Original Article

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

  • The Journal of Antibiotics volume 70, pages 10651069 (2017)
  • doi:10.1038/ja.2017.98
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Abstract

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 (IC50=19.8 μM) 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.

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Acknowledgements

We thank the members in the laboratory of Dr SUK for their technical support and helpful discussions. We are also deeply grateful to Dr Dae-Seop Shin (KRICT, Daejeon, Korea) for his useful advice.

Author information

Affiliations

  1. Research Institute, JeonjinBio Co., Ltd, Daegu, Korea

    • Won-Sik Choi
    • , Tae Hun Lee
    • , Se Jin Son
    •  & Tae Gyu Kim
  2. Department of Nano Science and Technology, Graduate School, Kyungpook National University, Daegu, Korea

    • Won-Sik Choi
    •  & Sang-Han Lee
  3. Genome Editing Research Center, Korea Research Institute of Bioscience and Biotechnology, Daejeon, Korea

    • Byoung-Mog Kwon
  4. Department of Food Science and Biotechnology, and Food and Bio-Industry Research Institute, Kyungpook National University, Daegu, Korea

    • Hyeong-U Son
    •  & Sang-Han Lee
  5. Industrial Bio-materials Research Center, Korea Research Institute of Bioscience and Biotechnology, Daejeon, Korea

    • Sung Uk Kim
  6. Department of Food Science and Engineering, Seowon University, Cheongju, Korea

    • Sung Uk Kim

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Competing interests

The authors declare no conflict of interest.

Corresponding authors

Correspondence to Sung Uk Kim or Sang-Han Lee.