Distinguishing the molecular diversity, nutrient content, and energetic potential of exometabolomes produced by macroalgae and reef-building corals.

Metabolites exuded by primary producers comprise a significant fraction of marine dissolved organic matter, a poorly characterized, heterogenous mixture that dictates microbial metabolism and biogeochemical cycling. We present a foundational untargeted molecular analysis of exudates released by coral reef primary producers using liquid chromatography-tandem mass spectrometry to examine compounds produced by two coral species and three types of algae (macroalgae, turfing microalgae, and crustose coralline algae [CCA]) from Mo'orea, French Polynesia. Of 10,568 distinct ion features recovered from reef and mesocosm waters, 1,667 were exuded by producers; the majority (86%) were organism specific, reflecting a clear divide between coral and algal exometabolomes. These data allowed us to examine two tenets of coral reef ecology at the molecular level. First, stoichiometric analyses show a significantly reduced nominal carbon oxidation state of algal exometabolites than coral exometabolites, illustrating one ecological mechanism by which algal phase shifts engender fundamental changes in the biogeochemistry of reef biomes. Second, coral and algal exometabolomes were differentially enriched in organic macronutrients, revealing a mechanism for reef nutrient-recycling. Coral exometabolomes were enriched in diverse sources of nitrogen and phosphorus, including tyrosine derivatives, oleoyl-taurines, and acyl carnitines. Exometabolites of CCA and turf algae were significantly enriched in nitrogen with distinct signals from polyketide macrolactams and alkaloids, respectively. Macroalgal exometabolomes were dominated by nonnitrogenous compounds, including diverse prenol lipids and steroids. This study provides molecular-level insights into biogeochemical cycling on coral reefs and illustrates how changing benthic cover on reefs influences reef water chemistry with implications for microbial metabolism.

Chemometrics and genome mining reveal an unprecedented family of sugar acid-containing fungal nonribosomal cyclodepsipeptides.

Xylomyrocins, a unique group of nonribosomal peptide secondary metabolites, were discovered in Paramyrothecium and Colletotrichum spp. fungi by employing a combination of high-resolution tandem mass spectrometry (HRMS/MS)-based chemometrics, comparative genome mining, gene disruption, stable isotope feeding, and chemical complementation techniques. These polyol cyclodepsipeptides all feature an unprecedented d-xylonic acid moiety as part of their macrocyclic scaffold. This biosynthon is derived from d-xylose supplied by xylooligosaccharide catabolic enzymes encoded in the xylomyrocin biosynthetic gene cluster, revealing a novel link between carbohydrate catabolism and nonribosomal peptide biosynthesis. Xylomyrocins from different fungal isolates differ in the number and nature of their amino acid building blocks that are nevertheless incorporated by orthologous nonribosomal peptide synthetase (NRPS) enzymes. Another source of structural diversity is the variable choice of the nucleophile for intramolecular macrocyclic ester formation during xylomyrocin chain termination. This nucleophile is selected from the multiple available alcohol functionalities of the polyol moiety, revealing a surprising polyspecificity for the NRPS terminal condensation domain. Some xylomyrocin congeners also feature N-methylated amino acid residues in positions where the corresponding NRPS modules lack N-methyltransferase (M) domains, providing a rare example of promiscuous methylation in the context of an NRPS with an otherwise canonical, collinear biosynthetic program.

Decreased metabolic diversity in common beans associated with domestication revealed by untargeted metabolomics, information theory, and molecular networking.

The process of crop domestication leads to a dramatic reduction in the gene expression associated with metabolic diversity. Genes involved in specialized metabolism appear to be particularly affected. Although there is ample evidence of these effects at the genetic level, a reduction in diversity at the metabolite level has been taken for granted despite having never been adequately accessed and quantified. Here we leveraged the high coverage of ultra high performance liquid chromatography-high-resolution mass spectrometry based metabolomics to investigate the metabolic diversity in the common bean (Phaseolus vulgaris). Information theory highlights a shift towards lower metabolic diversity and specialization when comparing wild and domesticated bean accessions. Moreover, molecular networking approaches facilitated a broader metabolite annotation than achieved to date, and its integration with gene expression data uncovers a metabolic shift from specialized metabolism towards central metabolism upon domestication of this crop.

