Fuente: Microorganisms - Revista científica (MDPI) Microorganisms, Vol. 14, Pages 795: Comprehensive Profiling of Aseer Medicinal Plants: Connections Between Molecular Identity, Chemical Composition, and Antifungal–Antibiofilm Activity Against Oral Yeasts
Microorganisms doi: 10.3390/microorganisms14040795
Authors:
Aisha Shathan
Azhar Najjar
Ali Jourk
Samah Noor

Oral fungal infections resulting from non-albicans Candida species and new opportunistic yeasts are increasingly linked to antifungal resistance, especially in individuals with periodontal disease. Bioactive compounds may serve as potential alternatives; nevertheless, there is a paucity of research that has comprehensively assessed their antifungal and antibiofilm efficacy against clinically defined oral yeast isolates. This study aimed to (i) describe the variety and antifungal resistance profiles of oral yeasts isolated from women with various periodontal diseases; (ii) assess four ethanolic extracts of Aseer medicinal plants (Foeniculum vulgare, Solanum incanum, Forsskaolea tenacissima, and Abutilon pannosum) for their antifungal and antibiofilm properties; and (iii) correlate phytochemical composition determined by GC–MS with biological activity. Oral samples (saliva and subgingival plaque) were collected from 50 female participants with documented periodontal parameters. Fungal isolates were identified using morphological, biochemical (VITEK 2), and molecular (ITS rDNA sequencing) methods. Testing for antifungal susceptibility was performed according to CLSI guidelines. Plant extracts were evaluated for antifungal activity (disk diffusion, MIC, MFC), antibiofilm activity (crystal violet assay and light microscopy), and phytochemical profiling (GC–MS). Fungal growth was detected in 37 of 50 samples (74%), yielding six yeast species: Nakaseomyces glabratus (40.5%), Candida tropicalis (18.9%), C. parapsilosis (13.5%), Pichia kudriavzevii (10.8%), Rhodotorula mucilaginosa (8.1%), and Aureobasidium melanogenum (8.1%). N. glabratus demonstrated reduced susceptibility to fluconazole. A. pannosum and F. vulgare exhibited the strongest in vitro antifungal activity (inhibition zones up to 19.2 mm; MIC 0.19–0.78 mg/mL; MFC 0.39–1.56 mg/mL), significantly greater than F. tenacissima (p < 0.0001). Sub-MIC concentrations of A. pannosum reduced C. tropicalis biofilm biomass by 59.6%. GC–MS analysis identified methyl salicylate (20.3–40.2%) and cyclohexanol derivatives (8.0–23.2%) as major constituents. Antifungal activity showed a trend in relation to methyl salicylate content (R2 = 0.78). However, because only four plant extracts were included, this relationship should be interpreted as a descriptive observation rather than a statistically testable association. Ethanolic extracts of Abutilon pannosum and Foeniculum vulgare demonstrated significant in vitro antifungal and antibiofilm activity against clinically relevant oral yeasts, including azole-tolerant Nakaseomyces glabratus. The observed trends between phytochemical composition and biological activity warrant further investigation into their potential as adjunct therapeutic agents for oral fungal infections. Further studies are required to confirm these results and see if they can be used in therapeutic settings.