Feature-based molecular networking and MS2LDA analysis for the dereplication of adjacent bis-tetrahydrofuran Annonaceous acetogenins.

INTRODUCTION: Annonaceous acetogenins are a group of natural polyketide compounds possessing notable cytotoxic and antitumor properties. Mass spectrometry (MS) techniques can be used for the structural determination of these compounds, including the location of functional groups along the long alkyl chain. OBJECTIVE: This study aims to develop a convenient liquid chromatography (LC)-MS-based method for the dereplication of acetogenins in plant extracts using a molecular networking approach. METHODOLOGY: The LC-electrospray ionization (ESI)-MS/MS spectra of pure adjacent bis-tetrahydrofuran (THF) acetogenins isolated from Uvaria rufa (Annonaceae) were acquired, along with those of the crude ethyl acetate and hexanes fractions of the plant extract, followed by dereplication and molecular networking analysis using the Global Natural Products Social Molecular Networking (GNPS) platform. RESULTS: A high level of fragmentation of the protonated molecules [M + H]+ was observed at collision energies of 37.5 and 25.0 eV. The application of feature-based molecular networking (FBMN) allowed for distinguishing diastereoisomers based on different retention times in the reversed-phase high-performance liquid chromatography method. The acetogenin possessing one or more additional OH groups on the methyl-terminal chain side of the OH-flanked bis-THF ring unit were grouped separately from those lacking such substructure. Furthermore, the MS2LDA analysis revealed shared Mass2Motifs among acetogenins, confirming the structural relations within the molecular network. CONCLUSIONS: The ESI-MS/MS-based molecular networking method provided an effective strategy for the dereplication of acetogenins in plant extracts. It is anticipated that this molecular networking approach could be extended to other types of acetogenins to facilitate rapid identification of this class of compounds.

Metabolites profiling of Sapota fruit pulp via a multiplex approach of gas and ultra performance liquid chromatography/mass spectroscopy in relation to its lipase inhibition effect.

Background: Sapota, Manilkara zapota L., are tasty, juicy, and nutrient-rich fruits, and likewise used for several medicinal uses. Methods: The current study represents an integrated metabolites profiling of sapota fruits pulp via GC/MS and UPLC/MS, alongside assessment of antioxidant capacity, pancreatic lipase (PL), and α-glucosidase enzymes inhibitory effects. Results: GC/MS analysis of silylated primary polar metabolites led to the identification of 68 compounds belonging to sugars (74%), sugar acids (18.27%), and sugar alcohols (7%) mediating the fruit sweetness. Headspace SPME-GC/MS analysis led to the detection of 17 volatile compounds belonging to nitrogenous compounds (72%), ethers (7.8%), terpenes (7.6%), and aldehydes (5.8%). Non-polar metabolites profiling by HR-UPLC/MS/MS-based Global Natural Products Social (GNPS) molecular networking led to the assignment of 31 peaks, with several novel sphingolipids and fatty acyl amides reported for the first time. Total phenolic content was estimated at 6.79 ± 0.12 mg gallic acid equivalent/gram extract (GAE/g extract), but no flavonoids were detected. The antioxidant capacities of fruit were at 1.62 ± 0.2, 1.49 ± 0.11, and 3.58 ± 0.14 mg Trolox equivalent/gram extract (TE/g extract) via DPPH, ABTS, and FRAP assays, respectively. In vitro enzyme inhibition assays revealed a considerable pancreatic lipase inhibition effect (IC50 = 2.2 ± 0.25 mg/mL), whereas no inhibitory effect towards α-glucosidase enzyme was detected. This study provides better insight into sapota fruit's flavor, nutritional, and secondary metabolites composition mediating for its sensory and health attributes.

An Integrated Strategy of UHPLC-ESI-MS/MS Combined with Bioactivity-Based Molecular Networking for Identification of Antitumoral Withanolides from Athenaea fasciculata (Vell.) I.M.C. Rodrigues & Stehmann.

