ObjectiveTo investigate the influence of TTS-12, a steroid saponin from Tribulus terrestris L., on the formation of Candida albicans biofilm, and to discuss the possible mechanism. MethodsThe inhibition of C.albicans biofilm formation by TTS -12 was observed by confocal scanning laser microscopy; XTT method was used to investigate the influence of different concentrations of TTS-12 on C.albicans biofilm formation. The water-hydrocarbon two-phase assay was used to measure the cell surface hydrophobicity of C.albicans treated with different concentrations of TTS-12. The expression of CSH1 mRNA was measured by real-time RT-PCR. ResultsCompared with control group, TTS-12 treatment resulted in loose C.albicans biofilm,and it dose-dependently inhibited C.albicans biofilm formation. The cell surface hydrophobicity in the TTS-12-treated groups was lower than that in the control group; consistent with this, TTS-12-treated cells also expressed significantly lower levels of CSH1 mRNA than cells in control group (P<0.01). ConclusionTTS-12 may inhibit the formation of C.albicans biofilm through inhibiting CSH1 gene expression.