Bridging Pharmacopeial Standards and Chemical Reality of Triterpene Glycosides in Actaea racemosa.

Actaea racemosa L. (syn. Cimicifuga racemosa (L.) Nutt., black cohosh) rhizomes contain triterpene glycosides (TTGs) that serve as principal quality markers in the European Pharmacopoeia (Ph. Eur.) monograph. However, discrepancies between chromatographic profiles of the plant material and the herbal reference standard (HRS) dry extract complicate quality assessment. This study elucidated the chemical origin of these discrepancies and evaluated whether the extract-based HRS can represent the analytical fingerprint of the plant material. Thirteen TTGs were identified and characterized within the official Ph. Eur. HPLC-ELSD method using centrifugal partition chromatography, semi-preparative UPLC, HRMS, GC-MS and NMR spectroscopy, employing reference standards and isolated compounds. Three malonylated TTGs (8a, 9a, 10a) were detected in wild and cultivated rhizomes but were absent from the A. racemosa dry extract HRS and other dry extracts. Quantitative analysis revealed that cultivated plants contained an insufficient amount of TTGs; however, after extraction, both the amount and the profile aligned with the Ph. Eur. requirements. This behavior is explained by the degradation and rearrangement pathways of the TTGs. Overall, these findings clarify the origin of chemical variability between plant and extract fingerprints and support the inclusion of malonylated TTGs in the quantitative determination of A. racemosa triterpene glycosides in the Ph. Eur.