RESUMO

Candida albicans is the main fungal species involved in oral candidiasis, and its increasing resistance to pharmacological treatment encourages the search for improved antifungal agents. Lavandula dentata L. essential oil (LD-EO) has been recognized for its antimicrobial activity, but little is known about its role against oral C. albicans. This study evaluated the antifungal and antibiofilm activities, mechanisms of action, and toxicity of LD-EO from Brazil against oral strains of C. albicans. Antifungal activity was assessed based on Minimum Inhibitory Concentration (MIC), Minimum Fungicidal Concentration (MFC), association study with miconazole (Checkerboard method), and sorbitol and ergosterol assays. Inhibition of biofilm formation and disruption of preformed biofilm were considered when studying the effects of the product. Additionally, the toxicity of LD-EO was evaluated by a hemolysis assay on human erythrocytes. Phytochemical analysis by gas chromatography-mass spectrometry identified eucalyptol (33.1%), camphor (18.3%), and fenchone (15.6%) as major constituents. The test substance showed mainly fungicidal activity (MIC100 = 8 µg/mL; MFC = 16 µg/mL), including against two miconazole-resistant isolates of C. albicans. The effects of LD-EO were synergistic with those of miconazole and appeared not to involve damage to the fungal cell wall or plasma membrane. Its effectiveness in inhibiting biofilm formation was higher than the effect of disrupting preformed biofilm. Finally, the product exhibited low hemolytic activity at MIC. Based on the favorable and novel results described here, LD-EO could constitute a promising therapeutic alternative for oral candidiasis, including miconazole-resistant cases.

Assuntos

RESUMO

The present study sought to evaluate the antimicrobial and anti-adherent potential of Eucalyptus radiata essential oil against food-borne strains of Escherichia coli. The study was performed using the Minimum Inhibitory Concentration (MIC) and Minimum Bactericidal Concentration (MBC). In addition, the disk diffusion technique was used to evaluate the association of Eucalyptus radiata essential oil with synthetic antimicrobials. The Minimum Inhibitory Adherence Concentration (MIC) was also performed. The results revealed that E. radiata showed antimicrobial activity against the E. coli strains tested, with MIC values ranging from 500 µg/mL to 1000 µg/mL and MBC values ranging from 500 µg/mL to 1,024 µg/mL. As for the associations, it was observed that E. radiata oil exhibited a synergistic effect for some antibiotics, especially Ceftriaxone, with greater interference from the essential oil. Furthermore, it was effective in inhibiting the adherence of bacterial strains of E. coli, showing a more significant antibiofilm effect than the antibacterial agent 0.12% chlorhexidine digluconate. In summary, the essential oil of E. radiata showed antimicrobial potential against strains of E. coli of food origin, and can therefore, through in-depth studies, be used alone or in association with synthetic antimicrobials to combat infections caused by this pathogen.

Assuntos

RESUMO

Abstract In the current context of emerging drug-resistant fungal pathogens such as Candida albicans and Candida parapsilosis, discovery of new antifungal agents is an urgent matter. This research aimed to evaluate the antifungal potential of 2-chloro-N-phenylacetamide against fluconazole-resistant clinical strains of C. albicans and C. parapsilosis. The antifungal activity of 2-chloro-N-phenylacetamide was evaluated in vitro by the determination of the minimum inhibitory concentration (MIC), minimum fungicidal concentration (MFC), inhibition of biofilm formation and its rupture, sorbitol and ergosterol assays, and association between this molecule and common antifungal drugs, amphotericin B and fluconazole. The test product inhibited all strains of C. albicans and C. parapsilosis, with a MIC ranging from 128 to 256 µg.mL-1, and a MFC of 512-1,024 µg.mL-1. It also inhibited up to 92% of biofilm formation and rupture of up to 87% of preformed biofilm. 2-chloro-N-phenylacetamide did not promote antifungal activity through binding to cellular membrane ergosterol nor it damages the fungal cell wall. Antagonism was observed when combining this substance with amphotericin B and fluconazole. The substance exhibited significant antifungal activity by inhibiting both planktonic cells and biofilm of fluconazole-resistant strains. Its combination with other antifungals should be avoided and its mechanism of action remains to be established.

Resumo No atual contexto de patógenos fúngicos resistentes emergentes tais como Candida albicans e Candida parapsilosis, a descoberta de novos agentes antifúngicos é uma questão urgente. Esta pesquisa teve como objetivo avaliar o potencial antifúngico da 2-cloro-N-fenilacetamida contra cepas clínicas de C. albicans e C. parapsilosis resistentes a fluconazol. A atividade antifúngica da substância foi avaliada in vitro através da determinação da concentração inibitória mínima (CIM), concentração fungicida mínima (CFM), ruptura e inibição da formação de biofilme, ensaios de sorbitol e ergosterol, e associação entre esta molécula e antifúngicos comuns, anfotericina B e fluconazol. O produto teste inibiu todas as cepas de C. albicans e C. parapsilosis, com uma CIM variando de 128 a 256 µg.mL-1, e uma CFM de 512-1,024 µg.mL-1. Também inibiu até 92% da formação de biofilme e causou a ruptura de até 87% de biofilme pré-formado. A 2-cloro-N-fenilacetamida não promoveu atividade antifúngica pela ligação ao ergosterol da membrana celular fúngica, tampouco danificou a parede celular. Antagonismo foi observado ao combinar esta substância com anfotericina B e fluconazol. A substância exibiu atividade antifúngica significativa ao inibir tanto as células planctônicas quanto o biofilme das cepas resistentes ao fluconazol. Sua combinação com outros antifúngicos deve ser evitada e seu mecanismo de ação deve ser estabelecido.

