Atividade Inibitória de Óleos Essenciais Vegetais Frente à Candida glabrata, Resistente a Fluconazol / Inhibitory Activity of Essential Oils Extracted From Plants Against Fluconazole-Resistant Candida glabrata

Introdução: A candidose oral é uma infecção fúngica que se manifesta frequentemente em pacientes imunocomprometidos ou naqueles que fazem uso de prótese dental removível, associada a hábitos de higiene deficitários. Antifúngicos sintéticos, a exemplo do fluconazol, são utilizados no tratamento desta infecção; entretanto algumas cepas apresentam resistência a estes fármacos. Objetivo: Este estudo avaliou o efeito antifúngico dos óleos essenciais de Persea americana (abacate), Cinnamomumzeylanicum (canela ­ folha), Cinnamomumcassia (canela ­ casca) e Cymbopogonwinterianus (citronela), frente à Candidaglabrata. Material e Métodos: O screening da atividade antifúngica dos óleos foi determinado por difusão em meio sólido, utilizando um inóculofúngico ajustado em 1 × 106 UFC/mL. A Concentração Inibitória Mínima (CIM) foi determinada pela técnica da microdiluição. Os óleos essenciais foram avaliados em concentrações entre 1000 µg/mL e 7,81 µg/mL, enquanto que os fármacos Fluconazol e Nistatina foram avaliados nas concentrações que entre 64 µg/mL e 0,5 µg/mL. Resultados: Os halos de inibição mensurados variaram entre 8,2 e 9,2 mm de diâmetro, respectivamente para C. winterianuse C. cassia.Os óleos essenciais de C. winterianuse C. zeylanicumapresentaram CIM de 125 µg/mL, enquanto a CIM de C. cassiafoi 62,5 µg/mL. A CIM dos fármacos utilizados como controle foram estabelecidasem 16 µg/mL(fluconazol) e 2,0 µg/mL(nistatina). O óleo essencial de P. americana não apresentou atividade antifúngica nas concentrações avaliadas. Conclusão: Conclui-se que os óleos essenciais de canela (casca e folha) e citronela apresentaram atividade antifúngica frente a cepa de C. glabrataresistente a fluconazol. (AU)

Introduction: Oral candidiasis is a fungal infection diagnosed mainly in patients with immunosuppression or in denture wearers with deficient hygiene habits. Synthetic antifungal agents, such as fluconazole, have been used to treat this infection, but some strains are resistant to these drugs. Objective: This study aimed to evaluate the antifungal effect of the essential oils from Persia americana (avocado), Cinnamomum zeylanicum (cinnamon - leaf), Cinnamomum cassia (cinnamon - bark) and Cymbopogon winterianus (citronella) against Candida glabrata. Materials and Methods: The essential oils were screened for their antifungal activity using the solid medium diffusion method, with fungal inoculum adjusted to 1 x 106 CFU/mL. The Minimum Inhibitory Concentration (MIC) was determined by the microdilution technique. The essential oils were evaluated at concentrations ranging between 1,000 µg/mL and 7.81 µg/mL, while fluconazole and nystatin were evaluated at concentrations between 64 µg/mL and 0.5 µg/ mL. Results: The zones of inhibition measured varied between 8.2 and 9.2 mm diameter for C. winterianus and C. cassia, respectively. The essential oils from C. winterianusand and C. zeylanicum had MIC of 125 µg/ml, while C. cassia essential oil had MIC of 62.5 µg/ml. The drugs used as controls showed MIC values of 16 µg/mL (fluconazole) and 2.0 µg/mL (nystatin). P. americana essential oil showed no antifungal activity at the concentrations evaluated. Conclusion: We conclude that the essential oils from cinnamon (bark and leaf) and citronella showed antifungal activity against fluconazole-resistant C. glabrata. (AU)

Efficacy of citronella and cinnamon essential oils on Candida albicans biofilms.

INTRODUCTION: The discovery of new antimicrobials derived from plants could aid in the management of biofilm-associated infections, including denture-induced stomatitis (DS). DS is an oral infection caused by Candida biofilms on the surfaces of poorly cleansed dentures. Effective treatment of DS requires the use of an appropriate denture cleanser and preferably one that exhibits antimicrobial properties. OBJECTIVE: This study aimed to evaluate the anti-Candida and anti-biofilm efficacy of two essential plant oils from Cymbopogon winterianus (citronella) and Cinnamon cassia (cinnamon). MATERIALS AND METHODS: Minimum Inhibitory Concentrations (MICs) and Minimum Fungicidal Concentrations (MFCs) were determined by broth microdilution, whilst anti-biofilm activity was measured against mature (cultured for 72 h) biofilms on acrylic surfaces. Candida cell viability was assessed immediately (0 h) after treatment (T0) and 48 h after biofilm re-growth (T48). Biofilm structure was determined using Scanning Electron Microscopy (SEM) at T0 and T48. RESULTS: The respective MICs of cinnamon and citronella oils were 65 and 250 µg/ml and these were also the MFC values. For anti-biofilm efficacy, both oils significantly (p < 0.05) reduced the number of viable micro-organisms and accumulation of biofilms at T0. However, at T48, there was no difference between treated and untreated biofilms. CONCLUSIONS: It is concluded that citronella and cinnamon essential oils have potential for daily anti-candidal denture cleansing.