Evaluating the Antifungal Activity of α-Bisabolol in Association with NaCl on Fusarium oxysporum in Maize Grains.

Fusarium infections result in reduced maize grain (Zea mays L.) yields and notable impacts on human and animal health. Research involving natural products to control fungi in food is a promising alternative. Combinations of α-bisabolol (AB) and sodium chloride (NaCl) may suggest the use of lower effective concentrations of the drugs. This study aimed to evaluate the antifungal potential of AB associated with NaCl against Fusarium oxysporum strains isolated from maize. Minimum inhibitory concentrations (MICs) values of AB and NaCl were determined by microdilution, and an association study was performed (checkerboard). Effects on fungal mycelial growth (poisoned substrate technique) and a maize grain contamination model were analyzed. AB presented MIC values ranging from 128 and 1024 µg/mL; NaCl inhibited fungal growth at 16,384 µg/mL. The AB/NaCl association study revealed synergism by decreasing inhibitory concentrations by eight times. In corn kernels, AB and NaCl, whether isolated (at MIC) or in association (at sub-inhibitory concentrations), significantly inhibited in vitro mycelial growth (P < 0.05). Further analysis of liquid from a canned maize sample also revealed the fungistatic effects of the compounds associations (P < 0.05). The results confirm the antifungal potential of AB, whether isolated or in association with NaCl to control F. oxysporum in maize.

Interference of Plectranthus amboinicus (Lour.) Spreng essential oil on the anti-Candida activity of some clinically used antifungals

Plants with medicinal properties have been applied for a long in the traditional health care, so that sometimes their use takes place concomitantly to the use of industrialized drugs. The aim of this study was to evaluate the interference of Plectranthus amboinicus essential oil on the anti-Candida activity of some clinically used antifungals by the solid medium diffusion procedure. Assayed antifungals were amphotericin B (100 µg/mL), ketoconazole (50 µg/mL) and itraconazole (50 µg/mL). C. albicans, C. tropicalis, C. guilliermondii, C. krusei and C. stellatoidea were used as test microorganisms. P. amboinicus essential oil showed MIC value for most assayed yeast strains. The essential oil when assayed in its MIC value showed some interference on the anti-Candida effectiveness of the assayed antifungals. It was noted yeast growth inhibition zones with different diameters when the antifungals were tested alone and combined with the essential oil. P. amboinicus essential oil showed prominent interference on the anti-yeast activity of itraconazole providing a synergic effect on C. albicans, C. tropicalis, C. krusei and C. stellatoidea. Also, the essential oil interfered on the anti-yeast activity of ketoconazole when interacting with C. albicans, C. guilliermondii and C. stellatoidea providing, respectively, an antagonic and synergic effect. On the other hand, it was found a small interference on the anti-yeast effect of amphotericin B. These data showed that combined use of medicinal plants and/or derivatives with industrialized drugs, particularly antimicrobials, could interfere on their expected therapeutic effects.

As plantas com propriedades medicinais têm sido utilizadas por um longo tempo no cuidado tradicional de saúde, de modo que algumas vezes seu uso ocorre concomitantemente ao uso de drogas industrializadas. O objetivo deste estudo foi avaliar a interferência do óleo essencial de Plectranthus amboinicus sobre atividade anti-Candida de alguns antifúngicos utilizados clinicamente através do método de difusão em meio sólido. Os antifúngicos ensaiados foram anfotericina B (100 µg/mL), cetoconazol (50 µg/mL) e itraconazol (50 µg/mL). C. albicans, C. tropicalis, C. guilliermondii, C. krusei e C. stellatoidea foram utilizadas como microrganismos testes. O óleo essencial de P. amboinicus mostrou um valor de CIM de 40 µL/mL para a maioria das cepas de leveduras ensaiadas. O óleo essencial quando ensaiado em sua CIM mostrou alguma interferência sobre a efetividade anti-Candida dos antifúngicos testados, sendo notada a formação de zonas de inibição do crescimento fúngico com diferentes diâmetros quando os antifúngicos foram testados isolados e em combinação com o óleo essencial. O óleo essencial de P. amboinicus mostrou destacável interferência sobre a atividade antifúngica de itraconazol, sendo observado um efeito sinérgico sobre C. albicans, C. tropicalis, C. krusei e C. stellatoidea. Ademais, o óleo essencial interferiu na atividade antifúngica de cetoconazol sobre C. albicans, C. guilliermondii e C. stellatoidea causando, respectivamente, efeito antagônico e sinérgico. De outra forma, foi observada uma pequena interferência do óleo essencial sobre o efeito antifúngico de anfotericina B. Estes dados mostram que o uso combinado de plantas medicinais e/ou seus produtos derivados com drogas industrializadas, particularmente, antimicrobianos podem interferir sobre os efeitos terapêuticos esperados.