RESUMO

In the current context of emerging drug-resistant fungal pathogens such as Candida albicans and Candida parapsilosis, discovery of new antifungal agents is an urgent matter. This research aimed to evaluate the antifungal potential of 2-chloro-N-phenylacetamide against fluconazole-resistant clinical strains of C. albicans and C. parapsilosis. The antifungal activity of 2-chloro-N-phenylacetamide was evaluated in vitro by the determination of the minimum inhibitory concentration (MIC), minimum fungicidal concentration (MFC), inhibition of biofilm formation and its rupture, sorbitol and ergosterol assays, and association between this molecule and common antifungal drugs, amphotericin B and fluconazole. The test product inhibited all strains of C. albicans and C. parapsilosis, with a MIC ranging from 128 to 256 µg.mL-1, and a MFC of 512-1,024 µg.mL-1. It also inhibited up to 92% of biofilm formation and rupture of up to 87% of preformed biofilm. 2-chloro-N-phenylacetamide did not promote antifungal activity through binding to cellular membrane ergosterol nor it damages the fungal cell wall. Antagonism was observed when combining this substance with amphotericin B and fluconazole. The substance exhibited significant antifungal activity by inhibiting both planktonic cells and biofilm of fluconazole-resistant strains. Its combination with other antifungals should be avoided and its mechanism of action remains to be established.

No atual contexto de patógenos fúngicos resistentes emergentes tais como Candida albicans e Candida parapsilosis, a descoberta de novos agentes antifúngicos é uma questão urgente. Esta pesquisa teve como objetivo avaliar o potencial antifúngico da 2-cloro-N-fenilacetamida contra cepas clínicas de C. albicans e C. parapsilosis resistentes a fluconazol. A atividade antifúngica da substância foi avaliada in vitro através da determinação da concentração inibitória mínima (CIM), concentração fungicida mínima (CFM), ruptura e inibição da formação de biofilme, ensaios de sorbitol e ergosterol, e associação entre esta molécula e antifúngicos comuns, anfotericina B e fluconazol. O produto teste inibiu todas as cepas de C. albicans e C. parapsilosis, com uma CIM variando de 128 a 256 µg.mL-1, e uma CFM de 512-1,024 µg.mL-1. Também inibiu até 92% da formação de biofilme e causou a ruptura de até 87% de biofilme pré-formado. A 2-cloro-N-fenilacetamida não promoveu atividade antifúngica pela ligação ao ergosterol da membrana celular fúngica, tampouco danificou a parede celular. Antagonismo foi observado ao combinar esta substância com anfotericina B e fluconazol. A substância exibiu atividade antifúngica significativa ao inibir tanto as células planctônicas quanto o biofilme das cepas resistentes ao fluconazol. Sua combinação com outros antifúngicos deve ser evitada e seu mecanismo de ação deve ser estabelecido.

Assuntos

RESUMO

Meat products represent an important component of the human diet and are a good source of nutrients. Food-borne microorganisms are the main pathogens that cause human diseases as a result of food consumption, especially products of animal origin. The objective of the present research was to verify the antibacterial activity of the essential oil of Thymus vulgaris against strains of Klebsiella pneumoniae, Pseudomonas aeruginosa and Staphylococcus saprophyticus isolated from meat products. For this, the analyses of Minimum Inhibitory Concentration (MIC) and Minimum Bactericidal Concentration (MBC) were performed in microdilution plates. The association of the product with antimicrobials was also studied using disk diffusion. And the anti-adherent activity, which was determined in the presence of sucrose, in glass tubes. Thyme oil showed a strong inhibitory activity against K. pneumoniae, P. aeruginosa and S. saprophyticus, with the MIC values ranging from 64 to 512 µg/mL, and bactericidal effect for most strains, with MBC values ranging from 256 to 1,024 µg/mL. T. vulgaris oil exhibited varied interactions in association with the antimicrobials, with synergistic (41.67%), indifferent (50%) and antagonistic (8.33%) effects. Regarding the anti-adherent activity, the test product was effective in inhibiting the adherence of all bacterial strains under study. Therefore, thyme oil presents itself as an antibacterial and anti-adherent agent against K. pneumoniae, P. aeruginosa and S. saprophyticus, being a natural product that can represent an interesting alternative in the efforts to combat foodborne diseases.

