2D NMR Research Articles

Chemical Constituents of the Deep-sea Derived Fungus Purpureocillium lilacinum XIA-9.

Two new sphingosine derivatives (1 and 2), two new vicinal diol analogs (3 and 4), one new diol analog (5), one new fatty acid (9), together with 19 known compounds (6-8, 10-24), were isolated from Purpureocillium lilacinum XIA-9. Their structures were determined by detailed analysis of the 1D and 2D NMR, HRESIMS, and optical rotatory data. Fusarubin 3-methyl ether (17) exhibited potent inhibition on RSL3 induced ferroptosis with the EC50 value of 0.1 μM.

Comparative metabolic profiling and quantitative analysis of metabolites in different tissues of Ajuga turkestanica by ESI-UHPLC-QqTOF-MS and NMR.

Ajuga turkestanica preparations are used as anti-aging cosmeceuticals and for medicinal purposes. Herein we describe the characterization and quantification of its metabolites in different organs using UHPLC-MS and NMR spectroscopy. A total of 51 compounds belonging to various phytochemical classes (11 flavonoids, 10 ecdysteroids, 9 diterpenes, 6 fatty acids, 5 iridoids, 3 phenylpropanoids, 3 sugars, 2 phenolics, 1 coumarin, 1 triterpene) were annotated and tentatively identified by UHPLC-ESI-QqTOF-MS/MS of methanolic extracts obtained separately from the organs. 1D and 2D NMR spectroscopy independently confirmed the identity of six major compounds. The abundances of thesemain constituents in flowers, fruits, leaves, roots, seeds, and stems were compared and quantified using 1H NMR. The results showed that 8-O-acetylharpagide, 20-hydroxyecdysone (ecdysterone) and ajugachin B were the most abundant constituents in the species. The two major compounds, 8-O-acetylharpagide and 20-hydroxyecdysone, were chosen as the markers for the quality assessment of A. turkestanica material. The methanolic extract of the aerial parts of A. turkestanica showed no noteworthy anthelmintic (antihelmintic), antifungal, or cytotoxic effect in in vitro assays.

Cytotoxic compounds from Viscum coloratum (Kom.) Nakai.

Two new compounds (1-2) and a new artificial product (3) together with fifteen known compounds (4-18) were isolated from Viscum coloratum (Kom.) Nakai. Their structures were established by analysis of their spectroscopic data including MS, 1D and 2D NMR spectra, and comparison with existing literature. All the compounds were assessed for their cytotoxic activity against 4T1 and LN229 cells (with cisplatin as the positive control), and the anti-LN229 cytotoxicity of compounds 3, 4 and 5 were greater than that of 4T1 cells.

Cathagines A-D, new bisindole alkaloids from Catharanthus roseus.

Four new bisindole alkaloids, cathagines A (1)-D (4) consisting of an aspidosperma and the fused tetracyclic 3-spirooxindole derived from an iboga type skeleton were isolated from the whole plant of Catharanthus roseus. The structures including absolute stereochemistry were elucidated on the basis of 2D NMR data and CD spectra. Cathagine B (2) showed moderate anti-malarial activity against Plasmodium falciparum 3D7.

Synthesis and Properties of Covalently Linked Fluorescent Tetrads Containing Two BODIPYs and Two 3‐Pyrrolyl BODIPYs

Two covalently linked fluorescent tetrads containing two BODIPY units and two 3‐pyrrolyl BODIPY units have been synthesized over a sequence of steps starting with bis(3‐pyrrolyl BODIPY) as the key precursor. Both covalently linked tetrads 6 and 7 were confirmed by HR‐MS and characterized and studied by 1D and 2D NMR, absorption, cyclic voltammetry, steady state and time‐resolved fluorescence techniques, and also by DFT and TD‐DFT methods. The tetrad 6 exhibited one strong absorption band at 680 nm whereas the tetrad 7 showed strong absorption bands at 510 nm and 648 nm corresponding to BODIPY and 3‐pyrrolyl BODIPY units respectively and the absorption band of tetrad 6 was bathochromically shifted due to effective π‐conjugation in tetrad 6 compared to tetrad 7. The electrochemical studies revealed that tetrads exhibit only two reductions indicating their electron deficient nature. The steady state and time‐resolved fluorescence studies invoked a possibility of singlet‐singlet energy transfer from BODIPY units to 3‐pyrrolyl BODIPY units in one of the tetrads upon selective excitation of BODIPY unit. In this tetrad, the BODIPY unit acts as an energy donor whereas the 3‐pyrrolyl BODIPY unit acts as an energy acceptor. The theoretical studies were corroborated with experimental results.