Estudo da interferência de óleos essenciais sobre a atividade de alguns antibióticos usados na clínica / Study of the interference of essential oils on the activity of some antibiotic used clinically

O objetivo deste estudo foi investigar a interferência dos óleos essenciais de Lippia sidoides Cham, Plectranthus amboinicus Lour Spr., Conyza bonariensis L. e Eucalyptus citriodora Hook sobre o efeito de antibióticos utilizados na clínica. Os ensaios foram realizados com ampicilina (10 µg/mL), cefalotina (30 µg/mL), cloranfenicol (30 µg/mL), gentamicina (10 µg/mL) e tetraciclina (30 µg/mL) isolados e em associação com os óleos essenciais (4 por cento v/v) através do método de difusão em meio sólido utilizando discos de papel de filtro. Os resultados mostraram interferência de alguns óleos essenciais sobre a atividade dos antibióticos ensaiados. Observou-se o desenvolvimento de halos de inibição do crescimento bacteriano com diferentes diâmetros quando da aplicação de antibióticos isolados e em combinação com os óleos essenciais. A ocorrência de comportamento sinérgico ou antagônico foi observada mais proeminentemente nas interações com cepas de S. aureus e S. epidermidis. De outra forma, observou-se uma menor interferência dos óleos essenciais no efeito dos antibióticos sobre as cepas Gram negativas, principalmente P. aeruginosa. Estes resultados mostram que o uso de produtos derivados de plantas pode em algumas situações interferir sobre a efetividade de antibióticos de uso no tratamento clínico.

The aim of this study was to evaluate the interference of essential oils from Lippia sidoides Cham, Plectranthus amboinicus Lour Spr., Conyza bonariensis L. and Eucalyptus citriodora Hook on the antibacterial effect of clinically used antibiotics. The assays were carried out with ampicillin (10 µg/mL), cephalotin (30 µg/mL), chloraphenicol (30 µg/mL), gentamicin (10 µg/mL) and tetracyclin (30 µg/mL) isolated and associated with essential oils (4 percent v/v) by the solid medium diffusion procedure using filter paper discs. The results showed interference of some essential oils on the antibacterial activity of the assayed antibiotics. It was observed the development of growth inhibition halo with different diameters when the antibiotics were applied alone and associated with essential oils. Synergic or antagonic behavior was more prominent in interactions with S. aureus and S. epidermidis strains. On the other hand, it was observed a smaller interference of essential oils on the effect of the antibiotics against Gram negative strains, mainly P. aeruginosa. These results show that the use of plants by-products could some times interfere on the effectiveness of antibiotics used clinically.

Inhibitory effect of some phytochemicals in the growth of yeasts potentially causing opportunistic infections

Opportunistic infections caused by yeasts have been characterized as emerging diseases all over the world and this has caused the search for new products capable of inhibiting the survival of their etiological agents. In this study the sensitivity of some yeast potentially causing infections to `alpha´-pinene, ß-pinene, citral and engenol was avaluated. All phytochemicals showed inhibitory action on the assayed yeast strains: Candida, albicans, C. tropicalis, C. guilliermondïi, C. stellatoidea, C. krusei, C. parapsilosis and Cryptococcus neoformans, presenting their MIC values in the range of 1 and 4 por cento The phytochemicals presented effectiveness to provide high fungicide effect in a short time. These data support the possible use of some phytochemicals as useful tools to control the occurrence of opportunistic infections caused by yeasts

Review of the plants with anti-inflammatory activity studied in Brazil

The inflammatory reaction is a response of the organism against an injury and it involves the action of complex events and mediators through of the blood vessels. The present work is a literature survey of the extracts of plants with anti-inflammatory activity studied in Brazil. The review refers to 75 plants with their families, parts used, type of extract used, bioassay models and their activity.