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Antibiotic resistance among gram-negative bacteria continues to rise globally at an alarming rate. New vaccines that prevent bacterial infections and reduce antibiotic use could provide a potential solution to these problems. This study focused on development of an investigational vaccine to prevent recurrent urinary traction infections (UTI) caused by gram-negative bacteria that use type 1 pili to adhere to, invade, and colonize human bladders. The vaccine antigen is FimH, an adhesin protein on the tip of type 1 pili with a lectin binding domain that enables attachment to glycoproteins on mammalian bladders. This was a phase 1, open-label, dose escalation study evaluating the vaccine in 67 healthy women with and without histories of recurrent UTI. The objectives of the study were to evaluate the safety, tolerability, and immunogenicity of different dosages of the antigen and adjuvant of the vaccine. All dosages were well-tolerated and a low incidence of systemic reactions occurred. No serious adverse events related to the vaccine were reported. The vaccine induced both binding and functional antibodies. The women with histories of recurrent UTI demonstrated greater than 150-fold increases in antibodies against the N-terminal region of FimH. Based on the results of this phase 1 study, this vaccine is proceeding to a double-blind, randomized, placebo-controlled phase 2 study. If this vaccine is successful in future studies, it could potentially prevent millions of recurrent UTI globally and reduce the development of antibiotic resistance.

Recurrent urinary tract infections (rUTI) are a serious disease associated with morbidities and mortality. Resistance to the standard of care antibiotics is now widespread because of the continued use of antibiotics among people who suffer from rUTI. We are therefore developing a vaccine to prevent recurrences among patients with rUTI. The antigen of the vaccine is FimH, a bacterial adhesin protein, and the vaccine is adjuvanted with a TLR-4 agonist. In a Phase 1 clinical study evaluating the vaccine, immunized individuals produced FimH-binding antibodies. Here we describe the optimization, qualification, and use of an assay to assess the functionality of these anti-FimH antibodies. The suitability of the assay for its intended purpose was demonstrated by selectivity, specificity, sensitivity, and intra-assay and inter-assay precision. The acceptance criteria were achieved for all parameters including intra-assay precision with ≤10% relative standard deviations and inter-assay precision with ≤25% relative standard deviations. The results presented herein suggest this functional assay will be important for supporting the vaccine's efficacy in future human studies. Furthermore and of great significance, these results prove that vaccine-induced functional antibodies can be elicited in rUTI patients against an essential virulence factor, FimH.

Many human diseases, including cystic fibrosis lung infections, are caused or exacerbated by bacterial biofilms. Specialized modes of motility, including swarming and twitching, allow gram-negative bacteria to spread across surfaces and form biofilms. Compounds that inhibit these motilities could slow the spread of biofilms, thereby allowing antibiotics to work better. We previously demonstrated that a set of plant-derived triterpenes, including oleanolic acid and ursolic acid, inhibit formation of Escherichia coli and Pseudomonas aeruginosa biofilms, and alter expression of genes involved in chemotaxis and motility. In the present study, we have prepared a series of analogs of oleanolic acid. The analogs were evaluated against clinical isolates of E. coli and P. aeruginosa in biofilm formation assays and swarming assays. From these analogs, compound 9 was selected as a lead compound for further development. Compound 9 inhibits E. coli biofilm formation at 4 µg/mL; it also inhibits swarming at ≤1 µg/mL across multiple clinical isolates of P. aeruginosa, E. coli, Burkholderia cepacia, and Salmonella enterica, and at <0.5 µg/mL against multiple agricultural strains. Compound 9 also potentiates the activity of the antibiotics tobramycin and colistin against swarming P. aeruginosa; this is notable, as tobramycin and colistin are inhaled antibiotics commonly used to treat P. aeruginosa lung infections in people with cystic fibrosis. qPCR experiments suggested that 9 alters expression of genes involved in regulating Type IV pili; western blots confirmed that expression of Type IV pili components PilA and PilY1 decreases in P. aeruginosa in the presence of 9., Competing Interests: Declaration of Competing Interest The authors declare the following financial interests/personal relationships which may be considered as potential competing interests: This study was funded by Sequoia Sciences. All authors were employees or contractors of Sequoia Sciences., (Copyright © 2019 Elsevier Ltd. All rights reserved.)

