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

Abstract

Oliveria decumbens (Apiaceae) is an aromatic herb traditionally employed in the Persian medicine for the treatment of infectious and gastrointestinal disorders. In the present study, we analyzed the chemical composition of essential oils obtained from different Iranian populations and evaluated their efficacy on a panel of human pathogens (Staphylococcus aureus and Escherichia coli), probiotic (Bacillus subtilis), and phytopathogens (Clavibacter michiganensis, Curtobacterium flaccumfaciens, Xanthomonas citri, and Agrobacterium tumefaciens). The gas chromatographic-mass spectrometry analysis put in evidence four main volatile constituents such as thymol (20.3–36.4%), carvacrol (18.8–33.1%), γ-terpinene (10.6–25.9%), and p-cymene (9.5–17.3%), though with significant variability from an essential oil to another. Notably, the oils from the populations sited in Nourabad Mamasani and Dehdasht showed the highest amount of the phenolic monoterpenes thymol (36.4 and 35.2%, respectively) and carvacrol (33.1 and 30.6%, respectively). The antibacterial activity of O. decumbens essential oils was assessed by the minimum inhibitory concentration (MIC) and minimum bactericidal concentration (MBC) methods, showing high activity for the samples from Nourabad Mamasani and Dehdasht populations exhibiting high level of the above phenolics. The obtained MIC and MBC values (mg/ml) were in the ranges 0.0625–2 mg/ml and 1–16 mg/ml, respectively. Noteworthy, in some cases, the antibacterial activity of O. decumbens essential oils was higher than that of chloramphenicol used as positive control. The average MBCs displayed by the O. decumbens samples showed that C. flaccumfaciens had the highest sensitivity to the essential oils. Based on these results, our work shed light on selected O. decumbens populations deserving proper breeding and cultivation strategies in order to warrantee production of bioactive essential oils to be used at pharmaceutical and agricultural level to combat several pathogens.

Carvacrol Essential Oil: A Natural Antibiotic against Zoonotic Multidrug-Resistant Staphylococcus Species Isolated from Diseased Livestock and Humans

“…The MIC of carvacrol oil for the tested Staphylococcus isolates was 0.04%, as observed for a variety of microorganisms [50][51][52][53][54]. In addition, carvacrol was suggested as the bioactive compounds against S. aureus and other Gram-positive and Gram-negative bacteria [51]. Moreover, de Souza et al [53] evaluated the antimicrobial potential of carvacrol in vitro and in vivo in Swiss mice against MDR K. pneumoniae strains and indicated that the use of carvacrol as a therapeutic agent can exert significant in vitro and in vivo antimicrobial effects against carbapenemase-producing K. pneumoniae (KPC), increasing animal survival and significantly decreasing bacterial loads; such preliminary results in mice were hopeful and indicated that carvacrol has potential as an antimicrobial agent.…”

“…Carvacrol is a significant component of essential oils and has recently attracted much attention as a result of its biological properties including a wide spectrum of antimicrobial activity [50]. The MIC of carvacrol oil for the tested Staphylococcus isolates was 0.04%, as observed for a variety of microorganisms [50][51][52][53][54]. In addition, carvacrol was suggested as the bioactive compounds against S. aureus and other Gram-positive and Gram-negative bacteria [51].…”

“…Moreover, de Souza et al [ 53 ] evaluated the antimicrobial potential of carvacrol in vitro and in vivo in Swiss mice against MDR K. pneumoniae strains and indicated that the use of carvacrol as a therapeutic agent can exert significant in vitro and in vivo antimicrobial effects against carbapenemase-producing K. pneumoniae (KPC), increasing animal survival and significantly decreasing bacterial loads; such preliminary results in mice were hopeful and indicated that carvacrol has potential as an antimicrobial agent. Carvacrol can inhibit bacterial growth as a result of the disruption of the bacterial membrane integrity increasing its fluidity and permeability, resulting in inorganic ions and ATP leakage, pH homeostasis and cell death [ 50 , 51 ]. It also possesses antifungal and antibiofilm properties, thus it can be used as an antimicrobial alternative against MDR pathogenic bacteria [ 50 ].…”

Comparative de novo transcriptome analysis of flower and root of Oliveria decumbens Vent. to identify putative genes in terpenes biosynthesis pathway

“…Mostly collected from the >2500 m heights from the skirts of central Zagros mountains in Fars, Chaharmahal & Bakhtiari, Kohgilouyeh & Boyerahmad, Boushehr, and Khuzestan provinces. The top chemical compounds have been reported in the plant including thymol, carvacrol, gamma-terpinene, and para-cymene ( Khoshbakht et al, 2020 ). Each one of them has significant chemotherapeutic agent potential and also antibacterial properties ( Ashraf, 2020 ; Ashraf et al, 2022 ).…”

Using of Essential Oils and Plant Extracts against Pseudomonas savastanoi pv. glycinea and Curtobacterium flaccumfaciens pv. flaccumfaciens on Soybean

“…There are several reports on the determination of the antibacterial activity of EOs and PEs in vitro against Psg [ 6 ], Cff [ 34 , 35 ], and both bacteria simultaneously [ 36 , 37 ]. A single in vivo study of the control of Psg soybean seed infection has been reported [ 38 ], while no experiments on Cff infection in soybean have been performed to date.…”