Rita Baltazar de Lima

Antifungal activity of Cymbopogon winterianus jowitt ex bor against Candida albicans

Candida albicans is an opportunistic yeast and a member of the normal human flora that commonly causes infections in patients with any type of deficiency of the immune system. The essential oils have been tested for antimycotic activity and pose much potential as antifungal agents. This work investigated the activity of the essential oil of Cymbopogon winterianus against C. albicans by MIC, MFC and time-kill methods. The essential oil (EO) was obtained by hydrodistillation using a Clevenger-type apparatus. It was tested fifteen strains of C. albicans. The MIC was determined by the microdilution method and the MFC was determined when an aliquot of the broth microdilution was cultivated in SDA medium. The phytochemical analysis of EO showed presence of citronellal (23,59%), geraniol (18,81%) and citronellol (11,74%). The EO showed antifungal activity, and the concentrations 625 µg/mL and 1250 µg/mL inhibited the growth of all strains tested and it was fungicidal, respectively. The antimicrobial activity of various concentrations of EO was analyzed over time, it was found concentration-dependent antifungal activity, whose behavior was similar to amphotericin B and nystatin.

Growth inhibition and morphological alterations of Trichophyton rubrum induced by essential oil from Cymbopogon winterianus Jowitt ex Bor

Trichophyton rubrum is one of the most common fungi causer of dermatophytosis, mycosis that affect humans and animals around the world. Researches aiming new products with antifungal activity become necessary to overcome difficulties on treatment of these infections. Accordingly, this study aimed to investigate the antifungal activity of essential oil from Cymbopogon winterianus against the dermatophyte T. rubrum. The antifungal screening was performed by solid medium diffusion method with 16 T. rubrum strains, minimum inhibitory concentration (MIC) and minimum fungicide concentration (MFC) were determined using the microdilution method. The effects on mycelial dry weight and morphology were also observed. Screening showed essential oil in natura inhibited all the tested strains, with inhibition zones between 24-28 mm diameter. MIC50 and MIC90 values of the essential oil were 312 µg/mL for nearly all the essayed strains (93.75 %) while the MFC50 and MFC90 values were about eight times higher than MIC for all tested strains. All tested essential oil concentrations managed to inhibit strongly the mycelium development. Main morphological changes on the fungal strains observed under light microscopy, which were provided by the essential oil include loss of conidiation, alterations concerning form and pigmentation of hyphae. In the oil presence, colonies showed folds, cream color and slightly darker than the control, pigment production was absent on the reverse and with evident folds. It is concluded that C. winterianus essential oil showed activity against T. rubrum. Therefore, it could be known as potential antifungal compound especially for protection against dermatophytosis.Trichophyton rubrum is one of the most common fungi causer of dermatophytosis, mycosis that affect humans and animals around the world. Researches aiming new products with antifungal activity become necessary to overcome difficulties on treatment of these infections. Accordingly, this study aimed to investigate the antifungal activity of essential oil from Cymbopogon winterianus against the dermatophyte T. rubrum. The antifungal screening was performed by solid medium diffusion method with 16 T. rubrum strains, minimum inhibitory concentration (MIC) and minimum fungicide concentration (MFC) were determined using the microdilution method. The effects on mycelial dry weight and morphology were also observed. Screening showed essential oil in natura inhibited all the tested strains, with inhibition zones between 24-28 mm diameter. MIC50 and MIC90 values of the essential oil were 312 μg/mL for nearly all the essayed strains (93.75 %) while the MFC50 and MFC90 values were about eight times higher than MIC for all tested strains. All tested essential oil concentrations managed to inhibit strongly the mycelium development. Main morphological changes on the fungal strains observed under light microscopy, which were provided by the essential oil include loss of conidiation, alterations concerning form and pigmentation of hyphae. In the oil presence, colonies showed folds, cream color and slightly darker than the control, pigment production was absent on the reverse and with evident folds. It is concluded that C. winterianus essential oil showed activity against T. rubrum. Therefore, it could be known as potential antifungal compound especially for protection against dermatophytosis.

