Bioguided isolation of (9Z)-octadec-9-enoic acid from Phellodendron amurense Rupr. and identification of fatty acids as PTP1B inhibitors.

The therapy of type-2 diabetes mellitus is one of the major challenges of our age. A possible strategy to prevent the progression of this disease is the inhibition of protein tyrosine phosphatase 1B (PTP1B), a major negative regulator in the insulin and leptin signalling pathway. Phellodendri amurensis cortex is a well-known Asian herbal drug traditionally used as antiphlogistic, antibacterial, and anti-inflammatory agent, and its efficacy against diabetes-related symptoms is reported as well.

Recent advances on HPLC/MS in medicinal plant analysis.

With gaining popularity of herbal remedies worldwide, the need of assuring safety and efficacy of these products increases as well. By nature they are complex matrices, comprising a multitude of compounds, which are prone to variation due to environmental factors and manufacturing conditions. Furthermore, many traditional preparations compose of multiple herbs, so that only highly selective, sensitive and versatile analytical techniques will be suitable for quality control purposes.

Bioactivity-guided isolation of 1,2,3,4,6-Penta-O-galloyl-D-glucopyranose from Paeonia lactiflora roots as a PTP1B inhibitor.

The inhibition of protein tyrosine phosphatase 1B (PTP1B) is of substantial interest for the treatment of type-2 diabetes mellitus. Using an in vitro enzyme assay with human recombinant PTP1B 1,2,3,4,6-penta-O-galloyl-D-glucopyranose was isolated from the roots of Paeonia lactiflora as an inhibitor of PTP1B, with an IC(50) value of 4.8 μM.

Flow injection analysis-isotope ratio mass spectrometry for bulk carbon stable isotope analysis of alcoholic beverages.

A new method for bulk carbon isotope ratio determination of water-soluble samples is presented that is based on flow injection analysis-isotope ratio mass spectrometry (FIA-IRMS) using an LC IsoLink interface. Advantages of the method are that (i) only very small amounts of sample are required (2-5 microL of the sample for up to 200 possible injections), (ii) it avoids complex sample preparation procedures such as needed for EA-IRMS analysis (only sample dilution and injection,) and (iii) high throughput due to short analysis times is possible (approximately 15 min for five replicates). The method was first tested and evaluated as a fast screening method with industrially produced ethanol samples, and additionally the applicability was tested by the measurement of 81 alcoholic beverages, for example, whiskey, brandy, vodka, tequila, and others.