Unveiling biosynthetic potential of an Arctic marine-derived strain Aspergillus sydowii MNP-2.

BACKGROUND: A growing number of studies have demonstrated that the polar regions have the potential to be a significant repository of microbial resources and a potential source of active ingredients. Genome mining strategy plays a key role in the discovery of bioactive secondary metabolites (SMs) from microorganisms. This work highlighted deciphering the biosynthetic potential of an Arctic marine-derived strain Aspergillus sydowii MNP-2 by a combination of whole genome analysis and antiSMASH as well as feature-based molecular networking (MN) in the Global Natural Products Social Molecular Networking (GNPS). RESULTS: In this study, a high-quality whole genome sequence of an Arctic marine strain MNP-2, with a size of 34.9 Mb was successfully obtained. Its total number of genes predicted by BRAKER software was 13,218, and that of non-coding RNAs (rRNA, sRNA, snRNA, and tRNA) predicted by using INFERNAL software was 204. AntiSMASH results indicated that strain MNP-2 harbors 56 biosynthetic gene clusters (BGCs), including 18 NRPS/NRPS-like gene clusters, 10 PKS/PKS-like gene clusters, 8 terpene synthse gene clusters, 5 indole synthase gene clusters, 10 hybrid gene clusters, and 5 fungal-RiPP gene clusters. Metabolic analyses of strain MNP-2 grown on various media using GNPS networking revealed its great potential for the biosynthesis of bioactive SMs containing a variety of heterocyclic and bridge-ring structures. For example, compound G-8 exhibited a potent anti-HIV effect with an IC50 value of 7.2 nM and an EC50 value of 0.9 nM. Compound G-6 had excellent in vitro cytotoxicities against the K562, MCF-7, Hela, DU145, U1975, SGC-7901, A549, MOLT-4, and HL60 cell lines, with IC50 values ranging from 0.10 to 3.3 µM, and showed significant anti-viral (H1N1 and H3N2) activities with IC50 values of 15.9 and 30.0 µM, respectively. CONCLUSIONS: These findings definitely improve our knowledge about the molecular biology of genus A. sydowii and would effectively unveil the biosynthetic potential of strain MNP-2 using genomics and metabolomics techniques.

Severe 25E-NBOH intoxication associated with MDPHP intake: a case report, metabolism study, and literature review.

N-Benzylphenethylamine derivatives are 5-HT2A receptor agonists with hallucinogenic properties, including NBOMe (N-(2-methoxybenzyl)-2-(3,4,5-trimethoxyphenyl)ethan-1-amine) and NBOH (2-(((2,5-dimethoxyphenethyl)amino)methyl)phenol). We reported here the case of a 23-year-old man who presented a serotoninergic syndrome and a loss of consciousness following the consumption of a powder labelled as 25I-NBOH. Toxicological analyses of biological samples were carried out using a liquid chromatography high-resolution mass spectrometry. Two new psychoactive substances were identified and confirmed with certified reference materials: 25E-NBOH (2-(((4-ethyl-2,5-dimethoxyphenethyl)amino)methyl)phenol) and MDPHP (1-(benzo[d][1,3]dioxol-5-yl)-2-(pyrrolidin-1-yl)hexan-1-one). Pharmaceuticals administered to the patient during his medical care were found in plasma and urine. 25E-NBOH and MDPHP concentrations were respectively at 2.3 ng/mL and 3.4 ng/mL in plasma, and 25.7 ng/mL and 30.5 ng/mL in urine. 25I-NBOH (2-(((4-iodo-2,5-dimethoxyphenethyl)amino)methyl)phenol) was specifically searched in both samples and was not detected. These results are discussed along with a literature review on human cases of exposure to N-benzylphenethylamine derivatives. Using molecular networking approach, we propose the first 25E-NBOH metabolism study using authentic biological samples (plasma and urine). We described seven metabolites (M1 to M7), including two phase I (m/z 330.172; m/z 288.160) and five phase II metabolites (m/z 464.191, m/z 478.207, m/z 492.223, m/z 508.218; m/z 396.156). The M6 (m/z 492.223) was the most intense ion detected in plasma and urine and could be proposed as a relevant 25E-NBOH consumption marker. Overall, we described an original case of 25E-NBOH poisoning and identified metabolites that could potentially be used as consumption markers to detect 25E-NBOH intoxications with a higher confidence level and probably a longer detection window.

