Natural compounds containing mouthrinses in the management of dental plaque and gingivitis: a systematic review.

OBJECTIVES: To evaluate the effectiveness of natural compounds containing mouthrinse (NCCM) as an adjunct to unsupervised oral hygiene in the management of dental plaque and gingivitis. MATERIALS AND METHODS: An electronic search for clinical studies of NCCMs was conducted in Medline-PubMed, the Cochrane Central Register of Controlled Trials and EMBASE for a period spanning from the earliest available date in each database up to February 2013. Plaque index, gingival index, and gingival bleeding index were selected as primary outcomes. The methodological quality of the studies was assessed according to the "Levels of Evidence" outlined by the Center of Evidence-Based Medicine, and to the Jadad scale. RESULTS: The screen yielded 2,236 titles and abstracts that met the inclusion criteria. These identified 11 clinical trials testing 13 different NCCMs, and were used for data extraction. Heterogeneity and the limited number of studies on any individual NCCM precluded a formal meta-analysis. Of the 13 NCCMs tested, eight demonstrated positive results, and few reported any adverse effects or events. CONCLUSIONS: Evidence proving the effectiveness of NCCM as an adjunct to unsupervised oral hygiene for plaque and gingivitis control is still insufficient. However, some natural products (compounds) may have oral health benefits, so further high-quality study is warranted. CLINICAL RELEVANCE: This review provides an overview of the strength of clinical evidence regarding the effectiveness of natural compounds containing mouthrinses in promoting gingival health.

Unraveling the resistance of microbial biofilms: has proteomics been helpful?

Biofilms are surface-attached, matrix-encased, structured microbial communities which display phenotypic features that are dramatically different from those of their free-floating, or planktonic, counterparts. Biofilms seem to be the preferred mode of growth of microorganisms in nature, and at least 65% of all human infections are associated with biofilms. The most notable and clinically relevant property of biofilms is their greater resistance to antimicrobials compared with their planktonic counterparts. Although both bacterial and fungal biofilms display this phenotypic feature, the exact mechanisms underlying their increased drug resistance are yet to be determined. Advances in proteomics techniques during the past decade have facilitated in-depth analysis of the possible mechanisms underpinning increased drug resistance in biofilms. These studies have demonstrated the ability of proteomics techniques to unravel new targets for combating microbial biofilms. In this review, we discuss the putative drug resistance mechanisms of microbial biofilms that have been uncovered by proteomics and critically evaluate the possible contribution of the new knowledge to future development in the field. We also summarize strategic uses of novel proteomics technologies in studies related to drug resistance mechanisms of microbial biofilms.

Comparison of the antimicrobial activity of Listerine and Corsodyl on orthodontic brackets in vitro.

INTRODUCTION: The aim of this study was to evaluate the antimicrobial efficacy of 2 commercially available mouth rinses on a monospecies-biofilm model on orthodontic brackets in vitro. METHODS: The antimicrobial effects of the 2 mouth rinses, Listerine (tartar control; IDS Manufacturing, Bangkok, Thailand) and Corsodyl (SmithKline Beecham, Maidenhead, United Kingdom), on the planktonic Streptococcus mutans were tested by maximum inhibitory dilution assay. The cell viability of S mutans biofilm on Damon3 MX brackets (Ormco, Glendora, Calif) after exposure to the 2 mouth rinses was quantified by 2,3-bis (2-methoxy-4-nitro-5-sulfophenyl)-5-[(phenylamino) carbonyl]-2H-tetrazolium hydroxide (XTT) reduction assay. Visualization of the biofilm samples was performed by fluorescence microscopy and confocal laser scanning microscopy. RESULTS: The maximum inhibitory dilution assays of S mutans were 1:5 for Listerine and 1:320 for Corsodyl. The optical density values, which were measured by XTT reduction assay from S mutans biofilms after 1 minute of exposure to the different test agents, demonstrated that the cell viability of S mutans biofilms exposed to Listerine was less than that for Corsodyl, which was less than that for brain-heart infusion (P <0.001). Listerine caused more dead cells on the surface of the brackets than did Corsodyl when examined with the 2 microscope systems. CONCLUSIONS: Both mouth rinses showed marked antimicrobial effects on the monospecies biofilm in vitro. Listerine showed a stronger bactericidal effect but had less bacterial inhibitory effect than did Corsodyl.

Proteomics of drug resistance in Candida glabrata biofilms.

