Background: Vancomycin, an antibiotic with activity against methicillin-resistant Staphylococcus aureus (MRSA), is frequently included in empiric treatment for community-acquired pneumonia (CAP) despite the fact that MRSA is rarely implicated in CAP. Conducting polymerase chain reaction (PCR) testing on nasal swabs to identify the presence of MRSA colonization has been proposed as an antimicrobial stewardship intervention to reduce the use of vancomycin. Observational studies have shown reductions in vancomycin use after implementation of MRSA colonization testing, and this approach has been adopted by CAP guidelines.
View Article and Find Full Text PDFA key strategy to mitigate postprandial hyperglycemia involves inhibiting α-amylases, which commence the starch digestion process in the gut. This study examined the inhibitory effects of resveratrol and stilbenoid tetramers, vaticanol B, (-)-hopeaphenol, and vatalbinoside A on human salivary and pancreatic α-amylases experimentally and through molecular docking studies. Vaticanol B demonstrated the most potent inhibition with IC values of 5.
View Article and Find Full Text PDFDespite effective combination antiretroviral therapy (cART), people living with HIV (PLWH) continue to harbor replication-competent and transcriptionally active virus in infected cells, which in turn can lead to ongoing viral antigen production, chronic inflammation, and increased risk of age-related comorbidities. To identify new agents that may inhibit postintegration HIV beyond cART, we screened a library of 512 pure compounds derived from natural products and identified (-)-hopeaphenol as an inhibitor of HIV postintegration transcription at low to submicromolar concentrations without cytotoxicity. Using a combination of global RNA sequencing, plasmid-based reporter assays, and enzyme activity studies, we document that hopeaphenol inhibits protein kinase C (PKC)- and downstream NF-κB-dependent HIV transcription as well as a subset of PKC-dependent T-cell activation markers, including interleukin-2 (IL-2) cytokine and CD25 and HLA-DRB1 RNA production.
View Article and Find Full Text PDFThe COVID-19 pandemic has highlighted the significance of every role within the interdisciplinary team and has exacerbated the challenges posed to every member. From the nursing perspective, many of these challenges were present before the pandemic but have become significantly larger problems that continue to demand global attention. This has provided an opportunity to critically evaluate and learn from the challenges the pandemic has both highlighted and created.
View Article and Find Full Text PDFAntivirals are urgently needed to combat the global SARS-CoV-2/COVID-19 pandemic, supplement existing vaccine efforts, and target emerging SARS-CoV-2 variants of concern. Small molecules that interfere with binding of the viral spike receptor binding domain (RBD) to the host angiotensin-converting enzyme II (ACE2) receptor may be effective inhibitors of SARS-CoV-2 cell entry. Here, we screened 512 pure compounds derived from natural products using a high-throughput RBD/ACE2 binding assay and identified (-)-hopeaphenol, a resveratrol tetramer, in addition to vatalbinoside A and vaticanol B, as potent and selective inhibitors of RBD/ACE2 binding and viral entry.
View Article and Find Full Text PDFDue to the widespread occurrence and spread of anthelmintic resistance, there is a need to develop new drugs against resistant parasitic nematodes of livestock animals. The Nobel Prize-winning discovery and development of the anti-parasitic drugs avermectin and artemisinin has renewed the interest in exploring natural products as anthelmintics. In the present study, we screened 7500 plant extracts for in vitro-activity against the barber's pole worm, Haemonchus contortus, a highly significant pathogen of ruminants.
View Article and Find Full Text PDFTwo prenylated benzophenones, guttiferones O (1) and P (2), were isolated from the stem bark of the Papua New Guinean plant Garcina solomonensis. The structures of these compounds and their relative configurations were determined by spectroscopic methods. Both compounds inhibited the phosphorylation of the synthetic biotinylated peptide substrate KKLNRTLSVA by the serine/threonine protein kinase MAPKAPK-2 with IC(50) values of 22.