Synthesis of Betulonic and Betulinic Acids Derivatives with Sulfonamide Fragment Linked to the Triterpene Core by Amidoalkane Spaser

A series of potentially biologically active sulfonamides of betulonic and betulinic acids with a sulfonamide fragment containing residues of dibutylamine or N-heterocycles, which is linked to a triterpene core by an amidoethane or amidopropane spacer, was synthesized. Betulonic acid sulfonamides were obtained by chlorohydride conjugation of acid with 2-aminoethane and 3-aminopropanesulfonamides and used as precursor compounds for the transition to similar betulinic acid derivatives by selective reduction of the 3-keto group with the action of NaBH4 in EtOH. The structure of all synthesized triterpene sulfonamides was confirmed by 1D and 2D NMR spectroscopy and mass spectrometry.

Anti-Inflammatory Secoiridoids from the Medicinal Herb Gentianopsis barbata.

Five new secoiridoids, gentianopsins A-E (1-5), along with two known analogues (6 and 7) were isolated from the whole plants of the medicinal herb Gentianopsis barbata. Their structures were elucidated by a comparison of extensive spectroscopic analysis (1D and 2D NMR, and HRMS) and quantum chemical calculations. Gentianopsins A (1) and B (2) represented two unusual skeletons of trihomo-secoiridoids. Anti-inflammatory activity of these isolates was evaluated via suppressing the secretion of cytokines TNF-α and IL-6 in LPS-induced macrophages RAW264.7. Significant inhibitory activity was observed for compounds 3 and 7 on IL-6 secretion with IC50 values of 10.22 and 13.30 μM, respectively.

Unravelling the incorporation mechanisms of water in aluminous orthoenstatite: II. comprehensive 1H, 29Si and 27Al NMR measurements

AbstractAluminum has been shown to significantly enhance the water incorporation capacity of orthoenstatite (OEn), but the incorporation mechanisms remained to be clarified. We performed a comprehensive one- and two-dimensional 1H, 29Si and 27Al NMR study on four hydrous aluminous OEn samples containing 1–8 wt% Al2O3 synthesized at 1.5 GPa and 900 °C to clarify the issue. The combined 1H MAS and static (non-spinning) NMR, 1H double-quantum and triple-quantum MAS NMR, and 27Al→1H CP MAS NMR and HETCOR results, in particular, unambiguously revealed that a large part of the incorporated water are present as proton pairs in Mg vacancies adjacent to Al, with one proton of each pair for the dominant proton pairs exhibiting significantly weaker hydrogen bonding than those in Al-free OEn. Proton pairs in Mg vacancies remote from Al are minor or absent for samples with 4–8 wt% Al2O3, and more abundant for a sample with 1 wt% Al2O3. Isolated protons due to coupled substitutions of Al + H for 1Si and 2Mg (both with weak hydrogen bonding) were also detected, but are less abundant than hitherto considered. The observed NMR peaks match well with those predicted for the corresponding OH defect models from our first-principles calculations. Thus, the enhancement of water solubility by Al for OEn are due to not only coupled substitutions of Al + H for 1Si and 2Mg, but also interactions of Al with proton pairs in Mg vacancies. These mechanisms may also be important in other nominally anhydrous aluminous silicate minerals.

Structurally diverse bufadienolides from the skins of Bufo bufo gargarizans and their cytotoxicity

Natural products, with their extensive chemical diversity, distinctive biological activities, and vast reservoirs, provide a robust foundation for advancing cancer therapeutics. A comprehensive phytochemical investigation of the skins from Bufo bufo gargarizans afforded two new bufadienolide derivatives identified as bufalactamides A and B (1–2), along with six known compounds: argentinogenin (3), desacetylcinobufagin (4), desacetylcinobufaginol (5), cinobufaginol (6), bufalin (7) and gamabufalin (8). The structural elucidation of these compounds was meticulously carried out by analyses of spectroscopic data (1D and 2D NMR, HR-ESIMS), and comparison with the literature data. Plausible biosynthetic pathways for the new compounds were also discussed. Moreover, the cytotoxicity of the compounds was investigated using various cancer cell lines, including lung cancer (A549), colon cancer (HCT-116), liver cancer (SK-Hep-1), and ovarian cancer (SKOV3). Our research findings indicated that compounds 3, and 6–8 exhibit potent cytotoxic activity (IC50 < 2.5 µM). In contrast, compounds 4 and 5 display moderate cytotoxic activity (IC50 < 50 µM) while compounds 1 and 2 show no cytotoxic activity (IC50 > 100 µM). From this data, we conducted a comprehensive analysis of the structure-activity relationships among these compounds.

