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 4× 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.