Next Article in Journal
11β,20β-Epoxybriaranes from the Gorgonian Coral Junceella fragilis (Ellisellidae)
Next Article in Special Issue
1H NMR-Based Isolation of Anti-Inflammatory 9,11-Secosteroids from the Octocoral Sinularia leptoclados
Previous Article in Journal
Anti-Fouling Effects of Saponin-Containing Crude Extracts from Tropical Indo-Pacific Sea Cucumbers
Previous Article in Special Issue
Polyketide Derivatives from Mangrove Derived Endophytic Fungus Pseudopestalotiopsis theae
Open AccessArticle

LC–HRMS and Chemical Derivatization Strategies for the Structure Elucidation of Caribbean Ciguatoxins: Identification of C-CTX-3 and -4

1
Toxinology Research Group, Norwegian Veterinary Institute, P.O. Box 750 Sentrum, 0106 Oslo, Norway
2
Department of Marine Sciences, University of South Alabama, 5871 University Drive North, Mobile, AL 36688, USA
3
Dauphin Island Sea Laboratory, 101 Bienville Blvd, Dauphin Island, AL 36528, USA
4
National Research Council, 1411 Oxford Street, Halifax, NS B3H 3Z1, Canada
*
Author to whom correspondence should be addressed.
Mar. Drugs 2020, 18(4), 182; https://doi.org/10.3390/md18040182
Received: 25 February 2020 / Revised: 24 March 2020 / Accepted: 27 March 2020 / Published: 31 March 2020
Ciguatera poisoning is linked to the ingestion of seafood that is contaminated with ciguatoxins (CTXs). The structural variability of these polyether toxins in nature remains poorly understood due to the low concentrations present even in highly toxic fish, which makes isolation and chemical characterization difficult. We studied the mass spectrometric fragmentation of Caribbean CTXs, i.e., the epimers C-CTX-1 and -2 (1 and 2), using a sensitive UHPLC–HRMS/MS approach in order to identify product ions of diagnostic value. We found that the fragmentation of the ladder-frame backbone follows a characteristic pattern and propose a generalized nomenclature for the ions formed. These data were applied to the structural characterization of a pair of so far poorly characterized isomers, C-CTX-3 and -4 (3 and 4), which we found to be reduced at C-56 relative to 1 and 2. Furthermore, we tested and applied reduction and oxidation reactions, monitored by LC–HRMS, in order to confirm the structures of 3 and 4. Reduction of 1 and 2 with NaBH4 afforded 3 and 4, thereby unambiguously confirming the identities of 3 and 4. In summary, this work provides a foundation for mass spectrometry-based characterization of new C-CTXs, including a suite of simple chemical reactions to assist the examination of structural modifications. View Full-Text
Keywords: ciguatera; ciguatoxin; HRMS; Gambierdiscus; polyether toxin; LC–MS; fragmentation pathways; ladder-frame molecule; Scomberomorus cavalla; Sphyraena barracuda ciguatera; ciguatoxin; HRMS; Gambierdiscus; polyether toxin; LC–MS; fragmentation pathways; ladder-frame molecule; Scomberomorus cavalla; Sphyraena barracuda
Show Figures

Graphical abstract

MDPI and ACS Style

Kryuchkov, F.; Robertson, A.; Miles, C.O.; Mudge, E.M.; Uhlig, S. LC–HRMS and Chemical Derivatization Strategies for the Structure Elucidation of Caribbean Ciguatoxins: Identification of C-CTX-3 and -4. Mar. Drugs 2020, 18, 182.

Show more citation formats Show less citations formats
Note that from the first issue of 2016, MDPI journals use article numbers instead of page numbers. See further details here.

Article Access Map by Country/Region

1
Search more from Scilit
 
Search
Back to TopTop