A new dammarane-type triterpenoid saponin from the leaves of sour jujube

A new dammarane-type triterpenoid saponin, suanzaoside A (1) along with one known analogue 3-O-[α-L-rhamnopyranosyl(1→2)-α-L-arabinopyranosyl-]-30-O-[β-D-glucopyranosyl-(1→2)-β-D-glucopyranosyl]-3β,25,30-trihydroxy-16-one-20R,24R-epoxydammarane (2), were isolated from the leaves of sour jujube. The structure of these isolated compounds was elucidated by HRESIMS, 1D and 2D NMR spectroscopy, and literature comparison. In addition, the anti-inflammatory activities were further tested in LPS-induced RAW264.7 macrophage.

Structure Characterization of Four New Sesquiterpene Pyridine Alkaloids from Tripterygium wilfordii Hook. f. and Anti-Inflammatory Activity Evaluations

Sesquiterpene pyridine alkaloids (SPAs), as a main class of components in Tripterygium wilfordii Hook. f., possess a variety of bioactivities, such as immunosuppressive, insecticidal, and anti-tumor activities. SPAs can be structurally classed into four subtypes: wilfordate-, evoninate-, iso-wilfordate-, and iso-evoninate types. Our previous study unveiled ten new wilfordate-type SPAs, named wilfordatine A–J, isolated from the roots of Tripterygium wilfordii Hook. f., several of which exhibited significant immunosuppressive activities. As an extension and augmentation of the previous findings, we have now isolated one new iso-wilfordate-type SPA, wilfordatine K (1), alongside three new iso-evoninate-type SPAs, wilfordatines L–N (3–5), and six known analogs. Their structures were characterized by the extensive use of 1D and 2D NMR spectroscopic analysis, as well as HRMS data. Interestingly, compounds 4 and 6 were found to exhibit potent inhibitory effects on the nuclear factor-kappa B (NF-κB) pathway in lipopolysaccharide (LPS)-induced HEK293/NF-κB-Luc cells, with IC50 values of 1.64 μM and 9.05 μM, respectively. Notably, these two compounds had no influence on the cell viability at a concentration of 100 μM. Consequently, they hold significant promise as potential anti-inflammatory candidates for further exploration and development.

Near-infrared diffuse optical characterization of human thyroid using ultrasound-guided hybrid time-domain and diffuse correlation spectroscopies

Near-infrared diffuse optical characterization of human thyroid using ultrasound-guided hybrid time-domain and diffuse correlation spectroscopies

Characterization of a New Insecticidal Benzothiazole Derivative from Aspergillus sp. 1022LEF against the Fall Armyworm, Spodoptera frugiperda (Lepidoptera: Noctuidae).

The fall armyworm Spodoptera frugiperda is considered one of the most destructive crop pests, posing a significant threat to food and crop security. In this study, we conducted a chemical investigation of the endophytic fungus Aspergillus sp. 1022LEF, leading to the identification of a previously unreported benzothiazole derivative, 6-(2-hydroxyethyl)benzo[d]thiazol-4-ol (HBT). Its structure was unambiguously characterized using extensive spectroscopic methods, including 1D and 2D NMR data, HRESIMS data, and single-crystal X-ray diffraction analysis. The insecticidal assay revealed that HBT possessed remarkable activity against S. frugiperda with an LC50 value of 0.24 mg/mL. Further transcriptomic and proteomic analyses revealed that HBT induced mortality in S. frugiperda by impeding DNA replication and protein synthesis, influencing mitochondria-mediated autophagy, and perturbing hormone synthesis, thereby disrupting the fundamental biosynthetic processes. HBT demonstrated high activity in controlling S. frugiperda, which highlighted its potential use as a lead in the development of biopesticides.

Insight into the dynamics of protected and non-protected carbon pools in four soils with different land uses