Assuntos

RESUMO

Onychomycosis is the most common disease affecting the nail unit and accounts for at least 50% of all nail diseases. In addition, Candida albicans is responsible for approximately 70% of onychomycoses caused by yeasts. This study investigated the antifungal effect of (R) and (S)-citronellal enantiomers, as well as its predictive mechanism of action on C. albicans from voriconazole-resistant onychomycoses. For this purpose, in vitro broth microdilution and molecular docking techniques were applied in a predictive and complementary manner to the mechanisms of action. The main results of this study indicate that C. albicans was resistant to voriconazole and sensitive to the enantiomers (R) and (S)-citronellal at a dose of 256 and 32 µg/mL respectively. In addition, there was an increase in the minimum inhibitory concentration (MIC) of the enantiomers in the presence of sorbitol and ergosterol, indicating that these molecules possibly affect the integrity of the cell wall and cell membrane of C. albicans. Molecular docking with key biosynthesis proteins and maintenance of the fungal cell wall and plasma membrane demonstrated the possibility of (R) and (S)-citronellal interacting with two important enzymes: 1,3-ß-glucan synthase and lanosterol 14α-demethylase. Therefore, the findings of this study indicate that the (R) and (S)-citronellal enantiomers are fungicidal on C. albicans from onychomycoses and probably these substances cause damage to the cell wall and cell membrane of these micro-organisms possibly by interacting with enzymes in the biosynthesis of these fungal structures.

Assuntos

RESUMO

Bacteria may be the initial cause of certain pathologies as well as a secondary agent responsible for the development of complications such as pressure ulcer infections. Pressure ulcers are a persistent health problem, especially in immunocompromised patients, and associated with infection by opportunistic microorganisms with antimicrobial resistance, such as Klebsiella pneumoniae, highlight the need for the development of new antimicrobial approaches. Thus, the aim of this study was to evaluate the antibacterial and anti-adherent activity of Origanum vulgare L. (oregano) essential oil against Klebsiella pneumoniae strains, as well as the effect of its association with synthetic antimicrobials. To this end, the Minimum Inhibitory Concentration (MIC) and Minimum Bactericidal Concentration (MBC) analyses were performed on microdilution plates. The assay of the Minimum Inhibitory Adherence Concentration (MIAC), with test tubes. As well as, the association study through the infusion disc method containing ampicillin (AMP), gentamicin (GEN), ciprofloxacin (CIP) and ceftriaxone (CEF). Therefore, it was possible to obtain that the essential oil of oregano presents antimicrobial and bactericidal activity, with MIC ranging between 128µg/mL and 256 µg/mL and MBC between 256 µg/mL and 512 µg/mL, on the tested K. pneumoniae strains. When used in association with ampicillin and gentamicin, oregano essential oil showed synergistic effect for some strains. Therefore, it is observed that the tested essential oil can act as a promising antibacterial in the treatment of diseases caused by K. pneumoniae.

Assuntos

RESUMO

The present study sought to evaluate the antibacterial activity of trans-anethole against food-borne strains of Enterobacter cloacae and Enterococcus faecalis. The study was performed using Minimum Inhibitory Concentration (MIC), and Minimum Bactericidal Concentration (MBC) methods, in addition, disc diffusion technique was used to evaluate the association of trans-anethole with synthetic antimicrobials. Minimum Inhibitory Concentration for Adherence (MICA) testing was also performed. The results revealed that trans-anethole presents no antibacterial activity at any of the concentrations used against the E. cloacae strains tested. However, trans-anethole presented antibacterial effect against five of the six E. faecalis bacterial strains tested, with MIC values ranging from 500 µg/mL to 1000 µg/mL. Further, when analyzing the MBC results against E. faecalis, it was observed that the compound presented values ranging from 500 µg/mL to 1000 µg/mL. As for the associations, it was observed that trans-anethole when combined with the antimicrobials ampicillin, gentamicin, ciprofloxacin, and ceftriaxone presented synergistic effect against most strains of E. faecalis. However, both trans-anethole and the control chlorhexidine (0.12%) presented no antibiofilm effects against strains of E. faecalis. In short, trans-anethole presented potential antibacterial against E. faecalis strains of food origin, and may upon further study, it may be used alone or in association with synthetic antimicrobials to combat infections caused by this bacterium.

Assuntos

RESUMO

Tiliroside is a glycosidic flavonoid present in many plants species including Helicteres velutina K. Schum (Malvaceae sensu lato), commonly known in Brazil as "pitó". This molecule has been shown to have many biological activities, however no study has been carried out to investigate the toxicity of this substance. The present work aimed to evaluate the possible cellular toxicity in silico, in vitro and ex-vivo of the kaempferol-3-O-β-D-(6”-E-p-coumaroyl) glucopyranoside (tiliroside), through chemical structure analysis, toxicity assessment and predictive bioactive properties, using human samples for in vitro and ex-vivo tests. The in silico analysis suggests that tiliroside exhibited great absorption index when penetrating biological membranes. In addition, it also displayed considerable potential for cellular protection against free radicals, and anticarcinogenic, antioxidant, antineoplastic, anti-inflammatory, anti-hemorrhagic and antithrombotic activities. The assessment of the hemolytic and genotoxic effects of tiliroside showed low hemolysis rates in red blood cells and absence of cellular toxicity in the oral mucosa cells. The data obtained indicate that this molecule could be a promising therapeutic approach as a possible new drug with biotechnological potential.

