Research - Candida albicans
Antifungal activity and mode of action of thymol and its synergism with nystatin against Candida species involved with infections in the oral cavity: an in vitro study
Ricardo Dias de Castro1*, Trícia Murielly Pereira Andrade de Souza2, Louise Morais Dornelas Bezerra2, Gabriela Lacet Silva Ferreira1, Edja Maria Melo de Brito Costa3 andAlessandro Leite Cavalcanti3
Thymol (2-isopropyl-5-methylphenol) is a phytoconstituent classified as a monoterpene . It is the majority phytoconstituent in the essential oil of thyme (Thymus vulgaris)  and is a major component of the essential oil of oregano (Origanum vulgare)
Limitations of antifungal agents used in the treatment of oral candidiasis, as the development of resistant strains, are known by the scientific community. In this context, the aim of this study was to evaluate the antifungal activity of thymol against Candida albicans, Candida tropicalis andCandida krusei strains and to determine its mode of action and synergistic effect when combined with the synthetic antifungal nystatin.
The minimum inhibitory concentration (MIC) was determined using a microdilution technique, and the minimum fungicidal concentration (MFC) was determined via subculture sowing. The mode of action of thymol was established by verifying fungal growth in the presence of sorbitol or ergosterol. The fractional inhibitory concentration index (FIC) was determined using the checkerboard method.
Thymol presented an antifungal effect, with MICs of 39 μg/mL for C. albicans and C. krusei and 78 μg/mL for C. tropicalis. The results of the antifungal test remained unchanged in the presence of sorbitol; however, the MIC value of thymol against C. albicans increased eight times (from 39.0 to 312.5 μg/mL) in presence of exogenous ergosterol. The combination of thymol and nystatin reduced the MIC values of both products by 87.4 %, generating an FIC index of 0.25.
Thymol was found to have a fungicidal effect on Candida species and a synergistic effect when combined with nystatin.
Source : BMC Complementary and Alternative Medicine
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Assessment of Antifungal Activity of Bakuchiol on Oral-Associated Candida spp.
Mohd-Al-Faisal Nordin, Fathilah Abdul Razak, and Wan Harun Himratul-Aznita
Bakuchiol is an active component of Psoralea glandulosa and Psoralea corylifolia, used in traditional Chinese medicine. The study aimed at investigating the antifungal activity of bakuchiol on planktonic and biofilm forms of orally associated Candida species. The antifungal susceptibility testing was determined by the broth micro dilution technique. Growth kinetics and cell surface hydrophobicity (CSH) of Candida were measured to assess the inhibitory effect of bakuchiol on Candida planktonic cells. Biofilm biomass and cellular metabolic activity were quantitatively estimated by the crystal violet (CV) and the 2,3-bis(2-methoxy-4-nitro-5-sulfophenyl)-5-[(phenylamino)carbonyl]-2H-tetrazolium hydroxide (XTT) assays. All Candida strains have been shown to be susceptible to bakuchiol with the MIC ranges from 12.5 to 100 μg/mL. Significant decrease in specific growth rates and viable counts demonstrates the inhibitory effect of bakuchiol on Candida planktonic cells. A brief exposure to bakuchiol also reduced CSH of Candida (P<0.05), indicating altered surface properties of yeast cells towards hydrophobic interfaces. Biofilm biomass and cell metabolic activity were mostly decreased, except for C. glabrata (P=0.29). The antifungal properties of bakuchiol on Candida species in this in vitro study may give insights into the application in therapeutic strategy against Candida infections.
Source : Journal Evidence Based Complementary and Alternative Medicine
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Cinnamon Leaf Essential Oil Inhibits Candida Growth In Vitro and Appears Safe as an Oral Mouthwash
de Araújo Oliveira J, da Silva ICG, Trindade LA, et al. Safety and tolerability of essential oil from Cinnamomumzeylanicum Blume leaves with action on oral candidosis and its effect on the physical properties of the acrylic resin. Evid Based Complement Alternat Med. 2014;2014:325670. doi: 10.1155/2014/325670.