BACKGROUND: Athenaea fasciculata, a Brazilian native species from the Solanaceae family, is recognized as a promising source of bioactive withanolides, particularly Aurelianolide A and B, which exhibit significant antitumoral activities. Despite its potential, research on the chemical constituents of this species remains limited. This study aimed to dereplicate extracts and partitions of A. fasciculata to streamline the discovery of bioactive withanolides. METHODS: Using ultra-high-performance liquid chromatography-tandem mass spectrometry (UHPLC-MS/MS), various extracts-including n-hexane, methanol, and ethanol-were analyzed, and their mass spectrometry data were processed through the GNPS platform for the generation of molecular networking. The results indicated that crude extracts displayed comparable cytotoxicity against Jurkat cells, by treatment at 150 µg/mL, while alcoholic extracts achieved approximately 80% inhibition of K562 cells and K562-Lucena 1 at the same concentration. Notably, the dichloromethane partition exhibited the highest cytotoxicity across leukemia cell lines, particularly against Jurkat cells (IC50 = 14.34 µg/mL). A total of 22 compounds were annotated by manual inspection and different libraries, with six of them demonstrating significant cytotoxic effects. CONCLUSIONS: This research underscores the therapeutic potential of A. fasciculata and highlights the effectiveness of integrating advanced analytical methods in drug discovery, paving the way for further exploration of its bioactive compounds.

Interaction of Acinetobacter sp. RIT 592 induces the production of broad-spectrum antibiotics in Exiguobacterium sp. RIT 594.

Antimicrobial resistance (AMR) is one of the most alarming global public health challenges of the 21st century. Over 3 million antimicrobial-resistant infections occur in the United States annually, with nearly 50,000 cases being fatal. Innovations in drug discovery methods and platforms are crucial to identify novel antibiotics to combat AMR. We present the isolation and characterization of potentially novel antibiotic lead compounds produced by the cross-feeding of two rhizosphere bacteria, Acinetobacter sp. RIT 592 and Exiguobacterium sp. RIT 594. We used solid-phase extraction (SPE) followed by liquid chromatography (LC) to enrich antibiotic extracts and subsequently mass spectrometry (MS) analysis of collected fractions for compound structure identification and characterization. The MS data were processed through the Global Natural Product Social Molecular Networking (GNPS) database. The supernatant from RIT 592 induced RIT 594 to produce a cocktail of antimicrobial compounds active against Gram-positive and negative bacteria. The GNPS analysis indicated compounds with known antimicrobial activity in the bioactive samples, including oligopeptides and their derivatives. This work emphasizes the utility of microbial community-based platforms to discover novel clinically relevant secondary metabolites. Future work includes further structural characterization and antibiotic activity evaluation of the individual compounds against pathogenic multidrug-resistant (MDR) bacteria.

Characterization of the Phytotoxic Potential of Seven Copaifera spp. Essential Oils: Analyzing Active Compounds through Gas Chromatography-Mass Spectrometry Molecular Networking.

In recent years, there has been a need for environmentally friendly compounds for weed management in agriculture. This study is aimed to assess the phytotoxic constituents of oils obtained from oleoresins of seven Copaifera species (known as copaiba oils). Copaiba oils were separated from the resins by hydro-distillation, and the distillates were analyzed using gas chromatography-mass spectrometry (GC-MS) to characterize their chemical compositions. Multivariate analyses and molecular networking of GC-MS data were conducted to discern patterns in the chemical composition and phytotoxic activity of the oils, with the aim of identifying key compounds associated with phytotoxic activity. Seed germination bioassay revealed strong or complete germination inhibition against the monocot, Agrostis stolonifera but not the dicot Lactuca sativa. GC-MS analysis showed variations in composition among Copaifera species with some common compounds identified across multiple species. Caryophyllene oxide and junenol were associated with the observed phytotoxic effects. Automated flash chromatography was used to isolate the major compounds of the oils. Isolated compounds exhibited differing levels of phytotoxicity compared to the oils, suggesting the importance of interactions or synergism among oil components. These findings highlight the potential of copaiba oils as natural herbicidal agents and underscore the importance of considering species-specific responses in weed management strategies.