O tilirosídeo é um flavonóide glicosídico presente em muitas espécies de plantas, incluindo Helicteres velutina K. Schum (Malvaceae sensu lato), conhecida no Brasil como “pitó”. Esta molécula mostrou ter muitas atividades biológicas, porém nenhum estudo foi realizado para investigar a toxicidade dessa substância. O presente trabalho teve como objetivo avaliar a possível toxicidade celular in silico, in vitro e ex-vivo do kaempferol-3-O-β-D- (6 ”-Ep-coumaroil) glucopiranosídeo (tilirosídeo), por meio de análises de estrutura química, toxicidade avaliação e propriedades bioativas preditivas, utilizando amostras humanas para testes in vitro e ex-vivo. A análise in silico sugere que o tilirosídeo exibe bom índice de absorção para penetrar nas membranas biológicas. Além disso, apresentou considerável potencial de proteção celular contra os radicais livres e com atividades anticarcinogênica, antioxidante, antineoplásica, antiinflamatória, anti-hemorrágica e antitrombótica. A avaliação dos efeitos hemolíticos e genotóxicos do tilirosídeo mostrou baixas taxas de hemólise nas hemácias e ausência de toxicidade em células da mucosa oral. Os dados obtidos indicam que esta molécula pode possuir uma abordagem terapêutica promissora como uma possível nova droga com potencial biotecnológico.

Assuntos

RESUMO

Abstract Tiliroside is a glycosidic flavonoid present in many plants species including Helicteres velutina K. Schum (Malvaceae sensu lato), commonly known in Brazil as pitó. This molecule has been shown to have many biological activities, however no study has been carried out to investigate the toxicity of this substance. The present work aimed to evaluate the possible cellular toxicity in silico, in vitro and ex-vivo of the kaempferol-3-O--D-(6-E-p-coumaroyl) glucopyranoside (tiliroside), through chemical structure analysis, toxicity assessment and predictive bioactive properties, using human samples for in vitro and ex-vivo tests. The in silico analysis suggests that tiliroside exhibited great absorption index when penetrating biological membranes. In addition, it also displayed considerable potential for cellular protection against free radicals, and anticarcinogenic, antioxidant, antineoplastic, anti-inflammatory, anti-hemorrhagic and antithrombotic activities. The assessment of the hemolytic and genotoxic effects of tiliroside showed low hemolysis rates in red blood cells and absence of cellular toxicity in the oral mucosa cells. The data obtained indicate that this molecule could be a promising therapeutic approach as a possible new drug with biotechnological potential.

Resumo O tilirosídeo é um flavonóide glicosídico presente em muitas espécies de plantas, incluindo Helicteres velutina K. Schum (Malvaceae sensu lato), conhecida no Brasil como pitó. Esta molécula mostrou ter muitas atividades biológicas, porém nenhum estudo foi realizado para investigar a toxicidade dessa substância. O presente trabalho teve como objetivo avaliar a possível toxicidade celular in silico, in vitro e ex-vivo do kaempferol-3-O--D- (6 -Ep-coumaroil) glucopiranosídeo (tilirosídeo), por meio de análises de estrutura química, toxicidade avaliação e propriedades bioativas preditivas, utilizando amostras humanas para testes in vitro e ex-vivo. A análise in silico sugere que o tilirosídeo exibe bom índice de absorção para penetrar nas membranas biológicas. Além disso, apresentou considerável potencial de proteção celular contra os radicais livres e com atividades anticarcinogênica, antioxidante, antineoplásica, antiinflamatória, anti-hemorrágica e antitrombótica. A avaliação dos efeitos hemolíticos e genotóxicos do tilirosídeo mostrou baixas taxas de hemólise nas hemácias e ausência de toxicidade em células da mucosa oral. Os dados obtidos indicam que esta molécula pode possuir uma abordagem terapêutica promissora como uma possível nova droga com potencial biotecnológico.

RESUMO

Abstract Tiliroside is a glycosidic flavonoid present in many plants species including Helicteres velutina K. Schum (Malvaceae sensu lato), commonly known in Brazil as "pitó". This molecule has been shown to have many biological activities, however no study has been carried out to investigate the toxicity of this substance. The present work aimed to evaluate the possible cellular toxicity in silico, in vitro and ex-vivo of the kaempferol-3-O-β-D-(6"-E-p-coumaroyl) glucopyranoside (tiliroside), through chemical structure analysis, toxicity assessment and predictive bioactive properties, using human samples for in vitro and ex-vivo tests. The in silico analysis suggests that tiliroside exhibited great absorption index when penetrating biological membranes. In addition, it also displayed considerable potential for cellular protection against free radicals, and anticarcinogenic, antioxidant, antineoplastic, anti-inflammatory, anti-hemorrhagic and antithrombotic activities. The assessment of the hemolytic and genotoxic effects of tiliroside showed low hemolysis rates in red blood cells and absence of cellular toxicity in the oral mucosa cells. The data obtained indicate that this molecule could be a promising therapeutic approach as a possible new drug with biotechnological potential.

