AUTHOR=Kunert Olaf , Pferschy-Wenzig Eva Maria , Orthaber Andreas , Raspotnig Günther , Bodner Michaela 

TITLE=Alkaloids from millipedes: a re-evaluation of defensive exudates from Polyzonium germanicum

JOURNAL=Frontiers in Ecology and Evolution

VOLUME=11

YEAR=2023

URL=https://www.frontiersin.org/journals/ecology-and-evolution/articles/10.3389/fevo.2023.1212452

DOI=10.3389/fevo.2023.1212452

ISSN=2296-701X

ABSTRACT=<p>Millipedes are known to produce various sets of chemical compounds in exocrine defensive glands to protect themselves against predators and microorganisms. Here, we reanalyzed the gland secretion of <italic>Polyzonium germanicum</italic>, a millipede of the order Polyzoniida, by using a combination of analytical techniques such as GC-MS, LC-HRMS and high field 1D and 2D NMR spectroscopy. Previously only one compound (polyzonimine, <bold>1</bold>) had been described, but our approach allowed us to add six compounds to the defensive chemistry of this species. Besides polyzonimine (<bold>1</bold>), we found nitropolyzonamine (<bold>2</bold>) and five new compounds: <bold>3</bold> (2,3-dimethyl-7’-nitro-2’,3’,5’,6’,7’,7a’-hexahydrospiro[cyclopent-2-ene-1,1’-pyrrolizine]), <bold>4</bold> (2,3-dimethyl-7’-nitro-2’,3’,5’,6’,7’,7a’-hexahydrospiro[cyclopentane-1,1’-pyrrolizin]-2-ene), <bold>5</bold> ((1<italic>Z</italic>)-8,9-dimethyl-1-(nitromethylidene)-2-azaspiro[4.4]non-8-en-7-one), and not fully identified compounds A, B. For compounds <bold>3–5</bold> we were able to determine the molecular constitution, for two of them (<bold>4, 5</bold>) we were able to give relative configurations. Overall, the combination of advanced analytical techniques applied herein allowed detailed insights into the defensive chemistry of <italic>P. germanicum</italic> with a low number of individuals needed for analysis and without prior compound isolation.</p>