Hybrid nanocomposites impact on heat transfer efficiency and pressure drop in turbulent flow systems: application of numerical and machine learning insights.

This research explores the feasibility of using a nanocomposite from multi-walled carbon nanotubes (MWCNTs) and graphene nanoplatelets (GNPs) for thermal engineering applications. The hybrid nanocomposites were suspended in water at various volumetric concentrations. Their heat transfer and pressure drop characteristics were analyzed using computational fluid dynamics and artificial neural network models. The study examined flow regimes with Reynolds numbers between 5000 and 17,000, inlet fluid temperatures ranging from 293.15 to 333.15 K, and concentrations from 0.01 to 0.2% by volume. The numerical results were validated against empirical correlations for heat transfer coefficient and pressure drop, showing an acceptable average error. The findings revealed that the heat transfer coefficient and pressure drop increased significantly with higher inlet temperatures and concentrations, achieving approximately 45.22% and 452.90%, respectively. These results suggested that MWCNTs-GNPs nanocomposites hold promise for enhancing the performance of thermal systems, offering a potential pathway for developing and optimizing advanced thermal engineering solutions.

Extraction and Depolymerization of Lignin from Different Agricultural and Forestry Wastes to Obtain Building Blocks in a Circular Economy Framework.

Large amounts of agri-food waste are generated and discarded annually, but they have the potential to become highly profitable sources of value-added compounds. Many of these are lignin-rich residues. Lignin, one of the most abundant biopolymers in nature, offers numerous possibilities as a raw material or renewable resource for the production of chemical products. This study aims to explore the potential revalorization of agricultural by-products through the extraction of lignin and subsequent depolymerization. Different residues were studied; river cane, rice husks, broccoli stems, wheat straw, and olive stone are investigated (all local wastes that are typically incinerated). Traditional soda extraction, enhanced by ultrasound, is applied, comparing two different sonication methods. The extraction yields from different residues were as follows: river cane (28.21%), rice husks (24.27%), broccoli (6.48%), wheat straw (17.66%), and olive stones (24.29%). Once lignin is extracted, depolymerization is performed by three different methods: high-pressure reactor, ultrasound-assisted solvent depolymerization, and microwave solvolysis. As a result, a new microwave depolymerization method has been developed and patented, using for the first time graphene nanoplatelets (GNPs) as new promising carbonaceous catalyst, achieving a 90.89% depolymerization rate of river cane lignin and yielding several building blocks, including guaiacol, vanillin, ferulic acid, or acetovanillone.

Isolation of Alpha-Glucosidase Inhibitors from the Panamanian Mangrove Plant Mora oleifera (Triana ex Hemsl.) Ducke.

Panama boasts an expansive mangrove area and stands as one of the most biodiverse countries in America. While mangrove plants have long been utilized in traditional medicine, there are still unstudied species whose potential medicinal applications remain unknown. This study aimed to extract bioactive compounds from Mora oleifera (Triana ex Hemsl.) Ducke, an understudied mangrove species. Through bioassay-guided fractionation of the crude extract, we isolated seven active compounds identified as lupenone (1), lupeol (2), α-amyrin (3), ß-amyrin (4), palmitic acid (5), sitosterol (6), and stigmasterol (7). Compound structures were determined using spectroscopic analyses, including APCI-HR-MS and NMR. Compounds 1-7 displayed concentration-dependent inhibition of the alpha-glucosidase enzyme, with IC50 values of 0.72, 1.05, 2.13, 1.22, 240.20, 18.70, and 163.10 µM, respectively. Their inhibitory activity surpassed acarbose, the positive control (IC50 241.6 µM). Kinetic analysis revealed that all compounds acted as competitive inhibitors. Docking analysis predicted that all triterpenes bonded to the same site as acarbose in human intestinal alpha-glucosidase (PDB: 3TOP). A complementary metabolomic analysis of M. oleifera active fractions revealed the presence of 64 compounds, shedding new light on the plant's chemical composition. These findings suggest that M. oleifera holds promise as a valuable botanical source for developing compounds for managing blood sugar levels in individuals with diabetes.