Resumo O tilirosídeo é um flavonóide glicosídico presente em muitas espécies de plantas, incluindo Helicteres velutina K. Schum (Malvaceae sensu lato), conhecida no Brasil como "pitó". Esta molécula mostrou ter muitas atividades biológicas, porém nenhum estudo foi realizado para investigar a toxicidade dessa substância. O presente trabalho teve como objetivo avaliar a possível toxicidade celular in silico, in vitro e ex-vivo do kaempferol-3-O-β-D- (6 "-Ep-coumaroil) glucopiranosídeo (tilirosídeo), por meio de análises de estrutura química, toxicidade avaliação e propriedades bioativas preditivas, utilizando amostras humanas para testes in vitro e ex-vivo. A análise in silico sugere que o tilirosídeo exibe bom índice de absorção para penetrar nas membranas biológicas. Além disso, apresentou considerável potencial de proteção celular contra os radicais livres e com atividades anticarcinogênica, antioxidante, antineoplásica, antiinflamatória, anti-hemorrágica e antitrombótica. A avaliação dos efeitos hemolíticos e genotóxicos do tilirosídeo mostrou baixas taxas de hemólise nas hemácias e ausência de toxicidade em células da mucosa oral. Os dados obtidos indicam que esta molécula pode possuir uma abordagem terapêutica promissora como uma possível nova droga com potencial biotecnológico.

Assuntos

RESUMO

Tiliroside is a glycosidic flavonoid present in many plants species including Helicteres velutina K. Schum (Malvaceae sensu lato), commonly known in Brazil as "pitó". This molecule has been shown to have many biological activities, however no study has been carried out to investigate the toxicity of this substance. The present work aimed to evaluate the possible cellular toxicity in silico, in vitro and ex-vivo of the kaempferol-3-O-β-D-(6”-E-p-coumaroyl) glucopyranoside (tiliroside), through chemical structure analysis, toxicity assessment and predictive bioactive properties, using human samples for in vitro and ex-vivo tests. The in silico analysis suggests that tiliroside exhibited great absorption index when penetrating biological membranes. In addition, it also displayed considerable potential for cellular protection against free radicals, and anticarcinogenic, antioxidant, antineoplastic, anti-inflammatory, anti-hemorrhagic and antithrombotic activities. The assessment of the hemolytic and genotoxic effects of tiliroside showed low hemolysis rates in red blood cells and absence of cellular toxicity in the oral mucosa cells. The data obtained indicate that this molecule could be a promising therapeutic approach as a possible new drug with biotechnological potential.(AU)

O tilirosídeo é um flavonóide glicosídico presente em muitas espécies de plantas, incluindo Helicteres velutina K. Schum (Malvaceae sensu lato), conhecida no Brasil como “pitó”. Esta molécula mostrou ter muitas atividades biológicas, porém nenhum estudo foi realizado para investigar a toxicidade dessa substância. O presente trabalho teve como objetivo avaliar a possível toxicidade celular in silico, in vitro e ex-vivo do kaempferol-3-O-β-D- (6 ”-Ep-coumaroil) glucopiranosídeo (tilirosídeo), por meio de análises de estrutura química, toxicidade avaliação e propriedades bioativas preditivas, utilizando amostras humanas para testes in vitro e ex-vivo. A análise in silico sugere que o tilirosídeo exibe bom índice de absorção para penetrar nas membranas biológicas. Além disso, apresentou considerável potencial de proteção celular contra os radicais livres e com atividades anticarcinogênica, antioxidante, antineoplásica, antiinflamatória, anti-hemorrágica e antitrombótica. A avaliação dos efeitos hemolíticos e genotóxicos do tilirosídeo mostrou baixas taxas de hemólise nas hemácias e ausência de toxicidade em células da mucosa oral. Os dados obtidos indicam que esta molécula pode possuir uma abordagem terapêutica promissora como uma possível nova droga com potencial biotecnológico.(AU)

Assuntos

RESUMO

Meat products represent an important component of the human diet and are a good source of nutrients. Food-borne microorganisms are the main pathogens that cause human diseases as a result of food consumption, especially products of animal origin. The objective of the present research was to verify the antibacterial activity of the essential oil of Thymus vulgaris against strains of Klebsiella pneumoniae, Pseudomonas aeruginosa and Staphylococcus saprophyticus isolated from meat products. For this, the analyses of Minimum Inhibitory Concentration (MIC) and Minimum Bactericidal Concentration (MBC) were performed in microdilution plates. The association of the product with antimicrobials was also studied using disk diffusion. And the anti-adherent activity, which was determined in the presence of sucrose, in glass tubes. Thyme oil showed a strong inhibitory activity against K. pneumoniae, P. aeruginosa and S. saprophyticus, with the MIC values ranging from 64 to 512 µg/mL, and bactericidal effect for most strains, with MBC values ranging from 256 to 1,024 µg/mL. T. vulgaris oil exhibited varied interactions in association with the antimicrobials, with synergistic (41.67%), indifferent (50%) and antagonistic (8.33%) effects. Regarding the anti-adherent activity, the test product was effective in inhibiting the adherence of all bacterial strains under study. Therefore, thyme oil presents itself as an antibacterial and anti-adherent agent against K. pneumoniae, P. aeruginosa and S. saprophyticus, being a natural product that can represent an interesting alternative in the efforts to combat foodborne diseases.

