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Aims@#This study aims to determine the antibacterial potential and identify the bioactive compounds of Hypoxylon monticulosum isolated from marine macroalgae Ulva lactuca.@*Methodology and results @#Ulva lactuca was collected from the Desaru coast, Johor, Malaysia and three endophytes were isolated following surface sterilisation. One fungal isolate was further characterised by the morphology of white, yellowish colonies and fibrous with a waxy structure indicative of a member from the genus Hypoxylon. Molecular identification through internal transcribed spacer (ITS) sequence analysis matches the reference sequence with more than ≥98% homology to Hypoxylon monticulosum AS26-D8. Minimum inhibition concentration (MIC) of the fungal ethyl acetate (EA) extract was determined against five human pathogenic bacteria. Wide spectrum antibacterial activity was noted; with MIC against Escherichia coli was 1.25 ± 0 mg/mL, Bacillus subtilis and Enterobacter faecalis both at 5.00 ± 0 mg/mL, and finally, both Staphylococcus aureus and Klebsiella pneumoniae were 10.00 ± 0 mg/mL, respectively. Bioassay-guided fractionation was performed using solvents of increasing polarities, producing three fractions and analysis by liquid chromatography-mass spectrometry (LC/MS) identified 128 compounds. From these, nine compounds were identified as having biological activities. Dihydrocordoin, D-pantothenoyl-L-cysteine, caffeine and Tumonoic A acid were among the compounds identified as having antibacterial properties.@*Conclusion, significance and impact of study@#Hypoxylon monticulosum from marine source has antibacterial potential owing to the compounds previously reported to display antibacterial and other biological properties. The compounds differ from those previously reported in H. monticulosum from terrestrial sources.
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Medicinal plants constitute an arsenal of products with different potentials to be explored. Therefore, the objective of this paper was to assess the antimicrobial potential of the ethanolic extract from Brosimum gaudichaudii leaves and fractions against clinically important bacteria. The crude extracts and fractions from the leaves and stem bark were used against Escherichia coli, Klesbsiella pneumoniae, Pseudomonas aeruginosa and Staphylococcus aureus strains. The crude extracts and the fractions were obtained by means of maceration in ethanol and chemically characterized. In the results of the phytochemical screening, the presence of a variety of secondary metabolites was verified, such as flavonoids, steroids, saponins, alkaloids, tannins and coumarins. The extracts and their fractions showed inhibitory activity for all three bacteria tested. The inhibition halo varied from 8±0.00 to 14±0.00 mm fir K. pneumoniae, from 8±0.00 to 10±0.00 mm for P. aeruginosa and from 8±0.00 to 9±0.00 mm for S. aureus. Among the fractions tested, the ethyl acetate fraction from both the stem and the leaves presented the best inhibition potential. This indicates that the Brosimum gaudichaudii Trécul vegetable extracts present antimicrobial potential. Such being the case, it is suggested to isolate the metabolites present in this fraction to delimit the main compounds responsible for the antimicrobial action.
As plantas medicinais constituem um arsenal de produtos com diferentes potenciais a serem explorados. Portanto, o objetivo deste trabalho foi avaliar o potencial antimicrobiano do extrato etanólico das folhas e frações de Brosimum gaudichaudii contra bactérias de importância clínica. Os extratos brutos e as frações das folhas e da casca do caule foram usados contra cepas de Escherichia coli, Klesbsiella pneumoniae, Pseudomonas aeruginosa e Staphylococcus aureus. Os extratos brutos e as frações foram obtidos por meio de maceração em etanol e caracterizados quimicamente. Nos resultados da triagem fitoquímica, foi verificada a presença de uma variedade de metabólitos secundários, como flavonoides, esteroides, saponinas, alcaloides, taninos e cumarinas. Os extratos e suas frações apresentaram atividade inibitória para todas as três bactérias testadas. O halo de inibição variou de 8±0,00 a 14±0,00 mm para K. pneumoniae, de 8±0,00 a 10±0,00 mm para P. aeruginosa e de 8±0,00 a 9±0,00 mm para S. aureus. Entre as frações testadas, a fração de acetato de etila do caule e das folhas apresentou o melhor potencial de inibição. Isso indica que os extratos vegetais de Brosimum gaudichaudii Trécul apresentam potencial antimicrobiano. Sendo assim, sugere-se o isolamento dos metabólitos presentes nessa fração para delimitar os principais compostos responsáveis pela ação antimicrobiana.
Las plantas medicinales constituyen un arsenal de productos con diferentes potenciales por explorar. Por lo tanto, el objetivo de este estudio fue evaluar el potencial antimicrobiano del extracto etanólico de hojas de Brosimum gaudichaudii y fracciones contra bacterias clínicamente importantes. Los extractos crudos y las fracciones de las hojas y la corteza del tallo se utilizaron contra cepas de Escherichia coli, Klesbsiella pneumoniae, Pseudomonas aeruginosa y Staphylococcus aureus. Los extractos crudos y las fracciones se obtuvieron por maceración en etanol y se caracterizaron químicamente. Los resultados del cribado fitoquímico verificaron la presencia de diversos metabolitos secundarios, como flavonoides, esteroides, saponinas, alcaloides, taninos y cumarinas. Los extractos y sus fracciones presentaron actividad inhibitoria para las tres bacterias ensayadas. El halo de inhibición varió de 8±0,00 a 14±0,00 mm para K. pneumoniae, de 8±0,00 a 10±0,00 mm para P. aeruginosa y de 8±0,00 a 9±0,00 mm para S. aureus. Entre las fracciones probadas, la fracción de acetato de etilo del tallo y las hojas mostró el mejor potencial de inhibición. Esto indica que los extractos vegetales de Brosimum gaudichaudii Trécul tienen potencial antimicrobiano. Así, se sugiere el aislamiento de los metabolitos presentes en esta fracción para determinar los principales compuestos responsables de la acción antimicrobiana.
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The medical world is on an immense requirement to discover novel antibiotics due to widespread emergence of resistance among microbial pathogens against currently available antibiotics. Traditional plants have been proved to be better source in the search for novel antimicrobial compounds. In such effort, we accessed the susceptibilities of some clinically significant bacterial species against various extracts made up from leaves of Ocimum sanctum L. (family: Lamiaceae). Antibacterial activity of crude extracts was found to be reliant on the nature of extract and the bacterial strains evaluated. Methanol extract was found to have comparatively higher activity than other organic and aqueous extracts. Grampositive bacteria showed variable susceptibilities while Gram-negative Salmonella typhi has shown to be completely resistance to all the tested extracts. Minimum inhibitory concentration data showed hopeful results as some of the extracts exhibited significant inhibitions of bacteria even at low concentrations. This study indicated that leaves of Ocimum sanctum L. have significant antibacterial activity and it could be very useful in the discovery of novel antibacterial/antimicrobial agents.
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A comparative in vitro antibacterial potential of extracts (aqueous and ethanol) of five important medicinal plants (Aegle marmelos, Azadirachta indica, Terminalia chebula, Mangifera indica and Ocimum sanctum) were investigated using microbial growth inhibition assays against the common human pathogenic bacteria (Staphylococcus aureus, Pseudomonas aeruginosa and Escherichia coli) of clinical origin. All the plant materials showed varying degrees of strain specific inhibitory action and ethanol extract of the plant materials showed higher antibacterial activity than their aqueous counterparts. Besides, T. chebula and A. marmelos had the strongest antibacterial activity out of which, T. chebula possessed a wider spectrum and a superior antibacterial potential over the others. The bioactive compounds of T. chebula might have potential as therapeutic agents for the treatment of common bacterial infections.