UPLC-QTOF-MS/MS analysis and antibacterial activity of the Manilkara zapota (L.) P. Royen against Escherichia coli and other MDR bacteria.

With the spread of bacterial resistance against clinically used antibiotics, natural plant-derived products are being studied as new sources of antibacterial molecules. Manilkara zapota is a common plant species in the American continent that is used as a food source. Studies show the M. zapota extract is rich in phenolic substances that can serve as basic molecules for the pharmaceutical industry. An extract from fresh M. zapota leaves was produced and tested to identify the compounds present, as well as its direct antibacterial and clinical antibiotic modulatory activities. To analyze the results, a new statistical methodology based on the Shannon-Wiener index was tested, capable of correcting distortions in heterogeneous environments. The Hydroethanolic Extract of Manilkara zapota leaves (HEMzL) presented a wide variety of phenolic products, as well as tannins, in the UPLC analysis. The extract showed direct antibacterial activity against the standard Staphylococcus aureus strain, however, it either acted antagonistically when associated with the tested antibiotics, or it did not present statistical significance when compared to the control. This demonstrates a need to be cautious when associating natural products with antibiotics for clinical use, as a hindrance to infectious treatments may occur. As for the statistical analysis mechanism tested, this proved to be effective, reducing false negatives at low antibiotic concentrations and false positives at high concentrations in the microdilution plate.

Phytochemical characterization and mutagenicity, cytotoxicity, antimicrobial and modulatory activities of Poincianella pyramidalis (Tul.) L.P. Queiroz.

In this study, the chemical composition, genotoxic, cytotoxic and antibacterial-modulating activities of the P. pyramidalis (NPpE) extract was evaluated. The fingerprint chromatogram was determined using HPLC-DAD. The NPpE Minimal Inhibitory Concentration (MIC), as well as that of antimicrobial drugs in the presence and absence of the extract, were evaluated using the microdilution method against Gram positive bacteria. In vivo assays with mice were used for the determination of the extract's genotoxicity and cytotoxicity. The presence of the polyphenol catechin was confirmed in the extract. The extract showed significant antimicrobial activity (MIC ≤ 1000 µg mL-1) against Staphylococcus aureus, Streptococcus oralis and S. mutans. When the NPpE was associated with several antimicrobials, the MIC of most of these were significantly reduced (P < 0.001) demonstrating good prospective usage in antimicrobial therapy. The extract has mutagenic and cytotoxic potential, however, further studies should be performed to confirm their toxicity.

In vitro EVALUATION OF THE ANTIBACTERIAL AND MODULATORY ACTIVITIES OF CORN AND SOY FIXED OILS / Evaluación in vitro de la actividad antibacteriana y moduladora de aceites de maíz y soja

Nowadays, it is widely known that resistant pathogenic strains are becoming one of the greatest health problems related to human sciences. It is also known that fatty acids can present antimicrobial activity. The corn and soy oils are rich in fatty acids. In this regard, this work aimed to evaluate antibacterial and modulatory activity of these two industrial fixed oils. Both tests were performed using the microdilution method to Minimum inhibitory concentration under 1024 mg/ml. The aminoglycosides activity was enhanced by combining corn oil using E. coli 27. One of the mechanisms that might explain the synergism toward the corn oil, in part, might be due to the hidrophobic nature of the saturated and unsaturated lipids present in the sample. The results indicate that fixed oils might play a role as an alternative way to potentiate of the antimicrobial drugs.

Hoy en día, es ampliamente conocido que las cepas patógenas resistentes a antibioticos se están convirtiendo en uno de los mayores problemas de salud en el campo de la ciencias de la salud. También se sabe que los ácidos grasos pueden presentar actividad antimicrobiana. Los aceites de maíz y de soja son ricos en ácidos grasos. En este sentido, esta investigacion dirigida para evaluar la actividad antibacteriana y modulador de estos dos aceites fijos usados industrialmente. Ambas pruebas se realizaron utilizando el método de microdilución de concentración inhibitoria mínima en 1,024 mg/ml. La actividad de los aminoglucósidos se mejoró mediante la combinación de aceite de maíz usando E. coli 27. Uno de los mecanismos que podrían explicar la sinergia hacia el aceite de maíz, en parte, podría ser debido a la naturaleza hidrofóbica de los lípidos saturados e insaturados presentes en la muestra. Los resultados indican que los aceites fijos podrían desempeñar un papel como una forma alternativa para potenciar de los fármacos antimicrobianos.

Evaluation of antibacterial, antifungal and modulatory activity of methanol and ethanol extracts of Padina sanctae-crucis.

BACKGROUND: Multi-resistantmicroorganisms such as Escherichia coli, Staphylococcus aureus, Pseudomonas aeruginosa, Candida tropicalis e Candida krusei are the main causes of microbial infections. Padina sanctae-crucis is a seaweed often used to check the contamination of ecosystems by materials such as heavy metals, but studies of the antimicrobial activity of the same seaweed were not found. METHODS: The tests for the minimum inhibitory concentration and modulation of microbial resistance, with the use of ethanolic and methanolic extracts of Padina Sanctae-cruces combined with drugs of the class of aminoglycosides and antifungal were used to evaluate the activity against the cited microorganisms. RESULTS: Was observed a modulation of antibiotic activity between the natural products and the E. coli and S. aureus strains, indicating a synergism and antagonism respectively. CONCLUSIONS: The results showed a moderate modulatory effect against some microorganisms studied.

Herbs in association with drugs: Enhancement of the aminoglycoside-antibiotic activity by Pityrogramma calomelanos (L.) Link.

AIMS: In this work, the ethyl acetate and hexane fractions of Pityrogramma calomelanos (L.) were evaluated to antibacterial and antifungal activity against strains of Escherichia coli, Pseudomonas aeruginosa, Staphylococcus aureus, Candida albicans, Candida krusei and Candida tropicalis. METHODS: The study was performed aiming to assess the antimicrobial effect with the method of dilution in HIA. The hexane and ethyl acetate fractions were named HFPC and EAFPC, respectively. RESULTS: Both fractions of specie P. calomelanos displayed good activity against S. aureus when associated with gentamicin. When associated with the antifungal, the fractions did not exhibit relevant activity against species of Candida. CONCLUSIONS: These results indicate that this specie can be used as a possible source of natural products of antibacterial interest, mainly when combined with aminoglycosides.

Termite usage associated with antibiotic therapy: enhancement of aminoglycoside antibiotic activity by natural products of Nasutitermes corniger (Motschulsky 1855).

BACKGROUND: Several species from Insecta are used as remedies. Among these species, the termite Nasutitermes corniger is commonly used in traditional medicine in Northeast Brazil. The present work tests the modifying antibiotic activity of Nasutitermes corniger, a termite used in folk medicine in Northeastern region of Brazil. METHODS: Chlorpromazine and decocts of N. corniger were collected from two different plant species used in the traditional medicine were tested for their antimicrobial activity against strains of Escherichia coli resistant to aminoglycosides. The growth of two bacterial strains of E. coli was tested using decocts and chlorpromazine alone or associeted with aminogycosides. RESULTS: The MIC and MBC values were > or =1024 microg/ml for both strains of E. coli assayed. A significant synergism was observed between both decocts and chlorpromazine when assyed with neomycin. This synergism with neomycin indicates the involvement of an efflux system in the resistance to this aminoglycoside. CONCLUSION: Therefore it is suggested that natural products from N. corniger could be used as a source of zoo-derived natural products with modifying antibiotic activity to aminoglycosides, being a new weapon against the bacterial resistance to antibiotics.