Bifidenone is a novel natural tubulin polymerization inhibitor that exhibits antiproliferative activity against a range of human cancer cell lines, making it an attractive candidate for development. A synthetic route was previously developed to alleviate supply constraints arising from its isolation in microgram quantities from a Gabonese tree. Using that previously published route, we present here 42 analogues that were synthesized to examine the structure-activity relationship of bifidenone derivatives. In addition to in vitro cytotoxicity data, data from murine xenograft and pharmacokinetic studies were used to evaluate the analogues. Compounds 45b and 46b were found to demonstrate promising efficacy in murine xenograft experiments, and 46b had significantly more potent in vitro antiproliferative activity against taxane-resistant cell lines compared to that of paclitaxel.

The first total synthesis of bifidenone, a novel natural tubulin polymerization inhibitor, has been achieved in 12 steps starting from commercially available 1,4-dioxaspiro[4.5]decan-8-one. The synthesis includes a newly developed method to generate the dihydrobenzodioxolone core by palladium-catalyzed aerobic dehydrogenation. The three stereocenters were installed with an AD-mix-β dihydroxylation step followed by a late-stage palladium-catalyzed decarboxylation-allylation procedure. The absolute stereochemistry of 3 was determined via 13a by single-crystal X-ray analysis.

The pursuit of structurally novel compounds has led to the isolation of a series of neolignans (2-6), for which the structures have been determined from microgram quantities using microcryoprobe NMR technology. Compounds 2-6 provided some unexpectedly clear structure-activity relationship data, with compound 2 demonstrating significantly more potency in the in vitro cytotoxicity assay than the other analogues. Further screening found that compound 2 induces apoptosis with activation of caspase 3/7. The NCI Compare algorithm suggested that compound 2 acts through the inhibition of tubulin/microtubule dynamics. Compound 2 was confirmed to be a tubulin polymerization inhibitor that binds directly to tubulin.

The compass plant, Silphium laciniatum, is an iconic perennial plant of the North American tallgrass prairie. The plants of the tallgrass prairie historically have been subjected to a number of biological and environmental stresses. Among the adaptations developed by S. laciniatum is a large deep taproot. An investigation of the secondary metabolites found in the root of a S. laciniatum specimen has led to the identification of 15 new terpenoids (3-8, 10-17, and 22), which were screened for cytotoxic activity in the NCI-H460 human large-cell lung carcinoma cell line.

One new and seven known diterpenes were identified from an antibacterial chromatographic fraction of Taxodium ascendens. Of these, demethylcryptojaponol (2), 6-hydroxysalvinolone (3), hydroxyferruginol (4), and hinokiol (5) demonstrated potent activity against clinical isolates of methicillin-resistant Staphylococcus aureus (MRSA). These compounds represent a class of synthetically accessible compounds that could be further developed for treatment of drug-resistant bacterial infections.

Species extinction is tantamount to loss of chemical diversity, and so it is important to seize all opportunities to study species on the brink of extinction. Such studies are often hampered by the limited material available, but that obstacle is surmountable through collaboration with botanical gardens and advances in instrumentation. The goldenrod Solidago shortii is one example of an endangered species native to the United States. From S. shortii, one known diterpene (1), two new diterpenes (2 and 3), and three new hydrolysis products (4-6) are described. This work was made possible through collaboration with the Missouri Botanical Garden and with the use of highly sensitive microcryoprobe NMR technology for structure elucidation and VCD spectroscopy for the determination of absolute configuration.

