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Four new ansamycin derivatives, named 1,19-epithio-geldanamycin A (1), 17-demethoxylherbimycin H (2), herbimycin M (3), and seco-geldanamycin B (4), together with eight known ansamycin analogues (5 – 12) were isolated from the solid fermentation of marine-derived actinomycete Streptomyces sp. ZYX-F-97. The structures of new compounds were elucidated by extensive spectroscopic analysis as well as nuclear magnetic resonance (NMR) and electronic circular dichroism (ECD) calculations. All the compounds were assayed for their antibacterial activity. Among them, compounds 4 , 8 , and 12 exhibited remarkable inhibition against Listeria monocytogenes with minimum inhibitory concentrations (MIC) values ranging from 8 μg·mL−1 to 64 μg·mL−1, and displayed moderate inhibition against methicillin-resistant Staphylococcus aureus (MRSA) with MIC value of 64 μg·mL−1. Compounds 4 , 8 , 9 , and 12 showed moderate inhibition activities against both Staphylococcus aureus and Bacillus subtilis with MIC values ranging from 32 μg·mL−1 to 128 μg·mL−1. [Display omitted] [ABSTRACT FROM AUTHOR]

The occurrence of macrocyclic daphnane orthoesters (MDOs) with a 1-alkyl group originating from a C 14 aliphatic chain is extremely limited in the plant kingdom and has only been isolated from Edgeworthia chrysantha. In the present study, LC-ESI-MS/MS analysis was performed on different parts of E. chrysantha , including flower buds, flowers, leaves, and stems, and resulted in the identification of seven MDOs in all the four plant parts, including two previously unreported compounds 1 and 7. Further LC-MS guided isolation was carried out to afford compounds 1 and 7 , and their structures were determined by various spectroscopic analyses. These compounds were also evaluated for anti-HIV activity, thus expanding insights into the structure-activity relationships for MDOs. [Display omitted] • Seven macrocyclic daphnane orthoesters were identified from Edgeworthia chrysantha by LC-ESI-MS/MS analysis. • ESI-MS/MS fragmentation of macrocyclic daphnane orthoesters was elucidated. • Two unreported compounds were isolated by LC-MS guided isolation. • Structures of isolated compounds were determined by various spectroscopic analyses. • Isolated compounds were evaluated for anti-HIV activity. [ABSTRACT FROM AUTHOR]

Abstract Interactions with water are one of the key factors which determine protein stability and activity in aqueous solutions. However, the protein hydration is still insufficiently understood. N -methylacetamide (NMA) is regarded as a minimal part of the peptide backbone and the relative simplicity of its structure makes it a good model for studies on protein–water interactions. In this paper, the influence of NMA and N,N -dimethylacetamide (DMA) on surrounding water molecules in a range of temperature (25–75 °C) is studied by means of the FTIR spectroscopy. The results of the difference HDO spectra method are compared with the results of theoretical DFT calculations of NMA and DMA aqueous complexes. Both NMA and DMA can be regarded as "structure-makers", yet their hydration spheres are different. These molecules exhibit a mixed and mutually dependent types of hydration: hydrophilic and hydrophobic. In the case of a NMA molecule that has one methyl group less than DMA, the type of hydrophobic hydration is more important. The DMA hydration sphere is less stable: the interactions between water molecules around the methyl groups are strained. Moreover, the hydration of NMA is much more temperature dependant than in the case of DMA. The source of the differences may be hidden in the N H⋯H 2 O interaction. The delicate nature of water interactions with the peptide block models may be cautiously translated into the much more complicated interactions of proteins with their hydration shells. [ABSTRACT FROM AUTHOR]

With the aim to develop highly potential active heterocyclic compounds, two series of multi-substituted pyrrolizinone and indolizinones derived from lactam were designed, synthesized and evaluated for their potential antifungal activities against six species of the plant pathogen fungi ( Fusarium graminearum, Sclerotinia sclerotiorum, Phomopsis adianticola, Gloeosporium theae-sinensis, Alternaria tenuis Nees, Magnaporthe oryzae ). The structure of all the newly molecules were confirmed by analytical spectroscopic data, including 1 H NMR, 13 C NMR and ESI-MS. According to the preliminary studies on bio-evaluation assay, some of the obtained compounds exhibited moderate and broad-spectrum activities against six fungi compared to the intermediates 6a , 6f and the hymexazol. Particularly, the inhibition rate of compounds 7l , 7m and 7t reached 69.25%, 74.76%, 65.38% against Phomopsis adianticola and Magnaporthe oryzae in vitro activity. Furthermore, compounds 7l and 7t displayed obviously inhibition activities against Phomopsis adianticola compared to the hymexazol. Consequently, compounds 7l and 7t with six-membered alkane ring could be used as new motifs for further investigation. [ABSTRACT FROM AUTHOR]

