New Structures, Spectrometric Quantification, and Inhibitory Properties of Cardenolides from <i>Asclepias curassavica</i> Seeds
Cardiac glycosides are a large class of secondary metabolites found in plants. In the genus <i>Asclepias</i>, cardenolides in milkweed plants have an established role in plant–herbivore and predator–prey interactions, based on their ability to inhibit the membrane-bound Na<sup>+<...
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MDPI AG
2022-12-01
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| Series: | Molecules |
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| Online Access: | https://www.mdpi.com/1420-3049/28/1/105 |
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| author | Paola Rubiano-Buitrago Shrikant Pradhan Christian Paetz Hannah M. Rowland |
| author_facet | Paola Rubiano-Buitrago Shrikant Pradhan Christian Paetz Hannah M. Rowland |
| author_sort | Paola Rubiano-Buitrago |
| collection | DOAJ |
| description | Cardiac glycosides are a large class of secondary metabolites found in plants. In the genus <i>Asclepias</i>, cardenolides in milkweed plants have an established role in plant–herbivore and predator–prey interactions, based on their ability to inhibit the membrane-bound Na<sup>+</sup>/K<sup>+</sup>-ATPase enzyme. Milkweed seeds are eaten by specialist lygaeid bugs, which are the most cardenolide-tolerant insects known. These insects likely impose natural selection for the repeated derivatisation of cardenolides. A first step in investigating this hypothesis is to conduct a phytochemical profiling of the cardenolides in the seeds. Here, we report the concentrations of 10 purified cardenolides from the seeds of <i>Asclepias curassavica</i>. We report the structures of new compounds: 3-<i>O</i>-<i>β</i>-allopyranosyl coroglaucigenin (<b>1</b>), 3-[4′-<i>O</i>-<i>β</i>-glucopyranosyl-<i>β</i>-allopyranosyl] coroglaucigenin (<b>2</b>), 3′-<i>O</i>-<i>β</i>-glucopyranosyl-15-<i>β</i>-hydroxycalotropin (<b>3</b>), and 3-<i>O</i>-<i>β</i>-glucopyranosyl-12-<i>β</i>-hydroxyl coroglaucigenin (<b>4</b>), as well as six previously reported cardenolides (<b>5</b>–<b>10</b>). We test the in vitro inhibition of these compounds on the sensitive porcine Na<sup>+</sup>/K<sup>+</sup>-ATPase. The least inhibitory compound was also the most abundant in the seeds—4′-<i>O</i>-<i>β</i>-glucopyranosyl frugoside (<b>5</b>). Gofruside (<b>9</b>) was the most inhibitory. We found no direct correlation between the number of glycosides/sugar moieties in a cardenolide and its inhibitory effect. Our results enhance the literature on cardenolide diversity and concentration among tissues eaten by insects and provide an opportunity to uncover potential evolutionary relationships between tissue-specific defense expression and insect adaptations in plant–herbivore interactions. |
| first_indexed | 2024-03-09T03:30:28Z |
| format | Article |
| id | doaj.art-5f154664ad8046e9b9588bd2f913564c |
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| language | English |
| last_indexed | 2024-03-09T03:30:28Z |
| publishDate | 2022-12-01 |
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| spelling | doaj.art-5f154664ad8046e9b9588bd2f913564c2023-12-03T14:56:38ZengMDPI AGMolecules1420-30492022-12-0128110510.3390/molecules28010105New Structures, Spectrometric Quantification, and Inhibitory Properties of Cardenolides from <i>Asclepias curassavica</i> SeedsPaola Rubiano-Buitrago0Shrikant Pradhan1Christian Paetz2Hannah M. Rowland3Research Group Predators and Toxic Prey, Max Planck Institute for Chemical Ecology, Hans Knöll Straße 8, 07745 Jena, GermanyResearch Group Predators and Toxic Prey, Max Planck Institute for Chemical