TLC-Direct Bioautography for Determination of Antibacterial Activity of Artemisia adamsii Essential Oil

Abstract

The aim of the present study was the chemical characterization of the essential oil of a Mongolian medicinal plant, Artemisia adamsii Besser, and the investigation of the antibacterial effect of its oil on different human pathogenic bacteria (Staphylococcus aureus, methicillin-resistant S. aureus, and S. epidermidis). The chemical composition of the oil was established by GC and GC/MS. Direct bioautography was used for detecting the antibacterial activity of the essential oil. The result of GC experiments showed that a-thujone was the main component (64.4%) of the oil, while the amount of beta-thujone was 7.1%. 1,8-Cineole seemed to be the other relevant component (15.2%). The antibacterial activity of the A. adamsii essential oil against all three investigated bacteria was observed in the bioautographic system, but this effect was not proportional to the concentrations of a- or beta-thujone; therefore, from a microbiological aspect, thujone content does not determine the medicinal value of this oil. On the whole, the combination of TLC separation with biological detection is an appropriate method for evaluating multicomponent and hydrophobic plant extracts, for instance, essential oils, and it provides more reliable results than traditional microbiological methods (e.g., disc diffusion and agar plate techniques).

Challenges to antimicrobial susceptibility testing of plant-derived polyphenolic compounds

“…Contact bioautography is a variant of agar diffusion often used to screen for antimicrobial activity of plant extracts ( 49 , 50 , 51 ). Unlike with other diffusion methods, the analyte diffuses to inoculated agar medium from the chromatographic layer.…”

Layer chromatography-bioassays directed screening and identification of antibacterial compounds from Scotch thistle

“…Experiments with human pathogenic bacteria (S. aureus, MRSA and E. coli) were performed as described by Horváth et al [26]. In TLC/OPLC-direct bioautography experiments, the plates with the separated substances were immersed into one of the cell suspensions using a home-made cassette [7] to prepare the Similar method was utilized for human pathogenic bacteria, just the incubation was performed at 37 o C for 5 h and followed also after dipping into MTT for 2 h. Metabolically active cells reduce the yellow MTT to bluish MTT-formazan, revealing the inhibition zones as bright spots against bluish background, which was documented by a Sony Cybershot DSC-HX60 digital camera.…”

TLC-Direct Bioautography as a High Throughput Method for Detection of Antimicrobials in Plants

“…The components of a mixture can have synergistic or antagonistic effects, masking properties of single compounds. Still, the test can indicate if a given sample, e.g., plant extract, is worth further investigation [14,21,24,34]. The bioautographic dot-blot can be also advised if pure compounds are analyzed.…”