Planta Med 2022; 88(08): 576-586
DOI: 10.1055/a-1586-1915
Natural Product Chemistry and Analytical Studies
Original Papers

An in-depth look into a well-known herbal drug: Fingerprinting, isolation, identification, and content estimation of saponins in different Strophanthus seeds

Department of Pharmacognosy and Herbal Medicines, Faculty of Pharmacy, Wroclaw Medical University, Wroclaw, Poland
,
Department of Pharmacognosy and Herbal Medicines, Faculty of Pharmacy, Wroclaw Medical University, Wroclaw, Poland
› Author Affiliations
Supported by: Uniwersytet Medyczny im. Piastów Slaskich we Wroclawiu SUB.D110.19.005

Abstract

Seeds of Strophanthus species are known as a source of rapid-acting cardenolides. These water-soluble glycosides are listed as the sole critical constituents of this raw herbal drug. A non-standard cardioprotective medication with ouabain-containing oral remedies has become popular in Europe as a result of the withdrawal of corresponding registered drugs from the market. However, the bioequivalence of pure ouabain solutions, tinctures, and home-made extracts from Strophanthus seeds is unknown. Thus, this study aimed to update the information on the composition of Strophanthus seeds used for this purpose. The distribution of two main saponins and about 90 previously unreported compounds, tentatively identified as saponins in eleven Strophanthus species, was systematically evaluated by ultra-high-performance liquid chromatography mass spectrometry (UHPLC-MS) and -MS/MS. Seeds of S. gratus were selected to isolate the dominant unreported triterpenoids, bidesmosides of echinocystic and oleanolic acid. Their structures were established by HRMS, MS/MS, as well as by NMR techniques. The total saponin content, estimated by UHPLC-MS, was up to 1%. The detected saponins could influence the peroral bioavailability of hardly absorbable Strophanthus cardenolides and exhibit their own activity. This finding may be relevant when Strophanthus preparations (containing both saponins and cardiac glycosides) are used, particularly when homemade preparations are administered.

Supporting Information



Publication History

Received: 16 February 2021

Accepted after revision: 09 August 2021

Article published online:
02 September 2021

© 2021. Thieme. All rights reserved.

Georg Thieme Verlag KG
Rüdigerstraße 14, 70469 Stuttgart, Germany