Background: While more and more people tend to use herbal products thinking they are safer than conventional western medicine, the reality is other. If natural products are bio-active and possess potential therapeutic activities, then the benefit/risk balance should be considered like any other health product. Some herbs are known to have the potential to interact with patient's treatment and to cause adverse drug reactions.
View Article and Find Full Text PDFThe molecular network-guided exploration of the alkaloid extract of stems revealed a cluster attributed tentatively to dimeric monoterpene indole alkaloids of the rare criophylline subtype, initiating the dual study reported herein. A patrimonial-themed portion of this work was aimed at performing a spectroscopic reassessment of criophylline (), a monoterpene bisindole alkaloid for which the nature of the inter-monomeric connectivity and configurational assignments have remained dubious. A targeted isolation of the entity annotated as criophylline () was undertaken to strengthen the available analytical evidence.
View Article and Find Full Text PDFIn less than 10 years, molecular networking (MN) strategy has revolutionized the art of Natural Products (NP) isolation to enter a rational workflow greatly increasing the probabilities of isolating new chemical entities. To pinpoint and streamline the isolation of new Monoterpene Indole Alkaloids (MIAs) in producing plants, we rendered publicly available the MIA database (MIADB), comprising MS data for ca. 200 structurally diverse MIA, by uploading it to the Global Natural Products Social Molecular Networking (GNPS) platform.
View Article and Find Full Text PDFIntroduction: Plants of the Strychnos genus, which include about 200 species, are used for multiple traditional purposes as hunting poison, for example, and have shown interesting pharmacological properties, especially curarizing and tetanizing, but also against malaria. Many monoterpene indole alkaloids have already been isolated and identified. Among them, there is strychnine, a famous alkaloid that can cause death by asphyxiation.
View Article and Find Full Text PDFThis data descriptor reports on the upload to a public repository (GNPS) of the IQAMDB, IsoQuinoline and Annonaceous Metabolites Data Base, comprising 320 tandem mass spectra. This project originated from our in-house collection of isoquinolines. The diversity of compounds included in this database was further extended through the contribution of two additional laboratories involved in isoquinoline alkaloids research: University of Angers and University of Manaus.
View Article and Find Full Text PDFThe structure elucidation of theionbrunonine C, a thioether-bridged dimeric monoterpene indole alkaloid (MIA), and more generally, one of the very few sulfur-containing MIA, is reported after its isolation from Mostuea brunonis (Gelsemiaceae). This unstable structure had already been targeted for isolation in our former, molecular network-guided, investigation of this plant, but this compound had degraded before sufficient spectroscopic data could have been acquired for a complete structure assignment. With this constraint in mind, the rapid acquisition of nuclear magnetic resonance (NMR) data enabled retrieving sufficient spectroscopic information for full structure elucidation, although from a partial set of spectroscopic information ( H and C NMR; COSY, HSQC, and HMBC).
View Article and Find Full Text PDFAnnonaceous acetogenins are natural products held responsible for atypical Parkinsonism due to chronic consumption in traditional medicine or as food, leading to the development of analytical strategies for their complete chemical characterization in complex mixtures. Characterization by tandem mass spectrometry (MS/MS) of acetogenins using collision-induced dissociation from lithium adducts provides additional structural information compared to protonated or sodiated species such as ketone location on the acetogenin backbone. However, very low intensity diagnostic ions together with the lack of extensive structural information regarding position of OH and THF substituents limit this approach.
View Article and Find Full Text PDFMelonine is a basic monoterpene indole alkaloid (MIA) skeleton from that was reported in 1983. The scarcity of its spectroscopic data questioned the validity of its structure. This prompted us to reisolate this molecule and to revise its structure into an unprecedented MIA scaffold.
View Article and Find Full Text PDFHemitheion (), a new sulfur-containing vobasane-type indole alkaloid, was isolated, together with three known compounds, vobasine (), gelsedine (), and gelsemicine (), from the alkaloid extract of the stems of Didr. (Gelsemiaceae). Compound could be straightforwardly isolated.
View Article and Find Full Text PDFPhytochemistry
November 2020
Four undescribed alkaloids have been isolated from the bulbs of the previously unstudied Crinum scillifolium. These compounds were targeted following a state-of-the-art molecular networking strategy comprising a dereplication against in silico databases and re-ranking of the candidate structures based on taxonomically informed scoring. The unreported structures span across a variety of Amaryllidaceae alkaloids appendages.
View Article and Find Full Text PDFFive new cassane-type diterpenoid heterosides, i. e. two cassane-type amides (1-2), two erythrophlamine-type amine esters (3-4) and a non‑nitrogenous erythrophlamine analogue (5) were isolated from the root barks (1-2) and the seeds (3-5) of Erythrophleum suaveolens.
View Article and Find Full Text PDFInaequalisines A and B ( and ), the first examples of hybrid alkylated phenylpropane monoterpene indole alkaloids, were isolated from the roots of , guided by the combined use of molecular networking and substructure annotation. Their structures, including absolute configuration, were elucidated by spectroscopic methods and ECD calculations. A possible biosynthetic pathway for and was postulated.
View Article and Find Full Text PDFBioassay guided fractionation of the stem barks of led to the isolation of a new lactone, apoprunellelactone (APL, ), and two known compounds, 5-[1-hydroxyhexyl]-2H-furan-2-one () and oleic acid (). Their structures were elucidated by spectral analysis including MS, UV, IR, 1D and 2D-NMR spectroscopy. Evaluated for its antiprotozoal activities, APL () was found to be the most active on and promastigotes with EC values of 16.
