Synthesis,Characterization, and Antimicrobial Activity of Carboxymethyl Chitosan-Graft-Poly(N-acryloyl,N′-cyanoacetohydrazide) Copolymers

Carboxymethyl chitosan was grafted with N-acryloyl,N′-cyanoacetohydrazide in homogenous aqueous phase using potassium persulfate initiator. The maximum grafting yield achieved was 448% at 0.03 mol/L potassium persulfate, 0.75 mol/L N-acryloyl,N′-cyanoacetohydrazide, and 60°C within 2 h. The grafted copolymers showed better thermal stability than that of carboxymethyl chitosan. The samples with percent grafting values up to 98% were soluble in water, but a higher grafting extent resulted in insoluble copolymers. The grafted copolymers are nontoxic materials and showed an inhibition effect on both Escherichia coli and Staphylococcus aureus bacteria and Aspergillus flavus and Candida albicans fungi better than those of chitosan and carboxymethyl chitosan themselves.     

Synthesis and Characterization of Some New Quinoxalin-2(1H)one and 2-Methyl-3H-quinazolin-4-one Derivatives Targeting the Onset and Progression of CRC with SAR,Molecular Docking,and ADMET Analyses

The pathogenesis of colorectal cancer is a multifactorial process. Dysbiosis and the overexpression of COX-2 and LDHA are important effectors in the initiation and development of the disease through chromosomal instability, PGE2 biosynthesis, and induction of the Warburg effect, respectively. Herein, we report the in vitro testing of some new quinoxalinone and quinazolinone Schiff’s bases as: antibacterial, COX-2 and LDHA inhibitors, and anticolorectal agents on HCT-116 and LoVo cells. Moreover, molecular docking and SAR analyses were performed to identify the structural features contributing to the biological activities. Among the synthesized molecules, the most active cytotoxic agent, (6d) was also a COX-2 inhibitor. In silico ADMET studies predicted that (6d) would have high Caco-2 permeability, and %HIA (99.58%), with low BBB permeability, zero hepatotoxicity, and zero risk of sudden cardiac arrest, or mutagenicity. Further, (6d) is not a potential P-gp substrate, instead, it is a possible P-gpI and II inhibitor, therefore, it can prevent or reverse the multidrug resistance of the anticancer drugs. Collectively, (6d) can be considered as a promising lead suitable for further optimization to develop anti-CRC agents or glycoproteins inhibitors.     

A Novel Serine Metallokeratinase from a Newly Isolated <Emphasis Type="BoldItalic">Bacillus pumilus</Emphasis> A1 Grown on Chicken Feather Meal: Biochemical and Molecular Characterization

A keratinolytic enzyme (KerA1) secreted by a newly isolated Bacillus pumilus strain A1 cultivated in medium containing chicken feather meal was purified and characterized, and the gene was isolated and sequenced. The molecular mass of the purified enzyme was estimated to be 34,000 Da by sodium dodecyl sulfate (SDS) polyacrylamide gel electrophoresis and gel filtration. The optimum pH and temperature for the purified keratinase were 9.0 and 60 °C, respectively, using keratin as a substrate. KerA1 showed a high stability towards nonionic surfactants. It was found to be relatively stable toward the strong anionic surfactant (SDS). The deduced amino acid sequence of the keratinase KerA1 differs from both the organic solvent tolerant protease of B. pumilus 115b and the dehairing protease of B. pumilus UN-31-C-42 by one and nine amino acids, respectively. These results suggest that this keratinase may be a useful alternative and ecofriendly route for handling the abundant amount of waste feathers and for applications in detergent formulations.     

Soil Thin-Layer Chromatography of Heavy Metal Cations with Surfactant-Modified Mobile Phases: Mutual Separation of Zinc(II), Cadmium(II), and Mercury(II)

JPC – Journal of Planar Chromatography – Modern TLC - Thin-layer chromatography of ten metal ions has been performed on pure soil layers; the mobile phases were aqueous organic and...     

