Quantification of phenolic compounds from Fadogia agrestis and dietary supplements using UHPLC-PDA-MS

Authors: AVULA, BHARATHI - University Of Mississippi; BAE, JI-YEONG - University Of Mississippi; RAMAN, VIJAYASANKAR - University Of Mississippi; WANG, YAN-HONG - University Of Mississippi; FANTOUKH, OMER - University Of Mississippi; OSMAN, AHMED GALAL - University Of Mississippi; WANG, MEI - University Of Mississippi; ALI, ZULFIQAR - University Of Mississippi; KHAN, IKHLAS - University Of Mississippi

Submitted to: Analytical and Bioanalytical Chemistry
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 8/19/2018
Publication Date: 8/31/2018
Citation: Avula, B., Bae, J., Raman, V., Wang, Y., Fantoukh, O., Osman, A., Wang, M., Ali, Z., Khan, I.A. 2018. Quantification of phenolic compounds from Fadogia agrestis and dietary supplements using UHPLC-PDA-MS. Analytical and Bioanalytical Chemistry. 85(2):145-154. https://doi.org/10.1055/a-0715-1801.
DOI: https://doi.org/10.1055/a-0715-1801

Interpretive Summary: In the traditional medicine of Africa, F. agrestis is used for the treatment of fever, alleviation of kidney pain, in addition to possessing a diuretic effect. To date, there is no analytical method reported for the quality assessment of any Fadogia species and its dietary supplements. Little chemistry has been done on the Fadogia and the present study was undertaken for the analysis of chemical constituents from various parts (stem, root, leaf) of F. agrestis using UHPLC-PDA-MS and the method is also applied to dietary supplements claiming to contain F. agrestis. The method was validated for all the parameters (accuracy, precision, linear range, LOD, LOQ, system suitability, stability). A fast, sensitive and reliable UHPLC-PDA-MS method was developed for the quality evaluation and authentication of Fadogia raw materials from dietary supplements. Nineteen plant samples and seventeen Fadogia dietary supplements were used for analysis. Five out of seventeen Fadogia retail products tested were not detected for Fadogia chemical components.

Technical Abstract: An UHPLC method was developed for the determination of eleven phenolic compounds from roots and aerial parts of Fadogia agrestis Schweinf. ex Hiern (synonym Vangueria agrestis (Schweinf. ex Hiern) Lantz), Rubiaceae. The separation was achieved within 7 minutes by using C-18 column material, a water/acetonitrile mobile phase, both containing 0.1% formic acid gradient system with a temperature of 45 °C. The method was validated for linearity, repeatability, limits of detection (LOD) and limits of quantification (LOQ). The limits of detection of phenolic compounds were found to be in the range from 0.025-0.1 µg/mL. The wavelengths used for quantification with the diode array detector (DAD) were 238, 254, 291 and 325 nm. Twelve of 17 dietary supplements contained phenolic compounds in the range from 0.3-2.6 mg/day. The phenolic compounds were not detected in five dietary supplements. LC-mass spectrometry coupled with electrospray ionization (ESI) interface method is described for the identification and confirmation of compounds from plant samples and dietary supplements claiming to contain Fadogia. This method involved the use of [M+H]+ and [M+Na]+ ions in the positive ion mode and [M-H]- ions in the negative ion mode with extractive ion monitoring (EIM). The developed method is simple, economic, rapid and especially suitable for quality control analysis of Fadogia.