Two rare 2-phenoxychromone derivatives, 6-demethoxy-4`-O-capillarsine (
) and tenuflorin C (
), were isolated from the areal parts of
and
respectively, for the first time. Being rare in nature, the ...inhibition potentialities of
and
against SARS-CoV-2 was investigated using multistage in silico techniques. At first, molecular similarity and fingerprint studies were conducted for
and
against co-crystallized ligands of eight different COVID-19 enzymes. The carried-out studies indicated the similarity of
and
with
, the co-crystallized ligand of COVID-19 Papain-Like Protease (PLP), (PDB ID: 3E9S). Therefore, molecular docking studies of
and
against the PLP were carried out and revealed correct binding inside the active site exhibiting binding energies of -18.86 and -18.37 Kcal/mol, respectively. Further, in silico ADMET in addition to toxicity evaluation of
and
against seven models indicated the general safety and the likeness of
and
to be drugs. Lastly, to authenticate the binding and to investigate the thermodynamic characters, molecular dynamics (MD) simulation studies were conducted on
and PLP.
A new dicoumarin, jusan coumarin, (
), has been isolated from
aerial parts. The chemical structure of jusan coumarin was estimated, by 1D, 2D NMR as well as HR-Ms spectroscopic methods, to be ...7-hydroxy-6-methoxy-3-(2-oxo-2H-chromen-6-yl)oxy-2H-chromen-2-one. As the first time to be introduced in nature, its potential against SARS-CoV-2 has been estimated using various in silico methods. Molecular similarity and fingerprints experiments have been utilized for
against nine co-crystallized ligands of COVID-19 vital proteins. The results declared a great similarity between Jusan Coumarin and
, the ligand of COVID-19 main protease (PDB ID: 6W63), M
. To authenticate the obtained outputs, a DFT experiment was achieved to confirm the similarity of
and
. Consequently,
was docked against M
. The results clarified that
bonded in a correct way inside M
active site, with a binding energy of -18.45 kcal/mol. Furthermore, the ADMET and toxicity profiles of
were evaluated and showed the safety of
and its likeness to be a drug. Finally, to confirm the binding and understand the thermodynamic characters between
and M
, several molecular dynamics (MD) simulations studies have been administered. Additionally, the known coumarin derivative, 7-isopentenyloxycoumarin (
), has been isolated as well as β-sitosterol (
).
A new flavonoid, Jusanin, (
) has been isolated from the aerial parts of
. The chemical structure of Jusanin has been elucidated using 1D, 2D NMR, and HR-Ms spectroscopic methods to be ...5,2',4'-trihydroxy-6,7,5'-trimethoxyflavone. Being new in nature, the inhibition potential of
has been estimated against SARS-CoV-2 using different in silico techniques. Firstly, molecular similarity and fingerprint studies have been conducted for Jusanin against co-crystallized ligands of eight different SARS-CoV-2 essential proteins. The studies indicated the similarity between
and
, the co-crystallized ligand SARS-CoV-2 main protease (PDB ID: 6W63). To confirm the obtained results, a DFT study was carried out and indicated the similarity of (total energy, HOMO, LUMO, gap energy, and dipole moment) between
and
. Accordingly, molecular docking studies of
against the target enzyme have been achieved and showed that
bonded correctly in the protein's active site with a binding energy of -19.54 Kcal/mol. Additionally, in silico ADMET in addition to the toxicity evaluation of Jusanin against seven models have been preceded and indicated the general safety and the likeness of Jusanin to be a drug. Finally, molecular dynamics simulation studies were applied to investigate the dynamic behavior of the M
-Jusanin complex and confirmed the correct binding at 100 ns. In addition to 1, three other metabolites have been isolated and identified to be сapillartemisin A (
), methyl-3-S-hydroxyprenyl-cumarate (
), and β-sitosterol (
).
Novel indolo3,2-bcarbazole derivatives and a chromogenic-sensing 5,12-dihydroindolo3,2-bcarbazole have been synthesized starting from tetra-tert-butylated ...6,12-diaryl-5,11-dihydroindolo3,2-bcarbazoles, which were prepared via an efficient tert-butylation of 6,12-diaryl-5,11-dihydroindolo3,2-bcarbazoles.
The oxidative coupling reactions of 6-pentyl-5,11-dihydroindolo3,2-bcarbazole have been studied and as a result, a number of novel dimers of the indolo3,2-bcarbazole derivative have been prepared, ...forming C-C coupled compound when treated with FeCl(3) x 6H(2)O or C-N coupled compounds and when oxidized with air or Pd(OAc)(2), respectively.
A simple and highly sensitive reversed-phase high-performance liquid chromatographic method (RP-HPLC) has been developed for the determination of steviol (SV) using dihydroisosteviol (DHISV) as an ...internal standard (IS). SV and DHISV were derivatized by reaction of the acids with 4-(bromomethyl)-7-methoxycoumarin in an aprotic solvent (DMF or acetone). The resulting ester derivatives were separated on an ODS column (250 × 4.6 mm i.d., 5 μm particle size) using fluorescence detection with excitation at 321 nm and emission at 391 nm. The mobile phase consisted of acetonitrile/water (80:20 v/v) with a flow rate of 1 mL min-1. A linear relationship was observed for concentrations between 0.5 and 50 μg/mL of SV, and the detection limit was 100 pg. For application of this method to samples of beer fortified with stevioside, a simple procedure for extraction of the beer with diethyl ether and derivatization in DMF was applied. Whereas beer samples spiked with SV gave a linear response over the range 0.1−15 μg/mL beer, no SV could be detected in beer samples enriched in stevioside that had been stored for over 3 years. The application of the method to plant samples involved preparation of an acid fraction containing the SV analyte, derivatization, and sample cleanup using small silica columns and thin-layer chromatography. A sensitive determination of 594 ng of steviol present in 100 mg of dry plant material was performed with high precision and accuracy. Keywords: Stevia rebaudiana (Bertoni) Bertoni; steviol; dihydroisosteviol; 4-(bromomethyl)-7-methoxycoumarin; fluorescence detection; biological fluids; plants
Various analogues of
cis-5-amino-6-oxo-2-piperidinemethanol and
cis-5-amino-2-piperidinemethanol have been prepared via Diels–Alder reaction of substituted pyrazinones with ethene followed by acid ...methanolysis of the bridged lactam adducts. Further reduction of the resulting methyl 2-piperidinecarboxylate ester compounds led to the corresponding 2-piperidinemethanol products that were converted into potential SP antagonists.
Graphic
Dichloropyrazinone
3
was converted into a conformationally restricted dipeptide analogue
8
by means of a Diels–Alder strategy. The β-turn characteristics of molecule
8
were examined by molecular ...modeling and NMR spectroscopy.
Graphic
A number of new chiral monoaza-15-crown-5 derivatives (
4–9) and lariat ethers (
10–15) anellated to phenyl-β-D-glucopyranoside have been synthesized. Their extracting ability was measured with ...alkali metal (Li, Na, K) and ammonium cations. The derivatives show significant asymmetric induction as phase transfer catalysts in the Michael addition of 2-nitropropane to chalcone (82% ee) although in low yield, and in the Darzens condensation of phenacyl chloride with benzaldehyde (74% ee). The substituent at the nitrogen atom of the crown ethers has a major influence on both the extraction ability and the enantioselectivity.
Crown ethers anellated to phenyl-β-D-glucopyranoside have been used as catalyst in two enantioselective carbon-carbon bond forming reaction s: the Michael addition of 2-nitropropane to chalcone (e.e.: 82%) and the Derzens condensstion of phenacyl chloride with benzaldehyde (e.e.: 74%).
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