Baicalin inhibits Chlamydia trachomatis growth by impairing elementary body infectivity.

Chlamydia trachomatis (C. trachomatis) infection is a prevalent sexually transmitted disease worldwide. Although antibiotics are the standard first-line treatment, the rising incidence of treatment failure highlights the need for alternative therapeutic strategies. Baicalin, a natural flavonoid compound extracted from Scutellaria baicalensis, is known to possess antimicrobial properties. This study aimed to evaluate the anti-chlamydial effects of baicalin. Our results showed that baicalin significantly inhibited the growth of multiple C. trachomatis serovars (A, D, and L2) in HeLa cells, as indicated by reductions in inclusion number and size, as well as decreased cHSP60 level. Moreover, baicalin markedly diminished the production of infectious progeny. Mechanistic investigations suggest that the anti-chlamydial effect of baicalin likely involves direct targeting of elementary bodies to impair their infectivity, rather than interfering with host cell pathways. Furthermore, baicalin exhibited a synergistic inhibitory trend when combined with azithromycin. These findings indicate that baicalin is a promising novel therapeutic candidate for combating C. trachomatis infections.