Cinnamon essential oil and its emulsion as efficient antibiofilm agents to combat Acinetobacter baumannii

Abstract

Acinetobacter baumannii is an emerging nosocomial pathogen resistant to a wide spectrum of antibiotics, with great potential to form a biofilm, which further aggravates treatment of infections caused by it. Therefore, searching for new potent agents that are efficient against A. baumannii seems to be a necessity. One of them, which has already been proven to possess a wide spectrum of biological activities, including antimicrobial effect, is cinnamon essential oil. Still, further increase of antibacterial efficacy and improvement of bioavailability of cinnamon oil is possible by emulsification process. The aim of this study was comparative analysis of cinnamon essential oil and its emulsion against biofilm forming A. baumannii clinical isolates. Furthermore, the investigation of toxicological aspects of possible applications of essential oil and emulsion was done as well. Gas chromatography–mass spectrometry of essential oil indicated trans-cinnamaldehyde as the most abundant component. The cinnamon emulsion was synthesized from cinnamon essential oil by combining modified low- and high- energy methods. Synthesized emulsion was characterized with Fourier-transform infrared spectroscopy and photon correlation spectroscopy. Both substances exhibited significant antibacterial (minimal inhibitory concentrations in the range 0.125–0.5 mg/ml) and antibiofilm effects (inhibitions of formation and reduction of pre-formed biofilm were 47–81 and 30–62%, respectively). Compared to essential oil, the efficacy of emulsion was even stronger considering the small share of pure oil (20%) in the emulsion. The result of biofilm eradication assay was confirmed by scanning electron microscopy. Even though the cytotoxicity was high especially for the emulsion, genotoxicity was not determined. In conclusion, strong antibacterial/antibiofilm effect against A. baumannii of the cinnamon essential oil and the fact that emulsification even potentiated the activity, seems to be of great significance. Observed cytotoxicity implicated that further analysis is needed in order to clearly determine active principles being responsible for obtained antibacterial/antibiofilm and cytotoxic properties.

Lipid nanoparticles based on natural matrices with activity against multidrug resistant bacterial species

“…Similar result was found for strains of P. aeruginosa , tested under the same conditions, showed different responses to the same EO ( Coseriu et al., 2023 ), corroborating the difficulty to treat this type of infection. Other studies have also showed significant antibacterial properties for cinnamon EO, which inhibited the growth of A. baumannii , P. aeruginosa and K. pneumoniae ( El-Kattan and Allam, 2021 ; Ganić et al., 2022 ; Coseriu et al., 2023 ). Furthermore, this EO exhibited higher antibiofilm activity against K. pneumoniae , followed by peppermint EO ( Sarwar et al., 2022 ).…”

“…It was observed that the formulations that had cinnamon EO in their composition (F1, F6, F7 and F8) have showed activity against all the analysed strains/species and that the F1 formulation maintained in vitro antibacterial activity even after 1 year of storage at room temperature. Other work also revealed that the loaded cinnamon EO exhibited promising antibacterial activity and prevented both biofilm formation from A. baumannii strains, also exhibiting antibiofilm capacity ( Ganić et al., 2022 ). Another work described that the strains of P. aeruginosa also showed susceptibility to cinnamon EO at lowest concentrations, (0.125% v/v).…”

“…da Silva et al 10.3389/fcimb.2023.1328519 also exhibiting antibiofilm capacity (Ganićet al, 2022). Another work described that the strains of P. aeruginosa also showed susceptibility to cinnamon EO at lowest concentrations, (0.125% v/v).…”

Synergistic Antibiofilm Action of Cinnamomum verum and Brazilian Green Propolis Hydroethanolic Extracts against Multidrug-Resistant Strains of Acinetobacter baumannii and Pseudomonas aeruginosa and Their Biocompatibility on Human Keratinocytes

“…Furthermore, the same extract promoted a reduction of 67.17% of the clinical strain of A. baumannii A2, also with a similar action to chlorhexidine gluconate (79.22%). This may be explained by the cinnamon essential oil that acts to inhibit and eradicate the biofilm of clinical strains of A. baumannii with reductions of up to 71% of the biofilm formed at a concentration of 1 mg/mL [29].…”