Effects of baicalin on Chlamydia trachomatis infection in vitro.

Baicalin has emerged as a promising agent for the therapy of infectious diseases due to the increasing number of pathogenic microbial strains resistant to several antibiotics. In this study, we investigated the inhibitory activity of baicalin on Chlamydia infection in vitro. We found that baicalin blocked the infection of HeLa cells in vitro when added to the infected cells. In order to shed light on the inhibitory effects of baicalin on the Chlamydia-infected cells, the expression of RFX5 and Chlamydia protease-like activity factor (CPAF) mRNAs and proteins in the Chlamydia-infected cells were examined using Western blot and real-time RT-PCR analysis. The results demonstrated that RFX5 and CPAF were upregulated and downregulated, respectively, by baicalin. Because CPAF is responsible for degrading RFX5, it is suggested that CPAF is a primary target of baicalin and plays an important role in downregulating RFX5. In conclusion, our findings demonstrated that baicalin can effectively inhibit Chlamydia Trachomatis in HeLa cells and therefore can be considered a potential agent for the therapy of infectious diseases caused by C. trachomatis.