Denture wearers are prone to denture stomatitis which forms between the dentures and gums and is associated with oral Candida infection. Treatments include the use of antifungal medications to control oral Candidapopulations, and education on the proper care and cleaning of dentures. Often though, denture stomatitis returns after treatment with antifungal medication ceases. Cinnamon (Cinnamomum verum syn. C. zeylanicum, Lauraceae) is known to have analgesic, antiseptic, and antimicrobial qualities. Cinnamon has also been found to have low toxicity in human subjects. This study was divided into 3 sections. First, the antifungal activity of the essential oil from cinnamon leaves was measured in vitro on 12 strains of Candida. Second, the effect of cinnamon essential oil was measured on the roughness and hardness of acrylic used in dentures. Lastly, the tolerance of mouthwash containing cinnamon essential oil was tested on subjects without oral Candida infections in a phase I clinical trial.
For each part of this study, essential oil from cinnamon leaves was purchased from Ferquima Ind. eCom. (São Paulo, Brazil). Secondary compounds in the essential oil were evaluated with mass spectrometry. Seventeen peaks were measured, with eugenol comprising 82.3% of the oil. In addition, nystatin (Sigma-Aldrich Brasil Ltda.; São Paulo, Brazil) was used as a positive control in the first 2 parts of the study. The minimum inhibitory concentration (MIC) of cinnamon essential oil was determined in 8 strains of Candida albicans and 4 strains ofCandida tropicalis using serial dilutions. Once the MIC was determined, the minimum fungicidal concentration (MFC) was determined by growing the Candida strains in culture with the MIC for cinnamon essential oil. Two additional concentrations of essential oil (MICx2 and MICx4) were tested for MFC determination. The effect of cinnamon essential oil was measured on the roughness and hardness of polished denture-like acrylic samples. One side of each acrylic sample was marked with 3 lines. The samples were then stored in artificial saliva (source not given) for 15 days. A negative control treatment received no further manipulation. The samples in the cinnamon treatment and the nystatin treatment were removed from the saliva 3 times per day and submerged in their respective treatments for 1 minute each time. The cinnamon treatment consisted of the MIC for cinnamon essential oil, Tween® 80 (source not given), and deionized water. The nystatin treatment consisted of 100,000 UI/mL of nystatin in deionized water. After treatment, the lines were measured for roughness. The hardness of the acrylic samples was measured before and after treatment with a Vickers diamond-tipped indenter, and an average Vickers hardness number (VHN) was generated.
In the last section of the study, healthy subjects who wore dentures were recruited. Oral Candida infection was assessed for each prospective subject. Subjects were excluded if they had oral candidosis, had taken antimicrobial medications in the last 6 months, or if they had a known sensitivity to cinnamon. Subjects were instructed to rinse their mouths for 1 minute 3 times per day with cinnamon mouthwash (distilled water, cinnamon essential oil at 625 µg/mL, and Tween 80) for 15 days. Subjects also cleaned their dentures with the cinnamon mouthwash at the same intervals. Subjects' mouths were photographed and examined prior to and after treatment. Subjects were also asked to record any side effects over the course of the study. Data were analyzed with analysis of variance and post-hoc Tukey's tests.
All 12 strains of Candida were inhibited by the cinnamon and nystatin treatments. A concentration of 625 µg/mL of cinnamon inhibited all strains of Candida. A cinnamon concentration of 312.5 µg/mL was found to inhibit 3 of the strains of Candida. The MFC was determined to be 625 µg/mL. The roughness of all acrylic samples increased and the hardness decreased significantly after 15 days of treatment (P<0.05). The nystatin treatment resulted in a significantly rougher and softer surface than either the cinnamon treatment or the saliva control treatment (P<0.0001 for both measures). Subjects (n=15) did not show any change in gum appearance after 15 days of cinnamon mouthwash treatment. One subject noted a slight burning sensation on the tongue after using the cinnamon mouthwash that resolved in about 2 minutes. The sensation was not severe enough for the subject to discontinue treatment.
