Abstract Klebsiella pneumoniae is a species of Gram-negative bacteria related to a wide range of infections and high rates of drug resistance. The combined use of antibacterial agents is one of the strategies that has been analyzed in recent years as part of the alternatives in the treatment of drug-resistant infections. Recently, the antibacterial activity of of 2-chloro-N-(4-fluoro-3-nitrophenyl)acetamide has been demonstrated against K. pneumoniae, also indicating that this acetamide did not show significant cytotoxic potential in preliminary tests. Thus, it becomes an interesting substance for future studies that explore its antimicrobial capacity, including investigating its association with antibacterial drugs. Based on this, this research aimed to analyze the effects of the association of 2-chloro-N-(4-fluoro-3-nitrophenyl)acetamide (CFA) with ciprofloxacin, cefepime, ceftazidime, meropenem and imipenem against K. pneumoniae strains. The results showed additivity when the substance was combined with ciprofloxacin and cefepime, indifference when associated with ceftazidime and synergistic effect when combined with meropenem and imipenem. Thus, the acetamide was able to optimize the effects of antibacterial drugs, reducing the concentrations necessary to cause bacterial death. These data indicate a potential future clinical use of these combinations, and further studies are needed to analyze this viability.

A phytochemical investigation from aerial parts of Casearia arborea (Rich.) Urb. (Salicaceae) led to isolation and identification of: sitosterol, 4-en-stigmast-3-one, 13-hydroxy-trans-ent-cleroda-3,14-diene,3-hydroxy-2-oxo-trans-ent-cleroda-3,14-diene (kolavelone), a mixture of 13-hydroxy-trans-ent-cleroda-3,14-diene and an ester ethyl hexadecanoate, kaempferol-3-O-a-L-arabinofuranoside and 4',5,7-trihydroxy-3',5'-dimethoxyflavone (tricin). The compounds have been described for the first time in this species. Five trihydroxy-flavone-hexoside derivatives have been identified by LC-ESI-HR-MS. The antimicrobial activity of kolavelone was evaluated against strains of Staphylococcus, Bacillus, Pseudomonas, Shigella and Candida spores, and its minimum inhibitory concentration (MIC) was determined. The results showed the antimicrobial activity of kolavelone against several bacteria and Candida tropicalis indicating its potential use as antimicrobial agent.

Uma série de 21 derivados, 1,3,4-oxadiazolinas, foi sintetizada pela ciclização de N-acilhidrazonas com anidrido acético e avaliada in vitro quanto à sua atividade antifúngica contra seis espécies de Candida: Candida albicans (ATCC 90028 e LM V-42), Candida krusei (ATCC 6258 e LM 12 C) e Candida tropicalis (ATCC 13803 e LM 14). As espécies de Candida foram consideradas sensíveis a uma série dos compostos, os quais inibiram o crescimento de 50 a 90%, com um intervalo de concentração inibitória mínima (MIC) de 64 a 512 µg mL-1. As estruturas dos compostos foram totalmente confirmadas e caracterizadas pelas técnicas de infravermelho com transformada de Fourier (FTIR), ressonância magnética nuclear (NMR) de ¹H e 13C, e espectrometria de massa (MS).

A series of 21 1,3,4-oxadiazoline derivatives was synthesized by cyclization of N-acylhydrazones with acetic anhydride and evaluated for their in vitro antifungal activity against six Candida strains: Candida albicans (ATCC 90028 and LM V-42), C. krusei (ATCC 6258 and LM 12 C) and C. tropicalis (ATCC 13803 and LM 14). The Candida strains were found to be sensitive to some of the compounds, which inhibited the growth by 50-90%, with minimum inhibitory concentration (MIC) in the range of 64-512 µg mL-1. The compounds' structures were fully confirmed and characterized by Fourier transform infrared spectroscopy (FTIR), ¹H and 13C nuclear magnetic resonance (NMR) and mass spectrometry (MS).

Este estudo teve como objetivo avaliar a atividade moluscicida e larvicida de alguns óleos essenciais e fitoconstituintes de plantas medicinais. A atividade moluscicida e larvicida foi determinada empregando-se, respectivamente, o teste de letalidade contra náupilos de Artemia salina Leach. Artemiidae e contra larvas de Aedes aegypti L. Culicidae. Os óleos essenciais de Eugenia uniflora L. Myrtaceae, Laurus nobilis L. Lauraceae, Origanum vulgare L. Lamiaceae e os fitoconstituintes α-pineno e eugenol mostraram bioatividade citotóxica frente A. salina com valores de CL50 entre 9,59 e 253,43 μL/mL. Os óleos essenciais de E. uniflora, M. piperita, O. vulgare e R. officinalis apresentaram atividade de embriotoxicidade sobre as larvas de A. aegypti mostrando uma variação de inibição de viabilidade entre 40 e 100%. Estes resultados demonstram o potencial de bioatividade desses óleos essenciais e fitoconstituintes e justificam, parcialmente, o desenvolvimento de estudos com esses produtos para uso popular.

