Effects of epigallocatechin gallate on the cell-wall structure of Mycobacterial smegmatis mc²155

Abstract

Epigallocatechin gallate (EGCG) is the main component of green tea extracts that inhibits the growth of Mycobacterial smegmatis mc²155, and the mechanism is not clear. This study showed the effects of EGCG on the growth of mc²155. The content and the structure of EGCG in LB medium with mc²155 were identified by HPLC and LC/MS. Transmission electron microscopy was utilised to identify the cell envelope structure. As a result, the optional inhibition concentration was determined to be 20 μg mL^− 1. Most of EGCG was transferred into its isomeride in LB medium, but the inhibition effects against mc²155 had yet been maintained. The changes of cell envelope structure were showed after EGCG treatment for 18 h. The cell wall appeared to have a less electron-translucent zone, turn rougher and thicker. The results show that EGCG impacts the integrity of mycobacterial cell wall and is likely be a better prophylactic agent against tuberculosis.

Keywords::

• epigallocatechin gallate
• M. smegmatis mc²155
• antimicrobial effect
• cell-wall structure

Acknowledgement

The plasmid pSMT1 was gifted by Prof. Douglas Young.

Notes

^1. These authors contributed equally to this work.

Additional information

Funding

This study is supported by grants from the National Natural Science Foundation of China [31300672], Science Foundation of Liaoning Province [L2012315] and Specialized Research Foundation for the Doctoral Program of Higher Education Project [20122105120014].