Abstract Background and aims To provide insight into the patterns of soil organic matter decomposition, changes in the quantity of biopolymers and the correlation between them were followed using 2D correlation spectroscopy (2DCOS) FTIR. Methods Soil organic matter fractions with different vegetation/land use (grass, spruce, oak and arable) were examined in a 1-year laboratory incubation. The non-protected organic matter fraction was calculated in terms of particulate organic matter (POM), the carbon stabilized in aggregates as S + A (sand + aggregates), and the mineral-associated organic matter (MAOM) as the s + c (silt and clay) fraction. Results Forest soils (spruce, oak) exhibited high C and N accumulation in the POM fraction (48, 43% and 29, 22% for spruce and oak, respectively) due to the limited decomposition, caused by low pH and high soil C/N ratio. The 2DCOS analysis revealed that carbohydrate-protein and carbohydrate-lignin correlations could be observed most frequently during incubation. The carbohydrate-protein correlation was negative in all cases, for all fractions and for all vegetation types, which suggests biogeochemical linkage between these biopolymers. The temporal order of the spectral changes was widely varied for the vegetation types and especially for the SOM fractions. Lipid/Lignin → Carbohydrate or Lipid → Lignin/Carboxyl/Protein sequences were found for the protected carbon pools (S + A and s + c), possibly because of the readily available abundant N compounds present in MAOM. Conclusion Although lipids and lignin are considered as chemically stable materials that commonly remain constant during decomposition, these compounds were found to be very susceptible in all the fractions.

Triterpenoid saponins from the fruit pulp of Tetrapleura tetraptera (Fabaceae)

Tetrapleura tetraptera fruit, used as spice in West Africa was studied chemically; five previously undescribed triterpenoid saponins 1–5 and four known compounds 6–9 were isolated from the n-Butanol fraction. The chemical structures of all nine isolates were determined by comprehensive analysis of HRMS, 1D & 2D NMR experiments and by comparison with data in the literature. All nine compounds were evaluated for antibacterial activity by the broth microdilution through the rapid p-iodonitrotetrazolium chloride (INT) colorimetric technique. The results showed that only compounds 5 (MIC = 64 µg/mL against P. aeruginosa and P. stuartii) and 8 (MIC = 64 µg/mL against E. coli) exhibited moderate antibacterial activity. The rest of the compounds displayed weak antibacterial activity against the tested organisms. Molecular docking studies was used to comprehend antibacterial activities.

P-Terphenyl and Orsellinic Acid Derivatives from the European Polyporales Terana coerulea and Sparassis brevipes.

Investigation of the secondary metabolites of the solid-state rice cultures from the European basidiomycetes Terana coerulea and Sparassis brevipes afforded three previously undescribed secondary metabolites identified as two p-terphenyl derivatives (1 and 2) and one orsellinic acid congener (3) in addition to another known, isoeverninic acid (4). Chemical structures of the isolated compounds were elucidated through comprehensive 1D and 2D NMR spectroscopic analyses, coupled with HR-MS and other spectral methods. The isolated compounds were assessed for their cytotoxic and antimicrobial activities. Compound 1 revealed weak antimicrobial properties, whereas the inseparable mixture of 3 and 4 featured moderate cytotoxic and antimicrobial effects.

Evidence for Nanostructures of at Least 20 nm in a Phosphonium Ionic Liquid at Room Temperature Using Fluorescence Correlation Spectroscopy.

Fluorescence correlation spectroscopy (FCS) measurements are performed on the ionic liquid (IL), tetradecyl(trihexyl) phosphonium chloride, [P66614+][Cl-], using fluorescent probes of varying sizes: ATTO 532, ∼2 nm; and 20- and 40 nm fluorescent beads. The fluorescence correlation function, G(t), is analyzed in terms of a distribution of diffusion coefficients using a maximum entropy method (MEM). For ATTO 532 and the 20 nm beads, the fit to G(t) yields two well-defined distributions; for the 40 nm beads, however, only one is obtained. These results are consistent with the existence of two nanodomains whose size is greater than or equal to 20 nm and less than 40 nm. The origin of such nanodomains is attributed to a liquid-liquid phase transition. Other groups have observed liquid-liquid phase transitions experimentally in a number of systems, including [P66614+][Cl-]. We suggest that because large regions (i.e., greater than 1-2 nm) resulting from the liquid-liquid phase transition would be expected to have different properties, such as viscosity, and because their presence would necessarily increase the number of interfaces in the IL, these regions may provide an explanation for the exceptional behavior of ILs in various separation systems.

Cadophorin C, a new cyclic heptapeptide isolated from a mangrove-derived fungus Penicillium sp. GXIMD 03101

One new cyclic heptapeptide, cadophorin C (1), and one known analogue cadophorin B (2) were isolated from the mangrove-derived fungus Penicillium sp. GXIMD 03101 from the mangrove Acanthus ilicifolius L. The chemical structure of 1 was elucidated by comprehensive analysis of the spectroscopic data, including 1D and 2D NMR and HRESIMS, and the known compound was identified by comparing the data with literature values. Compounds 1 and 2 were screened for antibacterial activity and benign prostatic hyperplasia (BPH) inhibitory activity. The results showed that compounds 1 and 2 have weak activity against Vibrio harveyi with MIC values of 3.12 and 12.5 μg/mL, respectively. Compounds 1 and 2 have significant inhibitory activity against BPH with IC50 values of 2.62 and 2.23 μM, respectively.

