Quantitative and qualitative investigations of pharmacopoeial plant material polygoni avicularis herba by UHPLC-CAD and UHPLC-ESI-MS methods.

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.