Os produtos cárneos representam um importante componente da dieta humana e constituem uma boa fonte de nutrientes. Microrganismos de origem alimentar são os principais patógenos que causam doenças humanas como resultado do consumo de alimentos, principalmente, produtos de origem animal. O objetivo da presente pesquisa foi verificar a atividade antibacteriana do óleo essencial de Thymus vulgaris frente às cepas de Klebsiella pneumoniae, Pseudomonas aeruginosa e Staphylococcus saprophyticus isoladas de produtos cárneos. Para isso, foram realizadas as análises de Concentração Inibitória Mínima (CIM) e a Concentração Bactericida Mínima (CBM) em placas de microdiluição. Assim como, o estudo de associação do produto com antimicrobianos, realizado por difusão em disco. E a atividade antiaderente, que foi determinada na presença de sacarose, em tubos de vidro. O óleo de tomilho apresentou uma forte atividade inibitória contra K. pneumoniae, P. aeruginosa e S. saprophyticus, com os valores de CIM variando entre 64 a 512 µg/mL, e efeito bactericida para a maioria das cepas, com valores de CBM entre 256 a 1.024 µg/mL. O óleo de T. vulgaris exibiu interações variadas na associação com os antimicrobianos, com efeitos sinérgicos (41,67%), indiferente (50%) e antagonista (8,33%). Em relação a atividade antiaderente, o produto teste foi eficaz na inibição a aderência de todas cepas bacterianas em estudo. Portanto, o óleo de tomilho apresenta-se como agente antibacteriano e antiaderente frente a K. pneumoniae, a P. aeruginosa e a S. saprophyticus, sendo um produto natural que pode representar uma alternativa interessante nos esforços para combater doenças transmitidas por alimentos.

Assuntos

RESUMO

Onychomycosis is the most common disease affecting the nail unit and accounts for at least 50% of all nail diseases. In addition, Candida albicans is responsible for approximately 70% of onychomycoses caused by yeasts. This study investigated the antifungal effect of (R) and (S)-citronellal enantiomers, as well as its predictive mechanism of action on C. albicans from voriconazole-resistant onychomycoses. For this purpose, in vitro broth microdilution and molecular docking techniques were applied in a predictive and complementary manner to the mechanisms of action. The main results of this study indicate that C. albicans was resistant to voriconazole and sensitive to the enantiomers (R) and (S)-citronellal at a dose of 256 and 32 µg/mL respectively. In addition, there was an increase in the minimum inhibitory concentration (MIC) of the enantiomers in the presence of sorbitol and ergosterol, indicating that these molecules possibly affect the integrity of the cell wall and cell membrane of C. albicans. Molecular docking with key biosynthesis proteins and maintenance of the fungal cell wall and plasma membrane demonstrated the possibility of (R) and (S)-citronellal interacting with two important enzymes: 1,3-ß-glucan synthase and lanosterol 14α-demethylase. Therefore, the findings of this study indicate that the (R) and (S)-citronellal enantiomers are fungicidal on C. albicans from onychomycoses and probably these substances cause damage to the cell wall and cell membrane of these micro-organisms possibly by interacting with enzymes in the biosynthesis of these fungal structures.

A onicomicose é a doença mais comum que afeta a unidade ungueal e representa pelo menos 50% de todas as doenças ungueais. Além disso, a Candida albicans é responsável por aproximadamente 70% das onicomicoses causadas por leveduras. Nesse estudo, foi investigado o efeito antifúngico dos enantiômeros (R) e (S)-citronelal, bem como seu mecanismo de ação preditivo sobre C. albicans de onicomicoses resistentes ao voriconazol. Para este propósito, foram aplicadas técnicas in vitro de microdiluição em caldo e docking molecular de forma preditiva e complementar para os mecanismos de ação. Os principais resultados deste estudo indicam que C. albicans foi resistente ao voriconazol e sensível aos enantiômeros (R) e (S)-citronelal na dose de 256 e 32 µg/mL respectivamente. Além disso, houve aumento da concentração inibitória mínima (CIM) dos enantiômeros na presença do sorbitol e do ergosterol, indicando que estas moléculas possivelmente afetem a integridade da parede e da membrana celular de C. albicans. O docking molecular com proteínas chave da biossíntese e manutenção da parede celular e da membrana plasmática fúngica, demonstraram a possibilidade do (R) e (S)-citronelal interagir com duas importantes enzimas: 1,3-ß-glucan sintase e lanosterol 14α-demetilase. Portanto, os achados desse estudo indicam que os enantiômeros (R) e (S)-citronelal são fungicidas sobre C. albicans de onicomicoses e provavelmente essas substâncias causem danos a parede e a membrana celular desses microrganismos possivelmente por interagir com as enzimas da biossíntese destas estruturas fúngicas.