Spatial and Temporal Resolution of Cyanobacterial Bloom Chemistry Reveals an Open-Ocean Trichodesmium thiebautii as a Talented Producer of Specialized Metabolites.

While the ecological role that Trichodesmium sp. play in nitrogen fixation has been widely studied, little information is available on potential specialized metabolites that are associated with blooms and standing stock Trichodesmium colonies. While a collection of biological material from a T. thiebautii bloom event from North Padre Island, Texas, in 2014 indicated that this species was a prolific producer of chlorinated specialized metabolites, additional spatial and temporal resolution was needed. We have completed these metabolite comparison studies, detailed in the current report, utilizing LC-MS/MS-based molecular networking to visualize and annotate the specialized metabolite composition of these Trichodesmium blooms and colonies in the Gulf of Mexico (GoM) and other waters. Our results showed that T. thiebautii blooms and colonies found in the GoM have a remarkably consistent specialized metabolome. Additionally, we isolated and characterized one new macrocyclic compound from T. thiebautii, trichothilone A (1), which was also detected in three independent cultures of T. erythraeum. Genome mining identified genes predicted to synthesize certain functional groups in the T. thiebautii metabolites. These results provoke intriguing questions of how these specialized metabolites affect Trichodesmium ecophysiology, symbioses with marine invertebrates, and niche development in the global oligotrophic ocean.

Identification of Additives in Disposable Face Masks and Evaluation of Their Toxicity Using Marine Medaka (Oryzias melastigma).

The COVID-19 pandemic has resulted in huge amounts of face masks worldwide. However, there is a lack of awareness on the additives and their potential risk to aquatic ecosystems of face masks. To address this issue, the additives and their toxicity in 13 face masks (e.g., polypropylene, polyethylene, and polylactic acid) were determined using nontarget analysis and bioassays. A total of 826 organic additives including intermediates (14.8%), surfactants (9.3%), plasticizers (8.2%), and antioxidants (6.1%) were tentatively identified, with 213 compounds being assigned confidence levels of 1 and 2. Interestingly, polylactic acid masks contained more additives than most polypropylene or polyethylene masks. Among these additives, the concentration of tris(2-ethylhexyl) phosphate in masks was 9.4-978.2 ng/g with a 100% detection frequency. Furthermore, 13 metals such as zinc (up to 202.0 µg/g), copper (32.5 µg/g), and chromium (up to 5.7 µg/g) were detected in the face masks. The methanol extracts of the masks showed the developmental toxicity, swimming behavior, and/or endocrine disruption in embryos/larvae of Oryzias melastigma. The findings demonstrate that face masks contain various toxic additives to marine medaka, which deserves close attention to pollution by face masks.

Electron-activated dissociation (EAD) for the complementary annotation of metabolites and lipids through data-dependent acquisition analysis and feature-based molecular networking, applied to the sentinel amphipod Gammarus fossarum.

The past decades have marked the rise of metabolomics and lipidomics as the -omics sciences which reflect the most phenotypes in living systems. Mass spectrometry-based approaches are acknowledged for both quantification and identification of molecular signatures, the latter relying primarily on fragmentation spectra interpretation. However, the high structural diversity of biological small molecules poses a considerable challenge in compound annotation. Feature-based molecular networking (FBMN) combined with database searches currently sets the gold standard for annotation of large datasets. Nevertheless, FBMN is usually based on collision-induced dissociation (CID) data, which may lead to unsatisfying information. The use of alternative fragmentation methods, such as electron-activated dissociation (EAD), is undergoing a re-evaluation for the annotation of small molecules, as it gives access to additional fragmentation routes. In this study, we apply the performances of data-dependent acquisition mass spectrometry (DDA-MS) under CID and EAD fragmentation along with FBMN construction, to perform extensive compound annotation in the crude extracts of the freshwater sentinel organism Gammarus fossarum. We discuss the analytical aspects of the use of the two fragmentation modes, perform a general comparison of the information delivered, and compare the CID and EAD fragmentation pathways for specific classes of compounds, including previously unstudied species. In addition, we discuss the potential use of FBMN constructed with EAD fragmentation spectra to improve lipid annotation, compared to the classic CID-based networks. Our approach has enabled higher confidence annotations and finer structure characterization of 823 features, including both metabolites and lipids detected in G. fossarum extracts.

