|Harnly, James - Jim|
|Zhang, Mengliang - International Life Sciences Institute (ILSI)|
Submitted to: Analytical and Bioanalytical Chemistry
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 1/11/2017
Publication Date: 5/1/2017
Citation: Geng, P., Harnly, J.M., Sun, J., Zhang, M., Chen, P. 2017. Feruloyl dopamine-O-hexosides are efficient marker compounds for differentiation between Black Cohosh (Actaea racemosa) and related Actaea species – an UHPLC-HRAM-MS Chemometrics Study. Analytical and Bioanalytical Chemistry. 127:68-75. https://doi.org/10.1016/j.postharvbio.2017.01.006.
DOI: https://doi.org/10.1016/j.postharvbio.2017.01.006 Interpretive Summary: Black Cohosh is officially defined as the dried rhizome and roots of Actaea racemosa L. [formerly Cimicifuga racemosa (L.) Nutt.] of the family Ranunculaceae harvested in the summer. As a result of increasing commercial demand and shrinking natural stocks, black cohosh products in market may be adulterated with widely cultivated and less expensive Asian Actaea species. In this study, an easier and more practicable method to differentiate black cohosh from its Asian and American adulterants using high resolution accurate mass (HRAM) LC-MS fingerprinting combined with chemometric analysis was employed. Seven hydroxycinnamic acid amides (HCAAs) were identified as potential markers for the authentication of black cohosh, and PLS-DA models based on these markers were assessed by leave-one-out cross-validation. The most efficient marker compounds were determined.
Technical Abstract: Due to the complexity and variation of the chemical constituents in authentic black cohosh (Actaea racemosa) and its potential adulterant species, an accurate and feasible method for black cohosh authentication is not easy. A high resolution accurate mass (HRAM) LC-MS fingerprinting method combined with chemometric approach was employed to discover new marker compounds. Seven hydroxycinnamic acid amides (HCAAs) glycosides are reported as potential marker compounds for differentiation of black cohosh from related species, including two Asian species (A. foetida, A. dahurica) and two American species (A. pachypoda, A. podocarpa). These markers were putatively identified by comparing their mass spectral fragmentation behavior with those of their authentic aglycone compounds and phytochemistry reports. Two isomers of feruloyl methyldopamine 4-O-hexoside ([M+H]+ 506) and one feruloyl tyramine 4-O-hexoside ([M+H]+ 476) contributed significantly to the separation of Asian species in PCA score plot. The efficacy of these markers in differentiating black cohosh and non-black cohosh were evaluated and validated by partial least-square discriminant analysis (PLS-DA) models. The model using three feruloyl dopamine-O-hexoside isomers ([M+H]+ 492) and one feruloyl dopamine -O-dihexoside ([M+H-hexosyl]+ at m/z 492) was able to discriminate black cohosh from the other four Actaea species with 100% prediction rate.