The amide derivatives were synthesized from isopimaric acid and characterized by spectroscopy. These amides were examined in vitro for their cytotoxic activity against four cancer cell lines. The majority of the screened compounds displayed better inhibitory activity than isopimaric acid, and many amides displayed promising cytotoxic activity against hepatocarcinoma (HepG-2), breast carcinoma (MDA-MB-231), and prostate adenocarcinoma (PC-3). It was found that the substituent type, number, and position in the benzene and heterocyclic rings have an important influence on cytotoxicity against the three tested cancer cell lines. [ABSTRACT FROM AUTHOR]

Two novel nitrogenous diterpenoids, sarinfacetamides A (1) and B (2), featuring an uncommon tricyclo[6.3.1.01,5]dodecane scaffold, and a known related diterpene (3) were isolated from the South China Sea soft coral Sarcophyton infundibuliforme. Their structures, including the absolute configuration of 1, were established by extensive spectroscopic analysis and TDDFT-ECD calculation. Compounds 1 and 3 exhibited interesting promotion effects on the ConA-induced T lymphocyte proliferation. A plausible biosynthetic pathway for 1 and 2 was also proposed. [ABSTRACT FROM AUTHOR]

Catalytic allylic γ‐substitution with Morita‐Baylis‐Hillman (MBH) adducts for creating a new family of unsymmetrical dicarbonyl compounds was presented in this work, in which a variety of allylated amide products were achieved in good yields and high regioselectivity with excellent linear‐to‐branched ratios. Especially, it was found that the Pd/HZNU‐Phos complex exhibited remarkably high activity (with a TON up to 16800) in this transformation between dicarbonyl amides and MBH adducts. In addition, the possibly multisite interaction between multifunctional Pd/HZNU‐Phos catalyst system and substrates might responsible for its exceptionally high efficiency in this reaction. [ABSTRACT FROM AUTHOR]

Four metalloporphyrin dimers linked by bridging amide-bonded xanthene moieties and that contain either MnIII, CoII, NiII, or CuII metal centers were synthesized. Various spectroscopic, electrochemical, and spectroelectrochemical methods were used to study trends in their properties. Their electronic structure and optical properties were analyzed through a comparison of the electronic absorption and magnetic circular dichroism (MCD) spectral data with the results of time-dependent (TD)-DFT calculations. [ABSTRACT FROM AUTHOR]

A new strategy to analyze amide hydrogen/deuterium exchange mass spectrometry (HDX-MS) data is proposed, utilizing a wider time window and isotope envelope analysis of each peptide. While most current scientific reports present HDX-MS data as a set of time-dependent deuteration levels of peptides, the ideal HDX-MS data presentation is a complete set of backbone amide hydrogen exchange rates. The ideal data set can provide single amide resolution, coverage of all exchange events, and the open/close ratio of each amide hydrogen in EX2 mechanism. Toward this goal, a typical HDX-MS protocol was modified in two aspects: measurement of a wider time window in HDX-MS experiments and deconvolution of isotope envelope of each peptide. Measurement of a wider time window enabled the observation of deuterium incorporation of most backbone amide hydrogens. Analysis of the isotope envelope instead of centroid value provides the deuterium distribution instead of the sum of deuteration levels in each peptide. A one-step, global-fitting algorithm optimized exchange rate and deuterium retention during the analysis of each amide hydrogen by fitting the deuterated isotope envelopes at all time points of all peptides in a region. Application of this strategy to cytochrome c yielded 97 out of 100 amide hydrogen exchange rates. A set of exchange rates determined by this approach is more appropriate for a patent or regulatory filing of a biopharmaceutical than a set of peptide deuteration levels obtained by a typical protocol. A wider time window of this method also eliminates false negatives in protein-ligand binding site identification. [ABSTRACT FROM AUTHOR]