This study aimed to evaluate the molluscicidal and larvicidal activity of some essential oils and phytochemicals from medicinal plants. Molluscicide and larvicidal activity were determined by, respectively, the lethality bioassays using Artemia salina Leach. Artemiidae and Aedes aegypti L. Culicidae larvae. Essential oils from Eugenia uniflora L. Myrtaceae, Laurus nobilis L. Lauraceae, Origanum vulgare L. Lamiaceae and the phytochemicals α-pinene and eugenol presented citotoxicity toward Artemia salina with CL50 values between 9.59 and 253.43 μL/mL. Essential oils from E. uniflora, M. piperita, O. vulgare and R. officinalis showed embryotoxicity on Aedes aegypti larvae with a viability inhibition between 40 and 100%. These results show the bioactivity of the assayed essential oils and phytochemicals and, partially, justify their insertion in further evaluation in order to establish a safe exploitation of their biological potentiality.

A espécie Poiretia bahiana, popularmente conhecida como arrudinha, arruda da serra ou arruda brava, tem uma ocorrência restrita aos campos rupestres da Chapada Diamantina, BA. Suas partes aéreas apresentam um aroma pungente e é usada pelo povo do local no controle de infestações por pulgas e no tratamento de hemorróidas, dores nas articulações e sinusite. Neste trabalho, relatamos a composição dos óleos voláteis obtidos das partes aéreas de cinco espécimes e do óleo volátil obtido dos frutos de um espécime de P. bahiana, os quais foram coletados em diferentes regiões da Chapada Diamantina. Nos óleos voláteis que foram analisados por CG-FID e CG-EM foram identificados vinte e nove componentes sendo que os dois principais foram a umbelulona, em concentrações entre 55,0% e 75,3%, e sabineno, em concentrações entre 10,3% e 25,2%. O óleo das partes aéreas de um espécime e o óleo dos frutos de outro espécime foram avaliados quanto às suas propriedades antimicrobianas contra seis bactérias, duas leveduras e cinco fungos filamentosos pelos ensaios de difusão em ágar e microdiluição. Os óleos exibiram atividade contra Escherichia coli, Salmonella choleraesuis, Proteus mirabilis, Staphylococcus aureus, Staphylococcus aureus resistente à meticilina (MRSA), Candida albicans, Cryptococcus neoformans, Cladosporium herbarum, Microsporum canis, Trichophyton rubrum e foram inativos contra Pseudomonas aeruginosa, Aspergillus fumigatus e Penicillium notatum. A toxicidade do óleo das partes aéreas foi determinada contra Artemia salina apresentando uma LC50 de 459,03 mg mL-1.

Poiretia bahiana known as "arrudinha", "arruda da serra" or "arruda brava", has its occurrence restricted to the rock fields (campo rupestre) areas in Chapada Diamantina, Bahia, northeastern region of Brazil. Its aerial parts present a pungent smell and have been used by local communities as fumigant for the control of infestation of fleas and in the treatment of hemorrhoids, articulations pain and sinusitis. This work reports the composition of the volatile oils from aerial parts of five specimens and of the essential oil from the fruits of one specimen of Poiretia bahiana that were harvested in four different places of Chapada Diamantina. Twenty nine components were identified from the oils analyzed by GC-FID and GC-MS. Umbellulone, in concentrations between 55.0% and 75.3% and sabinene, in concentrations between 10.3% and 25.2% are the major components. The oil from the aerial parts of one specimen and the oil of fruits of another specimen had their antimicrobial properties evaluated against six bacteria, two yeasts and five filamentous fungi by the agar diffusion method and microdilution assay. The in vitro results demonstrated that these essential oils exhibit antimicrobial activity against Escherichia coli, Salmonella choleraesuis, Proteus mirabilis, Staphylococcus aureus, methicilin resistant Staphylococcus aureus (MRSA), Candida albicans, Cryptococcus neoformans, Cladosporium herbarum, Microsporum canis, Trichophyton rubrum and are inactive against Pseudomonas aeruginosa, Aspergillus fumigatus and Penicillium notatum. The oil obtained from the aerial parts of one specimen displayed moderate toxicity against Artemia salina with a LC50 value of 459.03 mg mL-1.

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.

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.

Os óleos essenciais das folhas, flores e frutos de Myrcia myrtifolia DC foram coletados ao longo dos anos de 2002 e 2003 e foram analisados utilizando CG-DIC e CG-EM. No total foram identificados 28 componentes sendo que o alfa-pineno foi a substância predominante em todas as amostras analisadas apresentando-se em concentrações que variaram entre 61.5 e 90.9%. As propriedades antimicrobianas do óleo essencial das folhas coletadas em outubro de 2002 foram avaliadas contra seis bactérias, duas leveduras e cinco fungos filamentosos sendo mais fortemente ativo contra Microsporum canis e Trichophyton rubrum, ativo contra Staphylococcus aureus, Staphylococcus aureus resistente à meticilina, Candida albicans, Cryptococcus neoformans e Aspergillus fumigatus. O óleo ainda mostrou uma toxicidade moderada, LC50 of 479,16 µg mL-1, contra Artemia salina.

