High-Value Chemicals from Electrocatalytic Depolymerization of Lignin: Challenges and Opportunities.

Lignocellulosic biomass is renewable and one of the most abundant sources for the production of high-value chemicals, materials, and fuels. It is of immense importance to develop new efficient technologies for the industrial production of chemicals by utilizing renewable resources. Lignocellulosic biomass can potentially replace fossil-based chemistries. The production of fuel and chemicals from lignin powered by renewable electricity under ambient temperatures and pressures enables a more sustainable way to obtain high-value chemicals. More specifically, in a sustainable biorefinery, it is essential to valorize lignin to enhance biomass transformation technology and increase the overall economy of the process. Strategies regarding electrocatalytic approaches as a way to valorize or depolymerize lignin have attracted significant interest from growing scientific communities over the recent decades. This review presents a comprehensive overview of the electrocatalytic methods for depolymerization of lignocellulosic biomass with an emphasis on untargeted depolymerization as well as the selective and targeted mild synthesis of high-value chemicals. Electrocatalytic cleavage of model compounds and further electrochemical upgrading of bio-oils are discussed. Finally, some insights into current challenges and limitations associated with this approach are also summarized.

Assessing the biological potential of new symmetrical ferrocene based bisthiourea analogues.

In the present work synthesis and characterization of five new bisferrocenyl bisthiourea analogues (G2M, S2M, G3F, G4F and T2M) is reported. UV-Visible and electrochemical studies were performed in order to have optical (absorption maximum, Molar absorption coefficient and optical band gap) and electrochemical parameters (Oxidation/reduction potentials and nature of the electrochemical process) of the compounds. In vitro various biological studies such as antibacterial, antifungal, anti-oxidant and antidiabetic activities were carried out to have comparative overview of the phermacochemical strength of the newly synthesized compounds. Similarly, theoretical analysis was accomplished utilizing density functional theory calculations. DFT/B3LYP (6-31G d, p) technique was used. With a view to explore the structure activity relationship (SAR) of the compounds theoretical docking analysis (against α-amylase, α-glucosidase) was also performed to have pictorial view and understanding of the actual interactions responsible for the activity. S2M displayed best antibacterial activity. Similarly, Antifungal and antidiabetic activities showed G3F as a best candidate, whereas T2M proved to be the best antioxidant agent.

New Heteroleptic 3D Metal Complexes: Synthesis, Antimicrobial and Solubilization Parameters.

The microbial resistance to current antibiotics is increasing day by day, which in turn accelerating the development of new effective drugs. Several studies have proved the high antimicrobial potential of the interaction of several organic ligands with a variety of metal ions. In the present study, a conventional method has been adopted in the synthesis of twelve new heteroleptic complexes of cobalt (II), nickel (II), copper (II) and zinc (II) using three aldimines, namely, (HL1 ((E)-2-((4-chloro-2-hydroxybenzylidene)amino)-3,4-dimethyl-5-phenylcyclopent-2-en-1-one), HL2 ((Z)-3-((4-chlorobenzylidene)amino)-4-hydroxy-5-nitrobenzenesulfonic acid) HL3 (2,2'-((1,2-phenylenebis(azaneylylidene))bis(methaneylylidene))diphenol)) as primary ligands, while phenyl glycine was the secondary ligand. The synthesized compounds were characterized by UV-vis, IR and multinuclear (1H and 13C) NMR spectroscopy, elemental analysis, and electrical conductance. The IR study revealed the coordination of the aldimine derivatives with the -OH and N atom of imine moiety. In contrary to this, the phenyl glycine coordinated to the metal ions via oxygen of carboxylate and nitrogen of the amino group. The spectroscopic analysis unveiled the tetrahedral geometry of the synthesized metal (II) complexes, except for ligand HL3 which exhibited octahedral geometry. The synthesized compounds generally showed antibacterial activity for all microbes, except Ni (II) complexes lacking sensitivity. Furthermore, to access the bioavailability, the synthesized complexes were screened for their solubilization in the micellar media of sodium lauryl sulphate. The metal complex-surfactant interaction was revealed by UV-vis spectroscopy and electrical conductivity measurements.

Heterochelates of metals as an effective anti - Urease agents couple with their docking studies.

The current article discusses the activities of several synthesized metal heterochelates in in-vitro as anti-ulcer agents followed by their docking study. For this purpose, two important ligands like 8-hydroxyquinoline and DL-methionine were used in synthesis of heterochelates of metal including Cr (III), Mn (II), Fe (III), Co (II), Ni (II), Cu (II), Zn (II), Cd (II) and Pb (II). It was observed that these complexes showed excellent urease inhibition activities in which thiourea was the standard having IC50 value 21.6 ± 0.12µM. The Cu (II) complex showed potent inhibitory activity (22.6 ± 0.72 µM) when compared with the standard thiourea (21.6±0.12µM) among the nine synthesized complexes while Mn (II), Fe (III), Cd (II) and Pb (II) also showed better inhibitory activities. The urease inhibitory activities of hetercochelates also tested and validated by docking analysis.

New ferrocene integrated amphiphilic guanidines: Synthesis, spectroscopic elucidation, DFT calculation and in vitro α-amylase and α-glucosidase inhibition combined with molecular docking approach.