Chaetoxylariones A-G: undescribed chromone-derived polyketides from co-culture of Chaetomium virescens and Xylaria grammica enabled via the molecular networking strategy.

By co-culturing two endophytic fungi (Chaetomium virescens and Xylaria grammica) collected from the medicinal and edible plant Smilax glabra Roxb. and analyzing them with MolNetEnhancer module on GNPS platform, seven undescribed chromone-derived polyketides (chaetoxylariones A-G), including three pairs of enantiomer ones (2a/2b, 4a/4b and 6a/6b) and four optical pure ones (1, 3, 5 and 7), as well as five known structural analogues (8-12), were obtained. The structures of these new compounds were characterized by NMR spectroscopy, single-crystal X-ray diffraction, 13C NMR calculation and DP4+ probability analyses, as well as the comparison of the experimental electronic circular dichroism (ECD) data. Structurally, compound 1 featured an unprecedented chromone-derived sulfonamide tailored by two isoleucine-derived δ-hydroxy-3-methylpentenoic acids via the acylamide and NO bonds, respectively; compound 2 represented the first example of enantiomeric chromone derivative bearing a unique spiro-[3.3]alkane ring system; compound 3 featured a decane alkyl side chain that formed an undescribed five-membered lactone ring between C-7' and C-10'; compound 4 contained an unexpected highly oxidized five-membered carbocyclic system featuring rare adjacent keto groups; compound 7 featured a rare methylsulfonyl moiety. In addition, compound 10 showed a significant inhibition towards SW620/AD300 cells with an IC50 value of PTX significantly decreased from 4.09 µM to 120 nM, and a further study uncovered that compound 10 could obviously reverse the MDR of SW620/AD300 cells.

(±)-Hypernumqulins A-H: Eight pairs of unexpected [2+2] cycloaddition sesquiterpenoid alkaloid with 6/6/6/4/10 ring system from Hypericum monogynum L.

(±)-Hypernumqulins A-H (1-8), eight pairs of enantiomeric quinoline alkaloids fused with an isopentenyl and a germacrane-type sesquiterpenoid, featuring an unprecedented skeleton with 6/6/6/4/10 ring system, were isolated from Hypericum monogynum L. under the guidance of molecular networking strategy. Their structures including absolute configuration were elucidated by NMR spectroscopy analysis, X-ray crystallography and quantum chemical calculation. The proposed [2+2] cycloaddition may play a key biogenic step in building the unexpected skeleton. Most of the isolates exhibited cytotoxicity with IC50 values ranging from 2.82 ± 0.03 to 45.25 ± 1.26 µM against MCF-7, A549 or SGC7901 cells. Furthermore, compounds (±)-1 and (-)-1 could induce apoptosis by upregulating the protein expression level of Bax and downregulating of Bcl-2 in MCF-7 cells. These findings provided the first example of germacrane sesquiterpene quinoline alkaloids, and supported the possibilities for the development of new anti-tumor agents.

Testacosides A-D, glycoglycerolipids produced by Microbacterium testaceum isolated from Tedania brasiliensis.

Marine bacteria living in association with marine sponges have proven to be a reliable source of biologically active secondary metabolites. However, no studies have yet reported natural products from Microbacterium testaceum spp. We herein report the isolation of a M. testaceum strain from the sponge Tedania brasiliensis. Molecular networking analysis of bioactive pre-fractionated extracts from culture media of M. testaceum enabled the discovery of testacosides A-D. Analysis of spectroscopic data and chemical derivatizations allowed the identification of testacosides A-D as glycoglycerolipids bearing a 1-[α-glucopyranosyl-(1 → 3)-(α-mannopyranosyl)]-glycerol moiety connected to 12-methyltetradecanoic acid for testacoside A (1), 14-methylpentadecanoic acid for testacoside B (2), and 14-methylhexadecanoic acid for testacosides C (3) and D (4). The absolute configuration of the monosaccharide residues was determined by 1H-NMR analysis of the respective diastereomeric thiazolidine derivatives. This is the first report of natural products isolated from cultures of M. testaceum. KEY POINTS: • The first report of metabolites produced by Microbacterium testaceum. • 1-[α-Glucopyranosyl-(1 → 3)-(α-mannopyranosyl)]-glycerol lipids isolated and identified. • Microbacterium testaceum strain isolated from the sponge Tedania brasiliensis.