Fourteen new sulphur-containing amides, glycocramides A-N (1–14), as well as nine known analogues (15–23) were isolated and characterized from Glycosmis craibii Tanaka. The chemical structures of new sulphur-containing amides 1–14 were ambiguously elucidated by extensive spectroscopic methods, while the known compounds 15–23 were identified by the comparison of their experimental spectral data with those described data in the literatures. The antiproliferative effects of all isolated sulphur-containing amides were evaluated in vitro. As a result, part of sulphur-containing amides showed remarkable inhibitory effects against MGC-803 cell line with IC 50 values ranging from 13.12 ± 0.10 to 20.03 ± 0.13 μM. These research results suggest that the sulphur-containing amides are potentially to be developed as a new natural anti-tumor drugs. [Display omitted] • Twenty-three sulphur-containing amides have been isolated and characterized from Glycosmis craibii Tanaka. • Fourteen new sulphur-containing amides, glycocramides A-N (1–14), were among them. • All of the isolated sulphur-containing amides represent two skeletons. • Antiproliferative effects of all isolated sulphur-containing amides were examined. [ABSTRACT FROM AUTHOR]

Fossil biomolecules from an endogenous source were previously identified in Cretaceous to Pleistocene fossilized bones, the evidence coming from molecular analyses. These findings, however, were called into question and an alternative hypothesis of the invasion of the bone by bacterial biofilm was proposed. Herewith we report a new finding of morphologically preserved blood-vessel-like structures enclosing organic molecules preserved in iron-oxide-mineralized vessel walls from the cortical region of nothosaurid and tanystropheid (aquatic and terrestrial diapsid reptiles) bones. These findings are from the Early/Middle Triassic boundary (Upper Roetian/Lowermost Muschelkalk) strata of Upper Silesia, Poland. Multiple spectroscopic analyses (FTIR, ToF-SIMS, and XPS) of the extracted "blood vessels" showed the presence of organic compounds, including fragments of various amino acids such as hydroxyproline and hydroxylysine as well as amides, that may suggest the presence of collagen protein residues. Because these amino acids are absent from most proteins other than collagen, we infer that the proteinaceous molecules may originate from endogenous collagen. The preservation of molecular signals of proteins within the "blood vessels" was most likely made possible through the process of early diagenetic iron oxide mineralization. This discovery provides the oldest evidence of in situ preservation of complex organic molecules in vertebrate remains in a marine environment. [ABSTRACT FROM AUTHOR]

Alkylacetamide-based model peptides display an intense Debye-type dielectric relaxation. In order to explore the extent to which this feature has to be regarded analogous to that in other supramolecular liquids, notably the monohydroxy alcohols, we applied broadband dielectric, time-dependent solvation, and near-infrared spectroscopies as well as shear rheology and various nuclear magnetic resonance techniques to mixtures of N-methylacetamide (NMA) or N-ethylacetamide (NEA) with N-methylformamide. Compared in the modulus format, dielectric relaxation, solvation dynamics, and mechanical response indicate a common global and local dynamics. The present spin-relaxation measurements reflect motional processes which are significantly faster than the dominant Debye dielectric response, and a similar conclusion is drawn from measurements of the shear viscosity. The NH overtone stretching vibrations reveal a temperature-dependent hydrogen-bond equilibrium that changes its characteristics near temperatures of 325 K. Finally, dielectric low-temperature data recorded for (NEA)0.4(NMF)0.6 mixed with 2-picoline indicate the existence of a critical concentration akin to the situation in various monohydroxy alcohol mixtures. [ABSTRACT FROM AUTHOR]

Spectroscopic Fourier self-deconvolution analysis was used to investigate β-sheet features in the secondary structure of hemoglobin under mobile phone microwaves at 900 MHz. To this end, four samples of hemoglobin in bidistilled water, sucrose, trehalose, and sodium chloride aqueous solutions were exposed for up to 4 hr to 900 MHz microwaves at an average H-field intensity of 42 mA/m. Quantitative spectral analyses highlighted significant increases in β-sheet contents in the Amide I region of hemoglobin samples in bidistilled water solution, but no appreciable change was observed in hemoglobin samples in sucrose, trehalose, and sodium chloride solutions. These results led us to conclude that mobile phone microwaves can denaturate hemoglobin in bidistilled water solution whereas sucrose, trehalose, and sodium chloride solutions produce a protective effect against microwaves, preserving the protein from unfolding. [ABSTRACT FROM AUTHOR]

