Mediterranean sea squill (Drimia maritima (L.) Stearn) is used in the production of medicinal products. Current HPLC methods comprise tedious sample clean-up and have been merely focused on the analysis of cardiac glycosides, whereas a thorough characterization of D. maritima considering both the latter compound class and more hydrophilic secondary metabolites in one HPLC run has not been performed so far. Consequently, a novel HPLC-DAD-MS(n) method has been developed allowing the simultaneous determination of both cardiac glycosides and phenolic compounds, which is characterized by simplified sample preparation. This method was applied to characterize sea squill, revealing a complex profile of its extractive compounds derived from the two classes. Furthermore, the potential of the method reported here to quantitate the predominant compounds, i.e., dihydroquercetin derivatives and bufadienolides, was demonstrated. The occurrence of phenolic compounds, not described for sea squill so far, and of characteristic compounds specific to individual plant parts or vegetation stages was further addressed. The data revealed that classification of various vegetation phases based on quantitative evaluation of bufadienolides and dihydroquercetin derivatives applying principal component analysis (PCA) appears possible. Thus, the methodology presented here forms the basis for future routine application in quality control of raw materials and pharmaceutical preparations derived from sea squill. This will allow systematic comparison of different plant parts, vegetation stages and origins based on an extended sample set.

The seeds of Strophanthus kombé Oliv. are known to contain high levels of cardioactive compounds. However, the therapeutic use of Strophanthus in the treatment of cardiopathy requires more detailed knowledge of the compound profile to profit from the full potential of Strophanthus preparations. Therefore, the objective was to characterize the cardenolide profile and lipophilic constituents in S. kombé seeds using methods applicable in routine quality control. Freshly prepared S. kombé seed extracts were analyzed without previous sample clean-up using a novel HPLC-DAD-MSn method. In addition, seed oils were analyzed by GC-MS following derivatization of the lipids. More than 20 cardenolides were tentatively assigned in the seed extracts including strophanthidin, strophanthidol, periplogenin and strophanthidinic acid aglycones, carrying various saccharide moieties. The findings revealed the presence of eight novel cardenolides, which have not been described for S. kombé so far. The occurrence of strophanthidinic acid derivatives was verified by comparison with synthesized strophanthidinic acid-cymaropyranoside. GC-MS characterization of the oils mainly revealed the presence of fatty acids, especially oleic acid and linoleic acid, as well as phytosterols, the latter representing intermediates of cardenolide biosynthesis. In summary, these findings broaden our knowledge on the secondary metabolism of Strophanthus.

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Five homologous acetylated acylglycerols of 3-hydroxyfatty acids (chain lengths C(14) - C(18)), named euphrasianins A - E, were characterized for the first time in Euphrasia rostkoviana Hayne (Orobanchaceae) by gas chromatography/mass spectrometry (GC/MS) and high-performance liquid chromatography/atmospheric pressure chemical ionization-mass spectrometry (HPLC/APCI-MS(n) ). In addition to mass spectrometric data, structures of euphrasianins were verified via a three-step total synthesis of one representative homologue (euphrasianin A). The structure of the latter was confirmed by 1D- and 2D-NMR experiments as well as high-resolution electrospray ionization-mass spectrometry (HR-ESI-MS). The absolute configuration of the 3-hydroxyfatty acid moiety at C(3) was found to be R in the natural euphrasianins, which was determined by alkaline hydrolysis and methylation of a purified fraction, followed by chiral GC analysis. Furthermore, in extracts of Euphrasia tetraquetra (Bréb.) Arrond. euphrasianins C and E were detected exclusively, indicating that this subclass of lipid constituents is possibly valuable for fingerprinting methods.