In vitro anticandidal activity of xanthorrhizol isolated from Curcuma xanthorrhiza Roxb.

OBJECTIVES Xanthorrhizol, isolated from the methanol extract of Curcuma xanthorrhiza Roxb., was investigated for its anticandidal activity using six Candida species. METHODS The in vitro susceptibility tests for xanthorrhizol were carried out in terms of MIC and minimal fungicidal concentration (MFC) using the NCCLS M27-A2 broth microdilution method. Time-kill curves were determined to assess the correlation between MIC and fungicidal activity of xanthorrhizol at concentrations ranging from 0 MIC to 4x MIC. RESULTS All Candida species showed susceptibility to xanthorrhizol in the MIC range 1.0-15.0 mg/L for Candida albicans, 1.0-10 mg/L for Candida glabrata, 2.0-8.0 mg/L for Candida guilliermondii, 2.5-7.5 mg/L for Candida krusei, 2.5-25 mg/L for Candida parapsilosis and 2.0-8.0 mg/L for Candida tropicalis. Time-kill curves demonstrated that xanthorrhizol was able to kill the Candida strains with MFCs of 20 mg/mL, 15 mg/mL, 12.5 mg/mL, 10 mg/L, 30 mg/mL and 10 mg/L for C. albicans, C. glabrata, C. guilliermondii, C. krusei, C. parapsilosis and C. tropicalis, respectively. CONCLUSIONS The potent anticandidal activity of xanthorrhizol may support the use of C. xanthorriza for the treatment of candidiasis.