Antifungal activity and potential mechanism of magnoflorine against Trichophyton rubrum.

Coptis alkaloids show potent antifungal activity against Trichophyton rubrum (T. rubrum), which was a Tinea pedis fungus, but little of the literature was reported to investigate the antifungal activity of magnoflorine against it. Meanwhile, the potential mechanism of magnoflorine against T. rubrum is unknown. In the present study, we found that Coptis alkaloids, especially magnoflorine had significant antifungal activities against T. rubrum and Trichophyton mentagrophyte (T. mentagrophyte). The MIC values of magnoflorine against T. rubrum and T. mentagrophyte were both 62.5 μg ml-1, but magnoflorine exerted a better fungicidal efficiency against T. rubrum than T. mentagrophyte. Magnoflorine inhibited the conidia germination and hyphal growth, and changed the mycelial morphology such as deformation growth, surface peeling, and cytoplasmic contraction in T. rubrum. Magnoflorine had no significant effect on cell wall integrity. However, magnoflorine destroyed the fungal cell membrane of T. rubrum through increasing the nucleic acid leakage, reducing the activities of squalene epoxidase and CYP51 enzyme, and decreasing the content of ergosterol in hyphae. Our study supported the potential use of magnoflorine as an antifungal agent against T. rubrum and made contributions to the clinical application of magnoflorine against fungi.