Six chromene stilbenoids and one chromane stilbenoid were isolated from the African tree Hymenocardia acida. Several were moderately active against methicillin-resistant Staphylococcus aureus clinical isolate MRSA-108, including hymenocardichromanic acid, which was active at 8 μg/ml. None had IC50 values <20 μM in antiproliferation assays against several human cancer cell lines., (Copyright © 2013 Elsevier Ltd. All rights reserved.)

The first study of the chemical constituents of Combretum inflatum has resulted in the isolation of seven new acetylated dammarane-type bisdesmosides (1-7). Their structures were determined from microgram quantities on hand using Bruker BioSpin TCI 1.7 mm MicroCryoProbe technology, ESIMS, and comparison to data found in the literature. Compounds 1-7 were screened for inhibition of an Escherichia coli strain UTI89 biofilm, MRSA inhibition, and cytotoxicity in NCI-H460 human lung cancer cells. Compounds 3-7 reduced the growth of MRSA at 16 μg/mL by 71-45%, and compound 7 had an IC₅₀ value of 3.9 μM in NCI-H460.

Seven stilbenes and one alkylresorcinol were isolated from the orchid Phragmipedium calurum during a screen for anticancer compounds. They were evaluated for antiproliferative activity against multiple human cancer cell lines, and two displayed moderate activity against several cell lines., (Copyright © 2012 Elsevier Ltd. All rights reserved.)

High-throughput natural products chemistry methods have facilitated the isolation of eight new (1-8) and two known (9 and 10) beilschmiedic acid derivatives from the leaves of a Gabonese species of Beilschmiedia. Compounds 3-10 were isolated in microgram quantities, and the NMR data for structure elucidation and dereplication were acquired utilizing a Bruker BioSpin TCI 1.7 mm MicroCryoProbe. All of the compounds were screened for cytotoxic and antibacterial activity against NCI-H460 human lung cancer cells and a clinical isolate of methicillin-resistant Staphylococcus aureus, respectively. This is the first report of cytotoxic activity for the endiandric/beilschmiedic acid class of compounds.

A phytochemical investigation of Monanthotaxis congoensis afforded eight polyoxygenated cyclohexenes as well as the known crotepoxide. Structures were determined using NMR, MS, and optical rotation analyses. One compound displayed moderate antiproliferative activity against NCI-H460 and M14 cancer cells., (Copyright © 2011 Elsevier Ltd. All rights reserved.)

High-throughput natural product research produced a suite of anticancer hits among several species of the Orchidaceae family (Oncidium microchilum, O. isthmi, and Myrmecophila humboldtii). A commercial Oncidium sp. was also examined as a convenient source of additional material. Isolation and structure elucidation led to the identification of fifteen stilbenoids including a new phenanthraquinone and two new dihydrostilbenes. NMR data for structure elucidation and dereplication were acquired utilizing a Bruker BioSpin TCI 1.7-mm MicroCryoProbe or a 5-μL CapNMR capillary microcoil. Several compounds inhibited proliferation of NCI-H460 and M14 cancer cell lines. All compounds were also examined for their ability to induce apoptosis. Apoptosis induction was determined by measuring caspase 3/7 activation and LDH release in a NCI-H460 cell line. Based on these results, a portion of the extract from a commercially available Oncidium sp. was chemically modified in an attempt to obtain additional phenanthraquinones., (© Georg Thieme Verlag KG Stuttgart · New York.)

One method that bacteria employ to reduce their susceptibility to antibiotics is the formation of biofilms. We developed a robust 6-well plate biofilm assay to evaluate early-stage discovery compounds against methicillin-resistant Staphylococcus aureus (MRSA). Tissue culture-treated 6-well plates were selected for this assay because they facilitate the adherence of MRSA and enable accurate determination of the number of CFU in each well. The MRSA biofilms formed in this assay exhibit increased tolerances to clinically used antibiotics. Using this biofilm assay, we identified a novel potentiator of gentamicin against MRSA biofilms. The combination of gentamicin and pentadecenyl tetrazole is superior to clinically used MRSA antibiotics against these MRSA biofilms. This novel combination also exhibits synergistic effects on MRSA planktonic cells. This plant-derived compound reveals promise for its effectiveness and warrants further lead optimization as an antibiotic and aminoglycoside potentiator.