Exploring the wound-healing potential and seasonal chemical variability of the Formosan Callery pear Pyrus calleryana: implications for therapeutic applications.

CONTEXT: Pyrus calleryana Decne (Rosaceae), renowned for its therapeutic properties, is known to moisturize the lungs (removing dryness; relieving cough), clear heat (acting as an antipyretic; febrifuge) and aid in detoxification (relieving pyogenic inflammation; eliminating toxins). However, scientific evidence supporting its efficacy in wound healing is lacking. OBJECTIVE: This study investigated P. calleryana samples collected over a year to explore metabolite variations and their impact on skin wound-healing activities. MATERIALS AND METHODS: P. calleryana (PC) twigs and leaves were collected from the Matsu Islands, Taiwan, spanning 2018-2020. Extracts were prepared using 95% ethanol or water, and we assessed the chemical composition, total phenolic/triterpenoid contents and antioxidant properties. Metabolites were analysed via LC-MS/MS and molecular networking. Wound healing potential was evaluated on WS-1 cells through MTT and migration assays, and gene expression analyses, with tests including control (DMSO), compounds 1 (3'-hydroxylbenzyl-4-hydroxybenzoate-4'-O-ß-glucopyranoside) and 2 (vanilloylcalleryanin) (100 µM), and a positive control (ascorbic acid, 100 µM) for 24 h. RESULTS: Significant variations in extract compositions were observed based on the solvent used, with distinct metabolomic profiles in extracts collected during different months. Notably, compounds 1 and 2 showed no cytotoxic effects on human dermal fibroblast cells and significantly accelerated wound closure at 100 µM. A gene expression analysis indicated upregulation of wound healing-associated genes, including MMP-1 (matrix metalloproteinase-1) and COL1A1 (collagen, type 1, alpha 1). CONCLUSIONS: This study reports the first evidence of PC compounds aiding wound healing. Utilizing Global Natural Products Social Molecular Networking (GNPS) and principal component analysis (PCA) approaches, we unveiled metabolomic profiles, suggesting the potential to expedite wound-healing.

A simulation study on the effect of penetration of gold nanoparticles in the cytoplasm of healthy eye organs on dose enhancement of brachytherapy.

PURPOSE: Special properties and recent advances in the synthesis and biomolecular functionalization of gold nanoparticles (GNPs) have led to the evolution of their use in biomedical applications such as photon radiotherapy. Simulation-based studies on the effect of various parameters that govern the dose enhancement due to utilizing GNPs have facilitated the progress of knowledge in this field. Due to their flexibility and easier accessibility compared with experimental works, simulations have the potential to be considered for pre-clinical tests and, therefore, should be close to the realistic conditions as much as possible. MATERIALS AND METHODS: To this aim, the present work investigates the effect of the presence of GNPs that are accumulated in the cytoplasm of the constituent cells in healthy tissues of a human eye phantom, inspired by the published experimental results which report that non-target tissues also receive the drugs containing GNPs. The GNPs' concentrations are assumed to decrease by moving from the tumor toward the depth of the phantom through a suggested pattern. The MCNPX Monte Carlo code is used for the simulations. RESULTS: The results show that for four concentrations tested, the dose enhancement factor in the shallower layer reaches 6, and decreases to 1.2 in the last layer. The dose enhancements are also examined for critical structures of the iris, cornea, sclera, and lens, showing maximum deviations of about 3 to 200% compared with the absence of GNPs in the healthy tissue. Considering the reported doses to the lens by clinical institutions, the effect of penetration of GNPs to deep layers on treatment time is also investigated. CONCLUSIONS: The results show that the penetration of GNPs from the tumor toward healthy tissues strongly controls the dose enhancement over the various eye structures and emphasizes the importance of modeling the GNPs' distribution in the medium on the overall dose enhancement. Considering the current challenges in the clinical use of GNPs, more effort needs to be made to reach an effective endpoint in treatment.