As the systematic investigation of salicylatocopper complexes with nicotinamide derivatives the preparation, characterization and X-ray structure determination of four new molecular copper(II) complexes with x -methylsalicylate anion ( x -Mesal − ) and nicotinamide (nia) or N -methylnicotinamide (mna) are reported. The molecular complexes [Cu(5-Mesal) 2 (nia) 2 ] ( 1 ), [Cu(3-Mesal) 2 (nia) 2 ] ( 2 ) build up 2-D supramolecular structures of different character. The ladder-type supramolecular structure of ( 1 ) is formed by the head-to-head H-bonds of neighbouring carboxamide groups, while the supramolecular structure of ( 2 ) is formed by N H⋯O H-bonds of carboxamide groups into 1-D chain that are by the additional H H⋯O H-bonds of N H carboxamide and the carboxylate group oxygen atoms linked to 2-D layers. The centrosymmetrical crystal molecular structure of [Cu(4-Mesal) 2 (mna) 2 (H 2 O) 2 ]⋅2EtOH ( 3 ) or [Cu(5-Mesal) 2 (mna) 2 (H 2 O) 2 ]⋅2MeOH ( 4 ) are forming 1-D supramolecular chains that involve the methylcarboxamide N H group, the crystalosolvate alcohol O H group, the coordinated water molecule O H bond and oxygen atom of neighbouring complex molecule. The coordination polyhedron symmetry corresponds with the isotropic character of EPR spectra of ( 1 ) and ( 2 ) while the EPR spectrum of ( 4 ) is of axial symmetry. [ABSTRACT FROM AUTHOR]

Coprisamides A and B (1 and 2) were isolated from a bacterium in the gut of the dung beetle Copris tripartitus. Spectroscopic analysis revealed that the planar structures of 1 and 2 are novel cyclic heptapeptides bearing unusual units, such as β-methylaspartic acid and 2,3-diaminopropanoic acid branched to valine and 2-heptatrienyl cinnamic acid. Absolute configurations were established by chemical derivatization and chiroptical spectroscopy. The coprisamides displayed significant activity for induction of quinone reductase. [ABSTRACT FROM AUTHOR]

Four new isoquinoline alkaloids including a benzophenanthridine alkaloid (1), a morphine derivative (2), a narceine-type alkaloid (3) and a simple isoquinoline alkaloid (4), a new amide alkaloid (5) and a new phthalic acid derivative (6), together with eleven known alkaloids (7 – 17) were obtained from the whole herbs extract of Corydalis bungeana Turcz. Their structures and absolute configurations were elucidated by extensive spectroscopic data analysis including HRESIMS, NMR and electronic circular dichroism (ECD) and ECD calculation. Compounds 1 – 17 were evaluated for dopamine D2 receptor activity in CHO-D2 cells. Among them, 16 showed the highest antagonistic activity on the D2 receptor with an IC 50 value of 2.04 ± 0.01 μM. Compounds 14 and 15 exhibited moderate antagonism with IC 50 values of 13.66 ± 2.28 and 31.72 ± 2.52 μM, respectively. [Display omitted] • Five new alkaloids and a new phthalic acid derivative were obtained from Corydalis bungeana. • Their structures were evaluated by the analysis of extensive spectroscopic data. • Compound 16 exhibited significant antagonistic activity on dopamine D2 receptor in CHO-D2 cells. [ABSTRACT FROM AUTHOR]

A soil Streptomycesnov. sp. (MST-115088) isolatedfrom semiarid terrain near Wollogorang Station, Queensland, returnedtwo known and two new examples of a rare class of cyclic hexapeptide,desotamides A and B (1and 2) and E andF (3and 4), respectively, together withtwo new d-Orn homologues, wollamides A and B (5and 6). Structures were assigned by detailed spectroscopicand C3Marfey’s analysis. The desotamides/wollamidesexhibit growth inhibitory activity against Gram-positive bacteria(IC500.6–7 μM) and are noncytotoxic to mammaliancells (IC50>30 μM). The wollamides exhibit antimycobacterialactivity (IC502.8 and 3.1 μM), including reductionin the intracellular mycobacterial survival in murine bone marrow-derivedmacrophages. [ABSTRACT FROM AUTHOR]