Rapid identification of the compounds of Bushen Huoxue Prescription based on offline two-dimensional liquid chromatography with high-resolution mass spectrometry and molecular network technology.

The comprehensive and efficient characterization of components in traditional Chinese medicine is crucial for elucidating its active constituents and uncovering its mechanism. Identifying the compounds of the Bushen Huoxue Prescription (BHP) is difficult because of its complex composition and the large difference in concentration among its compounds. In this study, a hydrophilic interaction liquid chromatography coupled with reversed-phase LC (HILIC × RPLC) offline 2D-LC tandem high-resolution mass spectrometry method was established to analyze the total compounds of the BHP. Database screening and molecular networking were performed to identify the compounds. In contrast to conventional 1D chromatography, 2D chromatography increased peak capacity, enriched trace ingredients, and prevented the masking of high-abundance compounds. A total of 165 compounds were identified, and 14 potential compounds needed to be further identified. This study provided an effective method for comprehensively analyzing the complex system of traditional Chinese medicine compounds.

Identification, synthesis and quantification of eutylone consumption markers in a chemsex context.

Eutylone is a cathinone-derived synthetic amphetamine scheduled by the World Health Organization and European Monitoring Centre for Drugs and Drug Addiction since 2022 due to its growing consumption. We report here an eutylone intoxication involving a 38-year-old man and a 29-year-old woman in a chemsex context. A bag containing a white crystalline powder labelled as a research product was found in their vehicle. Nuclear magnetic resonance and liquid chromatography-high-resolution mass spectrometry (LC-HRMS) analyses identified the powder as eutylone and confirmed purity superior to 99%. LC-HRMS data analysis using molecular networking allowed to propose new eutylone metabolites in blood samples in a graphical manner. We described 16 phase I (e.g. hydroxylated or demethylated) and phase II metabolites (glucuroconjugates and sulfoconjugates). The same metabolites were found both in male and female blood samples. Toxicological analyses measured eutylone concentration in blood samples at 1374 ng/mL and 1536 ng/mL for the man and the woman, respectively. A keto-reduced metabolite (m/z 238.144) was synthesized to permit its quantification at 67 ng/mL and 54 ng/mL in male and female blood samples, respectively. Overall, the identification of these metabolites will increase the knowledge of potential drug consumption markers and allow to implement mass spectrometry databases to better monitor future drug abuse or consumption.

Hirsutinolide- and Cadinanolide-type Sesquiterpene Lactones from Lessingianthus rubricaulis (Vernonieae, Asteraceae).

Sesquiterpene lactones are an important class of secondary metabolites frequently isolated from Lessingianthus genus that present a variety of biological properties, such as antimalarial, anti-inflammatory, antileishmanial, antitrypanosomal and anticancer. The limited phytochemical studies and the importance of this class of compounds isolated from Lessingianthus led us to study this genus. In this work, we focused on the phytochemical investigation and dereplication based on UHPLC-HRMS/MS and molecular networking of L. rubricaulis. Chemical investigation resulted in the isolation of several hirsutinolide-type sesquiterpene lactones including a new hirsutinolide derivative, 8,10α-hydroxy-1,13-bis-O-methylhirsutinolide, besides a cadinanolide and flavonoids. The dereplication study resulted in the identification of three known flavonoids, six known hirsutinolides and two known cadinanolides. Moreover, a fragmentation pathway for cadinanolide-type sesquiterpene lactones was proposed. These results contribute to chemotaxonomic studies and demonstrates the potential of Lessingianthus genus.

Antidiabetic Potential of a Trimeric Anthranilic Acid Peptide Isolated from Malbranchea flocciformis.