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Bacteria may be the initial cause of certain pathologies as well as a secondary agent responsible for the development of complications such as pressure ulcer infections. Pressure ulcers are a persistent health problem, especially in immunocompromised patients, and associated with infection by opportunistic microorganisms with antimicrobial resistance, such as Klebsiella pneumoniae, highlight the need for the development of new antimicrobial approaches. Thus, the aim of this study was to evaluate the antibacterial and anti-adherent activity of Origanum vulgare L. (oregano) essential oil against Klebsiella pneumoniae strains, as well as the effect of its association with synthetic antimicrobials. To this end, the Minimum Inhibitory Concentration (MIC) and Minimum Bactericidal Concentration (MBC) analyses were performed on microdilution plates. The assay of the Minimum Inhibitory Adherence Concentration (MIAC), with test tubes. As well as, the association study through the infusion disc method containing ampicillin (AMP), gentamicin (GEN), ciprofloxacin (CIP) and ceftriaxone (CEF). Therefore, it was possible to obtain that the essential oil of oregano presents antimicrobial and bactericidal activity, with MIC ranging between 128µg/mL and 256 µg/mL and MBC between 256 µg/mL and 512 µg/mL, on the tested K. pneumoniae strains. When used in association with ampicillin and gentamicin, oregano essential oil showed synergistic effect for some strains. Therefore, it is observed that the tested essential oil can act as a promising antibacterial in the treatment of diseases caused by K. pneumoniae.

As bactérias podem ser a causa inicial de determinadas patologias como também um agente secundário responsável pelo desenvolvimento de complicações como as infecções das lesões por pressão. As lesões por pressão configuram um problema de saúde persistente, principalmente em pacientes imunocomprometidos, e associadas a infecção por microrganismos oportunistas com resistência antimicrobiana, como por exemplo a Klebisiella pneumoniae, ressaltam a necessidade do desenvolvimento de novas abordagens antimicrobianas. Assim, o objetivo deste estudo foi avaliar a atividade antibacteriana e antiaderente do óleo essencial de Origanum vulgare L. (orégano) contra cepas da Klebisiella pneumoniae, bem como o efeito da sua associação com antimicrobianos sintéticos. Para isso foram realizadas as análises da Concentração Mínima Inibitória (CIM) e Concentração Bactericida Mínima (CBM) em placas de micro diluição. O ensaio da Concentração Mínima de Aderência (CIMA), com tubos de ensaio. Como também, o estudo de associação através do método de disco de infusão contendo ampicilina, gentamicina, ciprofloxacino e ceftriaxona. Assim sendo, foi possível obter que o óleo essencial de orégano apresenta atividade antimicrobiana e bactericida, com CIM variando entre 128µg/mL e 256 µg/mL e CBM entre 256 µg/mL e 512 µg/mL, sobre as cepas de K. pneumoniae testadas. Quando utilizado em associação com a ampicilina e gentamicina, o óleo essencial de orégano demonstrou efeito sinérgico para algumas cepas. Portanto, observa-se que o óleo essencial testado pode atuar como um promissor antibacteriano no tratamento de doenças causadas por K. pneumoniae.

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The present study sought to evaluate the antibacterial activity of trans-anethole against food-borne strains of Enterobacter cloacae and Enterococcus faecalis. The study was performed using Minimum Inhibitory Concentration (MIC), and Minimum Bactericidal Concentration (MBC) methods, in addition, disc diffusion technique was used to evaluate the association of trans-anethole with synthetic antimicrobials. Minimum Inhibitory Concentration for Adherence (MICA) testing was also performed. The results revealed that trans-anethole presents no antibacterial activity at any of the concentrations used against the E. cloacae strains tested. However, trans-anethole presented antibacterial effect against five of the six E. faecalis bacterial strains tested, with MIC values ranging from 500 µg/mL to 1000 µg/mL. Further, when analyzing the MBC results against E. faecalis, it was observed that the compound presented values ranging from 500 µg/mL to 1000 µg/mL. As for the associations, it was observed that transanethole when combined with the antimicrobials ampicillin, gentamicin, ciprofloxacin, and ceftriaxone presented synergistic effect against most strains of E. faecalis. However, both trans-anethole and the control chlorhexidine (0.12%) presented no antibiofilm effects against strains of E. faecalis. In short, trans-anethole presented potential antibacterial against E. faecalis strains of food origin, and may upon further study, it may be used alone or in association with synthetic antimicrobials to combat infections caused by this bacterium.

O presente estudo procurou avaliar a atividade antibacteriana do trans-anetol contra cepas de Enterobacter cloacae e Enterococcus faecalis de origem alimentar. O estudo foi realizado utilizando métodos de Concentração Inibitória Mínima (CIM), e Concentração Bactericida Mínima (CBM), além disso, foi utilizada a técnica de difusão de disco para avaliar a associação do trans-anetol com antimicrobianos. O teste de Concentração Inibitória Mínima de Aderência (CIMA) também foi realizado. Os resultados revelaram que o trans-anetol não apresentou atividade antibacteriana em nenhuma das concentrações utilizadas contra as cepas de E. cloacae testadas. No entanto, o trans-anetol apresentou efeito antibacteriano contra cinco das seis cepas bacterianas de E. faecalis testadas, com valores de CIM variando de 500 µg/mL a 1000 µg/mL. Além disso, ao analisar os resultados da CBM contra E. faecalis, observa-se que o composto apresentou valores variando de 500 µg/mL a 1000 µg/mL. Quanto às associações, observou-se que o trans-anetol quando combinado com os antimicrobianos ampicilina, gentamicina, ciprofloxacino, e ceftriaxona apresentou efeito sinérgico contra a maioria das cepas de E. faecalis. No entanto, tanto o trans-anetol quanto o controle clorexidina (0,12%) não apresentaram efeito antibiofilme contra a cepa de E. faecalis. Em suma, o transanetol apresentou potencial antibacteriano contra cepas de E. faecalis de origem alimentar, podendo, mediante estudos mais aprofundados, ser utilizado isoladamente ou em associação com antimicrobianos sintéticos para combater infecções causadas por esta bactéria.

