The chemical characterization of Eleutherococcus senticosus and Ci-wu-jia Tea using UHPLC-UV-QTOF/MS

Authors: WANG, YAN-HONG - University Of Mississippi; MENG, YONGHAI - Heilongjiang University; ZHAI, CHUNMEI - Heilongjiang University; WANG, MEI - University Of Mississippi; AVULA, BHARATHI - University Of Mississippi; YUK, JIMMY - Waters Corporation; SMITH, KERRI - Waters Corporation; ISAAC, GIORGIS - Waters Corporation; KHAN, IKHLAS - University Of Mississippi

Submitted to: International Journal of Molecular Sciences
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 1/17/2019
Publication Date: 1/22/2019
Publication URL: https://handle.nal.usda.gov/10113/6471207
Citation: Wang, Y., Meng, Y., Zhai, C., Wang, M., Avula, B., Yuk, J., Smith, K.M., Isaac, G., Khan, I.A. 2019. The chemical characterization of Eleutherococcus senticosus and Ci-wu-jia Tea using UHPLC-UV-QTOF/MS. International Journal of Molecular Sciences. 20(3):475-488. https://doi.org/10.3390/ijms20030475.
DOI: https://doi.org/10.3390/ijms20030475

Interpretive Summary: Eleutherococcus senticosus Maxim. (syn. Acanthopanax senticosus Harms) is a species of the Araliaceae family. This plant is in the same family as Panax ginseng and the leaves have been reported for glycosidase inhibition as well as having antibacterial properties. For this reason, E. senticosus leaves have been developed as a functional beverage called ci-wu-jia tea in China and Siberian ginseng tea in the United States and Europe. Phytochemical studies revealed that caffeoylquinic acid derivatives, triterpene glycosides, and flavonoids were the major secondary metabolites in leaves of E. senticosus. Several analytical methods have been reported for the quantitative or qualitative analysis of caffeoylquinic acid derivatives, triterpene glycosides, and flavonoids in E. senticosus leaves. However, no analytical method has been reported for the chemical analysis of caffeoylquinic acid derivatives, flavonoids, and triterpene glycosides in a single analytical method. Due to the higher sales of commercial natural products in the market, there has been increasing cases of intentional adulteration with different species to lower the cost. To ensure quality control of ci-wu-jia or Siberian ginseng tea in the market, it is important to develop an analytical method for the characterization of these types of major constituents in E. senticosus leaves. In this study, an analytical method was developed to characterize the different classes of compounds (organic acid derivatives, flavonoids, and triterpene glycosides) in E. senticosus leaves using a single Ultra-High Performance Liquid Chromatography (UHPLC) method coupled to Photo-Diode Array (PDA) and Quadrupole Time-of-Flight Mass Spectrometer (QToF MS) detectors. Characteristic Ultraviolet (UV), Mass Specrometry (MS), and tandem Mass Spectrometry (MS/MS) spectra of typical compounds in each class were defined. The commonly observed fragment ions and neutral loss were determined and edited into the UNIFI processing method, a Waters Corporation Scientific Information System. In total, 13 plant samples collected from different locations and 11 ci-wu-jia teas were tested using the developed method. Out of the 11 ci-wu-jia teas samples, three (EPS-1, EPS-2, and EPS-8) products were determined to contain caffeine, epigallocatechin, epicatechin, epigallocatechin gallate, and epicatechin gallate; all compounds that matched with the profile of green tea extract.

Technical Abstract: Eleutherococcus senticosus Maxim. belongs to the Araliaceae family. Phytochemical studies reveal that E. senticosus leaves contain triterpene glycosides along with organic acid derivatives and flavonoid compounds. It is believed that E. senticosus is similar to ginseng because they come from same family and both contain triterpene saponins. E. senticosus leaves have been developed as a functional beverage called ci-wu-jia tea in recent years. Triterpene glycosides are difficult to identify by Ultraviolet (UV) detection and contents of these compounds are low in E. senticosus leaves. In this study, a sensitive Ultra-High Performance Liquid Chromatography (UHPLC) method combining UV and tandem Mass Spectrometry (MS/MS) has been developed to characterize the triterpene glycosides from E. senticosus leaves and related commercial products. Fragmentation patterns of three sub-groups of triterpene glycosides in E. senticosus leaves were investigated. Additionally, fragmentation pathways and UV characteristics of organic acid derivatives and flavonoids were also characterized. A compound screening library including 241 compounds reported in literature was created and used to confirm the compounds in the samples. In this study, a total 24 samples including 13 plant samples of E. senticosus and 11 ci-wu-jia tea products were analyzed. Out of the 11 commercial products, three products were discovered to contain green tea (Camellia sinensis) that was considered to be an adulterant since it was not an ingredient on the labels. The developed UHPLC-UV-MS/MS analytical method combined with the UNIFI processing method (a Waters Corporation Scientific Information System) can simultaneously characterize organic acid derivatives, flavonoids, and triterpene saponins from E. senticosus. It provides a simple and sensitive way to perform quality control of E. senticosus and related ci-wu-jia tea products.