New Thiophene Derivatives as Antimicrobial Agents

Phenacylbromide derivatives constitute a multilateral group of precursors for the synthesis of numerous heterocycles of organic compounds. Briefly, 5‐(2‐bromo‐acetyl)‐substituted‐thiophene derivative has been used as a synthon for synthesis of new thiophene‐containing compounds through the reaction with nucleophilic nitrogen compounds and thioamides. The suggested structures of the newly synthesized thiophene compounds were confirmed and assured with different spectroscopic tools and with CHN elemental analysis. Additionally, the antimicrobial activity of these thiophene compounds was recorded to investigate their potency against various types of bacteria and fungi. Results showed that these compounds exhibit significant inhibitory activity against the growth of tested bacterial and fungal strains and that some derivatives were more potent than the employed reference drugs.     

Metal complexes derived from hydrazoneoxime ligands: IV. Molecular and supramolecular structures of some nickel(II) complexes derived from diacetylmonoxime S-benzyldithiocarbazonate

Four new nickel(II) complexes, [{Ni(L)}₂], [NiL · HPyr], [NiL · HIm] and [Ni(HL)₂] · H₂O, derived from diacetylmonoxime-S-benzyldithiocarbazonate (H₂L) have been synthesized and characterized by elemental analyses, field desorption and electrospray ionization mass spectra, UV–Vis, infrared absorption spectra, as well as ¹H NMR spectra. X-ray molecular structures showed that the Ni(II) in both [NiL · HPyr] and [NiL · HIm] are in a distorted square planar environment and is coordinated to the dianionic NNS tridentate hydrazoneoxime ligand via deprotonated oximate nitrogen, hydrazone imine nitrogen, and thiolate sulphur. The fourth coordination sites are occupied, respectively, by the pyrazole and imidazole nitrogens. The oximate O1 of [NiL · HPyr] is involved in intramolecular hydrogen bond with the pyrazole NH proton as well as intermolecular hydrogen bond pyrazole C6H proton, forming a helical chain propagating along the b-axis. The structure is stabilized by a set of π?π and CH?π interactions. The molecular units in [NiL · HIm] are linked together by hydrogen bond formation between the oximate oxygen and imidazole NH proton, giving rise to an infinite zigzag chain extended along the a-axis. The chains are interconnected by π?π and CH?O interactions. In [Ni(HL)₂] · H₂O, the Ni(II) is in a distorted octahedral environment. The two mononegative hydrazoneoxime ligands are coordinated in the meridional configuration where the two thiol sulphur atoms and the two oxime nitrogen atoms are cis to each other, while the imine nitrogen atoms are trans. The oxime proton O2H is involved in a reciprocal bifurcated hydrogen bond formation with both N2 and S3 of the adjacent molecule giving rise to hydrogen bonded dimer. This dimeric structure is further stabilized by a pair of reciprocal CH?O interactions. A one dimensional chain of alternating dimeric unit and water molecule propagating along the c-axis is formed via hydrogen bond formation between the oxime O1 oxygen and the bridged water molecule proton.     

Heck reaction with an alkenylidenecyclopropane: the formation of arylallylidenecyclopropanes

The palladium-tetraphosphine catalyzed arylation of an alkylidenecyclopropane gives a simple and direct access to 1-aryl-2-methyl-1-(2,2,3,3-tetramethylcyclopropylidene)propenes. This reaction tolerates several functional groups on the aryl bromides. Even heteroaryl bromides have been used successfully. This reaction probably proceeds via a classical oxidative addition of the aryl bromide to palladium, insertion of the CCMe₂ bond in the Ar-Pd bond followed by β-elimination to give the dienes.     

Spectrofluorometric determination of fluvoxamine in dosage forms, spiked plasma, and real human plasma by derivatization with fluorescamine

A sensitive, simple, and selective spectrofluorometric method was developed for the determination of fluvoxamine (FXM) in pharmaceutical formulations and biological fluids. The method is based upon the reaction between the drug and fluorescamine in borate buffer of pH 8.0 to yield a highly fluorescent derivative that is measured at 481 nm after excitation at 383 nm. The different experimental parameters affecting the development and stability of the reaction product were carefully studied and optimized. The method was applied for the determination of the drug over the concentration range of 0.1-1.1 microg/mL with a detection limit of 0.01 microg/mL (2 x 10(-8) M). The proposed method was successfully applied to the analysis of commercial tablets. The results obtained were in good agreement with those obtained using a reported spectrophotometric method. The method was applied for the determination of FXM in spiked human plasma with recovery (n=4) of 97.32 +/- 1.23%, while that in real human plasma (n=3) was 90.79 +/- 2.73%. A proposal for the reaction pathway is presented.