A high-throughput phytochemical investigation of Abronia villosa afforded a new rotenoid designated abronione (1) along with the known compounds boeravinone C and lupeol. The structure of 1 was determined using NMR, MS, and optical analysis with < 400 µg of material. Compound 1 displayed moderate cytotoxicity against NCI-H460 and HL-60 human cancer cell lines with IC(50) values of 14 and 36 µM, respectively.

High-throughput natural products chemistry methods have led to the isolation of three new (1-3) and two known indole sesquiterpene alkaloids (4, 5) from Greenwayodendron suaveolens. Their structures were determined using CapNMR and MS. Pentacyclindole (1) was determined to possess a new natural product framework. Pentacyclindole (1) and polyalthenol (4) showed activity against clinical isolates of Staphylococcus aureus with polyalthenol (4) demonstrating a MIC(90) of 4 microg/mL.

Bioassay-guided fractionation of the antibacterial ethyl acetate-ethanol (50 : 50) extract obtained from the aerial parts of Penstemon centranthifolius led to the isolation of six phenylethanoid glycosides (1-6) and eleven iridoid glycosides (7-17). Their structures were determined on the basis of spectroscopic analysis and comparison with the literature. Among them, two phenylethanoid glycosides, 4'''-O-acetylverbascoside (1) and verbascoside (2), were found to show significant inhibition of the formation of bacterial biofilms by Escherichia coli UTI89. Compound 1 showed 77% biofilm inhibition at 2.5 microg/mL, and compound 2 showed 60% inhibition at 5 microg/mL., (Copyright (c) 2009 John Wiley & Sons, Ltd.)

Nine clerodane diterpenes, solidagoic acids C-I (1-7), cleroda-3,13(14)-dien-16,15:18,19-diolide (8) and cleroda-3,13(14)-dien-15,16:18,19-diolide (9) were isolated and characterised from the ethanol-ethyl acetate (1:1) extract of Solidago virgaurea. The structures were determined by NMR spectroscopic analysis. Several displayed moderate antibacterial activity against Staphylococcus aureus., (2009 Elsevier Ltd. All rights reserved.)

The emergence and increasing prevalence of bacterial strains that are resistant to available antibiotics demand the discovery of new therapeutic approaches. Targeting bacterial virulence is an alternative approach to antimicrobial therapy that offers promising opportunities to inhibit pathogenesis and its consequences without placing immediate life-or-death pressure on the target bacterium. Certain virulence factors have been shown to be potential targets for drug design and therapeutic intervention, whereas new insights are crucial for exploiting others. Targeting virulence represents a new paradigm to empower the clinician to prevent and treat infectious diseases.

Asiatic acid and corosolic acid are two natural products identified as biofilm inhibitors in a biofilm inhibition assay. We evaluated the activities of these two compounds on Pseudomonas aeruginosa biofilms grown in rotating disk reactors (RDRs) in combination with tobramycin and ciprofloxacin. To determine the ruggedness of our systems, the antibiotic susceptibilities of these biofilms were assessed with tobramycin and ciprofloxacin. The biofilm bacteria produced in the RDR were shown to display remarkable tolerance to 10 mug/ml of ciprofloxacin, thus mimicking the tolerance observed in recalcitrant bacterial infections. These studies further demonstrate that a nonmucoid strain of P. aeruginosa can form a biofilm that tolerates ciprofloxacin at clinically relevant concentrations. Neither asiatic acid nor corosolic acid reduced the viable cell density of P. aeruginosa biofilms. However, both compounds increased the susceptibility of biofilm bacteria to subsequent treatment with tobramycin, suggesting asiatic acid and corosolic acid to be compounds that potentiate the activity of antibiotics. A similar statistical interaction was observed between ciprofloxacin and subsequent treatment with tobramycin.

