In vitro antifungal activity of 163 extracts from traditional Chinese medicine herbs

Abstract

IntroductionDifferent extraction, screening and testing methods have made it difficult to compare the antifungal activities of traditional Chinese medicine (TCM) extracts. In this study, the antifungal activities of TCM herbs recorded in the Chinese Materia Medica were evaluated using consistent methods and standards. MethodsA total of 163 TCM herbs were tested for antifungal activity against four strains of fungi using a broth microdilution assay and a hyphal growth inhibition assay was performed against Candida albicans. The antifungal activities of the most biologically active herbs were evaluated against six other fungal strains. They were also tested in combination with fluconazole against a fungicide-resistant Candida albicans strain. The main chemical constituents of Rosa chinensis were evaluated for their antifungal activity and mode of action. ResultsA total of 52 herb extracts exhibited inhibitory effects against Cryptococcus neoformans, 22 worked against Candida albicans and six acted against Aspergillus fumigatus. Syzygium aromaticum, Phellodendron chinense, Neopicrorhiza scrophulariiflora, Curcuma longa and Rosa chinensis exerted potent and broad-spectrum antifungal activities. The hyphal growth inhibition assay demonstrated that extracts of six herbs completely inhibited hyphal growth. The main antifungal constituents of Rosa chinensis were gallic acid and flavonoids. These compounds exhibited synergistic and additive antifungal effects. ConclusionRosa chinensis, Neopicrorhiza scrophulariiflora, Phellodendron chinense and Syzygium aromaticum displayed the strongest antifungal effects. The antifungal effects of the main chemical constituents of Rosa chinensis provide a basis for further studies on their biological activities.