Biotechnology Bulletin ›› 2015, Vol. 31 ›› Issue (8): 159-165.doi: 10.13560/j.cnki.biotech.bull.1985.2015.08.023

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A Study on Antibacterial Mechanisms of Ethanol-extracts from Scutellaria baicalensis Against Vibrio parahaemolyticus

Xie Liling, Peng Qi, Cai Lianchun, Zhou Liang, Zhu Yankun, Han Guangyao   

  1. College of Science,Shantou University,Shantou 515063
  • Received:2014-12-25 Online:2015-08-21 Published:2015-08-22

Abstract: The goal of this work is to screen one with strong antibacterial activities against Vibrio parahaemolyticus from 4 traditional Chinese medicines(TCMs), and study the underlying mechanisms. The sensitivity of ethanol-extracts from TCMs to Vibrio parahaemolyticus was determined by Oxford cup assay and liquid double dilution method. The antibacterial mechanism was investigated by measuring growth curve and bactericidal curve, electron microscope examination, and SDS-PAGE analysis. The results showed that different ethanol-extracts from 4 TCMs had different antibacterial activities upon V. parahaemolyticus, among them the ethanol-extract from S. baicalensis had the best antibacterial activity with an inhibition zone diameter of 22.00 ± 1.00 mm. Both the minimum inhibitory concentration(MIC)and minimum bactericidal concentration(MBC)of the extract against V. parahaemolyticus were 3.91 mg/mL. V. parahaemolyticus treated with Scutellaria extract in MIC still entered a normal log and stationary phase after a longer lag phase. Bacterial surface became rough, showing a sign of cell lysis. Protein concentration in the supernatant increased significantly. However, the concentration of soluble proteins changed lightly after the treatment of Scutellaria extract. Conclusively, Scutellaria extract has a significant inhibition effect against V. parahaemolyticus by destroying the integrity of cell membrane and causing cell lysis.

Key words: Scutellaria baicalensis, Vibrio parahaemolyticus, ethanol-extract, antibacterial mechanism.