Recognition of Pyrrolizidine Alkaloid Esters in the Invasive Aquatic Plant Gymnocoronis spilanthoides (Asteraceae). Issue 3 (27th January 2015)

• Record Type: Journal Article
• Authors: Boppré, Michael; Colegate, Steven M.
• Is Part Of: Phytochemical analysis. Volume 26:Issue 3(2015:May)
• Page Start: 215
• Page End: 225
• Publication Date: 2015-01-27
• Subjects: Plants -- Analysis -- Periodicals; Plants -- chemistry -- Periodicals; 572.2
• DOI: 10.1002/pca.2555
• Languages: English
• ISSNs: 0958-0344

Abstract

<abstract abstract-type="main"> <title>Abstract</title> <sec id="pca2555-sec-0001" sec-type="section"> <title>Introduction</title> <p>The freshwater aquatic plant <italic>Gymnocoronis spilanthoides</italic> (Senegal tea plant, jazmín del bañado, Falscher Wasserfreund) is an invasive plant in many countries. Behavioural observations of pyrrolizidine alkaloid‐pharmacophagous butterflies suggested the presence of pyrrolizidine alkaloids in the plant.</p> </sec> <sec id="pca2555-sec-0002" sec-type="section"> <title>Objective</title> <p>To determine whether the attraction of the butterflies to the plant is an accurate indicator of pyrrolizidine alkaloids in <italic>G</italic>. <italic>spilanthoides</italic>.</p> </sec> <sec id="pca2555-sec-0003" sec-type="section"> <title>Methods</title> <p>The alkaloid fraction of a methanolic extract of <italic>G</italic>. <italic>spilanthoides</italic> was analysed using HPLC with electrospray ionisation MS and MS/MS. Two HPLC approaches were used, that is, a C<sub>18</sub> reversed‐phase column with an acidic mobile phase, and a porous graphitic carbon column with a basic mobile phase.</p> </sec> <sec id="pca2555-sec-0004" sec-type="section"> <title>Results</title> <p>Pyrrolizidine alkaloids were confirmed, with the free base forms more prevalent than the <italic>N</italic>‐oxides. The major alkaloids detected were lycopsamine and intermedine. The porous graphitic carbon HPLC column, with basic mobile phase conditions, resulted in better resolution of more pyrrolizidine alkaloids including rinderine, the heliotridine‐based epimer of intermedine. Based on the MS/MS and high‐resolution MS data, gymnocoronine was tentatively identified as an unusual C9 retronecine ester with 2, 3‐dihydroxy‐2‐propenylbutanoic acid. Among several minor‐abundance monoester pyrrolizidines recognised, spilanthine was tentatively identified as an ester of isoretronecanol with the unusual 2‐acetoxymethylbutanoic acid.</p> </sec> <sec id="pca2555-sec-0005" sec-type="section"> <title>Conclusions</title> <p>The butterflies proved to be reliable indicators for the presence of pro‐toxic 1, 2‐dehydropyrrolizidine alkaloids in <italic>G. spilanthoides</italic>, the first aquatic plant shown to produce these alkaloids. The presence of the anti‐herbivory alkaloids may contribute to the plant's invasive capabilities and would certainly be a consideration in any risk assessment of deliberate utilisation of the plant. The prolific growth of the plant and the structural diversity of its pyrrolizidine alkaloids may make it ideal for investigating biosynthetic pathways or for large‐scale production of specific alkaloids. Copyright © 2015 John Wiley & Sons, Ltd.</p> </sec> </abstract>