Inhibitory effect of obovatol from Magnolia obovata on the Salmonella type III secretion system

• Published in: Journal of antibiotics 2017-11, Vol.70 (11), p.1065-1069
• Main Authors: Choi, Won-Sik, Lee, Tae Hun, Son, Se Jin, Kim, Tae Gyu, Kwon, Byoung-Mog, Son, Hyeong-U, Kim, Sung Uk, Lee, Sang-Han
• Format: Article
• Language: English
• Subjects: 631/326/22/1290; 631/326/2522; Anti-Bacterial Agents - administration & dosage; Anti-Bacterial Agents - isolation & purification; Anti-Bacterial Agents - pharmacology; Antibacterial agents; Antiinfectives and antibacterials; Bacteria; Bacterial diseases; Bacterial proteins; Bacteriology; Biomedical and Life Sciences; Bioorganic Chemistry; Biphenyl Compounds - administration & dosage; Biphenyl Compounds - isolation & purification; Biphenyl Compounds - pharmacology; Coliforms; Cytosol; E coli; Gene expression; Gram-negative bacteria; Hemolysis; Hemolysis - drug effects; Inhibitory Concentration 50; Life Sciences; Magnolia - chemistry; Magnolia obovata; Medicinal Chemistry; Microbiology; Organic Chemistry; original-article; Pathogens; Phenyl Ethers - administration & dosage; Phenyl Ethers - isolation & purification; Phenyl Ethers - pharmacology; Proteins; Salmonella; Salmonella - pathogenicity; Secretion; Sexually transmitted diseases; STD; Type III Secretion Systems - drug effects; Virulence; Virulence factors
• ISSN: 0021-8820; 1881-1469
• DOI: 10.1038/ja.2017.98

In many pathogenic Gram-negative bacteria, such as Salmonella , Escherichia coli , Yersinia and Chlamydia spp., which cause diseases in humans, the type III secretion system (TTSS) is an important virulence factor that translocates effector proteins into the cytosol of host cells. Thus, the TTSS is a good target for antibacterial agents. Here we used a hemolysis assay to search for TTSS inhibitors and found that a compound from Magnolia obovata called obovatol blocks the TTSS of Salmonella . Obovatol showed potent inhibitory activity (IC 50 =19.8 μ M ) against the TTSS-related hemolysis of Salmonella , which was not due to a reduction of bacterial growth. Instead, the compound inhibited bacterial motility, TTSS-related mRNA expression and effector protein secretion. These data demonstrate the inhibitory effect of obovatol on the Salmonella TTSS and suggest that it could be useful for the prevention and supplementary treatment of bacterial infections.