Band-selective NMR experiments for suppression of unwanted signals in complex mixtures.

Band-selective NMR experiments are presented that allow selective suppression of unwanted signals (SUN) from the spectra of complex metabolite mixtures. As a result, spectral overlap and dynamic range problems are substantially reduced and low-intensity signals normally covered by dominant signals can be observed. The usefulness of the experiments is exemplified with selective suppression of sugar signals from the NMR spectra of fruit juice and a plant sample.

Profiling and activity screening of Dammarane-type triterpen saponins from Gynostemma pentaphyllum with glucose-dependent insulin secretory activity.

The global prevalence of type 2 diabetes is increasing rapidly; consequently there is great need for new and novel therapeutic options. Gynostemma pentaphyllum (GP) is a traditional medicinal plant, mainly present in Southeast Asian countries, that has been reported to exert antidiabetic effects, by stimulating insulin secretion. The specific compound responsible for this effect is however as yet unidentified.

Extract Exerts an Anti-Diabetic Effect by Improving Insulin Release in Type 2 Diabetic Goto-Kakizaki Rats.

() is a legume part of Bolivian traditional diet that has a nutraceutical property reducing blood glucose levels. The prevalence of type 2 diabetes is increasing worldwide thus; the search for novel anti-diabetic drugs is needed. Based on its traditional use, we evaluated the anti-diabetic effect of in the spontaneously diabetic Goto-Kakizaki (GK) rat, a model of type 2 diabetes and in Wistar (W) rats as healthy control.

Amaranthus caudatus Stimulates Insulin Secretion in Goto-Kakizaki Rats, a Model of Diabetes Mellitus Type 2.

Diabetes Mellitus Type 2 prevalence is increasing worldwide; thus efforts to develop novel therapeutic strategies are required. () is a pseudo-cereal with reported anti-diabetic effects that is usually consumed in food preparations in Bolivia. This study evaluated the anti-diabetic nutraceutical property of an hydroethanolic extract that contains mainly sugars and traces of polyphenols and amino acids (as shown by nalysis with liquid chromatography-mass spectrometry (LC-MS) and nuclear magnetic resonance (NMR)), in type 2 diabetic Goto-Kakizaki (GK) rats and healthy Wistar (W) rats.

NMR study of the O-specific polysaccharide and the core oligosaccharide from the lipopolysaccharide produced by Plesiomonas shigelloides O24:H8 (strain CNCTC 92/89).

The structures of the O-specific polysacccharide and core oligosaccharide of the lipopolysaccharide from Plesiomonas shigelloides O24:H8, strain CNCTC 92/89, have been investigated by NMR spectroscopy and ESI mass spectrometry. The O-specific polysaccharide was found to be composed of a tetrasaccharide repeating unit consisting of [→3)-α-FucpNAc-(1→3)-α-GalpNAcA-(1→3)-α-QuipNAc-(1→] and of α-RhapNAc (1→4) linked to the GalpNAcA residue. An identical structure has been reported for the capsular polysaccharide of the clinical isolate of Vibrio vulnificus strain BO62316 [1].

Comparative characterization of two marine alginate lyases from Zobellia galactanivorans reveals distinct modes of action and exquisite adaptation to their natural substrate.

Cell walls of brown algae are complex supramolecular assemblies containing various original, sulfated, and carboxylated polysaccharides. Among these, the major marine polysaccharide component, alginate, represents an important biomass that is successfully turned over by the heterotrophic marine bacteria. In the marine flavobacterium Zobellia galactanivorans, the catabolism and uptake of alginate are encoded by operon structures that resemble the typical Bacteroidetes polysaccharide utilization locus.

Substrate specificity of the recombinant alginate lyase from the marine bacteria Pseudomonas alginovora.

The gene coding for an alginate lyase from the marine bacteria Pseudomonas alginovora X017 was cloned and heterologously expressed in Escherichia coli strains. The protein was produced in inclusion bodies and the active form was obtained by applying a refolding protocol based upon dilution. The biochemical characterization was performed on the active, refolded form of the alginate lyase.

NMR study on hydroxy protons of κ- and κ/μ-hybrid carrageenan oligosaccharides: experimental evidence of hydrogen bonding and chemical exchange interactions in κ/μ oligosaccharides.

The hydroxy protons of κ- and κ/μ-hybrid carrageenan oligosaccharides have been studied by NMR spectroscopy in 85% H(2)O/15% acetone-d(6). Hydration and hydrogen bonding interactions in di- (κ), tetra- (κκ), hexa (κκκ), and octa- (κκκκ) κ-oligosaccharides and hexa- (κμκ), octa- (κμμκ), and deca- (κμμμκ) κ/μ-oligosaccharides have been investigated by measuring the chemical shifts, temperature coefficients, and chemical exchange of the hydroxy protons. These NMR parameters indicate that no strong and persistent intramolecular hydrogen bonds involving hydroxy protons stabilize the structure of κ-carrageenan oligosaccharides in aqueous solution.