Chamaecyparis obtusa Essential Oil Inhibits Methicillin-Resistant Staphylococcus aureus Biofilm Formation and Expression of Virulence Factors.
The emergence of antibiotic-resistant bacteria has caused difficulty in treating infectious diseases. Methicillin-resistant Staphylococcus aureus (MRSA) is one of the most commonly recognized antibiotic-resistant bacteria. Novel antibiotics are urgently required to treat these bacteria. Raw materials derived from natural sources can be used for the development of novel antibiotics, such as Chamaecyparis obtusa (C. obtusa), which has been traditionally used in treating asthmatic disease. In this study, the antibacterial activity of the essential oil (EO) extracted from C. obtusa leaves against MRSA was investigated. MRSA growth and acid production from glucose metabolism were inhibited at concentrations greater than 0.1 mg/mL C. obtusa EO. MRSA biofilm formation was observed using scanning electron microscopy and safranin staining. C. obtusa EO inhibited MRSA biofilm formation at concentrations greater than 0.1 mg/mL. Using real-time polymerase chain reaction, mRNA expression of virulence factor genes, sea, agrA, and sarA, was observed. agrA expression was inhibited with C. obtusa EO concentrations greater than 0.2 mg/mL, whereas inhibition of sea and sarA expression was also observed at a concentration of 0.3 mg/mL. C. obtusa EO was analyzed by gas chromatography (GC) and GC coupled for mass spectrometry, which identified 59 constituents, accounting to 98.99% of the total EO. These findings suggest that C. obtusa EO has antibacterial effects against MRSA, which might be associated with the major components of C. obtusa EO, such as sabinene (19.06%), α-terpinyl acetate (16.99%), bornyl acetate (10.48%), limonene (8.54%), elemol (7.47%), myrcene (5.86%), γ-terpinene (4.04%), and hibaene (3.01%).
1 Wonkwang Research Institute for Food Industry, Wonkwang University , Jeonbuk, Korea.
Eun-Sook
ES
Kim
2 Department of Oral Biochemistry, School of Dentistry, Wonkwang University , Jeonbuk, Korea.
Sun-Young
SY
Kang
3 Department of Food Science and Technology, College of Agriculture and Life Sciences, Chonbuk National University , Jeonbuk, Korea.
Young-Hoi
YH
Kim
1 Wonkwang Research Institute for Food Industry, Wonkwang University , Jeonbuk, Korea.|4 Department of Food and Nutrition, Wonkwang University , Jeonbuk, Korea.
Young-Eun
YE
Lee
5 College of Education, Wonkwang University , Jeonbuk, Korea.
Na-Young
NY
Choi
1 Wonkwang Research Institute for Food Industry, Wonkwang University , Jeonbuk, Korea.|2 Department of Oral Biochemistry, School of Dentistry, Wonkwang University , Jeonbuk, Korea.
Yong-Ouk
YO
You
6 Department of Oral Microbiology and Immunology, School of Dentistry; Wonkwang University , Jeonbuk, Korea.
Kang-Ju
KJ
Kim
D000900:Anti-Bacterial Agents / Q000494:pharmacology*; D018441:Biofilms / Q000187:drug effects* / Q000254:growth & development; D029780:Chamaecyparis / Q000737:chemistry*; D004305:Dose-Response Relationship, Drug; D015870:Gene Expression / Q000187:drug effects; D055624:Methicillin-Resistant Staphylococcus aureus / Q000187:drug effects / Q000502:physiology*; D008855:Microscopy, Electron, Scanning; D009822:Oils, Volatile / Q000494:pharmacology*; D008517:Phytotherapy; D018515:Plant Leaves / Q000737:chemistry; D010938:Plant Oils / Q000494:pharmacology; D012333:RNA, Messenger / Q000032:analysis; D060888:Real-Time Polymerase Chain Reaction; D037521:Virulence Factors / Q000235:genetics*
D000900:Anti-Bacterial Agents; D009822:Oils, Volatile; D010938:Plant Oils; D012333:RNA, Messenger; D037521:Virulence Factors
agrA; antimicrobial activity; cypress; hinoki; sarA; sea