Compound 3, a trimeric anthranilic acid peptide, and another three metabolites were isolated from an organic extract from the culture medium of Malbranchea flocciformis ATCC 34530. The chemical structure proposed previously for 3 was unequivocally assigned via synthesis and X-ray diffraction analysis. Tripeptide 3 showed insulinotropic properties by decreasing the postprandial peak in healthy and hyperglycemic mice. It also increased glucose-induced insulin secretion in INS-1E at 5 µM, specifically at higher glucose concentrations. These results revealed that 3 might act as an insulin sensitizer and a non-classical insulin secretagogue. Altogether, these findings are in harmony with the in vivo oral glucose tolerance test and acute oral hypoglycemic assay. Finally, the chemical composition of the extract was established by the Global Natural Products Social Molecular Network platform. Phylogenetic analysis using the internal transcribed spacer region revealed that M. flocciformis ATCC 34530 is related to the Malbrancheaceae.

Biosynthetic pathway analysis combined with feature-based molecular networking to comprehensively characterize the chemical constituents in seeds of Sterculia lychnophora.

INTRODUCTION: The seeds of Sterculia lychnophora Hance, commonly known as Pangdahai (PDH) in Chinese, have found extensive use in both culinary and traditional medicinal practices. However, a comprehensive understanding of the chemical composition of PDH has been lacking. OBJECTIVES: This study proposes a strategy that integrates biosynthetic pathway analysis with feature-based molecular networking (FBMN), aiming for a thorough and global characterization of the chemical compositions of PDH. METHODOLOGY: The FBMN map reveals potential compounds with structural similarity, and the MS/MS fragments could be annotated based on library matches, which could predict the plausible biosynthetic pathways in PDH, accomplishing the annotation of compounds clustered in FBMN by integrating biosynthetic pathways. RESULTS: Consequently, 126 compounds were plausibly or unambiguously identified, including 37 phenolic acids and glycosides, 20 flavonoids and glycosides, 12 procyanidins, 21 alkaloids, 22 lipids, and 14 others. Leveraging the information, 40 compounds, including 1 unique isoquinoline alkaloid and 2 rare linear furocoumarins, were isolated and confirmed. CONCLUSIONS: This study not only demonstrates a highly effective approach for identifying compounds within complex herbal mixtures but also establishes a robust foundation for the further development of PDH.

Application of molecular networking to improve the compound annotation in liquid chromatography-mass spectrometry-based metabolomics analysis: A case study of Bupleuri radix.

INTRODUCTION: Compound annotation is always a challenging step in metabolomics studies. The molecular networking strategy has been developed recently to organize the relationship between compounds as a network based on their tandem mass (MS2) spectra similarity, which can be used to improve compound annotation in metabolomics analysis. OBJECTIVE: This study used Bupleuri Radix from different geographic areas to evaluate the performance of molecular networking strategy for compound annotation in liquid chromatography-mass spectrometry (LC-MS)-based metabolomics. METHODOLOGY: The Bupleuri Radix extract was analyzed by LC-quadrupole time-of-flight MS under MSe acquisition mode. After raw data preprocessing, the resulting dataset was used for statistical analysis, including principal component analysis (PCA) and partial least squares discriminant analysis (PLS-DA). The chemical makers related to the sample growth place were selected using variable importance in projection (VIP) > 2, fold change (FC) > 2, and p < 0.05. The molecular networking analysis was applied to conduct the compound annotation. RESULTS: The score plots of PCA showed that the samples were classified into two clusters depending on their growth place. Then, the PLS-DA model was constructed to explore the chemical changes of the samples further. Sixteen compounds were selected as chemical makers and tentatively annotated by the feature-based molecular networking (FBMN) analysis. CONCLUSION: The results showed that the molecular networking method fully exploits the MS information and is a promising tool for facilitating compound annotation in metabolomics studies. However, the software used for feature extraction influenced the results of library searching and molecular network construction, which need to be taken into account in future studies.

Tandem mass spectrometry (MS/MS) molecular networking guided profiling of small molecules from Aquilaria sinensis (Lour.) Gilg leaves and their bioactivity evaluation.

