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Find video protocols related to scientific articles indexed in Pubmed.
A new plant-derived antibacterial is an inhibitor of efflux pumps in Staphylococcus aureus.
Int. J. Antimicrob. Agents
PUBLISHED: 07-12-2013
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An in-depth evaluation was undertaken of a new antibacterial natural product (1) recently isolated and characterised from the plant Hypericum olympicum L. cf. uniflorum. Minimum inhibitory concentrations (MICs) were determined for a panel of bacteria, including: meticillin-resistant and -susceptible strains of Staphylococcus aureus, Staphylococcus epidermidis and Staphylococcus haemolyticus; vancomycin-resistant and -susceptible Enterococcus faecalis and Enterococcus faecium; penicillin-resistant and -susceptible Streptococcus pneumoniae; group A streptococci (Streptococcus pyogenes); and Clostridium difficile. MICs were 2-8mg/L for most staphylococci and all enterococci, but were ?16mg/L for S. haemolyticus and were >32mg/L for all species in the presence of blood. Compound 1 was also tested against Gram-negative bacteria, including Escherichia coli, Pseudomonas aeruginosa and Salmonella enterica serovar Typhimurium but was inactive. The MIC for Mycobacterium bovis BCG was 60mg/L, and compound 1 inhibited the ATP-dependent Mycobacterium tuberculosis MurE ligase [50% inhibitory concentration (IC50)=75?M]. In a radiometric accumulation assay with a strain of S. aureus overexpressing the NorA multidrug efflux pump, the presence of compound 1 increased accumulation of (14)C-enoxacin in a concentration-dependent manner, implying inhibition of efflux. Only moderate cytotoxicity was observed, with IC50 values of 12.5, 10.5 and 8.9?M against human breast, lung and fibroblast cell lines, respectively, highlighting the potential value of this chemotype as a new antibacterial agent and efflux pump inhibitor.
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Antibacterial acylphloroglucinols from Hypericum olympicum.
J. Nat. Prod.
PUBLISHED: 09-07-2011
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New antibacterial acylphloroglucinols (1-5) were isolated and characterized from the aerial parts of the plant Hypericum olympicum L. cf. uniflorum. The structures of these compounds were confirmed by extensive 1D- and 2D-NMR experiments to be 4,6-dihydroxy-2-O-(3?,7?-dimethyl-2?,6?-octadienyl)-1-(2-methylbutanoyl)benzene (1), 4,6-dihydroxy-2-O-(7?-hydroxy-3?,7?-dimethyl-2?,5?-octadienyl)-1-(2-methylbutanoyl)benzene (2), 4,6-dihydroxy-2-O-(6?-hydroxy-3?,7?-dimethyl-2?,7?-octadienyl)-1-(2-methylbutanoyl)benzene (3), 4,6-dihydroxy-2-O-(6?-hydroperoxy-3?,7?-dimethyl-2?,7?-octadienyl)-1-(2-methylbutanoyl)benzene (4), and 4,6-dihydroxy-2-O-(6?,7?-epoxy-3?,7?-dimethyloct-2?-enyl)-1-(2-methylbutanoyl)benzene (5). These new natural products have been given the trivial names olympicins A-E (1-5). All compounds were evaluated against a panel of methicillin-resistant Staph. aureus and multidrug-resistant strains of Staph. aureus. Compound 1 exhibited minimum inhibitory concentrations (MICs) of 0.5-1 mg/L against the tested Staph. aureus strains. Compounds 2 to 5 were also shown to be active, with MICs ranging from 64 to 128 mg/L. Compound 1 was synthesized using a simple four-step method that can be readily utilized to give a number of structural analogues of 1.
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Prenylated benzophenone peroxide derivatives from Hypericum sampsonii.
Chem. Biodivers.
PUBLISHED: 04-17-2010
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Two new prenylated benzophenone peroxide derivatives, peroxysampsones A and B (1 and 2, resp.), together with a known compound, plukenetione C (3), were isolated from the roots of the Chinese medicinal plant Hypericum sampsonii, and their structures were elucidated by detailed spectral analysis. These compounds are the unusual peroxides of polyprenylated benzophenone derivatives, containing the unique caged moiety of 4,5-dioxatetracyclo[9.3.1.1(9,13).0(1,7)]hexadecane-12,14,15-trione. In the biological test, peroxysampsone A (1) showed comparable activity with norfloxacin against a NorA over-expressing multidrug-resistant (MDR) strain of Staphylococcus aureus SA-1199B.
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Dibenzofuran and pyranone metabolites from Hypericum revolutum ssp. revolutum and Hypericum choisianum.
Phytochemistry
PUBLISHED: 02-04-2009
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In a project to isolate and characterise anti-staphylococcal compounds from members of the genus Hypericum, a dibenzofuran and a pyranone were isolated from the dichloromethane and hexane extracts of Hypericum revolutum ssp. revolutum Vahl (Guttiferae) and Hypericum choisianum Wall. ex. N. Robson (Guttiferae), respectively. The structures of these compounds were elucidated by 1- and 2D-NMR spectroscopy and mass spectrometry as 3-hydroxy-1,4,7-trimethoxydibenzofuran (1) and 4-(3-O-3)-3-methylbutenyl-6-phenyl-pyran-2-one (2). The metabolites were evaluated against a panel of multidrug-resistant strains of Staphylococcus aureus. Compound 1 exhibited a minimum inhibitory concentration (MIC) of 256 microg/ml, whereas compound 2 was inactive at a concentration of 512 microg/ml.
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JoVE Visualize is a tool created to match the last 5 years of PubMed publications to methods in JoVE's video library.

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We use abstracts found on PubMed and match them to JoVE videos to create a list of 10 to 30 related methods videos.

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In developing our video relationships, we compare around 5 million PubMed articles to our library of over 4,500 methods videos. In some cases the language used in the PubMed abstracts makes matching that content to a JoVE video difficult. In other cases, there happens not to be any content in our video library that is relevant to the topic of a given abstract. In these cases, our algorithms are trying their best to display videos with relevant content, which can sometimes result in matched videos with only a slight relation.