Five new (1-5) and four known (6-9) C14-oxygenated 1alpha-hydroxy-11(13)-pseudoguaien-6beta,12-olides with potent inhibition of hepatitis C virus (HCV) replication were obtained from Parthenium hispitum via high-throughput natural product chemistry methods. A semipreparative HPLC system was used to purify these compounds. The miniaturization of the structure elucidation and dereplication for the mass-limited samples were performed primarily utilizing a capillary-scale NMR probe. Compounds 2-4 were found to possess in vitro anti-HCV activity in the subgenomic HCV replicon system containing luciferase reporter with significant inhibition above 90% at 2 microM concentration.

Three new (1-3) and five known (4-8) partially acetylated oligorhamnoside derivatives were obtained from Cleistopholis patens via high-throughput natural products chemistry procedures. The rapid structure elucidation and dereplication were performed primarily utilizing a capillary-scale NMR probe and LR-/HRESIMS spectroscopic methods. Compounds 1, 2, and 6 were found to possess significant in vitro antibacterial activity against the Gram-positive bacteria methicillin-resistant Staphylococcus aureus ATCC 33591 and S. aureus 78-13607A with MICs of < or =16 microg/mL. Furthermore, 2 and 6 were found to show significant in vitro antibacterial activity against an expanded panel of Gram-positive pathogens including either ATCC strains or well-characterized clinical isolates from the global SENTRY Antimicrobial Surveillance Program.

One new (1) and four known (2-5) ursene triterpenes with potent inhibition of the formation of the bacterial biofilm Pseudomonas aeruginosa PA01 were obtained from Diospyros dendo using a high-throughput natural products chemistry procedure. These compounds were isolated as mass-limited samples. The miniaturization of the structure elucidation and dereplication was performed primarily utilizing a capillary-scale NMR probe.

After 13,000 samples of compounds purified from plants were screened, a new biofilm inhibitor, ursolic acid, has been discovered and identified. Using both 96-well microtiter plates and a continuous flow chamber with COMSTAT analysis, 10 microg of ursolic acid/ml inhibited Escherichia coli biofilm formation 6- to 20-fold when added upon inoculation and when added to a 24-h biofilm; however, ursolic acid was not toxic to E. coli, Pseudomonas aeruginosa, Vibrio harveyi, and hepatocytes. Similarly, 10 microg of ursolic acid/ml inhibited biofilm formation by >87% for P. aeruginosa in both complex and minimal medium and by 57% for V. harveyi in minimal medium. To investigate the mechanism of this nontoxic inhibition on a global genetic basis, DNA microarrays were used to study the gene expression profiles of E. coli K-12 grown with or without ursolic acid. Ursolic acid at 10 and 30 microg/ml induced significantly (P < 0.05) 32 and 61 genes, respectively, and 19 genes were consistently induced. The consistently induced genes have functions for chemotaxis and mobility (cheA, tap, tar, and motAB), heat shock response (hslSTV and mopAB), and unknown functions (such as b1566 and yrfHI). There were 31 and 17 genes repressed by 10 and 30 microg of ursolic acid/ml, respectively, and 12 genes were consistently repressed that have functions in cysteine synthesis (cysK) and sulfur metabolism (cysD), as well as unknown functions (such as hdeAB and yhaDFG). Ursolic acid inhibited biofilms without interfering with quorum sensing, as shown with the V. harveyi AI-1 and AI-2 reporter systems. As predicted by the differential gene expression, deleting motAB counteracts ursolic acid inhibition (the paralyzed cells no longer become too motile). Based on the differential gene expression, it was also discovered that sulfur metabolism (through cysB) affects biofilm formation (in the absence of ursolic acid).

