Antimicrobial activity and mode of action of 1,8-cineol against carbapenemase-producing Klebsiella pneumoniae

Abstract

Antimicrobial resistance remains one of the most challenging issues that threatens the health of people around the world. Plant-derived natural compounds have received considerable attention for their potential role to mitigate antibiotic resistance. This study was carried out to assess the antimicrobial activity and mode of action of a monoterpene, 1,8-cineol (CN) against carbapenemase-producing Klebsiella pneumoniae (KPC-KP). Results showed that resazurin microplate assay and time-kill analysis revealed bactericidal effects of CN at 28.83 mg/mL. Zeta potential showed that CN increased the surface charge of bacteria and an increase of outer membrane permeability was also detected. CN was able to cause leakage of proteins and nucleic acids in KPC-KP cells upon exposure to CN and ethidium bromide influx/efflux experiment showed the uptake of ethidium bromide into the cell; this was attributed to membrane damage. CN was also found to induce oxidative stress in CN-treated KPC-KP cells through generation of reactive oxygen species which initiated lipid peroxidation and thus damaging the bacterial cell membrane. Scanning and transmission electron microscopies further confirmed the disruption of bacterial cell membrane and loss of intracellular materials. In this study, we demonstrated that CN induced oxidative stress and membrane damage resulting in KPC-KP cell death.

The Combination of Amoxicillin and 1,8-Cineole Improves the Bioavailability and the Therapeutic Effect of Amoxicillin in a Rabbit Model

“…Moreover, 1,8-cineole had strong effect against Bacillus cereus and Cryptococcus neoformans at a dose of 2 mg/mL [ 32 ]. A trial conducted by Moo et al [ 33 ], illustrated that 1,8-cineol has potent activity against carbapenemase-producing Klebsiella pneumoniae (KPC-KP) at 28.83 mg/mL. In this study, the authors demonstrated that 1,8-cineol induced oxidative stress and membrane damage, resulting in KPC-KP cell death.…”

“…In this study, the authors demonstrated that 1,8-cineol induced oxidative stress and membrane damage, resulting in KPC-KP cell death. This was observed by scanning and transmission electron microscopies, which confirmed bacterial cell membrane rupture and loss of intracellular materials [ 33 ]. It is well known that there are limits to the use of essential oils and their main compounds because of their toxicity.…”

Phytochemical Profile, Preliminary Toxicity, and Antioxidant Capacity of the Essential Oils of Myrciaria floribunda (H. West ex Willd.) O. Berg. and Myrcia sylvatica (G. Mey) DC. (Myrtaceae)

“…In addition, the encapsulation of 1,8-cineole in nanofibers can prolong fungal activities against Candida species given that the isolated compound is not a strong fungal agent [ 52 , 53 , 54 ]. 1,8-Cineole also has potential as an antimicrobial, repellent, and anticancer agent and can be used in the treatment of respiratory diseases, including COVID-19 [ 55 , 56 , 57 , 58 , 59 , 60 , 61 , 62 , 63 ].…”

In vitro and in silico β-lactamase inhibitory properties and phytochemical profile of Ocimum basilicum cultivated in central delta of Egypt

“…To obtain cineol in a sufficient yield for antimicrobial testing, it was isolated from eucalyptus oil (TechnicoFlor, Allauch, France) by using the method which depends on the fact that cineole combines with acids as phosphoric acid to form loose compounds that are easily decomposed when treated with water (Mukherjee 2019 ). The isolated cineole (yield 80% w/w) was dehydrated over anhydrous sodium sulphate and subjected to NMR analysis to confirm its purity before using for antimicrobial study.…”