scholarly journals Anti-Infective and Antiviral Activity of Valinomycin and Its Analogues from a Sea Cucumber-Associated Bacterium, Streptomyces sp. SV 21

Marine Drugs ◽  
2021 ◽  
Vol 19 (2) ◽  
pp. 81
Author(s):  
Joko T. Wibowo ◽  
Matthias Y. Kellermann ◽  
Matthias Köck ◽  
Masteria Y. Putra ◽  
Tutik Murniasih ◽  
...  

The manuscript investigated the isolation, characterization and anti-infective potential of valinomycin (3), streptodepsipeptide P11A (2), streptodepsipeptide P11B (1), and one novel valinomycin analogue, streptodepsipeptide SV21 (4), which were all produced by the Gram-positive strain Streptomycescavourensis SV 21. Although the exact molecular weight and major molecular fragments were recently reported for compound 4, its structure elucidation was not based on compound isolation and spectroscopic techniques. We successfully isolated and elucidated the structure based on the MS2 fragmentation pathways as well as 1H and 13C NMR spectra and found that the previously reported structure of compound 4 differs from our analysis. Our findings showed the importance of isolation and structure elucidation of bacterial compounds in the era of fast omics technologies. The here performed anti-infective assays showed moderate to potent activity against fungi, multi drug resistant (MDR) bacteria and infectivity of the Hepatitis C Virus (HCV). While compounds 2, 3 and 4 revealed potent antiviral activity, the observed minor cytotoxicity needs further investigation. Furthermore, the here performed anti-infective assays disclosed that the symmetry of the valinomycin molecule is most important for its bioactivity, a fact that has not been reported so far.

1984 ◽  
Vol 49 (7) ◽  
pp. 1605-1616 ◽  
Author(s):  
Jan Schraml ◽  
Ján Hirsch ◽  
Eva Petráková ◽  
Eduard Krahé ◽  
Claus Bliefert

It is shown that a combination of homo- and heteronuclear shift correlated 2 D NMR yields correct and complete assignment of 1H and 13C NMR spectra. The amount of the work necessary can be considerably reduced if some of the lines can be unambiguously assigned on the basis of other information or if suitable model compounds are available.The pattern of homonuclear cross-peaks is characteristic for molecular fragments and can be used with advantage to trace out the lines in the spectral regions with heavy overlap. The exactly assigned 13C chemical shifts of disaccharide and trisaccharide related to arabinoxylan agree satisfactorily with the shifts predicted according to the shifts found in the spectra of model mono- and disaccharides measured under the same conditions.


2018 ◽  
Vol 69 (1) ◽  
pp. 64-69
Author(s):  
Liviu Birzan ◽  
Mihaela Cristea ◽  
Constantin C. Draghici ◽  
Alexandru C. Razus

The 1H and 13C NMR spectra of several 2,6-diheteroarylvinyl heterocycles containing 4-azulenyl moiety were recorded and their proton and carbon chemical shifts were compared with those of the compounds without double bond between the heterocycles. The influence of the nature of central and side heterocycles, molecule polarization and anisotropic effects were revealed. The highest chemical shifts were recorded for the pyrylium salts and the lowest at pyridines, but in the case of the pyridinium salts, the protons chemical shifts at the central heterocycle are more shielded due to a peculiar anisotropy of the attached vinyl groups.


2020 ◽  
Vol 26 (15) ◽  
pp. 1676-1681
Author(s):  
Sana Gul ◽  
Ruqaiya Khalil ◽  
Zaheer Ul-Haq ◽  
Mohammad S. Mubarak

: Tuberculosis (TB) ranks among the diseases with the highest morbidity rate with significantly high prevalence in developing countries. Globally, tuberculosis poses the most substantial burden of mortality. Further, a partially treated tuberculosis patient is worse than untreated; they may lead to standing out as a critical obstacle to global tuberculosis control. The emergence of multi-drug resistant (MDR) and extremely drug-resistant (XDR) strains, and co-infection of HIV further worsen the situation. The present review article discusses validated targets of the bacterial enzyme thymidine monophosphate kinase (TMPK). TMPKMTB enzyme belongs to the nucleoside monophosphate kinases (NMPKs) family. It is involved in phosphorylation of TMP to TDP, and TDP is phosphorylated to TTP. This review highlights structure elucidation of TMP enzymes and their inhibitors study on TMP scaffold, and it also discusses different techniques; including molecular docking, virtual screening, 3DPharmacophore, QSAR for finding anti-tubercular agents.


1991 ◽  
Vol 56 (10) ◽  
pp. 2160-2168 ◽  
Author(s):  
Josef Jirman

The 1H and 13C NMR spectra have been measured of six trans-azobenzenes substituted at 2 and 2’ positions with substituents favourable for complex formation with a metal (OH, NH2, NHCOCH3, COOH). From the standpoint of NMR such substituted trans-azobenzenes are present in solution in a rapid equilibrium following from rotation around the bond between C-1 of phenyl group and N atom of azo linkage. The predominant form has the substituent in the syn-position with respect to the free electron pair of the nearer azo nitrogen atom. The equilibrium is affected by dipolar aprotic solvents (such as hexadeuteriodimethyl sulfoxide) by decreasing the presence of the predominant form by 1 to 11%.


1984 ◽  
Vol 39 (8) ◽  
pp. 1154-1155 ◽  
Author(s):  
Johannes Respondek

Abstract200 MHz 1H and 50 MHz 13C NMR spectra were recorded from the reaction product of form aldehyd 1 and O -benyzlhydroxylamine 2 for the purpose of its structure elucidation


Molecules ◽  
2021 ◽  
Vol 26 (11) ◽  
pp. 3235
Author(s):  
Melissa M. Cadelis ◽  
Hugo Gordon ◽  
Alex Grey ◽  
Soeren Geese ◽  
Daniel R. Mulholland ◽  
...  

Fungi have become an invaluable source of bioactive natural products, with more than 5 million species of fungi spanning the globe. Fractionation of crude extract of Neodidymelliopsis sp., led to the isolation of a novel polyketide, (2Z)-cillifuranone (1) and five previously reported natural products, (2E)-cillifuranone (2), taiwapyrone (3), xylariolide D (4), pachybasin (5), and N-(5-hydroxypentyl)acetamide (6). It was discovered that (2Z)-cillifuranone (1) was particularly sensitive to ambient temperature and light resulting in isomerisation to (2E)-cillifuranone (2). Structure elucidation of all the natural products were conducted by NMR spectroscopic techniques. The antimicrobial activity of 2, 3, and 5 were evaluated against a variety of bacterial and fungal pathogens. A sodium [1-13C] acetate labelling study was conducted on Neodidymelliopsis sp. and confirmed that pachybasin is biosynthesised through the acetate polyketide pathway.


1994 ◽  
Vol 262 (2) ◽  
pp. 173-184 ◽  
Author(s):  
Tadasu Urashima ◽  
William A. Bubb ◽  
Michael Messer ◽  
Yuhnagi Tsuji ◽  
Yasuko Taneda

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