Two 2,7'-cyclolignans, ocholignans A and B, were obtained as mass-limited samples from Scyphocephalium ochocoa via high-throughput natural products chemistry methods. The rapid structure elucidation of each compound was primarily facilitated by NMR data acquisition using a capillary-scale NMR probe, CapNMR probe. Ocholignan A was found to possess significant in vitro antibacterial activity against Gram-positive bacteria methicillin-resistant Staphylococcus aureus ATCC 33591 and S. aureus 78-13607A with a MIC of 16 microg/mL, respectively.

Employing a capillary-scale NMR probe enables the miniaturisation of structure determination and de-replication of purified natural products from plants using only 5-100 microg of material. Approximately 5 microg are required to perform one-dimensional proton and two-dimensional homonuclear (COSY and NOESY) NMR experiments; some 30 microg are needed to acquire HMQC- or HSQC-NMR spectra; ca. 75-100 microg are necessary to measure HMBC-NMR spectra; and around 200 microg of a compound are needed to perform 13C- and DEPT-NMR experiments. In order to illustrate the integration of the outputs from high-throughput natural product chemistry methods with the capabilities of the state-of-the-art CapNMR technology, the preparation of a natural product library from the extract of Penstemon centranthifolius, and the subsequent isolation, purification and structure determination of six known iridoid glycosides with 25-300 microg of material are presented.

High-throughput isolation, purification and analysis methods applied to natural products libraries from plants gave rise to the discovery of two novel acylated caprylic alcohol glycosides (1, 2) produced by Arctostaphylos pumila. The NMR spectra were acquired using the CapNMR probe and performed on mass-limited samples, which enabled us to elucidate the structures of 2,6-diacetyl-3,4-diisobutyl-1- O-octylglucopyranoside (1, 200 microg) and 2,6-diacetyl-3,4-dimethylbutyl-1- O-octylglucopyranosid (2, 70 microg). Compounds 1 and 2 exhibited antibacterial activity against Gram-positive methicillin-resistant Staphylococcus aureus with an MIC of 128 microg/mL and 64 microg/mL, respectively.

Utilizing high-throughput isolation, purification, and analysis methods applied to a natural products library, a new mass-limited antibacterial indolosesquiterpene, suaveolindole (1), was obtained from Greenwayodendron suaveolens. The miniaturization of the structure elucidation of 1 was performed primarily using the CapNMR probe. Compound 1 was found to possess significant in vitro antibacterial activity against the Gram-positive bacteria Bacillus subtilis (ATCC 43223), Staphylococcus aureus (ATTC 6538P), and methicillin-resistant Staphylococcus aureus (ATTC 33591), with MIC values of 4, 8, and 8 microg/mL, respectively.

High-throughput methods were applied to the production, analysis, and characterization of libraries of natural products in order to accelerate the drug discovery process for high-throughput screening in the pharmaceutical and biotechnology industries. Library production integrates automated flash chromatography, solid-phase extraction, filtration, and high-throughput parallel four-channel preparative high-performance liquid chromatography to obtain the libraries in 96- or 384-well plates. Libraries consist of purified fractions with approximately one to five compounds per well. Libraries are analyzed prior to biological screening by a high-throughput parallel eight-channel liquid chromatography-evaporative light scattering detection-mass spectrometry system to determine the molecular weight, number, and quantity of compounds in a fraction. After biological screening, active fractions are rapidly purified at the microgram level and individual compounds are rescreened for confirmation of activity. Structures of active compounds are elucidated by NMR spectroscopy and mass spectrometry. Utilization of a novel microcoil probe allows NMR data to be gathered on 50 microg. As a demonstration, a library was made from the stem bark of Taxus brevifolia. Biological screening in the National Cancer Institute's in vitro panel of three cancer cell lines demonstrates that the process enables the discovery of active anticancer compounds not detected in the flash fractions from which the library originates.