View Article and Find Full Text PDFEpicatechocorynantheines A and B, and epicatechocorynantheidine were isolated from the stem bark of . These molecules were pinpointed, and their isolation streamlined, by a molecular networking strategy. The structural elucidation was unambiguously accomplished from HRMS and 1D/2D NMR data.
View Article and Find Full Text PDFThe data are related to the research article entitled ''New cassane diterpenoids from the root bark of Erythrophleum suaveolens'' (Jacques et al., 2019). The article provides method of purification and data to determine structure of two novel cassane diterpenoid amines: 3β-hydroxy-3-methylbutanoyloxy-6α-hydroxy-nor-cassamine (1) and 3β-hydroxy-3-methylbutanoyloxy-erythrosuamine (2).
View Article and Find Full Text PDFDuring our research to contribute to the elucidation of the chemical composition of the root bark of , six non-nitrogenous cassane diterpenoids () were isolated and identified. Of these secondary metabolites, three have never been previously described: Cassan-13,15-dien-3-oxo-17-oic acid (), Cassan-15-en-[7,17]-γ-lactone () and 6-hydroxy-cassamic acid (). The other are known but, never isolated from the root barks of (Fabaceae): Cassan-13,15-dien-17-oic acid (), hydroxycassamic acid methyl esther () and cassamic acid ().
View Article and Find Full Text PDFTraditional natural products discovery workflows implying a combination of different targeting strategies, including structure- and/or bioactivity-based approaches, afford no information about new compound structures until late in the discovery pipeline. By integrating a MS/MS prediction module and a collaborative library of (bio)chemical transformations, we have developed a new platform, coined MetWork, that is capable of anticipating the structural identity of metabolites starting from any identified compound. In our quest to discover new monoterpene indole alkaloids, we demonstrate the utility of the MetWork platform by anticipating the structures of five previously undescribed sarpagine-like -oxide alkaloids that have been targeted and isolated from the leaves of using a molecular networking-based dereplication strategy fueled by computer-generated annotations.
View Article and Find Full Text PDFCovering: up to 2019Landmark advances in bioinformatics tools have recently enhanced the field of natural products research, putting today's natural product chemists in the enviable position of being able to perform the efficient targeting/discovery of previously undescribed molecules by expediting the prioritization of the isolation workflow. Among these advances, MS/MS molecular networking has appeared as a promising approach to dereplicate complex natural product mixtures, leading to a real revolution in the "art of natural product isolation" by accelerating the pace of research of this field. This review illustrates through selected cornerstone studies the new thinking in natural product isolation by drawing a parallel between the different underlying philosophies behind the use of molecular networking in targeting natural products.
View Article and Find Full Text PDFThis Data Descriptor announces the submission to public repositories of the monoterpene indole alkaloid database (MIADB), a cumulative collection of 172 tandem mass spectrometry (MS/MS) spectra from multiple research projects conducted in eight natural product chemistry laboratories since the 1960s. All data have been annotated and organized to promote reuse by the community. Being a unique collection of these complex natural products, these data can be used to guide the dereplication and targeting of new related monoterpene indole alkaloids within complex mixtures when applying computer-based approaches, such as molecular networking.
View Article and Find Full Text PDFTheionbrunonines A and B (1 and 2), the first examples of monoterpene bisindole alkaloids linked by a thioether bridge, were isolated from the stems of Mostuea brunonis, guided by a molecular networking-based dereplication strategy. Their structures were elucidated by a combination of spectroscopic data and ECD calculations. A plausible biosynthetic pathway for 1 and 2 was postulated.
View Article and Find Full Text PDFPleiokomenines A and B (1 and 2), first examples of dimeric aspidofractinine alkaloids linked by a methylene bridge, were isolated from the stem bark of Pleiocarpa mutica. Their structures were elucidated by a combination of spectroscopic analyses and semisynthetic derivatization of pleiocarpinine (3) and a formaldehyde equivalent mediated by scandium trifluoromethanesulfonate. Pleiokomenines A (1) and B (2) showed moderate antiplasmodial activities in the micromolar range against the FcB1 strain.
View Article and Find Full Text PDFIntroduction: Acetogenins are plant polyketides known to be cytotoxic and proposed as antitumor candidates. They are also suspected to be alimentary neurotoxins. Their occurrence as complex mixtures renders their dereplication and structural identification difficult using liquid chromatography coupled to tandem mass spectrometry and efforts are required to improve the methodology.
View Article and Find Full Text PDFThree new monoterpene indole alkaloids (1-3) have been isolated from the bark of Geissospermum laeve, together with the known alkaloids (-)-leuconolam (4), geissolosimine (5), and geissospermine (6). The structures of 1-3 were elucidated by analysis of their HRMS and NMR spectroscopic data. The absolute configuration of geissolaevine (1) was deduced from the comparison of experimental and theoretically calculated ECD spectra.
View Article and Find Full Text PDFAnnonaceous acetogenins (AAGs) are neurotoxins possibly responsible for atypical Parkinsonism/dementia clusters, via the consumption of edible Annonaceae fruits. Their presence was investigated in fruit pulps of Annona squamosa from different locations. Qualitative analysis of other AAGs was performed.
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