Three new spirocyclic terpenoids from Euphorbia amygdaloides exhibit cytotoxicity against cancerous cell lines through early and late apoptosis

Bioassay-guided fractionation led to the isolation of three new spirocyclic terpenoid compounds from Euphorbia amygdaloides L., named Zagrosin I–III. Their structures were identified by 1D and 2D NMR (1H NMR, 13C NMR, DEPT 135, HMBC, and HSQC-TOCSY) and LC-MS-MS spectrometry. The cytotoxicity of the isolated spirocyclic terpenoids (Zagrosin I-III) was assessed against human breast cancer (MCF-7), human fibrosarcoma (HT1080), and normal human foreskin fibroblast cells with MTT assays (24, 48, and 72 h treatments). The FITC-Annexin V apoptosis flow cytometry assays and cell cycle analysis were performed for Zagrosin I–III.These isolated compounds were identified as: (9)-8a-((benzoyloxy)methyl)-2-methoxy-4,9-dimethyltetrahydro-4H,5H-2,4a-methanobenzo[d] [1,3] dioxine-4-carboxylate (Zagrosin I), ((9)-4-hydroxy-2-methoxy-4,9-dimethyltetrahydro-4H,8aH-2,4a-methanobenzo[d] [1,3] dioxin-8a-yl) methyl benzoate (Zagrosin II), and (9)-2-methoxy-4,9-dimethyl-8a-(phenoxy methyl) tetrahydro-4H,5H-2,4a-methanobenzo[d][1,3]dioxin-4-yl 4-methylpentanoate (Zagrosin III).The IC50 of Zagrosin I on 48-h-treated MCF-7 was calculated as 1.5 μg/mL. Zagrosin II and III exhibited cytotoxicity on 48-h-treated MCF-7 with IC50s of 14.04 and 12.50 μg/mL, respectively. The IC50 of Zagrosin I on human fibrosarcoma (HT1080) was 115.5 μg/mL, Zagrosin III, 16.81 μg/mL (48 h treatment), and Zagrosin II, 142.7 μg/mL (72 h treatment). Zagrosin I-III exhibited significant cytotoxicity against the MCF-7 cell line and human fibrosarcoma (HT1080), with the mechanism of early and late apoptosis affecting cells mostly in G0/G1 fallowed by S and G2 phases. MCF-7 had a higher rate of phosphatidyl serine exposure on the cell membrane than two other studied cells. The cytotoxicity on normal human foreskin fibroblasts was low. Zagrosin I-III can be considered an effective chemical backbone for anticancer drug development.Abbreviations: 2D NMR: Two-Dimensional Nuclear Magnetic Resonance Spectroscopy; API: Atmospheric Pressure Ionization; DEPT: Distortionless Enhancement by Polarization Transfer; ELISA: Enzyme-Linked Immunosorbent assay; ERK: Extracellular signal-regulated kinase; ESI: Electrospray ionization; FBS: Fetal Bovine Serum; FITC: Fluorescein isothiocyante; fr: fraction; HMBC: Heteronuclear Multiple Bond Correlation; HPLC: High-Performance Liquid Chromatography; HSQC: Heteronuclear Single Quantum Coherence; HT1080: Human fibrosarcoma cell line; IC50: Half-maximal inhibitory concentration; MCF-7: Human breast cancer cell line; MHz: Megahertz; MTT: 3-[4,5-dimethylthiazol-2-yl]-2,5 diphenyl tetrazolium bromide; NMR: Nuclear Magnetic Resonance; PBS: Phosphate Buffered Saline; PI: Propidium Iodide; ppm: Part Per Million; Rf: Retention Factor; TLC: Thin-layer chromatography; TOCSY: Total Correlation Spectroscopy; VLC: Vacuum Liquid Chromatography.

A new benzodioxole derivative from the marine-derived Streptomyces sp. SYPHU 0002

a new benzodioxole derivative 1,3-benzodioxole-2-one-4-N-methylcarboxylamide (1), two new natural products N-(aminocarbonyl)-2,3-dimethoxy-benzamide (2) and 2,3-dimethoxy-N-methylbenzamide (3), along with eight known compounds (4-11), were isolated from the marine-derived Streptomyces sp. SYPHU 0002. The structures of compounds 1-11 were determined through comprehensive spectroscopic analyses, including HRESIMS, 1D and 2D NMR. Compound 9 showed weak antibacterial activity against Bacillus pumilus with the MIC value of 64 μg mL−1.