Plectranthus amboinicus essential oil and carvacrol bioactive against planktonic and biofilm of oxacillin- and vancomycin-resistant Staphylococcus aureus

Abstract

BackgroundThe emergence of multidrug-resistant bacteria is a worldwide concern and in order to find an alternative to this problem, the occurrence of antimicrobial compounds in Plectranthus amboinicus essential oil was investigated. Thus, this study aims to determine susceptibility of Staphylococcus aureus isolated from food to antibiotics, P. amboinicus essential oil (PAEO) and carvacrol.MethodsLeaves and stem of P. amboinicus were used for extraction of essential oil (PAEO) by hydrodistillation technique and EO chemical analysis was performed by gas chromatography coupled to a mass spectrometer. S. aureus strains (n = 35) isolated from food and S. aureus ATCC 6538 were used to evaluate the antimicrobial and antibiofilm activity of PAEO and carvacrol. All strains (n = 35) were submitted to antimicrobial susceptibility profile by disk diffusion method. Determination of MIC and MBC was performed by microdilution technique and antibiofilm activity was determined by microtiter-plate technique with crystal violet assay and counting viable cells in Colony Forming Units (CFU).ResultsCarvacrol (88.17%) was the major component in the PAEO. Antibiotic resistance was detected in 28 S. aureus strains (80%) and 12 strains (34.3%) were oxacillin and vancomycin-resistant (OVRSA). From the 28 resistant strains, 7 (25%) showed resistance plasmid of 12,000 bp. All strains (n = 35) were sensitive to PAEO and carvacrol, with inhibition zones ranging from 16 to 38 mm and 23 to 42 mm, respectively. The lowest MIC (0.25 mg mL−1) and MBC (0.5 mg mL−1) values were observed when carvacrol was used against OVRSA. When a 0.5 mg mL−1 concentration of PAEO and carvacrol was used, no viable cells were found on S. aureus biofilm.ConclusionThe antibacterial effect of carvacrol and PAEO proves to be a possible alternative against planktonic forms and staphylococcal biofilm.

Pharmacological Assessment of the Carvacrol Chemotype Essential Oil FromPlectranthus amboinicusGrowing in Cuba

“…For example, as the main compound and in the same range, carvacrol comprised 65.2% from Mérida in Venezuela 28 and 64% from Cartagena in Colombia. 17 However, a higher concentration of carvacrol was observed from EO-Pa collected in Cariré and Ceará from Brazil, with 88.2% 29 and >90%, 30 respectively. Nevertheless, it is known that the chemical constituents of EO-Pa differed from those of the collected samples from diverse geographical places, in which more than 70 different constituents have been described.…”

Leveraging Phytochemicals: The Plant Phylogeny Predicts Sources of Novel Antibacterial Compounds

“…BF formation is consequently affected, though essential oil components (e.g. terpenoids) may directly impact BF, as observed from C. sempervirens (Cupressaceae) [32], Plectranthus amboinicus (Lamiaceae) [49] and Myrtaceae species [44]. A terpenic skeleton was used as basis to develop an anti-BF synthetic compound [50].…”

Chemical Composition and Mechanism of Vibriocidal Action of Essential Oil from Resin of Protium heptaphyllum

“…MIC was determined as the lowest concentration of EOPH that was able to inhibit the visible growth of V. parahemolyticus in the plates. MBC was the lowest concentration of OEPH that killed V. parahaemolyticus and was indicated by the absence of microbial growth in tryptone soy agar [10].…”