INTRODUCTION: Agarwood, a fragrant resinous wood mainly formed by Aquilaria spp., is used worldwide as a natural fragrance and traditional medicine. A large amount of Aquilaria sinensis (Lour.) Gilg leaves are underutilised during the process of the agarwood industry, and the development of A. sinensis leaves as tea has recently attracted more and more attention. However, the small molecule profile of A. sinensis leaves and their bioactivities has been rarely reported. OBJECTIVE: To conduct a rapid untargeted liquid chromatography-mass spectrometry (LC-MS) analysis of A. sinensis leaves with a molecular networking (MN) strategy and evaluate its antioxidant and antidiabetic value. METHOD: A MN-assisted tandem mass spectrometry (MS/MS) analysis strategy was used to investigate the small molecule profile of A. sinensis leaves. Additionally, the integration of antioxidant and α-glucosidase inhibitory assays with MN analysis was executed to expeditiously characterise the bioactive compounds for potential prospective application. RESULTS: Five main chemical groups including phenol C-glycosides, organic acids, 2-(2-phenylethyl) chromones, benzophenone O-glycosides and flavonoids were rapidly revealed from the A. sinensis leaves. Eighty-one compounds were provisionally identified by comparing their MS/MS fragments with canonical pathways. The featured xanthone C-glycosides and benzophenone C-glycosides were recognised as the primary components of A. sinensis leaves. Several dimers and a trimer of mangiferin were reported firstly in A. sinensis leaves. Furthermore, 17 and 14 potential bioactive molecules were rapidly annotated from antioxidant and α-glucosidase inhibitory fraction, respectively. CONCLUSION: Our findings will help expand the utilisation of A. sinensis leaves and thus promote the high-quality development of agarwood industry.

Targeted chemical profiling for p-HAP glycosides by using molecular networking and comparative analysis of their contents between Artemisia japonica and Artemisia capillaris.

A total of 65 phenolic acid compounds were annotated or identified by UHPLC-MS/MS method, among them, 17 p-HAP (p-hydroxyacetophenone) glycosides were firstly targeted profiled based on molecular networking. Their characteristic product ions of MS/MS spectra were found and examined on the guideline of targeted isolation. As a result, a new p-HAP glycoside was thus obtained and determined as 2'-O-caffeoyl-p-HAP-4-O-ß-D-glucopyranoside (33) based on 1D and 2D NMR data. Besides, multicomponents quantitative analysis indicated the distinct regional variability in chemicals distribution of A. japonica, and meanwhile, the contents of p-HAP glycosides from A. japonica were higher than those in A. capillaris as a whole, which further suggested the potential medicinal value of A. japonica.

Computational Methods Reveal a Series of Cyclic and Linear Lichenysins and Surfactins from the Vietnamese Marine Sediment-Derived Streptomyces Strain G222.

The Streptomyces strain G222, isolated from a Vietnamese marine sediment, was confidently identified by 16S rRNA gene sequencing. Its AcOEt crude extract was successfully analyzed using non-targeted LC-MS/MS analysis, and molecular networking, leading to a putative annotation of its chemical diversity thanks to spectral libraries from GNPS and in silico metabolite structure prediction obtained from SIRIUS combined with the bioinformatics tool conCISE (Consensus Annotation Propagation of in silico Elucidations). This dereplication strategy allowed the identification of an interesting cluster of a series of putative cyclic and linear lipopeptides of the lichenysin and surfactin families. Lichenysins (3-7) were isolated from the sub-fraction, which showed significant anti-biofilm activity against Pseudomonas aeruginosa MUC-N1. Their structures were confirmed by detailed 1D and 2D NMR spectroscopy (COSY, HSQC, HMBC, TOCSY, ROESY) recorded in CD3OH, and their absolute configurations were determined using the modified Marfey's method. The isolated lichenysins showed anti-biofilm activity at a minimum concentration of 100 µM. When evaluated for antibacterial activity against a panel of Gram-positive and Gram-negative strains, two isolated lichenysins exhibited selective activity against the MRSA strain without affecting its growth curve and without membranotropic activity. This study highlights the power of the MS/MS spectral similarity strategy using computational methods to obtain a cross-validation of the annotated molecules from the complex metabolic profile of a marine sediment-derived Streptomyces extract. This work provides the first report from a Streptomyces strain of combined cyclic and linear lichenysins and surfactins, known to be characteristic compounds of the genus Bacillus.