Antidermatophyte Activity of the Gentiopicroside-Rich n-Butanol Fraction from Gentiana siphonantha Maxim. Root on a Guinea Pig Model of Dermatophytosis

Abstract

Background:Gentiana siphonantha Maxim. is a traditional medicine for the treatment of rheumarthritis, icterepatitis, pain and hypertension; it is rich in gentiopicroside with anti-inflammatory, antibacterial, and free radical-scavenging activities. This study was to evaluate the antidermatophyte activity of G. siphonantha on a guinea pig model in vitro and in vivo. Material andMethods: The antidermatophyte activities of 10 plants were tested by the broth microdilution method. Fractions and an extract of G. siphonantha were tested against Trichophyton mentagrophytes by the disc diffusion method. The morphological changes of T. mentagrophytes were observed. Component analysis of the n-butanol (n-BuOH) fraction was made by HPLC. Finally, the antifungal activity in an in vivo guinea pig model of dermatophytosis was examined. Results:G. siphonantha had strong antidermatophyte activity with MIC50 values of 32-64 μg/mL. The n-BuOH fraction of G. siphonantha showed the most potent activity compared to the other fractions. After being exposed to the n-BuOH fraction at 80 and 160 μg/mL, the hyphae were distorted and collapsed. Gentiopicroside is the main active ingredient in the n-BuOH fraction of G. siphonantha. The lesion scores of the guinea pig model of dermatophytosis significantly declined in the 10% and 30% extract and positive control groups in comparison with the untreated control group. Periodic acid-Schiff and hematoxylin/eosin staining displayed similar results. Conclusion: The n-BuOH fraction of G. siphonantha demonstrated antidermatophyte efficacy in experimental dermatophytosis.