On the basis of spectroscopic investigations (1H-NMR, 13C-NMR, UV, IR and MS spectroscopy), elemental analysis and degradation reactions the structure of a new alkaloid discarine G from the bark extract of Discaria febrifuga Mart. is elucidated.

Effects of peripheral venous injection of glucagon and insulin on [l-13C]glucose incorporation into hepatic glycogen of rats were studied by 13C NMR in vivo. Each animal was given a continuous somatostatin infusion and a 100-mg intravenqus injection of [1-13C] glucose in NMR experiments or unlabeled glucose in parallel experiments for determination of serum glucose. Insulin administration cause...

A previous 13C NMR technique (Malloy, C. R., Sherry, A.D., and Jeffrey, F.M.H. (1987) FEBS Lett. 212, 58-62) for measuring the relative flux of molecules through the oxidative versus anaplerotic pathways involving the citric acid cycle of the rat heart has been extended to include a complete analysis of the entire glutamate 13C spectrum. Although still simple in practice, this more sophisticate...

A technique for obtaining dipolar-mediated INADEQUATE NMR spectra with a large spectral window in the double-quantum dimension is presented. Using the dipolar recoupling sequence C7 to excite the double-quantum coherence under magic-angle spinning, the technique involves incrementing the evolution period in synchrony with the phase of the radiofrequency pulses in the C7 sequence. The technique ...

Novel 1D and multidimensional solid-state NMR (SSNMR) methods using very fast magic-angle spinning (VFMAS) (spinning speed > 20 kHz) for performing 13C high-resolution SSNMR of paramagnetic organometallic complexes are discussed. VFMAS removes a majority of 13C-1H and 1H-1H dipolar couplings, which are often difficult to remove by RF pulse techniques in paramagnetic complexes because of large p...

Two different formulations of cyclodextrin nanosponges (CDNS), obtained by polycondensation of β-cyclodextrin with ethylenediaminetetraacetic acid dianhydride (EDTAn), were treated with aqueous solutions of ibuprofen sodium salt (IbuNa) affording hydrogels that, after lyophilisation, gave two solid CDNS-drug formulations. 1H fast MAS NMR and 13C CP-MAS NMR spectra showed that IbuNa was converte...

The online version of the SpecInfo system consists of a factual database with spectroscopic information and a set of special tools for the spectral data analysis and interpretation. It has been designed to support experts in laboratories in their analytical work. The database contains high-quality spectral data of various types, experimental conditions, chemical substance information including ...

A new glutarimide antibiotic named actiketal was isolated from the culture fluid of the epiderstatin-producing streptomycete, Streptomyces pulveraceus subsp. epiderstagenes. The IC50 of the antibiotic for inhibition of the incorporation of [3H]thymidine into epidermal growth factor-stimulated Balb/MK cells was 14.5 microM. The structure of this compound was determined by 1H and 13C NMR spectros...

High-resolution, solid-state 13C NMR spectra have been obtained for unsonicated multilamellar dispersions of 1,2-dilauryl-sn-glycero-3-phosphocholine (DLPC), recombinant membranes containing DLPC and rhodopsin, and native retinal rod disk membranes. The roles of 1H dipolar decoupling, 1H-13C cross-polarization, and magic-angle sample spinning have been investigated. Rotating-frame 13C relaxatio...