Cinnamon essential oil was found to inhibit the growth of Candida in vitro, result in less damage to acrylic dentures than nystatin, and be safe for use in the phase I clinical trial. The authors found only 1 prior pilot study on the use of cinnamon bark essential oil in controlling oral Candida infections in 5 patients; however, no studies were found on the use of cinnamon leaf essential oil mouthwash in subjects who wore dentures. The antifungal properties of cinnamon are attributed to the high concentration of eugenol in cinnamon leaf essential oil (and cinnamaldehyde plus eugenol in the bark essential oil). The authors recommend continued studies of the use of cinnamon mouthwash in the treatment of denture stomatitis and Candida infection in patients who wear dentures.
Source : American Botanical Council —Cheryl McCutchan, PhD
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The Effect of Essential Oils and Bioactive Fractions on Streptococcus mutans and Candida albicans Biofilms: A Confocal Analysis
Irlan Almeida Freires,1 Bruno Bueno-Silva,2 Lívia Câmara de Carvalho Galvão,1 Marta Cristina Teixeira Duarte,3 Adilson Sartoratto,3 Glyn Mara Figueira,3 Severino Matias de Alencar,4 and Pedro Luiz Rosalen1
1Pharmacology, Anesthesiology and Therapeutics, Department of Physiological Sciences, Piracicaba Dental School, University of Campinas, 13414-903 Piracicaba, SP, Brazil
2Department of Microbiology, Institute of Biomedical Sciences, University of São Paulo, 05508-900 São Paulo, SP, Brazil
3Research Center for Chemistry, Biology and Agriculture, University of Campinas, 13083-970 Campinas, SP, Brazil
4Department of Agri-Food Industry, Food and Nutrition, “Luiz de Queiroz” College of Agriculture, University of São Paulo, 13418-900 Piracicaba, SP, Brazil
The essential oils (EO) and bioactive fractions (BF) from Aloysia gratissima, Baccharis dracunculifolia, Coriandrum sativum, Cyperus articulatus, and Lippia sidoides were proven to have strong antimicrobial activity on planktonic microorganisms; however, little is known about their effects on the morphology or viability of oral biofilms. Previously, we determined the EO/fractions with the best antimicrobial activity against Streptococcus mutans and Candida spp. In this report, we used a confocal analysis to investigate the effect of these EO and BF on the morphology of S. mutans biofilms (thickness, biovolume, and architecture) and on the metabolic viability of C. albicans biofilms. The analysis of intact treated S. mutans biofilms showed no statistical difference for thickness in all groups compared to the control. However, a significant reduction in the biovolume of extracellular polysaccharides and bacteria was observed for A. gratissima and L. sidoides groups, indicating that these BF disrupt biofilm integrity and may have created porosity in the biofilm. This phenomenon could potentially result in a weakened structure and affect biofilm dynamics. Finally, C. sativum EO drastically affected C. albicans viability when compared to the control. These results highlight the promising antimicrobial activity of these plant species and support future translational research on the treatment of dental caries and oral candidiasis.
Source : Evidence Based CAM
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Essential oil of Melaleuca alternifolia for the treatment of oral candidiasis induced in an immunosuppressed mouse model
Vanessa Maria de Campos Rasteiro, Anna Carolina Borges Pereira da Costa, Cássia Fernandes Araújo, Patrícia Pimentel de Barros, Rodnei Dennis Rossoni*, Ana Lia Anbinder,Antonio Olavo Cardoso Jorge and Juliana Campos Junqueira
The search for alternative therapies for oral candidiasis is a necessity and the use of medicinal plants seems to be one of the promising solutions. The objective of this study was to evaluate thein vitro and in vivo effects of the essential oil of Melaleuca alternifolia on Candida albicans.
The minimum inhibitory concentration (MIC) and minimum biofilm eradication concentration (MBEC) of M. alternifolia were determined by the broth microdilution assay. For the in vivo study, twelve immunosuppressed mice with buccal candidiasis received topical applications of M. alternifolia with MBEC. After treatment, yeasts were recovered from the mice and quantified (CFU/mL). Mice were killed for morphologic analysis of the tongue dorsum by optical and scanning electron microscopy. Data were analyzed using Student’s t test or Mann-Whitney test.
