In vitro study of antifungal and antibiofilm of syzygium polyanthum against candida species on different type of denture bases

Abstract

Denture stomatitis is primarily caused by Candida biofilm formation on denture bases. Conventional antifungal treatments face challenges such as side effects and increasing resistance. Natural alternatives like Syzygium polyanthum (S. polyanthum), known for its medicinal properties, show promise but remain underexplored in this context. This study aimed to determine antifungal and antibiofilm of Syzygium polyanthum against Candida albicans and Candida parapsilosis on polymethyl methacrylate (PMMA) and cobalt chrome (CoCr) denture base materials. A total of forty-six PMMA and forty-six CoCr discs were fabricated to simulate denture base materials using conventional heat-curing methods for PMMA and the lost-wax casting technique for CoCr, followed by standardized polishing. The baseline surface roughness of ten specimens from each material was determined using a laser microscope (LEXT OLS5100). C. albicans (ATCC MYA-4901) and C. parapsilosis (ATCC 22019) were cultured in yeast peptone dextrose (YPD) broth at 37 °C for 24 hours and inocula were standardized to 0.5 McFarland (1.5 × 10⁶ CFU/mL). Meanwhile, S. polyanthum leaves were extracted using ultrasonic-assisted aqueous extraction. Antifungal susceptibility was evaluated using a denture plate diffusion assay with 80% (w/v) extract which nystatin served as the positive control. Antibiofilm activity was assessed using static biofilm assay and crystal violet assay on PMMA and CoCr surfaces to quantify the biofilm biomass. Finally, the biofilm morphology was observed using scanning electron microscopy (SEM). All experiments were conducted in three biological replicates (N=3) to ensure reproducibility. The results showed that C. albicans and C. parapsilosis were observed to be resistant towards S. polyanthum aqueous extract on both PMMA and CoCr denture base materials. Statistical analysis using three-way ANOVA revealed significant differences in C. albicans biofilm formation among the treatment groups on both PMMA and CoCr denture base materials (p < 0.05). On PMMA, nystatin demonstrated the lowest biofilm biomass (0.026 ± 0.031), followed by S. polyanthum (0.212 ± 0.184), while the untreated biofilm exhibited the highest biomass (0.815 ± 0.145). The significant reductions were observed in both nystatin (p < 0.05) and S. polyanthum (p < 0.05) compared to the untreated group. On CoCr, similar trends were observed, with nystatin producing complete inhibition and S. polyanthum (0.113 ± 0.196) showing significantly lower biofilm measurements compared to the untreated group (0.779 ± 0.076; p < 0.05). The biofilm biomass of C. parapsilosis on PMMA was observed to be reduced completely when treated with nystatin (p < 0.05) and S. polyanthum (p < 0.05) compared to the untreated. A significant difference was only observed for nystatin (1.143 ± 0.022) compared to untreated groups when the biofilm was developed on CoCr (p < 0.05). A significant difference was observed between PMMA and CoCr under all treatment conditions (p < 0.05). SEM confirmed the antibiofilm activity of S. polyanthum aqueous extract by showing disrupted biofilm architecture and diminished surface coverage compared with untreated specimens. In conclusion, S. polyanthum aqueous extract does not inhibit the growth of C. albicans and C. parapsilosis on PMMA and CoCr denture base materials however, it exhibits antibiofilm properties against both species.