View Article and Find Full Text PDFBioassay-guided fractionation of an organic extract from the leaves of Cupaniopsis macropetala resulted in the isolation of a new alkaloid, galloyl tyramine ( 1), together with the known flavonoid glycoside quercitrin ( 2). The structure of 1 was determined following 1D and 2D NMR, IR, UV, and MS data analysis. Compounds 1 and 2 displayed IC 50 values of 161 and 25 microM, respectively, in a Pim2 enzyme assay.
View Article and Find Full Text PDFExhaustive hydro-distillation of the leaves of Piper aduncum and fruits of Piper gibbilimbum (Piperaceae) afforded colorless and pale orange colored oils in 0.35 and 0.30 % yields, respectively.
View Article and Find Full Text PDFExhaustive hydro-distillation of the bark, heartwood and fruits of Cryptocarya massoy (Lauraceae) afforded pale yellow-coloured oils in 0.7, 1.2 and 1.
View Article and Find Full Text PDFIn the first chemical investigation of the Papua New Guinean plant Elaeocarpus fuscoides, one new indolizidine alkaloid, elaeocarpenine (1), and three known alkaloids, isoelaeocarpicine (2), isoelaeocarpine (3), and elaeocarpine (4), were isolated from the leaves. Their structures were determined by 1D and 2D NMR spectroscopy. Since treatment of elaeocarpenine (1) with ammonia produced a 1:1 mixture of the diastereomers 3 and 4, we propose that elaeocarpenine (1) is the biogenetic precursor of isoelaeocarpine (3) and elaeocarpine (4).
View Article and Find Full Text PDFThe first phytochemical investigation of the Papua New Guinean plant Elaeocarpus habbemensis resulted in the isolation of two new pyrrolidine alkaloids, habbemines A (2) and B (3), as a 1:1 mixture of inseparable diastereomers. The structures of these compounds and their relative configurations were determined by spectroscopic means. An equimolar mixture of habbemines A and B showed human delta-opioid receptor binding affinity with an IC50 of 32.
View Article and Find Full Text PDFAs part of our search for natural products active against the JNK3 kinase, two novel, charged benzylisoquinolines, latifolian A (1) and latifolian B (2), were isolated from the stem bark of the Papua New Guinean vine Gnetum latifolium. The planar structures were determined through detailed 2D NMR analysis. The relative configurations were assigned after examination of the ROESY data and through detailed molecular modeling studies.
View Article and Find Full Text PDFPhytochemistry
August 2001
A new cytotoxic 1,7-dioxa-dispiro[5.1.5.
View Article and Find Full Text PDFEight new tirucallane-type triterpenes, dyvariabilins A-H (1-8), three known tirucallanes, niloticin (9), dihydroniloticin (10), and tirucalla-7,24-diene-3 beta,23-diol (11), and two known sesquiterpenes, 1-(1-hydroxy-2-methylpropyl)-3a-methyl-7-methyleneoctahydroinden-4-ol and (+)-aphanamol I, were isolated from the stem bark of Dysoxylum variabile. Tirucallanes 1 and 11 with an allylic hydroxy group in the side chain and dyvariabilin C (3) with an alpha-epoxy group at positions 7 and 8 showed high instability in acidic medium and formed five hitherto unknown semisynthetic tirucallanes. Dyvariabilins B (2) and C (3) as well as the mixtures of dyvariabilins E and F (5 and 6) and dyvariabilins G and H (7 and 8) showed weak cytotoxicity against KB cells.
View Article and Find Full Text PDFFive new prenylated tricyclic and three new bicyclic acylphloroglucinol derivatives have been isolated by bioactivity-guided fractionation of the petroleum ether extract of the dried aerial parts of Hypericum papuanum. The tricyclic compounds (1--5) were named papuaforins A--E. The bicyclic compounds were isolated together with their corresponding tautomers and were named hyperguinones A and B (6/6a,7/7a) and hyperpapuanone (8/8a), respectively.
