Chemical characterization and quantitative determination of flavonoids and phenolic acids in yerba santa (Eriodictyon spp.) using UHPLC/DAD/Q-ToF

Authors: Wang, Mei; ZHAO, JIANPING - University Of Mississippi; AVULA, BHARATHI - University Of Mississippi; LEE, JOSEPH - University Of Mississippi; UPTON, ROY - American Herbal Pharmacop; KHAN, IKHLAS - University Of Mississippi

Submitted to: Journal of Pharmaceutical and Biomedical Analysis
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 7/9/2023
Publication Date: 7/10/2023
Citation: Wang, M., Zhao, J., Avula, B., Lee, J., Upton, R., Khan, I. 2023. Chemical characterization and quantitative determination of flavonoids and phenolic acids in yerba santa (Eriodictyon spp.) using UHPLC/DAD/Q-ToF. Journal of Pharmaceutical and Biomedical Analysis. https://doi.org/10.1016/j.jpba.2023.115570.
DOI: https://doi.org/10.1016/j.jpba.2023.115570

Interpretive Summary: This investigation was initiated at the request of the American Herbal Pharmacopoeia (AHP) to develop analytical methods for the chemical characterization and quantitative determination of the primary constituents in yerba santa (Eriodictyon spp.). Over 100 samples were provided by AHP in order to give a comprehensive data set. Eriodictyon species are native to the Southwestern United States and northern Mexico. The plants are known for their medicinal properties and have been used by indigenous people for centuries to treat various ailments. Despite a long history of traditional use, a full chemical characterization of many of the species is lacking. In addition, the constituent range of these species has not been comprehensively reported. The submitted manuscript describes the development and validation of an UHPLC/DAD/Q-ToF method for the investigation of 111 samples belonging to six different Eriodictyon species, viz., E. californicum, E. angustifolium, E. trichocalyx, E. crassifolium, E. tomentosum, E. traskiae, and E. capitatum. Fourteen compounds, comprised of flavonoids and phenolic acids, were quantified. Furthermore, by using UHPLC/ESI/Q-ToF data in positive and negative ion modes, we were able to identify 53 compounds in yerba santa plant samples. To the best of our knowledge, this work encapsulates the most comprehensive data set currently available for the chemical characterization and quantification of the primary constituents in Eriodictyon species.

Technical Abstract: Eriodictyon species, commonly known as yerba santa, are plants native to the Southwestern United States and Northern Mexico. The plants are known for their medicinal properties and have been used by indigenous people for centuries to treat various ailments, in particular, respiratory conditions. Despite a long history of traditional use, many of the species have never been fully chemically characterized and the constituent range of the species has not been comprehensively reported. In an effort to establish a quality control and chemical characterization method, an extensive set of Eriodictyon species samples including E. californicum (n = 85), E. angustifolium (n = 8), E. trichocalyx (n = 5), E. crassifolium (n = 9), E. tomentosum (n = 2), E. traskiae (n = 1), and E. capitatum (n = 1) were investigated. Fourteen compounds from flavonoids and phenolic acids were quantified utilizing an UHPLC/DAD/Q-ToF method. The results from the method validation demonstrated excellent linearity (R2 >0.99) and sensitivity as evident by LOD (0.01-0.1 µg/mL) and LOQ (0.05-0.11 µg/mL). Likewise, the method was found to be precise (RSD < 2.78%) with recoveries between 88.9-103.2%. Furthermore, by using UHPLC/ESI/Q-ToF data and protonated, deprotonated, and adduct and fragment ions in positive and negative ion modes, we were able to identify 53 compounds in yerba santa plant samples. To the best of our knowledge, this work encapsulates the most comprehensive data set currently available for the chemical characterization and quantification of the primary constituents in Eriodictyon species. Additionally, results of this study also demonstrated the applicability of the developed method for quality assessment of raw material and commercial herbal products containing different Eriodictyon species.