Inhibitory effect of Streblus asper leaf-extract on adhesion of Candida albicans to denture acrylic

This in vitro study aimed at determining the effects of various sublethal concentrations of Streblus asper leaf ethanolic extract (SAE) on adherence of Candida albicans to acrylic surface. A colorimetric tetrazolium assay using (2,3)-bis (2-methoxy-4-nitro-5-sulfophenyl)-5-[(phenylamino)-carbonyl]-2H-tetrazolium hydroxide was used to make the quantitative determination. The SAE at a concentration equivalent to nystatin (6.24 μg/ml) pinpointed the minimal exposure time of SAE in suppressing candidal adhesion to acrylic. Adhesion of Candida albicans to acrylic was determined after exposure to SAE for 1, 15, 30, 60, 120 and 180 min. The minimum concentration of SAE that significantly reduced adherence (P < 0.05) after a 4-h exposure was 31.25 mg/ml. In addition, a significant reduction (P < 0.01) of candidal adhesion to acrylic occurred after a 1 min exposure to 62.5 mg/ml of SAE. Pre-treatment of yeast with 62.5 mg/ml of SAE for 1 h before adhesion assay significant reduced the adherence as 20.54% compared to the untreated control, whereas the same treatment with acrylic strips did not show any effect. These findings indicate that exposure of Candida albicans to sublethal concentrations of SAE results in a reduction in the ability of the yeasts to adhere to denture acrylic, possibly preventative of denture stomatitis.