Comparative Study of In Vitro Inhibitory Effects of UVC, Terbinafine Hydrochloride 1% and Paeonia Natural Extracts on Trichophyton rubrum

Jung, Ho Jung; Lee, Yang Won; Choe, Yong Beom; Ahn, Kyu Joong

Abstract

BACKGROUND
Trichophyton(T.) rubrum is most common fungal pathogen that causes tinea pedis and onychomycosis. It recurrently infects human and usually persists for very long time, provoking public health concern. Due to the limitation in current treatment options, alternative therapies are desirable. We investigated the inhibitory effect of UVC, terbinafine hydrochloride 1% and paeonia natural extracts on T. rubrum in vitro.
OBJECTIVE
AND METHOD: Total 25 T. rubrum strains were cultured for 10 days on Mycosel agar plate; 5 strains of T. rubrum and 5 copies for each strain. They were divided into 5 groups: control, UVC irradiation, terbinafine spray, paeonia natural extracts spray, UVC and paeonia natural extracts sprays. The cultured media were irradiated for 1 hour daily for 3 weeks in the germicidal lamp emitting 253.7 nm (UVC), power of 2.875 mW/cm2 at 10 cm distance. Terbinafine and paeonia extracts was sprayed twice on the surface to fully cover the colony area. The median diameter of each colony were measured every other day for 3 weeks. The change of colony diameter and the growth rate were analyzed.
RESULTS
The UVC had virtually no effect on restraining the growth of T. rubrum, similar with the growth of the control group. However, both the terbinafine spray and paeonia extracts slowed down the growth rate remarkably and showed a similar effect.
CONCLUSION
We could only figure out the fungistatic effect, and not the fungicidal effect of paeonia extract and terbinafine hydrochloride in vitro. UVC irradiation setting in this study was totally ineffective. More studies are needed on more variable wavelength and the fluence of UVC irradiation. In addition, further verification on the mechanism and the effect of anti-fungal activity by paeonia extracts are needed.