The antibacterial and antifungal activity of six essential oils and their cyto/genotoxicity to human HEL 12469 cells

Abstract

Six essential oils (from oregano, thyme, clove, lavender, clary sage, and arborvitae) exhibited different antibacterial and antifungal properties. Antimicrobial activity was shown against pathogenic (Escherichia coli, Salmonella typhimurium, Yersinia enterocolitica, Staphylococcus aureus, Listeria monocytogenes, and Enterococcus faecalis) and environmental bacteria (Bacillus cereus, Arthrobacter protophormiae, Pseudomonas fragi) and fungi (Chaetomium globosum, Penicillium chrysogenum, Cladosporium cladosporoides, Alternaria alternata, and Aspergillus fumigatus). Oregano, thyme, clove and arborvitae showed very strong antibacterial activity against all tested strains at both full strength and reduced concentrations. These essential oils showed different fungistatic and fungicidal activities when tested by direct application and in the vapor phase. The genotoxic effects of these oils on HEL 12469 human embryo lung cells were evaluated using an alkaline comet assay for the first time, revealing that none of the oils induced significant DNA damage in vitro after 24 h. This study provides novel approaches for assessing the antimicrobial potential of essential oils in both direct contact and the vapor phase and also demonstrates the valuable properties of the phenol-free arborvitae oil. These results suggest that all the tested essential oils might be used as broad-spectrum anti-microbial agents for decontaminating an indoor environment.

The Effect of Ten Essential Oils on Several Cutaneous Drug-Resistant Microorganisms and Their Cyto/Genotoxic and Antioxidant Properties

“…According to our previous data using human embryo lung cells (HEL 12469), the cytotoxic effect of the studied EOs was detected in similar concentrations (IC 50 ). The IC 50 values in HEL 12469 cells declined in the order SA > LA > AR = TY > CL > OR, which is very similar to our current results [16].…”

“…The select concentrations of EOs for comet assay were not cytotoxic. These results are in very good correlation with our previous study, where Eos, similarly, did not induce DNA damage in the HEL 12469 cells [16]. A comparable effect was also shown using the plant extracts of Salvia officinali and Thymus vulgaris using HepG2 and primary rat hepatocytes [54,55].…”

“…This is in accordance with a known study on the antimicrobial efficiency of the Eos from Salvia officinalis, which reported a very low antibacterial activity for 1,8-cineole against S. aureus, B. subtilis, and E. coli [39]. Similarly, Puškárová et al [16] confirmed that LA and SA were both less active against pathogenic bacteria (E. coli, S. typhimurium, Y. enterocolitica, S. aureus, L. monocytogenes, E. faecalis) and environmental bacteria (B. cereus, A. protophormiae, P. fragi), with inhibition zones ranging from 8 to 14 mm. The disc diffusion assay is limited by the hydrophobic nature of most EOs, which prevents their uniform diffusion through the agar medium; therefore, most researchers prefer liquid medium methods [40].…”

“…Generally, essential oils characterized by a high level of phenolic compounds, such as carvacrol, eugenol, and thymol, have important antibacterial and antifungal properties [13][14][15]. EOs from eucalyptus (EU), clove (CL), oregano (OR), thyme (TY), clary sage (SA) lavender (LA) and Cassia (CA) demonstrated various antibacterial, antifungal, antiseptic, antitumor, antihyperglycemic, antioxidant and anti-inflammatory effects [16][17][18][19]. The EOs of lemongrass (LE) and arborvitae (AR) have been tested for antimicrobial [11,16,20] and insecticidal abilities [21].…”

Antioxidant activity of essential oils from condiment plants and their effect on lactic cultures and pathogenic bacteria

“…This plant is one of the richest sources of phenolic compounds such as eugenol, eugenol acetate and gallic acid, fact that explains its great potential for pharmaceutical, cosmetic, food and agricultural applications (CORTÉS-ROJAS et al, 2014). The essential oil from S. aromaticum (L.) is known by its great antioxidant (BAKOUR et al, 2018, CORTÉS-ROJAS et al, 2014 and antimicrobial activity (PUŠKÁROVÁ et al, 2017), mainly against multidrug-resistant bacteria (NAVEED et al, 2013;ABDULLAH et al, 2015).…”