Characterization of the cardiac glycoside and lipid profiles of Strophanthus kombé Oliv. seeds

Abstract

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.

In defense of Apocynaceae: inference on evolution of pyrrolizidine alkaloids from evolution of an enzyme in their biosynthetic pathway, homospermidine synthase

“…PA occurrence among Malouetieae (all VXXXD) is uncertain; there is low to moderate confidence for their presence in species of Galactophora , Holarrhena , and Kibatalia (Barny et al, 2021). Among Nerieae, Strophanthus (VXXXD HSS in S. boivinii , HSS pseudogene in S. preussii ) has been much investigated for specialized metabolites, but PAs have never been reported (Knittel et al, 2016). Therefore, while we can predict HSS genotype (VXXXD) from PA phenotype with some accuracy in Apocynaceae (and across angiosperms), there is much more ambiguity in predicting phenotype from genotype.…”

Strophantus (Apocynaceae): Composition and Biochemical Properties with a Focus on S. sarmentosus

“…Analyses in S. divaricus proved that cardenolides occur in different parts of the plant and that their concentrations there vary; most glycosides were isolated from the leaves in that study [28]. Based on their seed glycosides, Strophantus species were assigned to four groups [1]: [12] and were an early and important commercial source for these molecules; the purified total mixture of these substances was widely used as an injectable solution (strophantin K) for treatment of cardiac deficiencies [29,30]. Research has been ongoing for more than 100 years, but new cardenolides are still being isolated such as glycosides of 17α-strophadogenin in S. kombe [29,30].…”

“…Based on their seed glycosides, Strophantus species were assigned to four groups [1]: [12] and were an early and important commercial source for these molecules; the purified total mixture of these substances was widely used as an injectable solution (strophantin K) for treatment of cardiac deficiencies [29,30]. Research has been ongoing for more than 100 years, but new cardenolides are still being isolated such as glycosides of 17α-strophadogenin in S. kombe [29,30]. A dedicated electrospray mass spectrometry (MS)-method characterized strophantidin and six different glycosides including cymarin, helveticoside, erysimoside and neoglucoerysimoside in strophantin K [31].…”

“…Gas chromatography (GC)-MS of the seed oils of S. kombe characterized mainly fatty acids, especially oleic acid and linoleic acid, as well as phytosterols, the latter representing intermediates of cardenolide biosynthesis [30]. In seed oil of S. sarmentosus, major component acids were palmitic (12%), oleic (38%), and linoleic (30%) acids; the minor components included stearic acid (9%), some saturated acids (4%) higher than stearic, and an unsaturated hydroxy-acid (7%) not previously reported [52].…”

Bulbous Plants Drimia: “A Thin Line between Poisonous and Healing Compounds” with Biological Activities

“…In animals, intoxication may lead to muscular weakness, paralysis and even fatality caused by heart failure [ 96 ]. A number of studies have reported cardiac glycoside as a major toxic compound produced by Drimia species [ 19 , 99 , 100 , 101 ]. According to Kellerman et al [ 23 ], livestock ingest the flowers, leaves and sometimes the bulb of this plant as substitutes to green grass, and it was found to be toxic to livestock due to cardiac glycoside extracted from the plant’s bulb.…”