The MIC of M. alternifolia was 0.195% and the MBEC was 12.5%. Treatment with M. alternifoliaachieved a 5.33 log reduction in C. albicans and reduced the microscopic lesions of candidiasis.
M. alternifolia oil at a 12.5% was effective to eradicate a C. albicans biofilm formed in vitro and to reduce yeasts of C. albicans in an immunosuppressed mouse model.
Source : BMC Complementary and Alternative Medicine
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Safety and Tolerability of Essential Oil from Cinnamomum zeylanicum Blume Leaves with Action on Oral Candidosis and Its Effect on the Physical Properties of the Acrylic Resin
Julyana de Araújo Oliveira,1 Ingrid Carla Guedes da Silva,1 Leonardo Antunes Trindade,1 Edeltrudes Oliveira Lima,1 Hugo Lemes Carlo,1 Alessandro Leite Cavalcanti,2 and Ricardo Dias de Castro1,2
1Post-Graduate Program in Dentistry, Federal University of Paraíba, Campus I, João Pessoa, PB, Brazil
2Post-Graduate Program in Dentistry, State University of Paraíba, Campina Grande, PB, Brazil
The anti-Candida activity of essential oil from Cinnamomum zeylanicum Blume, as well as its effect on the roughness and hardness of the acrylic resin used in dental prostheses, was assessed. The safety and tolerability of the test product were assessed through a phase I clinical trial involving users of removable dentures. Minimum inhibitory concentration (MIC) and minimum fungicidal concentrations (MFC) were determined against twelve Candida strains. Acrylic resin specimens were exposed to artificial saliva (GI), C. zeylanicum(GII), and nystatin (GIII) for 15 days. Data were submitted to ANOVA and Tukey posttest (alpha=5%). For the phase I clinical trial, 15 healthy patients used solution of C. zeylanicum at MIC (15 days, 3 times a day) and were submitted to clinical and mycological examinations. C. zeylanicum showed anti-Candida activity, with MIC = 625.0 µg/mL being equivalent to MFC. Nystatin caused greater increase in roughness and decreased the hardness of the material (P<0.0005), with no significant differences between GI and GII. As regards the clinical trial, no adverse clinical signs were observed after intervention. The substance tested had a satisfactory level of safety and tolerability, supporting new advances involving the clinical use of essential oil from C. zeylanicum.
Source : Evidence Based Complementary and Alternative Medicine
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In vitro activity of Melaleuca alternifolia (Tea tree) and Eucalyptus globulus essential oils on oral Candida biofilm formation on polymethylmethacrylate
Noumi Emira1*, Snoussi Mejdi2 and Mahjoub Aouni1
1Laboratoire des Maladies Transmissibles et des Substances Biologiquement Actives, Faculté de Pharmacie, Université de Monastir, Tunisie.
2Laboratoire de Traitement des Eaux Usées, Centre de Recherches et des Technologies des Eaux (CERTE), Technopole de Borj-Cédria, BP 273- Soliman 8020, Tunisie
Melaleuca alternifolia and Eucalyptus globulus essential oils are known for their antifungal activities and efficacy in the treatment of oral candidiasis. Candida biofilm increased resistance to antifungal agents that have activity against their planktonic cells. The aim of this study was to evaluate the potential role of M. alternifolia and E. globulus essential oils in the inhibition of Candida biofilm formation on polymethylmethacrylate (PMMA). The antifungal activity of M. alternifolia and E. globulus essential oils and adhesion and biofilm on PMMA inhibition capacity were tested on two oral Candida isolates and two reference type strains. The biofilm formation by Candida strains was quantified by colorimetric method based on the reduction of the 2, 3-bis (2-methoxy-4-nitro-5-sulfophenyl)-5-[(phenyl amino) carbonyl]-2H-tetrazolium hydroxide (XTT). M. alternifolia and E. globulus essential oils were active against clinical and reference Candida albicans and Candida glabrata strains in their planktonic and adherent phases. In fact, both minimum inhibition concentration (MIC) and 1/2 MIC values of these two plants essential oils can inhibit adhesion and biofilm formation of clinical and reference strains of Candida on PMMA. Also, E. globulus essential oil was more active on Candida biofilm formation on PMMA. M. alternifolia and E. globulus essential oils can inhibit Candida biofilm formation on PMMA. This may contribute to the use of these plants as alternative products for oral Candida biofilm prevention, control and treatment.
