H2O2-sensitive release of curcumin and zinc in normal and infected simulated cell tissues from a curcumin-zinc coordination complex with prolonged antibacterial activity

Abstract

Concerns arising from the improper use of antibacterial chemicals, which has resulted in antibacterial resistance, environmental pollution, high costs, and so on., have prompted the development of new compounds that offer effective antibacterial agents by gradually releasing over time. In this work [Zn(CH₃COO)(cur)(bpy)].CH₃OH·2H₂O (1), (cur = curcuminate, derived from curcumin, bpy = 2,2′-bipyridine) has been synthesized as an antibacterial inorganic coordination complex by using three different techniques, sonochemical reactions (1S), mechanochemical reactions (1M), and crystallization (1C). These methods were employed to obtain various morphologies and gradual release profiles, with the sonochemical and mechanochemical methods being used for the first time in the synthesis of this compound. To ensure the successful synthesis of the samples, FT-IR spectroscopy, PXRD, BET, SEM, and TGA analysis techniques were used. The results indicated that the samples were synthesized with the correct structure and obtained in nanoscale (1M), microscale (1C) and mixture of both nanoscale and microscale particles (1S). Then the rate of H₂O₂-sensitive release of curcumin and zinc ions as antibacterial agents from 1 was studied by UV–Vis and ICP-OES methods respectively by monitoring the concentration of released agents for about 120 h (5 days), in two phosphate-buffered solutions (PBS) with different hydrogen peroxide concentration as a simulated normal and infected cell tissues. Compound 1 demonstrated prolonged and gradual release of curcumin and zinc ions. Finally, S. aureus and E. coli bacteria as representatives of Gram-positive and Gram-negative bacteria, respectively, were used to study the antibacterial activity of the samples by the agar well diffusion and MIC/MBC method. Also, the time-kill kinetics of bacteria by samples investigated. All antibacterial analyses demonstrated significant and potent antibacterial activity of compound 1. The high antibacterial efficiency of 1, especially 1C, is clearly demonstrated when compared to previous studies. It is possible to prevent the creation of antibacterial resistance as well as numerous environmental pollutions by using such compounds with the gradual release agents.