Análise da Variação Microclimática em Diferentes Níveis de Fragmentação (Analysis of Microclimate Variation at Different Levels of Fragmentation)

A fragmentacao da vegetacao inserida no ambiente urbano, decorrente da ocupacao desordenada do solo, gera transformacoes significativas na dinâmica dos fatores termodinâmicos. Este trabalho analisa o sistema microclimatico urbano, subsistema termodinâmico da Universidade Federal da Paraiba, em diferentes niveis de fragmentacao. Foram realizadas coletas de dados de temperatura e umidade relativa do ar, em tres pontos com diferentes fragmentacoes, durante os periodos: chuvoso (marco a agosto) e seco (setembro a fevereiro). Tambem foi avaliado o nivel de estresse termico e foi efetuada a classificacao dos tipos de cobertura de solo em cada ponto monitorado, resultando em nove classes, de acordo com a percentagem da presenca de vegetacao, de materiais permeaveis e de materiais impermeaveis, tendo sido utilizados metodos quantitativos e qualitativos. Os resultados demonstraram que os diferentes niveis de fragmentacao da Mata Atlântica, no espaco urbano da UFPB, tem alterado o campo termico, e consequentemente alterado tambem o conforto termico desse espaco. A B S T R A C T The fragmentation of vegetation inserted in the urban environment, resulting from the disorderly occupation of soil, generates significant transformation in the dynamics of the thermodynamic factors. This paper analyzes the urban microclimate system, thermodynamic subsystem at the Federal University of Paraiba, in different levels of fragmentation. Temperature data collection and relative humidity were held at three points with different fragmentation during periods: rainy (March to August) and dry (September to February). It also assessed the level of thermal stress and it was performed the classification of the soil cover types at each point monitored, resulting in nine classes, according to the percentage of the presence of vegetation, for permeable materials and impervious materials, having been used quantitative and qualitative methods. The results demonstrated that the different levels of fragmentation of the Atlantic Forest, in the urban space from UFPB, have changed the thermal field, and consequently also changed the thermal comfort of this space. Keywords: Microclimate, fragmentation levels, UFPB

Effects of the essential oil of Cymbopogon winterianus against Candida albicans

Candida spp. are commensal and opportunistic pathogens virtually present in all humans. Candida albicans is pathogenic for man and became resistant to antifungal agents, therefore it is important in the search of new antifungals. The study aimed to investigate the mechanism of action of Cymbopogon winterianus essential oil against C. albicans. Morphological changes were observed in C. albicans when exposed to several concentrations of oil by microculture technique for yeasts, using agar-rice in moist chamber. Cellular leakage was analyzed after cell lysis by absorbing compounds at 260 nm; it was also assessed the bind of essential oil with ergosterol. C. winterianus essential oil inhibited the formation of pseudohyphae and chlamydoconidia in all concentrations tested, it caused cellular lysis and the minimum inhibitory concentration of the oil in presence of ergosterol increased until eight times, indicating binding to ergosterol.

Melastomataceae na Área de Proteção Ambiental Tambaba, Litoral Sul da Paraíba, Brasil

Paraiba. A area de estudo abrangeu os municipios do Conde, Pitimbu e Alhandra, localizados na microrregiao do Litoral Sul Paraibano, incluindo os limites da APA Tambaba, uma unidade de conservacao de uso sustentavel, no Bioma Mata Atlântica. A familia esta representada na area por seis generos e dez especies: Clidemia biserrata DC., C. hirta (L.) D. Don, Comolia villosa (Aubl.) Triana, Henriettea sp., Miconia albicans (Sw.) Triana, M. amoena Triana, M. ciliata (Rich.) DC., M. prasina (Sw.) DC., Nepsera aquatica Naudin e Pterolepis glomerata (Rottb.) Miq. Sao apresentadas chaves de identificacao, descricoes, ilustracoes e comentarios para as especies. Palavras-chave: Mata Atlântica, levantamento floristico, sistematica.