Innovative material containing the natural product curcumin, with enhanced antimicrobial properties for active packaging

Highlights: • Active packaging • Zinc curcumin materials • Antimicrobial activity - Abstract: Curcumin (Curc) reacts with zinc di‑iodine (ZnI₂) in 2:1 molar ratio in the presence of an excess of a base triethylamine ((CH₃CH₂)₃N) in methanol (CH₃OH) solution towards the amorphous solid material of formula [ZnI₂(Curc)₂] (1). The complex was characterized by melting point (m.p.), Fourier Transform-Infra Red (FT-IR) and Nuclear Magnetic Resonance of hydrogen nucleus (¹H NMR) spectroscopy. The formula of 1 was determined by X-ray fluorescence (XRF) analysis. The retention of the structure in solution was confirmed by ¹H NMR spectroscopy. The antimicrobial activity of the complex has been studied against the bacteria Pseudomonas aeruginosa (PAO1). The Minimum Inhibitory Concentrations (MIC) of the compounds 1 and Curc against P. aeruginosa (PAO1) are: 71.3 μΜ (75.3 μg/mL) for [ZnI₂(Curc)₂] and 339 μM (125 μg/mL) for Curc, respectively. Moreover, the antimicrobial activity of the new material which was diffused in polystyrene against biofilm formed by PAO1 was also calculated.