Candida glabrata is a fungal pathogen that causes a variety of mucosal and systemic infections among compromised patient populations with higher mortality rates. Previous studies have shown that biofilm mode of the growth of the fungus is highly resistant to antifungal agents compared with the free-floating or planktonic mode of growth. Therefore, in the present study, we used 2-D DIGE to evaluate the differential proteomic profiles of C. glabrata under planktonic and biofilm modes of growth. Candida glabrata biofilms were developed on polystyrene surfaces and age-matched planktonic cultures were obtained in parallel. Initially, biofilm architecture, viability, and antifungal susceptibility were evaluated. Differentially expressed proteins more than 1.5-fold in DIGE analysis were subjected to MS/MS. The transcriptomic regulation of these biomarkers was evaluated by quantitative real-time PCR. Candida glabrata biofilms were highly resistant to the antifungals and biocides compared with the planktonic mode of growth. Candida glabrata biofilm proteome when compared with its planktonic proteome showed upregulation of stress response proteins, while glycolysis enzymes were downregulated. Similar trend could be observed at transcriptomic level. In conclusion, C. glabrata biofilms possess higher amount of stress response proteins, which may potentially contribute to the higher antifungal resistance seen in C. glabrata biofilms.

In vitro synergistic effects of metergoline and antifungal agents against Candida krusei.

Metergoline, a serotonin receptor antagonist, was evaluated for its antifungal activity against the opportunistic human fungal pathogen Candida krusei by a broth microdilution assay. The minimal inhibitory concentration and minimal fungicidal concentration of metergoline against C. krusei were 4 and 8 µg ml(-1) respectively. Significant synergism was found in combination of metergoline with amphotericin B (fractional inhibitory concentration index: 0.375-0.5) by a chequerboard assay. Metergoline also inhibited extracellular phospholipase secretion in a dose-dependent manner, which may be a possible action mechanism of metergoline on C. krusei.

Distribution coefficients of dietary sugars in artificial Candida biofilms.

Candida species are the most important fungal pathogens in humans and cause a variety of superficial and systemic diseases. Biofilm formation is a major virulence attribute contributing to Candida pathogenicity. Although the concentration and distribution of nutrients as well as antifungals across the biofilm thickness play a pivotal role in the development and persistence of Candida biofilms, only limited information is available on the latter aspects of Candida biofilms. Therefore, we attempted to characterize the diffusion coefficient (De) of common dietary sugars such as glucose, galactose, and sucrose in Candida albicans biofilms using horizontal attenuated total reflection-Fourier transform infrared spectroscopy (HATR-FTIR). Artificial Candida biofilms were formed using agarose polymers. De of three sugars tested, glucose, galactose, and sucrose in this artificial Candida biofilm model was found to be 4.08E-06 +/- 3.63E-08, 4.08E-06 +/- 3.70E-08, and 5.38E-06 +/- 4.52E-08 cm(2) s(-1), respectively. We demonstrate here the utility of HATR-FTIR for the determination of diffusion of solutes such as dietary sugars across Candida biofilms.

Candida albicans biofilm formation is associated with increased anti-oxidative capacities.

Candida albicans is a common, opportunistic, human fungal pathogen that causes a variety of mucosal and systemic afflictions. It exists in nature both in the biofilm or the sessile phase, as well as in the free-floating or the planktonic phase. Candida biofilms, in particular, display unique characteristics that confer survival advantages over their planktonic counterparts, such as their recalcitrance to common antifungals. The mechanisms underlying Candida biofilm formation and their attributes are poorly understood. In this study, we used a 2-DE-based approach to characterize the protein markers that are differentially expressed in Candida biofilms in comparison to their planktonic counterparts. Using tandem mass spectrometric analysis, we have identified a significant number of proteins including alkyl hydroperoxide reductase, thioredoxin peroxidase, and thioredoxin involved in oxidative stress defenses that are upregulated in the biofilm phase. These proteomic findings were further confirmed by real-time PCR and lucigenin-based chemiluminescence assays. In addition, we demonstrate that a drug target for the new antifungal agent echinocandin, is abundantly expressed and significantly upregulated in Candida biofilms. Taken together, these data imply that the biofilm mode, Candida, compared with their planktonic counterparts, exhibits traits that can sustain oxidative stress (anti-oxidants), and thereby exert resistance to commonly used antifungals.

Potent anti-microbial activity of traditional Chinese medicine herbs against Candida species.

Anti-candidial activities of eight traditional Chinese medicinal (TCM) herbs were evaluated against six different Candida species. TCM preparations were screened for antifungal activity using a standard agar diffusion assay. Following identification of potential candidate herbs, their minimum inhibitory concentration (MIC) values were determined using the standardised NCCLS M-27A broth microdilution assay. Among TCM herbs, Rhizoma Coptidis had potent antifungal activity against Candida glabrata, Candida krusei and Candida tropicalis, but not against Candida albicans, Candida dubliniensis and Candida parapsolosis. The MIC values of the Rhizoma Coptidis against C. glabrata, C. krusei and C. tropicalis were 50, 50 and 100 microg ml(-1) respectively. We report here, for the first time, the potent antifungal activity of Rhizoma Coptidis and Cortex phellodendri Chinesis on three different non-albicans Candida species, C. glabrata, C. krusei and C. tropicalis and hence their possible use as therapeutic agents.