View Article and Find Full Text PDFThree new coumarin derivatives, compounds 1-3, three new furanocoumarins, compounds 4-6, and a novel dioxocane derivative, compound 7, were isolated from the fern Cyclosorus interruptus (Willd.) H. Itô.
View Article and Find Full Text PDFBioactivity-guided fractionation of the petroleum ether extract of the aerial parts of Hypericum papuanum led to the isolation of five new tricyclic phloroglucinol derivatives. On the basis of extensive 1D and 2D NMR experiments as well as MS studies, their structures were elucidated as the C-3 epimers of 8-hydroxy-4,4, 7-trimethyl-9-(2-methylpropionyl)-3-(1-methylvinyl)-5beta -H-tricyclo[ 5.3.
View Article and Find Full Text PDFFrom the leaves of Stenochlaena palustris five new O-acylated flavonol glycosides, stenopalustrosides A-E (1-5), have been isolated along with five known compounds, kaempferol 3-O-(3' '-O-E-p-coumaroyl)-(6' '-O-E-feruloyl)-beta-D-glucopyranoside (6), kaempferol 3-O-(3' ',6' '-di-O-E-p-coumaroyl)-beta-D-glucopyranoside (7), kaempferol 3-O-(3' '-O-E-p-coumaroyl)-beta-D-glucopyranoside (8), kaempferol 3-O-(6' '-O-E-p-coumaroyl)-beta-D-glucopyranoside (9); and kaempferol 3-O-beta-D-glucopyranoside (10). The structures of the isolates were elucidated by spectroscopic methods, mainly 1D and 2D NMR. Compounds 1-4 showed significant antibacterial activities against Gram-positive strains.
View Article and Find Full Text PDFFractionation of the petroleum ether extract from the leaves of Piper gibbilimbum collected in Papua New Guinea afforded four new alkenylphenols, gibbilimbols A-D (1-4). The structures of the isolates were elucidated by spectroscopic methods, mainly 1D- and 2D-NMR spectroscopy. Gibbilimbols A-D were found to be toxic to brine shrimp with an LC50 of approximately 5 microg/mL.
View Article and Find Full Text PDFTwo new dammarane triterpenoids, trans-securinegin [(20S)-24-methylidenedammarane-3alpha-yl(2E)-3-(4-hydroxyphenyl)-2-propenate (1)] and cis-securinegin [(20S)-24-methylidenedammarane-3alpha-yl(2Z)-3-(4-hydroxyphenyl)-2-propenate (2)], were isolated from the leaves of Securinega melanthesoides, along with the known compound bergenin. The structures of 1 and 2 were elucidated using spectroscopic methods, mainly 2D NMR techniques.
View Article and Find Full Text PDFJ Ethnopharmacol
December 1995
Based on ethnopharmacological literature, 17 species of medicinal plants used in the traditional medicine in Papua New Guinea were collected. Extracts of different polarities were tested in a preliminary biological screening for their antimicrobial (Escherichia coli, Bacillus subtilis, Micrococcus luteus and Penicillium oxalicum) and molluscicidal activity against Biomphalaria glabrata as well as for their toxicity to brine shrimp. The pretreated plant extracts were also investigated for their ability to inhibit protein kinase C and tyrosine-specific protein kinase of epidermal growth factor receptor.
View Article and Find Full Text PDFPhytochemistry
December 1995
Two new oleanene-type triterpenoids, dillenic acids D and E, have been isolated from the leaves and stems of Dillenia papuana together with the new natural product 3-oxoolean-12-en-30-oic acid. Together with these compounds, the known compound, betulinic acid (3 beta-hydroxy-20(29)-lupen-28-oic acid) was isolated as the major component of the fractions studied. Dillenic acids D and E were characterized as 2,3-seco-2-oxoolean-12-en-3-methylester-30-oic acid and 1 alpha,3 beta-dihydroxyolean-12-en-30-oic acid and their nuclear magnetic resonance data were unambiguously assigned using two-dimensional nuclear magnetic resonance techniques.
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