Designing of chitosan/gelatin based nanocomposite films integrated with Vachellia nilotica gum carbon dots for smart food packaging applications.

Microbial growth and exposure to UV light is a persistent global concern resulting in food spoilage, therefore, smart packaging is crucial for the availability of safer and quality food. Present work describes fabrication of chitosan (CH) and gelatin (GL) based nanocomposite films by introducing green source, highly fluorescent Vachillia nilotica gum-derived carbon dots (VNG-CDs). The VNG-CDs and incorporated CH/GL nanocomposite films were characterized by UV-Visible, FTIR, XRD, SEM and TGA analysis. The FTIR and XRD data revealed that VNG-CDs, chitosan, gelatin, and glycerol are combined/interlinked to form homogeneous nanocomposite films. The inclusion of VNG-CDs to CS/GL-CDs nanocomposite film efficiently enhanced the thermal stability and improved mechanical properties. VNG-CDs added to films markedly blocked the ultraviolet light and their effectiveness improved as concentration of CDs increases, being >90 % in UVC (200-280 nm) region. The prepared CS/GL-CDs nanocomposite films manifested radical scavenging activity, reducing capability and also excellently inhibited growth of E. coli, K. pneumonia and S. aureus bacteria. The viability of CS/GL-CDs nanocomposite films examined using banana as a model fruit extending the storage time by two weeks. In conclusion, CH/GL films containing VNG-CDs can be developed into smart packaging materials with enhanced protection and antimicrobial properties.

Isolation of Thioinosine and Butenolides from a Terrestrial Actinomycetes sp. GSCW-51 and Their in Silico Studies for Potential against SARS-CoV-2.

In our continuous screening for bioactive microbial natural products, the culture extracts of a terrestrial Actinomycetes sp. GSCW-51 yielded two new metabolites, i. e., 5-hydroxymethyl-3-(1-hydroxy-6-methyl-7-oxooctyl)dihydrofuran-2(3H)-one (1), 5-hydroxymethyl-3-(1,7-dihydroxy-6-methyloctyl)dihydrofuran-2(3H)-one (2), and two known compounds; 5'-methylthioinosine (3), and 5'-methylthioinosine sulfoxide (4), which are isolated first time from any natural source, along with four known compounds (5-8). The structures of the new compounds were deduced by HR-ESI-MS, 1D and 2D NMR data, and in comparison with related compounds from the literature. Additionally, owing to the current COVID-19 pandemic situation, we also computationally explored the therapeutic potential of our isolated compounds against SARS-CoV-2. Compound 4 showed the best binding energies of -6.2 and -6.6 kcal/mol for Mpro and spike proteins, respectively. The intermolecular interactions were also studied using 2-D and 3-D imagery, which also supported the binding energies as well as put several insights under the spotlight. Furthermore, Lipinski's rule of 5 was used to predict the drug likeness of compounds 1-4, which indicated all compounds obey Lipinski's rule of 5. The study of bioavailability radars of the compounds 1-4 also confirmed their drug likeness properties where all the five crucial drug likeness parameters are in color area, which is safe to be used as drugs. Our isolation and computational findings highly encourage the scientific community to do further in vitro and in vivo studies of compounds 1-4.

New norterpenoids and a sphingolipid from Carissa opaca.

Chemical investigations on the aerial parts of Carissa opaca resulted in the isolation and characterization of two new nor-triterpenoids (compounds 1 and 2) and a new sphingolipid (compound 3) together with six known compounds. The structures of all the isolates were established using spectral data. All the isolated compounds showed DPPH radical scavenging and enzyme inhibitory activities against enzymes acetylcholinesterase, butyrylcholinesterase, and lipoxygenase.

Synthesis of Fluoroalkoxy Substituted Arylboronic Esters by Iridium-Catalyzed Aromatic C-H Borylation.

The preparation of fluoroalkoxy arylboronic esters by iridium-catalyzed aromatic C-H borylation is described. The fluoroalkoxy groups employed include trifluoromethoxy, difluoromethoxy, 1,1,2,2-tetrafluoroethoxy, and 2,2-difluoro-1,3-benzodioxole. The borylation reactions were carried out neat without the use of a glovebox or Schlenk line. The regioselectivities available through the iridium-catalyzed C-H borylation are complementary to those obtained by the electrophilic aromatic substitution reactions of fluoroalkoxy arenes. Fluoroalkoxy arylboronic esters can serve as versatile building blocks.

Lipoxygenase inhibitory sphingolipids from Launaea nudicaulis.

Four new sphingolipids: nudicaulin A [(2S,3S,4R,14E)-2-{[octadecanoyl]amino}tetraeicos-14-ene-1,3,4-triol; 1], nudicaulin B [(2S,3S,4R,14E)-2-{[(2R)-2-hydroxyoctadecanoyl]amino}tetraeicos-14-ene-1,3,4-triol; 2], nudicaulin C [(2S,3S,4R,14E)-2-{[(2R)-2-hydroxyoctadecanoyl]amino}tetraeicos-14-ene-1,3,4-triol-1-O-ß-D-glucopyranoside; 3], and nudicaulin D [(2S,3S,4R)-2-{[(2R,3S,12E)-2,3-dihydroxyeicos-12-enoyl]amino}octadecane-1,3,4-triol; 4] together with 1-hexatriacontanol, ß-sitosterol, octadecyl 4-hydroxycinnamate, elaidic acid, cholesta-5,22-diene-3,7-diol, oleanolic acid, apigenin, and ß-sitosterol 3-O-ß-D-glucopyranoside were isolated from the methanolic extract of the whole plant of Launaea nudicaulis. Their structures were elucidated using ¹H and ¹³C NMR spectra and 2D NMR analyses (HMQC, HMBC, and COSY) in combination with mass spectrometry (EI-MS, HR-EI-MS, FAB-MS, and HR-FAB-MS) experiments and comparison with literature data of related compounds. Compounds 1-4 displayed moderate inhibitory potential against enzyme lipoxygenase in concentration-dependent manner with IC50 value ranges 103-193 µM.