Search

Introduction: Polygonum aviculare L. also known as common knotgrass is an annual herbaceous weed occurring all over the world in the temperate regions. Recent studies report that flavonol glucuronides are major constituents of common knotgrass. There is no comprehensive analytical procedure for the standardisation of Polygoni Avicularis Herba available on the European market., Objective: To develop a method for the proper authentication and standardisation of Polygoni Avicularis Herba and to preliminary evaluate variability in qualitative and quantitative composition among commercial samples and samples from wild harvesting defined as Polygonum aviculare sensu lato., Methodology: The UHPLC-ESI(+)-MS method was used for the qualitative screening of nine independent samples of Polygonum aviculare herb. The UHPLC-CAD method was developed for the quantitation of the major compounds in an extract using quercetin-3-O-glucuronide as a standard., Results: Twenty-five major constituents were detected and characterised. Among them three new natural products were tentatively identified. Twelve compounds were quantitated using a validated UHPLC-CAD method. In all nine samples flavonol glucuronides were confirmed as major compounds. The total flavonoid content was estimated for all samples and varied from 0.70 to 2.20%., Conclusion: The developed procedure may be used for the routine standardisation of common knotgrass. The results indicate that the pharmacopoeial approach to the authentication and standardisation of Polygonum aviculare herb should be revised., (Copyright © 2015 John Wiley & Sons, Ltd.)

The present study reports a novel method for the production and purification of analytical standards of glucuronide conjugates of bile acids, chenodeoxycholic (CDCA), lithocholic, (LCA) and hyodeoxycholic (HDCA) acids. CDCA-3G (CDCA-3-glucuronide) and -24G, LCA-3G and -24G, and HDCA-6G and -24G were enzymatically formed by using microsomes from human liver, purified by liquid chromatography, digested with recombinant beta-glucuronidase, and quantified by liquid chromatography/electrospray ionization coupled to mass spectrometry (LC-ESI/MS). The position of the glucuronosyl moiety on the bile acids was determined by analyzing the susceptibility to hydrolysis under elevated pH and temperature conditions of the standards. By using the purified analytical standards, a LC-ESI/MS/MS method was developed for the determination of these glucuronide conjugates in in vitro assays. The linearity of the assay ranged from 0.5 to 40 ng/mL for the six glucuronides, and the limit of quantification (LOQ) was 0.5 ng/mL. Intra- and interday precisions and accuracy values were all lower than 10.2%. Furthermore, processed sample stability analyses revealed that the six standards were stable at 4 degrees C for more than 24 h. This method was successfully used for the quantification of CDCA, LCA, and HDCA glucuronides formed by human liver or hepatoma HepG2 cells. In conclusion, such a method allows the purification of high-quality analytical standards of glucuronide derivatives and may easily be used for the quantification of other endo- and xenobiotics that are glucuronidated.