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Introduction: Natural products of pharmaceutical interest often do not reach the drug market due to the associated low yields and difficult extraction. Knowledge of biosynthetic pathways is a key element in the development of biotechnological strategies for plant specialized metabolite production. Erythrina species are mainly used as central nervous system depressants in folk medicine and are important sources of bioactive tetracyclic benzylisoquinoline alkaloids (BIAs), which can act on several pathology-related biological targets., Objectives: In this sense, in an unprecedented approach used with a non-model Fabaceae species grown in its unique arid natural habitat, a combined transcriptome and metabolome analyses (seeds and leaves) is presented., Methods: The Next Generation Sequencing-based transcriptome ( de novo RNA sequencing) was carried out in a NextSeq 500 platform. Regarding metabolite profiling, the High-resolution Liquid Chromatography was coupled to DAD and a micrOTOF-QII mass spectrometer by using electrospray ionization (ESI) and Time of Flight (TOF) analyzer. The tandem MS/MS data were processed and analyzed through Molecular Networking approach., Results: This detailed macro and micromolecular approach applied to seeds and leaves of E. velutina revealed 42 alkaloids, several of them unique. Based on the combined evidence, 24 gene candidates were put together in a putative pathway leading to the singular alkaloid diversity of this species., Conclusion: Overall, these results could contribute by indicating potential biotechnological targets for modulation of erythrina alkaloids biosynthesis as well as improve molecular databases with omic data from a non-model medicinal plant, and reveal an interesting chemical diversity of Erythrina BIA harvested in Caatinga., Competing Interests: The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (© 2021 The Authors. Published by Elsevier B.V. on behalf of Cairo University. This is an open access article under the CC BY-NC-ND license (http://creativecommons.org/licenses/by-nc-nd/4.0/).)

Tropane alkaloids are specialized plant metabolites mostly found in the Erythroxylaceae and Solanaceae families. Although tropane alkaloids have a high degree of structural similarity because of the tropane ring, their pharmacological actions are quite distinct. Brazil is one of the main hotspots of Erythroxylum spp. diversity with 123 species (almost 66% of the species catalogued in tropical America). Erythroxylum pungens occurs in the Caatinga, a promising biome that provides bioactive compounds, including tropane alkaloids. As part of our efforts to investigate this species, 15 alkaloids in specimens harvested under different environmental conditions are presented herein. The occurrence of 3-(2-methylbutyryloxy)tropan-6,7-diol in the stem bark of plants growing in their natural habitat, greenhouse controlled conditions, and after a period of water restriction, suggests that it is a potential chemical marker for the species. This alkaloid was evaluated for several parameters in zebrafish ( Danio rerio ) as a model organism. Regarding toxicity, teratogenic effects were observed at 19.5 µM and the lethal dose for embryos was 18.4 µM. No mortality was observed in adults, but a behavioral screen showed psychostimulatory action at 116.7 µM. Overall, the alkaloid was able to cause zebrafish behavioral changes, prompting further investigation of its potential as a new molecule in the treatment of depression-like symptoms. In silico , targets involved in antidepressant pathways were identified by docking., Competing Interests: The authors declare that they have no conflict of interest., (Thieme. All rights reserved.)

Stem bark, root bark, and leaf extracts of Erythroxylum pungens were subjected to phytochemical analysis. N,N-dimethyltryptamine (DMT) was isolated and characterized from E. pungens roots. This unprecedented result is remarkable since no indole alkaloid has been previously reported from Erythroxylaceae so far. Eleven known tropane alkaloids were identified by their mass spectra and 3-(2-methylbutyryloxy)tropan-6,7-diol as well as 3-(2-methylbutyryloxy)nortropan-6,7-diol were isolated and characterized based on mass spectrometry, 1 H, 13 C, COSY, and NOESY NMR analysis. The complete NMR data are reported for the first time. Inverse Structure-based and Ligand-Based virtual screening were carried out to identify possible targets for 3-(2-methylbutyryloxy)tropan-6,7-diol. The level of cytotoxicity of this tropane alkaloid aliphatic ester was discrete with potencies on the order of 0.3-1.0 mg/mL and better results against HeLa (50% cell viability reduction). Otherwise, atropine (0.3 mg/mL), a Solanaceae tropane alkaloid, and DMT (0.5 mg/mL) from E. pungens roots impaired at 50% the cell viability against HeLa, SiHa, PC3, and 786-0. This study stimulates scientific investigation of the impact of edaphoclimatic features in a semi-arid environment on tropane alkaloid biosynthesis., (Copyright © 2018 Elsevier Ltd. All rights reserved.)