Conclusively, the preliminary evidence for the antifungal activity of M. alternifolia and E. globulus essential oils against oral Candida were presented. Its action against this yeast includes inhibition of adhesion and biofilm formation on prosthetic biomaterial (PMMA) and this raises the possibility that these plants may have therapeutic use for oral candidiasis and possibly other oral infections.
Source : Journal of Medicinal Plants Research
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Inhibition of planktonic and biofilm growth of Candida albicans reveals novel antifungal activity of caffeine
Jayant S. Raut, Nitin M. Chauhan, Ravikumar B. Shinde and S. Mohan Karuppayil*
Infections associated with drug resistant strains and biofilms of Candida albicans have necessitated search for novel molecules with antifungal properties. Caffeine, a major component of the most widely consumed beverages, coffee and tea, is known to possess various biological properties. To evaluate antifungal potential, its effect on growth and virulence attributes of C. albicans was studied using standard methodologies. Caffeine showed fungistatic effect on planktonic growth of two strains of C. albicans (including a fluconazole resistant strain), exhibiting minimum inhibitory concentration (MIC) at 12.5 mM concentration. Around 30% decrease in the adhesion of cells in the presence of caffeine indicated considerable anti-adhesion activity. Caffeine prevented formation of biofilms (which are drug resistant forms), in a concentration dependent manner. Analysis by 2,3-bis-(2-methoxy-4-nitro-5-sulfophenyl)-2H-tetrazolium-5-carboxanilide (XTT) metabolic assay and microscopic observations showed inhibition of biofilm development at 25 mM concentration. This study, for the first time demonstrates dietary chemical, caffeine, as a potential inhibitor of growth, adhesion and biofilm formation by C. albicans.
Source : Journal of Medicinal Plant Research
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Liquid and vapour-phase antifungal activities of selected essential oils against candida albicans: microscopic observations and chemical characterization of cymbopogon citratus
Amit K Tyagi*, Anushree Malik
Use of essential oils for controlling Candida albicans growth has gained significance due to the resistance acquired by pathogens towards a number of widely-used drugs. The aim of this study was to test the antifungal activity of selected essential oils against Candida albicans in liquid and vapour phase and to determine the chemical composition and mechanism of action of most potent essential oil.
Minimum Inhibitory concentration (MIC) of different essential oils in liquid phase, assayed through agar plate dilution, broth dilution & 96-well micro plate dilution method and vapour phase activity evaluated through disc volatilization method. Reduction of C. albicans cells with vapour exposure was estimated by kill time assay. Morphological alteration in treated/untreated C. albicans cells was observed by the Scanning electron microscopy (SEM)/Atomic force microscopy (AFM) and chemical analysis of the strongest antifungal agent/essential oil has been done by GC, GC-MS.
Lemon grass (Cymbopogon citratus) essential oil exhibited the strongest antifungal effect followed by mentha (Mentha piperita) and eucalyptus (Eucalyptus globulus) essential oil. The MIC of lemon grass essential oil in liquid phase (288 mg/l) was significantly higher than that in the vapour phase (32.7 mg/l) and a 4 h exposure was sufficient to cause 100% loss in viability of C. albicans cells. SEM/AFM of C. albicans cells treated with lemon grass essential oil at MIC level in liquid and vapour phase showed prominent shrinkage and partial degradation, respectively, confirming higher efficacy of vapour phase. GC-MS analysis revealed that lemon grass essential oil was dominated by oxygenated monoterpenes (78.2%); a-citral or geranial (36.2%) and b-citral or neral (26.5%), monoterpene hydrocarbons (7.9%) and sesquiterpene hydrocarbons (3.8%).
Lemon grass essential oil is highly effective in vapour phase against C. albicans, leading to deleterious morphological changes in cellular structures and cell surface alterations.
Source : BMC Complementary and Alternative Medicine 2010, 10:65 http://www.biomedcentral.com/1472-6882/10/65
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