Chemical Composition and Antibacterial Activity of Essential Oils from the Algerian Endemic Origanum glandulosum Desf. against Multidrug-Resistant Uropathogenic E. coli Isolates

Abstract

Antibiotics are becoming ineffective against resistant bacteria. The use of essential oils (EOs) may constitute an alternative solution to fight against multidrug-resistant bacteria. This study aims to determine the chemical composition of EOs from five populations of the endemic Algerian Origanum glandulosum Desf. and to investigate their potential antibacterial activity against multidrug-resistant uropathogenic E. coli strains. The EOs were obtained by hydrodistillation and their composition was investigated by gas chromatography/mass spectrometry (GC/MS). The antibacterial activity was evaluated by the disc diffusion method against eight E. coli strains (six uropathogenic resistant and two referenced susceptible strains). Minimum inhibitory and bactericidal concentrations (MIC/MBC) were obtained by the broth microdilution method. The main EO components were thymol (15.2-56.4%), carvacrol (2.8-59.6%), γ-terpinene (9.9-21.8%) and p-cymene (8.5-13.9%). The antibacterial tests showed that all the EOs were active against all the strains, including the multidrug-resistant strains. The EO from the Bordj location, which contained the highest amount of carvacrol (59.6%), showed the highest antibacterial activity (inhibition diameters from 12 to 24.5 mm at a dilution of 1/10). To our knowledge, this is the first description of the activity of O. glandulosum EOs against resistant uropathogenic strains. Our study suggests that O. glandulosum EO could be used in some clinical situations to treat or prevent infections (e.g., urinary tract infections) with multidrug-resistant strains.

The Variability of Thymol and Carvacrol Contents Reveals the Level of Antibacterial Activity of the Essential Oils from Different Accessions of Oliveria decumbens

“…Our results are in agreement with previous studies which documented the effectiveness of thymol and carvacrol compounds against various bacteria [ 46 ]. In addition, thymol and carvacrol were suggested as the bioactive compounds against Escherichia coli , Staphylococcus aureus, and Candida albicans [ 17 ].…”

Chemical Composition, Antibacterial and Radical Scavenging Activity of Essential Oils from Satureja macrantha C.A.Mey. at Different Growth Stages

“…During the vegetative stage, carvacrol and γ-terpinene achieved the highest amount while p-cymene reached its highest level at the fruiting stage. As thymol and carvacrol are important bioactive compounds supporting applications in pharmaceutical and food industries [37][38][39][40][41], the flowering stage of S. macrantha can be the best one to obtain a high quality EO. Previous studies indicated that thymol and carvacrol can be found in high amounts at the flowering stage in other Lamiaceae and Apiaceae species [37,42,43].…”

Essential Oil Chemical Variability in Oliveria decumbens (Apiaceae) from Different Regions of Iran and Its Relationship with Environmental Factors

“…Thymol and carvacrol are the most important components of O. decumbens EO; they are commonly found in several members of the Lamiaceae, Ranunculaceae, Apiaceae and Verbenaceae families. Numerous biological activities of these phenolic monoterpenes such as antioxidant, antiseptic, antibacterial, antifungal, antiviral, insecticidal, acaricidal, antiprotozoal, antispasmodic, growth promoter, anti-inflammatory and antitussive have been documented [ 10 , 11 , 12 , 13 , 14 , 15 , 16 , 17 , 18 ]. These numerous properties of its main volatile compounds make this plant a valuable herb for cosmetic, food and feed, and pharmaceutical industries.…”