Neopyrrolomycins with broad spectrum antibacterial activity.

Three new antibiotics, neopyrrolomycins B (1), C (2), and D (3), with potent activity against Gram-positive pathogens were discovered. They exhibited MIC values < 1 microg/mL versus a number of resistant strains. The compounds were obtained from the ethyl acetate extracts of a Streptomyces sp. after purification by column chromatography and RP-HPLC. Their structures were elucidated using X-ray crystallography (1) and NMR spectroscopy (2 and 3).

Comparison of Neisseria gonorrhoeae minimum inhibitory concentrations obtained using agar dilution versus microbroth dilution methods.

With increasing antibiotic resistance observed amongst clinical isolates of Neisseria gonorrhoeae, the second most prevalent sexually transmitted bacterial disease in the United States, there is still a need for antimicrobial susceptibility testing (AST). The current method recommended by the Clinical and Laboratory Standards Institute is agar dilution. In this study, we show that a commercially available version of Fastidious Broth is capable of supporting N. gonorrhoeae in the evaluation of minimum inhibitory concentrations of 4 antibiotics (ceftriaxone, azithromycin, ciprofloxacin, and tetracycline), when comparing the agar dilution (AD) versus microbroth dilution (MBD) method and the susceptibilities obtained for 32 N. gonorrhoeae isolates. Herein, 3 out of the 4 antibiotics tested showed 94% or greater essential agreement (EA) and 91% or greater categorical agreement (CA) respectively, when comparing the MBD versus AD methods.

Citreamicins with potent gram-positive activity.

Two new xanthone antibiotics, citreamicin delta (1) and epsilon (2), with potent activity against Gram-positive pathogens including multidrug-resistant Staphylococcus aureus (MDRSA) were discovered. Compounds 1 and 2 exhibited MIC values < 1 microg/mL versus a number of resistant strains. The compounds were obtained from EtOAc extracts of Streptomyces vinaceus and were purified by countercurrent chromatography and reversed-phase HPLC. Their structures were elucidated using primarily NMR and mass spectroscopy.

Mutactimycin E, a new anthracycline antibiotic with gram-positive activity.

Resistance to currently available antibiotics has become a widely recognized crisis in the medical community. To address this, many companies and researchers are refocusing their attention towards natural products, which have an excellent track record of producing effective antibacterial drugs. The AMRI natural product library was screened for activity against multi-drug resistant Staphylococcus aureus (MDRSA). The active samples were counter screened for cytotoxicity against the human hepatocellular carcinoma HepG2 cell line to determine an in vitro therapeutic index (in vitro TI). Those samples with a high in vitro TI were selected for fractionation and dereplication. This led to the discovery of a new anthracycline structure. This metabolite, named mutactimycin E (1), exhibited moderate activity against several gram positive organisms. Here we report the isolation, structure elucidation and biological activities of this new compound.

Synthesis and Biological Evaluation of N-((1-(4-(Sulfonyl)piperazin-1-yl)cycloalkyl)methyl)benzamide Inhibitors of Glycine Transporter-1.

We previously disclosed the discovery of rationally designed N-((1-(4-(propylsulfonyl)piperazin-1-yl)cycloalkyl)methyl)benzamide inhibitors of glycine transporter-1 (GlyT-1), represented by analogues 10 and 11. We describe herein further structure-activity relationship exploration of this series via an optimization strategy that primarily focused on the sulfonamide and benzamide appendages of the scaffold. These efforts led to the identification of advanced leads possessing a desirable balance of excellent in vitro GlyT-1 potency and selectivity, favorable ADME and in vitro pharmacological profiles, and suitable pharmacokinetic and safety characteristics. Representative analogue (+)-67 exhibited robust in vivo activity in the cerebral spinal fluid glycine biomarker model in both rodents and nonhuman primates. Furthermore, rodent microdialysis experiments also demonstrated that oral administration of (+)-67 significantly elevated extracellular glycine levels within the medial prefrontal cortex (mPFC).

Development of a high-throughput cell-based assay for identification of IL-17 inhibitors.

Human interleukin 17 (IL-17) is a proinflammatory cytokine derived mainly from activated T cells. Extensive evidence points to a significant role of IL-17 in many autoimmune and infectious diseases, as well as tumorigenesis and transplant rejection, and suggests that targeting IL-17 could be a promising therapeutic strategy. Robust cell-based assays would thus be essential for lead identification and the optimization of therapeutic candidates. Herein, we report a well-characterized two-step assay, consisting of (a) in vitro activation and stimulation of CD4(+) T lymphocytes by a defined complex of antibodies and cytokines, leading to T helper 17 (Th17) cell differentiation and IL-17 production, and (b) IL-17 quantification in cell supernatants using a homogeneous time-resolved fluorescence (HTRF) assay. The system was optimized for and shown to be reliable in high-throughput compatible 96- and 384-well plate formats. The assay is robust (Z' > 0.5) and simple to perform, yields a stable response, and allows for sufficient discrimination of positive (IL-17-producing cells) and negative controls (uninduced cells). The assay was validated by performing dose-response testing of rapamycin and cyclosporine A, which had previously been reported to inhibit IL-17, and determining, for the first time, their in vitro potencies (IC(50)s of 80 ± 23 pM and 223 ± 52 nM, respectively). Also, IKK 16, a selective small-molecule inhibitor of IκB kinase, was found to inhibit IL-17 production, with an IC(50) of 315 ± 79 nM.