Liquid and vapour-phase antifungal activities of selected essential oils against candida albicans: microscopic observations and chemical characterization of cymbopogon citratus

<p>Abstract</p> <p>Background</p> <p>Use of essential oils for controlling <it>Candida albicans </it>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 <it>Candida albicans </it>in liquid and vapour phase and to determine the chemical composition and mechanism of action of most potent essential oil.</p> <p>Methods</p> <p>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 <it>C. albicans </it>cells with vapour exposure was estimated by kill time assay. Morphological alteration in treated/untreated <it>C. albicans </it>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.</p> <p>Results</p> <p>Lemon grass (<it>Cymbopogon citratus</it>) essential oil exhibited the strongest antifungal effect followed by mentha (<it>Mentha piperita</it>) and eucalyptus (<it>Eucalyptus globulus</it>) 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 <it>C. albicans </it>cells. SEM/AFM of <it>C. albicans </it>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%); α-citral or geranial (36.2%) and β-citral or neral (26.5%), monoterpene hydrocarbons (7.9%) and sesquiterpene hydrocarbons (3.8%).</p> <p>Conclusion</p> <p>Lemon grass essential oil is highly effective in vapour phase against <it>C. albicans</it>, leading to deleterious morphological changes in cellular structures and cell surface alterations.</p

7,7-Dimethylaporphine Alkaloids from the Stem of Guatteriopsis friesiana

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)Phytochemical investigation of a methanolic extract of the stem of Guatteriopsis friesiana afforded two new 7,7-dimethylaporphine alkaloids, 6,6a-dihydrodemethoxyguadiscine (1) and guatteriopsiscine (3), together with demethoxyguadiscine (2), liriodenine (4), corypalmine (5), and coreximine (6). Their structures were elucidated on the basis of spectroscopic methods (UV, IR, EIMS, HRESIMS, 1D/2D NMR). The absolute configurations of 1 and 3 were determined. from the circular dichroism curves. The presence of 7,7-dimethylaporphine alkaloids in this species is important for the chemotaxonomy of Guatteriopsis. Antimicrobial activity of compounds 1-5 was investigated, and 4 showed activity against Rhodococcus equi, with a MIC value of 10 mu g.mL(-1).72815161519Universidade Federal do Amazonas (UFAM), BrazilHRESIMSCoordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)Fundacao Araucaria, ParanaCoordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq

Prevalência de fluorose dentária em escolares de 12 anos de idade, Ouro Preto/MG - 2003 Prevalence of dental fluorosis in 12 year-old schoolchildren, Ouro Preto/MG - 2003

OBJETIVO: verificar a prevalência da fluorose dentária em escolares de 12 anos de idade em Ouro Preto. METODOLOGIA: estudo seccional incluindo 248 crianças selecionadas aleatoriamente em 11 escolas do município. A amostra foi calculada de acordo com a metodologia descrita no Projeto SB2000. Os exames foram realizados por cirurgião-dentista treinado e calibrado. Os índices utilizados para medir a fluorose foram: índice de Dean e índice comunitário de fluorose. RESULTADOS: De 248 crianças selecionadas, 159 (64,1%) participaram deste estudo. A prevalência de fluorose (índice de Dean) encontrada foi de 11,4%, sendo composta pela condição muito leve (10,1%) e leve (1,3%). A condição moderada e severa de fluorose não foi encontrada. Os dentes mais acometidos por fluorose foram os pré-molares, molares, incisivos e caninos. Não houve diferença entre os sexos quanto ao grau de fluorose, e o índice comunitário de fluorose foi de 0,29. CONCLUSÃO: a fluorose em crianças de 12 anos não é um problema de saúde pública em Ouro Preto, dado que a prevalência não é alta e quase todos os casos encontrados são muito leves.<br>OBJECTIVE: to find out the prevalence of dental fluorosis in 12-year-old schoolchildren in Ouro Preto. METHODOLOGY: cross-sectional study including 248 children randomly selected from 11 schools in the town. The sample was calculated according to the methodology described in Project SB2000. Exams were undertaken by a trained and calibrated dentist. Dental fluorosis was evaluated by the Dean index and index of community fluorosis. RESULTS: 159 (64.1%) children, among the 248 who were selected, participated in the study. The prevalence of fluorosis (Dean index) found was 11.4%, and it was found to be a very mild (10.1%) or mild (1.3%) condition. Moderate and severe fluorosis were not found. The teeth most affected by fluorosis were pre-molars, molars, incisors and canines. There was no difference between genders as to the degree of fluorosis, and the index of community fluorosis was 0.29. CONCLUSION: fluorosis in 12 year-old children is not a public dental health problem in Ouro Preto, as the prevalence is not high and nearly all cases are very mild