Detailed Phenolic Characterization of Protea Pure and Hybrid Cultivars by Liquid Chromatography–Ion Mobility–High Resolution Mass Spectrometry (LC-IM-HR-MS)

• Published in: Journal of agricultural and food chemistry Vol. 68; no. 2; pp. 485 - 502
• Main Authors: Masike, Keabetswe, de Villiers, André, Hoffman, Eleanor W, Brand, D. Jacobus, Causon, Tim, Stander, Maria A
• Format: Journal Article
• Language: English
• Published: WASHINGTON American Chemical Society 15.01.2020; Amer Chemical Soc
• Subjects: Agriculture; Agriculture, Multidisciplinary; Chemistry; Chemistry, Applied; Chromatography, High Pressure Liquid; Food Science & Technology; Life Sciences & Biomedicine; Mass Spectrometry; Molecular Structure; Phenols - chemistry; Physical Sciences; Plant Extracts - chemistry; Plant Leaves - chemistry; Proteaceae - chemistry; Proteaceae - genetics; Science & Technology; UHPLC-MSE; ion mobility (IM) spectrometry; anthocyanins; caffeoyl-O-polygalatol (1,5-anhydro-[6-O-caffeoyl]- sorbitol(glucitol)); proteaceae; NMR spectroscopy; Protea; phenolics; STRUCTURAL-CHARACTERIZATION; TIME; ANALYTICAL STRATEGY; IDENTIFICATION; L; caffeoyl-O-polygalatol (1,5-anhydro-(6-O-caffeoyl]- sorbitol(glucitol)); DIODE-ARRAY DETECTION; POPULATION DIFFERENTIATION; COLLISION CROSS-SECTION; WINE ANTHOCYANINS; ELECTROSPRAY-IONIZATION
• ISSN: 0021-8561; 1520-5118
• DOI: 10.1021/acs.jafc.9b06361

In this study we report a detailed investigation of the polyphenol composition of Protea pure (P. cynaroides and P. neriifolia) and hybrid cultivars (Black beauty and Limelight). Aqueous methanol extracts of leaf and bract tissues were analyzed by ultrahigh pressure liquid chromatography hyphenated to photodiode array and ion mobility-high resolution mass spectrometric (UHPLC-PDA-IM-HR-MS) detection. A total of 67 metabolites were characterized based on their relative reversed phase (RP) retention, UV–vis spectra, low and high collision energy HR-MS data, and collisional cross section (CCS) values. These metabolites included 41 phenolic acid esters and 25 flavonoid derivatives, including 5 anthocyanins. In addition, an undescribed hydroxycinnamic acid-polygalatol ester, caffeoyl-O-polygalatol (1,5-anhydro-[6-O-caffeoyl]-sorbitol­(glucitol)) was isolated and characterized by 1D and 2D NMR for the first time. This compound and its isomer are shown to be potential chemo-taxonomic markers.