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In the current context of emerging drug-resistant fungal pathogens such as Candida albicans and Candida parapsilosis, discovery of new antifungal agents is an urgent matter. This research aimed to evaluate the antifungal potential of 2-chloro-N-phenylacetamide against fluconazole-resistant clinical strains of C. albicans and C. parapsilosis. The antifungal activity of 2-chloro-N-phenylacetamide was evaluated in vitro by the determination of the minimum inhibitory concentration (MIC), minimum fungicidal concentration (MFC), inhibition of biofilm formation and its rupture, sorbitol and ergosterol assays, and association between this molecule and common antifungal drugs, amphotericin B and fluconazole. The test product inhibited all strains of C. albicans and C. parapsilosis, with a MIC ranging from 128 to 256 µg.mL-1, and a MFC of 512-1,024 µg.mL-1. It also inhibited up to 92% of biofilm formation and rupture of up to 87% of preformed biofilm. 2-chloro-N-phenylacetamide did not promote antifungal activity through binding to cellular membrane ergosterol nor it damages the fungal cell wall. Antagonism was observed when combining this substance with amphotericin B and fluconazole. The substance exhibited significant antifungal activity by inhibiting both planktonic cells and biofilm of fluconazole-resistant strains. Its combination with other antifungals should be avoided and its mechanism of action remains to be established.

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Phytochemical studies of the species Pavonia glazioviana were performed. Quercetin, kaempferol, acacetin, and trimethoxylated flavonoid compounds (which present biological activity) were isolated. We aimed to evaluate the in silico, in vitro, and ex vivo toxicity of flavonoid 5,7-dihydroxy-3,8,4'-trimethoxy (Pg-1) obtained from P. glazioviana through chemical structure analyses, toxicity assessment, and predictive bioactive properties, using human samples in in vitro tests. In silico analysis suggested that Pg-1 presents a good absorption index for penetrating biological membranes (for oral bioavailability), while also suggesting potential antimutagenic, anticarcinogenic, antioxidant, antineoplastic, anti-inflammatory, anti-hemorrhagic, and apoptosis agonist bioactivities. Assessment of hemolytic and genotoxic effects revealed low hemolysis rates in red blood cells with no cellular toxicity in oral mucosa cells. The reduced cytotoxic activity suggested the safety of the concentrations used (500-1000 µg/mL), and demonstrated the varied interactions of Pg-1 with the analyzed cells. The data obtained in the present study suggested potential therapeutic application, and the non-toxic profile indicated viability for future studies.

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Tiliroside is a glycosidic flavonoid present in many plants species including Helicteres velutina K. Schum (Malvaceae sensu lato), commonly known in Brazil as "pitó". This molecule has been shown to have many biological activities, however no study has been carried out to investigate the toxicity of this substance. The present work aimed to evaluate the possible cellular toxicity in silico, in vitro and ex-vivo of the kaempferol-3-O-ß-D-(6"-E-p-coumaroyl) glucopyranoside (tiliroside), through chemical structure analysis, toxicity assessment and predictive bioactive properties, using human samples for in vitro and ex-vivo tests. The in silico analysis suggests that tiliroside exhibited great absorption index when penetrating biological membranes. In addition, it also displayed considerable potential for cellular protection against free radicals, and anticarcinogenic, antioxidant, antineoplastic, anti-inflammatory, anti-hemorrhagic and antithrombotic activities. The assessment of the hemolytic and genotoxic effects of tiliroside showed low hemolysis rates in red blood cells and absence of cellular toxicity in the oral mucosa cells. The data obtained indicate that this molecule could be a promising therapeutic approach as a possible new drug with biotechnological potential.

Assuntos

RESUMO

Phytochemical studies of the species Pavonia glazioviana were performed. Quercetin, kaempferol, acacetin, and trimethoxylated flavonoid compounds (which present biological activity) were isolated. We aimed to evaluate the in silico, in vitro, and ex vivo toxicity of flavonoid 5,7-dihydroxy-3,8,4'-trimethoxy (Pg-1) obtained from P. glazioviana through chemical structure analyses, toxicity assessment, and predictive bioactive properties, using human samples in in vitro tests. In silico analysis suggested that Pg-1 presents a good absorption index for penetrating biological membranes (for oral bioavailability), while also suggesting potential antimutagenic, anticarcinogenic, antioxidant, antineoplastic, anti-inflammatory, anti-hemorrhagic, and apoptosis agonist bioactivities. Assessment of hemolytic and genotoxic effects revealed low hemolysis rates in red blood cells with no cellular toxicity in oral mucosa cells. The reduced cytotoxic activity suggested the safety of the concentrations used (500-1000 µg/mL), and demonstrated the varied interactions of Pg-1 with the analyzed cells. The data obtained in the present study suggested potential therapeutic application, and the non-toxic profile indicated viability for future studies.

Assuntos