngoc Nguyen, Thi Thu Ha Tran, Thi Kim Oanh Vu, Thi Ha Lien Nghiem, Thi Minh Tu Hoa, Thi Minh Huyen Nguyen, Phuong Nhung Bui, Minh Hue Nguyen, Duc Minh Pham, and Thi Chung Thuy Tran

Institute of Physics, VAST, Hanoi, Vietnam

E-mail: halien@iop.vast.vn

Received: 15 February 2022  Accepted: 8 July 2022

Abstract:

Although it is unclear how Zn²⁺ cooperates with Cu²⁺ in synergistic antibacterial activity, a 1:10 ratio of Cu²⁺/Zn²⁺ atoms and ethylenediaminetetra-acetic acid and urea ligands can be used to form a chelation complex containing Cu²⁺ and Zn²⁺. This study investigated the effects of the combination of Cu²⁺ and Zn²⁺ in chelation with EDTA and urea. The results were compared with the outcomes of either copper or zinc alone against gram-negative Escherichia coli (E. coli) and gram-positive Staphylococcus aureus (S. aureus) bacteria. The antibacterial activity was determined through MICs, disc diffusion method, and bacterial cell growth curves. In addition, bacterial destruction by this chelation complex has been observed through SEM images. The presence of copper ion and zinc ion inside the bacterial cells has been proved through EDS measurements. The obtained results allowed us to draw conclusions that the use of both Cu²⁺ and Zn²⁺ in a chelation complex with EDTA and urea enhances the antimicrobial activity against these bacteria. The bacterial inhibition of this complex was stronger than that of Cu²⁺ alone chelated with EDTA or CuSO₄ solution by approximately 100-fold for S. aureus and 20-fold for E. coli.

Keywords: Antibacterial activity; Gram-positive bacteria; Gram-negative bacteria; Copper ion; Zinc chelate complex

Full paper is available at www.springerlink.com.

DOI: 10.1007/s11696-022-02361-3

Chemical Papers 76 (11) 7163–7176 (2022)