Geraniol and thymoquinone inhibit Candida spp. biofilm formation on acrylic denture resin without affecting surface roughness or color

Abstract

Purpose: This study was designed to investigate the in vitro effects of geraniol (GE) and thymoquinone (TQ) on Candida biofilms on denture acrylic and any accompanying changes in acrylic surface roughness or color. Methods: The susceptibility of Candida species to GE and TQ was determined using the broth microdilution method and time-kill assay. A minimum biofilm eradication concentration (MBEC) assay was performed using 7-day Candida biofilms grown on denture acrylic. Results: The minimum inhibitory concentration (MIC) of GE and TQ for Candida spp. was 256 and 32 µg/mL, respectively. The Candida strain complete kill rates for GE and TQ at 5-fold MIC were determined after 1 h of incubation. At 5-fold MIC, GE and TQ inhibited the preformed biofilm activity (MBEC80) of all Candida strains on denture acrylic by more than 80% after treatment for 3 h. At sub-MIC levels, GE and TQ prevented the development of C. albicans and C. tropicalis hyphae. SEM images demonstrated that GE and TQ damaged the fungal cell membrane and induced cell lysis. On the other hand, GE and TQ at 10-fold MIC did not alter the surface roughness or color of the denture acrylic. Conclusion: GE and TQ are interesting natural substances that could be developed as promising disinfectants for removable dentures.

Strategies for Preventing and Treating Oral Mucosal Infections Associated with Removable Dentures: A Scoping Review

“…The chemical cleaning methods under investigation included effervescent tablets and gels containing alkaline peroxide with enzymes (Corega Tabs, Polident, Toughdent, Ortoform, Bonyplus) or without enzymes (Nitradine), sodium hypochlorite (in various concentrations), surfactants, microbial agents, chlorhexidine, and natural agents such as copaiba oil, tea tree oil, Ricinus communis solution, and propolis [ 9 , 22 , 23 , 24 , 38 , 40 , 80 , 82 , 89 , 92 , 105 , 108 , 110 , 111 , 123 , 124 , 125 , 135 , 139 , 140 , 161 ]. The findings from studies published between 2010 and 2023 indicate that sodium hypochlorite stands out as the most effective and cost-efficient solution for biofilm control.…”

“…The clinical investigations aimed to assess various biofilm control strategies, ranging from the home use of biofilm-revealing solutions by patients to the evaluation of dentifrices and disinfectant solutions for dentures, incorporating synthetic and natural active ingredients [ 116 ]. These interventions were often combined with ultrasound and palate brushing, or conducted with palate brushing alone [ 22 , 32 , 33 , 80 , 89 , 105 , 106 ].…”

“…Over this period, a notable evolution in the research landscape is evident, particularly characterized by a substantial increase in controlled clinical studies, contributing a high level of evidence to the area [ 18 , 24 , 27 , 40 , 44 , 57 , 68 , 70 , 71 , 72 , 74 , 75 , 85 , 89 , 92 , 110 , 112 , 115 ]. Employing crossover or parallel group models, these studies explored several methods, with particular emphasis on the combination of brushing and disinfection using solutions and indicated anti-biofilm effectiveness, as well as the remission of inflammation results that can be considered clinically relevant.…”

“…In addition to denture hygiene methods for treatment of inflammation and/or mucosal infections, the literature indicates the use of a low-power laser [ 62 ], antifungals for local or systemic application, whether associated or not with photodynamic therapy [ 50 , 52 , 63 , 64 , 65 , 66 , 67 , 68 , 69 , 70 , 71 , 72 ], combined treatments using drugs with a local effect for stomatitis [ 73 ] and drugs with a systemic effect for patients with gastrointestinal pathologies, type 2 diabetes [ 74 ], or pathologies in the cardiovascular system [ 75 ]. Although less used, products based on organic acid, titanium dioxide, and inorganic silver antibacterial agents, and chlorine dioxide, as well as natural products used for immersion or incorporation into prosthetic materials, are also found in the literature [ 7 , 19 , 76 , 77 , 78 , 79 , 80 , 81 , 82 , 83 , 84 , 85 , 86 , 87 , 88 , 89 , 90 ].…”

Preventive effects of geraniol in schizophrenia-like symptoms in mice models of psychosis

“…10,11 Its isolates from plants (such as Monarda fistulosa, Cinnamomum tenuipilum, Dracocephalum moldavica, Valeriana officinalis, Rosa damascene, and others) have been shown to exhibit anti-microbial, anticancer, anti-ulcer, antioxidant, anti-inflammatory, and neuroprotective activities in-vivo and in-vitro investigations. [12][13][14][15][16][17][18] Interestingly, geraniol supplementation have been reported to mitigate motor disturbance seen in rotenone-and 1methyl-4-phenyl-1, 2, 3, 6-tetrahydropyridine-induced Parkinson's disease, as well as prevent cognitive impairment and other neurotoxicity phenotypes induced by D-galactose, zinc oxide nanoparticles, lipopolysaccharide, acrylamide, and streptozotocin brain insults by modulating various signaling pathways. [18][19][20][21][22] Previous studies have also reported that geraniol produced CNS depressant-like effect and anticonvulsant-like activity in pentylenetetrazole-induced convulsion via augmentation of the GABA system.…”