This work reports the seasonal variation of the composition of leaf volatile oils and the composition of volatile oils from flowers and fruits of Myrcia myrtifolia DC harvested in the sand dunes of Salvador, Bahia, northeastern region of Brazil between 2002 and 2003. The oils were analyzed by GC-FID and GC-MS so that 28 components were identified. alpha-Pinene was predominant in a range from 61.5 to 90.9% in all samples analyzed. The leaf oil collected in October 2002 had their antimicrobial properties tested against six bacteria, two yeasts and five filamentous fungi being active against Staphylococcus aureus, methicilin-resistant Staphylococcus aureus, Candida albicans, Cryptococcus neoformans and Aspergillus fumigatus, and showed strongest activity against Microsporum canis and Trichophyton rubrum. The oil displayed moderate toxicity against Artemia salina showing a LC50 of 479.16 µg mL-1.

A família Aristolochiaceae apresenta entre seus constituintes terpenóides, alcalóides e lignóides. Papo-de-peru, jarrinha, mil-homens e capivara são nomes populares da espécie Aristolochia birostris, a qual é utilizada na medicina popular como antiofídica, sudorífica, anticatarral e abortiva. Um estudo fitoquímico anterior com as partes aéreas desta espécie reportou o isolamento de quatro terpenóides, um lignóide e uma antraquinona. Dando continuidade a esse estudo, este trabalho relata a identificação de 4 lignóides, sendo dois do tipo ariloxiarilpropânico (4-metilenodioxi-5,3',5' -trimetoxi-1'-alil-8.O.4'-neolignana e 3,4,5,3',5'-pentametoxi-1'-alil-8.O.4'-neolignana), um do tipo tetraidrofurano (grandisina) e uma lignana dibenzilbutirolactônica [(-)-hinoquinina], além de vanilina. As estruturas foram estabelecidas através de métodos espectroscópicos de infravermelho e ressonância magnética nuclear uni e bidimensionais. Os lignóides foram avaliados quanto a atividade antimicrobiana frente a algumas cepas de bactérias, fungos e leveduras, entretanto foram inativos.

The family Aristolochiaceae presents among its chemical constituents terpenoids, alkaloids and lignoids. Aristolochia birostris is a species of this family popularly known as "papo-de-peru", "jarrinha", "mil-homens" and "capivara", and it is used in the folk medicine to treat snake bites, as a sudorific, expectorant and abortive. A previous phytochemical study of the aerial parts of this plant reported the isolation of four terpenoids, lignoids and antraquinone. Continuing this study it is now reported the isolation of four lignoids, two of the type aryloxyarylpropane (4-methylenedioxy-5,3',5'-trimethoxy-1'-alyl-8.O.4' -neolignan and 3,4,5,3',5'-pentamethoxy-1'-alyl-8.O.4'-neolignan), one tetrahydrofuran (grandisin) and a dibenzylbutyrolactone lignans [(-)-hinokinin], and also vanillin. The chemical structures of the isolated compounds were established based on spectral data, mainly IR and NMR including 1D and 2D experiments. The lignoids were evaluated for their activity against some bacteria (Staphylococcus epidermidis, Staphylococcus aureus, Pseudomonas aeruginosa, Enterococcus faecalis and Escherichia coli), fungi (Aspergilus flavus and Microsporum canis) and yeast (Candida albicans, Candida tropicalis and Criptococcus neoformans), but they were inactive.

Infecções oportunistas causadas por leveduras têm sido caracterizadas como doenças emergentes em todo o mundo e este fenômeno tem levado ao desenvolvimento de novos produtos capazes de inibir a sobrevivência de seus agentes etiológicos. Este estudo avaliou o perfil de sensibilidade de leveduras potencialmente causadoras de infecções oportunistas frente aos fitoconstituintes alfa-pineno, beta-pineno, citral e eugenol. Todos os fitoconstituintes mostraram ação inibitória sobre as leveduras ensaiadas, as quais foram Candida albicans, C. tropicalis, C. guilliermondii, C. stellatoidea, C. krusei, C. parapsilosis e Cryptococcus neoformans, tendo valores de CIM oscilando entre 1 e 4%. Os fitoconstituintes mostraram eficácia para provocar um alto efeito fungicida em curto tempo de ação. Estes dados subsidiam o possível uso de alguns fitoconstituintes como ferramentas úteis para controlar a ocorrência de infecções oportunistas causadas por leveduras.

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, beta-pinene, citral and eugenol was evaluated. All phytochemicals showed inhibitory action on the assayed yeast strains: Candida. albicans, C. tropicalis, C. guilliermondii, C. stellatoidea, C. krusei, C. parapsilosis and Cryptococcus neoformans, presenting their MIC values in the range of 1 and 4%. 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.