In vitro inhibitory activities of essential oils from two Korean thymus species against antibiotic-resistant pathogens.
The in vitro inhibitory activities of essential oils from Thymus magnus and T. quinquecostatus as well as their main constituents were evaluated against susceptible and resistant species of Streptococcus pneumoniae, Staphylococcus aureus, Salmonella enteritidis, and Salmonella typhimurium. Notably, the essential oil fraction of T. magnus and its main components displayed significant inhibitory action against both antibiotic-susceptible and resistant strains of S. pneumoniae, S. aureus, and S. typhimurium with minimum inhibitory concentrations (MICs) ranging from 0.125 to 8 mg/mL. The differential MIC values imply that the oil fraction and its main components exhibit distinct patterns of activity against the tested bacterial species. Moreover, the disk diffusion test revealed that the inhibitory activities of oil fraction and components were dose-dependent. Data from the checkerboard titer test confirmed synergism between the antibiotic, norfloxacin, and T. magnus oil or thymol, particularly against the resistant strains of S. aureus.
Shin
Seungwon
S
College of Pharmacy, Duksung Women's University, Seoul 132-714, Korea. swshin@duksung.ac.kr
Kim
Ji Hyun
JH
D000900:Anti-Bacterial Agents / Q000302:isolation & purification / Q000494:pharmacology*; D001419:Bacteria / Q000187:drug effects*; D000081007:Cymenes; D004305:Dose-Response Relationship, Drug; D004352:Drug Resistance, Microbial; D004357:Drug Synergism; D007723:Korea; D008826:Microbial Sensitivity Tests; D039821:Monoterpenes / Q000302:isolation & purification / Q000494:pharmacology*; D009643:Norfloxacin / Q000494:pharmacology; D010938:Plant Oils / Q000302:isolation & purification / Q000494:pharmacology*; D012486:Salmonella typhimurium / Q000187:drug effects; D013211:Staphylococcus aureus / Q000187:drug effects; D013296:Streptococcus pneumoniae / Q000187:drug effects; D013943:Thymol / Q000302:isolation & purification / Q000494:pharmacology*; D046930:Thymus Plant / Q000737:chemistry / Q000235:genetics
D000900:Anti-Bacterial Agents; D000081007:Cymenes; D039821:Monoterpenes; D010938:Plant Oils; D013943:Thymol; C073316:carvacrol; D009643:Norfloxacin