Molecular networking‐based dereplication of strictosidine‐derived monoterpene indole alkaloids from the curare ingredient Strychnos peckii

Abstract

Rationale Monoterpene indole alkaloids (MIAs) are a large group of biologically active compounds produced by hundreds of plant species in numerous plant families, such as Apocynaceae, Loganiaceae and Rubiaceae. Although this diversity is biosynthetically intermediated by strictosidine, there are no works focused on the fragmentation patterns under collision‐induced dissociation of strictosidine‐derived alkaloids. Methods Initially, the alkaloid fingerprint of Strychnos peckii was established using leaf spray with tandem mass spectrometry (LS‐MS/MS). Then, high‐performance liquid chromatography coupled to tandem mass spectrometry (HPLC/MS/MS) analyses were carried out to focus on the patterns of neutral losses in product ion scan experiments with the leaf aqueous extract. Finally, the product ion spectra from a set of presumable strictosidine‐type derivatives were analyzed and organized via molecular networking (MN), and dereplicated by manual interpretation of MS/MS spectra. Results LS‐MS/MS allowed the tentative identification of strictosidine‐derived alkaloids in the leaves of S. peckii, showing useful neutral losses for the dereplication of strictosidine analogues by HPLC/MS/MS experiments. The use of MN combined with manual interpretation of the fragmentation patterns highlighted characteristic fragmentation pathways, and allowed the tentative identification of strictosidine, desoxycordifoline, strictosidinic acid, 10‐hydroxystrictosidine, 5‐carboxystrictosidine, lyaloside, 3,4‐dehydrostrictosidine and strictosidine lactam. Conclusions The use of MN combined with the analysis of the fragmentation patterns proved to be a useful strategy for the dereplication of strictosidine‐derived MIAs from S. peckii, highlighting known and unprecedented structures, as well as useful diagnostic product ions. Therefore, this workflow is an effective approach for the characterization of strictosidine‐type alkaloids in future dereplication works.

Chromosome‐level assembly of the Neolamarckia cadamba genome provides insights into the evolution of cadambine biosynthesis

“…The MS/MS spectrum of the ion at m / z 531 (Figure 2g) displayed the same fragmentation pattern as the molecules at: m / z 369 (C 21 H 24 N 2 O 8 ) ( m / z 531 → 369, loss of glucose with 162 Da); m / z 514 (C 27 H 31 NO 9 ) ( m / z 531 → 514, loss of NH 3 with 17 Da); and m / z 352 (C 21 H 21 NO 8 ) (m/z 531 → m/z 352, loss of glucose and NH 3 ). This identical fragmentation pattern is consistent with the MIA strictosidine previously reported in Strychnos peckii (Santos et al, 2020).…”

“…m/z 352, loss of glucose and NH 3 ). This identical fragmentation pattern is consistent with the MIA strictosidine previously reported in Strychnos peckii (Santos et al, 2020).…”

Mass spectrometry as a tool for the dereplication of saponins from Ampelozizyphus amazonicus Ducke bark and wood

“…In this work we used MZmine 2 , which contains methods for all data processing stages, such as spectral filtering, peak detection, alignment, normalisation and identification 21 . Recent literature reports this tool for the structural determination of compounds from several metabolite classes such as flavonoids, 19,22 alkaloids, 17,23,24 and saponins 25,26 …”

Structural evaluation of polymeric microbial films grown on kefir loaded with Maytenus rigida extract

“…The LS‐MS analysis was performed with a home‐made ion source and a TSQ Quantum Access triple quadrupole mass spectrometer (Thermo Fisher, San Jose, CA) according to previously reported methodologies (de Lima et al, 2020; C. L. G. Santos et al, 2019). In brief, biofilms without and with different concentrations of M. rigida extract were cut into triangle‐shaped pieces (base and height of 10 mm each) and held by a metal clip at 10 mm from the mass spectrometer inlet.…”