ARS | Publication request: A profiling method for the identification of glycosylated flavonoids and other phenolic compounds using a standard analytical approach for all plant materials

Submitted to: Meeting Abstract
Publication Type: Abstract Only
Publication Acceptance Date: February 11, 2008
Publication Date: March 26, 2008
Citation: Harnly, J.M., Lin, L. 2008. A profiling method for the identification of glycosylated flavonoids and other phenolic compounds using a standard analytical approach for all plant materials. National Nutrient Databank Conference, May 12-14, 2008, Ottawa, Ontario, Canada, and 5th Annual Natural Health Product Research Society of Canada (NHPRS) Conference, March 26-29, 2008, Toronto, Canada.

Technical Abstract: Objectives: A screening method was developed for the systematic identification of glycosylated flavonoids and other phenolic compounds in plant food materials based on an initial, standard analytical method. Materials and Methods: Samples were frozen, lyophilized, powdered, extracted with methanol-water (60:40, v/v), and analyzed by reverse phase liquid chromatography with tandem diode array and electrospray ionization/mass spectrometric detection (LC-DAD-ESI/MS). The DAD acquired spectra from 200-600 nm and the MS acquired positive and negative spectra with high and low fragmentation energies. Each chromatographic peak was characterized by retention time, full UV/Vis spectrum, and 4 mass spectra. Results: This profiling method applies the same analytical scheme to every sample and standard as an initial protocol. This standardized approach allows the cross comparison of compounds in samples, standards, and plant materials previously identified in the published literature. Thus, every analysis contributes to a growing library of data for retention times and UV/Vis and mass spectra. Without authentic standards, this method provides provisional identification of the phenolic compounds and identification of flavonoid backbones, phenolic acids, saccharides, and alkyls, but not the positions of the linkages between these subgroups. With standards, this method provides positive identification of the full compound and identification of subgroups and linkages. In cases of unidentified compounds, the profiling method can be followed by more extensive analyses if there is sufficient interest. The utility of the screening method has been demonstrated by the identification of 78 phenolic compounds in cranberry, elder flower, Fuji apple peel, navel orange peel, and soybean seed. Significance: The standardized profiling method allows the rapid detection and identification of phenolic compounds in foods. This method will enhance our capability to produce analytical data for food databases.