title: Combination of microbiological, spectroscopic and molecular docking techniques to study the antibacterial mechanism of thymol against Staphylococcus aureus: membrane damage and genomic DNA binding.
abstract: Thymol (2-isopropyl-5-methylphenol) is a natural ingredient used as flavor or preservative agent in food products. The antibacterial mechanism of thymol against Gram-positive, Staphylococcus aureus was investigated in this work. A total of 15 membrane fatty acids were identified in S. aureus cells by gas chromatography-mass spectrometry. Exposure to thymol at low concentrations induced obvious alterations in membrane fatty acid composition, such as decreasing the proportion of branched 12-methyltetradecanoic acid and 14-methylhexadecanoic acid (from 22.4 and 17.3% to 7.9 and 10.3%, respectively). Membrane permeability assay and morphological image showed that thymol at higher concentrations disrupted S. aureus cell membrane integrity, which may decrease cell viability. Moreover, the interaction of thymol with genomic DNA was also investigated using multi-spectroscopic techniques, docking and atomic force microscopy. The results indicated that thymol bound to the minor groove of DNA with binding constant (Ka) value of (1.22 ± 0.14) × 104M-1, and this binding interaction induced a mild destabilization in the DNA secondary structure, and made DNA molecules to be aggregated. Graphical Abstract Thymol exerts its antibacterial effect throught destruction of bacterial cell membrane and binding directly to genomic DNA.
authors.affiliation: School of Food Science and Engineering, South China University of Technology, Guangzhou, Guangdong, 510641, China.|Food Green Processing and Nutrition Regulation Research Center of Guangdong Province, South China University of Technology, Guangzhou, Guangdong, 510641, China.
authors.forename: Lang-Hong
authors.initials: LH
authors.lastname: Wang
authors.affiliation: School of Food Science and Engineering, South China University of Technology, Guangzhou, Guangdong, 510641, China.|Food Green Processing and Nutrition Regulation Research Center of Guangdong Province, South China University of Technology, Guangzhou, Guangdong, 510641, China.
authors.forename: Zhi-Hong
authors.initials: ZH
authors.lastname: Zhang
authors.affiliation: School of Food Science and Engineering, South China University of Technology, Guangzhou, Guangdong, 510641, China. xazeng@scut.edu.cn.|Food Green Processing and Nutrition Regulation Research Center of Guangdong Province, South China University of Technology, Guangzhou, Guangdong, 510641, China. xazeng@scut.edu.cn.
authors.forename: Xin-An
authors.initials: XA
authors.lastname: Zeng
authors.affiliation: School of Biological Sciences, The University of Auckland, Private Bag 92019, Auckland, 1142, New Zealand. dgong01@gmail.com.
authors.forename: De-Ming
authors.initials: DM
authors.lastname: Gong
authors.affiliation: Institute of Bast Fiber Crops, Chinese Academy of Agricultural Sciences, No. 348 West Xianjiahu Road, Changsha, Hunan, 410205, China.
authors.forename: Man-Sheng
authors.initials: MS
authors.lastname: Wang
mesh_terms: D000900:Anti-Bacterial Agents / Q000494:pharmacology*; D004269:DNA, Bacterial / Q000737:chemistry / Q000378:metabolism; D008401:Gas Chromatography-Mass Spectrometry / Q000379:methods; D006801:Humans; D008826:Microbial Sensitivity Tests / Q000379:methods; D050296:Microbial Viability / Q000187:drug effects; D018625:Microscopy, Atomic Force / Q000379:methods; D008958:Models, Molecular; D062105:Molecular Docking Simulation; D009690:Nucleic Acid Conformation / Q000187:drug effects; D013203:Staphylococcal Infections / Q000188:drug therapy; D013211:Staphylococcus aureus / Q000166:cytology / Q000187:drug effects* / Q000378:metabolism; D013943:Thymol / Q000494:pharmacology*
chemical_list: D000900:Anti-Bacterial Agents; D004269:DNA, Bacterial; D013943:Thymol
keywords: Atomic force microscopy; Gas chromatography–mass spectrometry; Membrane integrity; Staphylococcus aureus; Thymol