Ecology, Hans Knöll Straße 8, 07745 Jena, GermanyResearch Group Biosynthesis/NMR, Max Planck Institute for Chemical Ecology, Hans Knöll Straße 8, 07745 Jena, GermanyResearch Group Predators and Toxic Prey, Max Planck Institute for Chemical Ecology, Hans Knöll Straße 8, 07745 Jena, GermanyCardiac glycosides are a large class of secondary metabolites found in plants. In the genus <i>Asclepias</i>, cardenolides in milkweed plants have an established role in plant–herbivore and predator–prey interactions, based on their ability to inhibit the membrane-bound Na<sup>+</sup>/K<sup>+</sup>-ATPase enzyme. Milkweed seeds are eaten by specialist lygaeid bugs, which are the most cardenolide-tolerant insects known. These insects likely impose natural selection for the repeated derivatisation of cardenolides. A first step in investigating this hypothesis is to conduct a phytochemical profiling of the cardenolides in the seeds. Here, we report the concentrations of 10 purified cardenolides from the seeds of <i>Asclepias curassavica</i>. We report the structures of new compounds: 3-<i>O</i>-<i>β</i>-allopyranosyl coroglaucigenin (<b>1</b>), 3-[4′-<i>O</i>-<i>β</i>-glucopyranosyl-<i>β</i>-allopyranosyl] coroglaucigenin (<b>2</b>), 3′-<i>O</i>-<i>β</i>-glucopyranosyl-15-<i>β</i>-hydroxycalotropin (<b>3</b>), and 3-<i>O</i>-<i>β</i>-glucopyranosyl-12-<i>β</i>-hydroxyl coroglaucigenin (<b>4</b>), as well as six previously reported cardenolides (<b>5</b>–<b>10</b>). We test the in vitro inhibition of these compounds on the sensitive porcine Na<sup>+</sup>/K<sup>+</sup>-ATPase. The least inhibitory compound was also the most abundant in the seeds—4′-<i>O</i>-<i>β</i>-glucopyranosyl frugoside (<b>5</b>). Gofruside (<b>9</b>) was the most inhibitory. We found no direct correlation between the number of glycosides/sugar moieties in a cardenolide and its inhibitory effect. Our results enhance the literature on cardenolide diversity and concentration among tissues eaten by insects and provide an opportunity to uncover potential evolutionary relationships between tissue-specific defense expression and insect adaptations in plant–herbivore interactions.https://www.mdpi.com/1420-3049/28/1/105Na<sup>+</sup>/K<sup>+</sup> ATPase activityApocynaceaetoxicitysecondary metabolitesphytochemistry |
| spellingShingle | Paola Rubiano-Buitrago Shrikant Pradhan Christian Paetz Hannah M. Rowland New Structures, Spectrometric Quantification, and Inhibitory Properties of Cardenolides from <i>Asclepias curassavica</i> Seeds Molecules Na<sup>+</sup>/K<sup>+</sup> ATPase activity Apocynaceae toxicity secondary metabolites phytochemistry |
| title | New Structures, Spectrometric Quantification, and Inhibitory Properties of Cardenolides from <i>Asclepias curassavica</i> Seeds |
| title_full | New Structures, Spectrometric Quantification, and Inhibitory Properties of Cardenolides from <i>Asclepias curassavica</i> Seeds |
| title_fullStr | New Structures, Spectrometric Quantification, and Inhibitory Properties of Cardenolides from <i>Asclepias curassavica</i> Seeds |
| title_full_unstemmed | New Structures, Spectrometric Quantification, and Inhibitory Properties of Cardenolides from <i>Asclepias curassavica</i> Seeds |
| title_short | New Structures, Spectrometric Quantification, and Inhibitory Properties of Cardenolides from <i>Asclepias curassavica</i> Seeds |
| title_sort | new structures spectrometric quantification and inhibitory properties of cardenolides from i asclepias curassavica i seeds |
| topic | Na<sup>+</sup>/K<sup>+</sup> ATPase activity Apocynaceae toxicity secondary metabolites phytochemistry |
| url | https://www.mdpi.com/1420-3049/28/1/105 |
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