Three N, N', N″-trisubstituted ferrocenyl guanidines (MG-10, MG-12 and MG-14) were synthesized, characterized by several analytical methods such as FT-IR, 1H and 13C NMR, elemental analysis and UV-visible spectroscopy. These compounds have long chain aliphatic groups therefore their aliphatic nature has been evaluated by determining their critical micelle concentration (CMC). CMC point decreases from 0.036 mM to 0.013 mM with increase in the aliphatic chain length. The quantum mechanical parameters such as the energy of frontier molecular orbitals (EHOMO and ELUMO) and the Mulliken charge distribution on the optimized structures were determined using a DFT/B3LYP method combined with the 6-31G (d,p) basis set in the gas phase. The in vitro antidiabetic activity of synthesized compounds showed that MG-12 has IC50value 23.10 µg/mL against α-amylase while MG-10 has IC50value 27.32 µg/mL against α-glucosidase with the respective standard Acarbose (IC50value 20.12 µg/mL). Theoretical docking analysis demonstrated that MG-10 and MG-12 interacted with α-amylase by 3 types of interaction, including hydrogen bonds, hydrophobic interactions and electrostatic interactions.

Exploring novel fluorine-rich fuberidazole derivatives as hypoxic cancer inhibitors: Design, synthesis, pharmacokinetics, molecular docking, and DFT evaluations.

Sixteen fuberidazole derivatives as potential new anticancer bioreductive prodrugs were prepared and characterized. The in vitro anticancer potential was examined to explore their cytotoxic properties by employing apoptosis, DNA damage, and proliferation tests on chosen hypoxic cancer cells. Eight substances (Compound 5a, 5c, 5d, 5e, 5g, 5h, 5i, and 5m) showed promising cytotoxicity values compared to the standard control. The potential of compounds was also examined through in silico studies (against human serum albumin), including chem-informatics, to understand the structure-activity relationship (SAR), pharmacochemical strength, and the mode of interactions responsible for their action. The DFT calculations revealed that only the 5b compound showed the lowest ΔET (2.29 eV) while 5i showed relatively highest ßtot (69.89 x 10-31 esu), highest αave (3.18 x 10-23 esu), and dipole moment (6.49 Debye). This study presents a novel class of fuberidazole derivatives with selectivity toward hypoxic cancer cells.

The Biogenic Synthesis of Bimetallic Ag/ZnO Nanoparticles: A Multifunctional Approach for Methyl Violet Photocatalytic Degradation and the Assessment of Antibacterial, Antioxidant, and Cytotoxicity Properties.

In this study, bimetallic nanoparticles (NPs) of silver (Ag) and zinc oxide (ZnO) were synthesized using Leptadenia pyrotechnica leaf extract for the first time. Monometallic NPs were also obtained for comparison. The characterization of the prepared NPs was carried out using various techniques, including UV-Visible spectroscopy (UV-Vis), scanning electron microscopy (SEM), and X-ray diffraction (XRD). The latter confirmed the crystalline nature and diameter of the monometallic and bimetallic NPs of Ag and ZnO. The SEM images of the prepared NPs revealed their different shapes. The biological activities of the NPs were evaluated concerning their antibacterial, antioxidant, and cytotoxic properties. The antibacterial activities were measured using the time-killing method. The results demonstrated that both the monometallic and bimetallic NPs inhibited the growth of Gram-negative (Escherichia coli) and Gram-positive (Staphylococcus aureus) bacteria. The antioxidant activities of the NPs were evaluated using the DPPH (2,2-diphenyl-1-picrylhydrazyl) assay and their cytotoxicity was checked using the MTT (3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide) assay. The results indicated that the controlled quantity of the monometallic and bimetallic NPs did not affect the viability of the cells. However, the decreased cell (L-929) viability suggested that the NPs could have anticancer properties. Furthermore, the photocatalytic degradation of methyl violet and 4-nitrophenol was investigated using the prepared Ag/ZnO NPs, examining the factors affecting the degradation process and conducting a kinetic and thermodynamic study. The prepared Ag/ZnO NPs demonstrated good photocatalytic degradation (88.9%) of the methyl violet (rate constant of 0.0183 min-1) in comparison to 4-nitrophenol (NPh), with a degradation rate of 81.37% and 0.0172 min-1, respectively. Overall, the bimetallic NPs showed superior antibacterial, antioxidant, cytotoxic, and photocatalytic properties compared to the monometallic NPs of Ag and ZnO.

Bioconjugate synthesis, phytochemical analysis, and optical activity of NiFe2O4 nanoparticles for the removal of ciprofloxacin and Congo red from water.

In this paper, Jr.NiFe2O4 nanoparticles (NPs) were synthesized first time using the leaves extract of Juglans regia via a straightforward process. The physio and phytochemical analysis of plant confirm the presence of macromolecules which function as bio-reductant and stabilize the nanoparticles. The Jr.NiFe2O4 NPs were characterized by UV-visible, FTIR spectroscopy, PXRD pattern, SEM and TGA/DTA analysis. The nanoparticles proved to be optically active having a value of indirect bandgap of energy in the range of 1.53 eV. The Jr.NiFe2O4 NPs have the ability in scavenging 2,2-diphenyl-1-picrylhydrazyl hydrate (DPPH) free radicals and showed 58.01% ± 1.2% scavenging activity at 100 µg/mL concentrations. The photocatalytic degradation study of ciprofloxacin (CIP) and Congo red (CR) reveals that the highest degradation rate was acquired for CIP using pH = 3, at 254 nm, while 85% of removal rate was analysed for CR. The kinetic studies in case of CR removal followed pseudo-first-order model with thermodynamic parameters (∆G° = - 5.87 kJ mol-1 K, ΔH° = 1393.50 kJ mol-1 and ΔS° = 22.537 kJ mol-1 K) with error analysis. Overall, these data recommend an innovative inspiring application of a plant-mediated synthesis of Jr.NiFe2O4 NPs.

Preparation, structural elucidation and biocidal applications of trimethyltin(IV) complexes derived from substituted carboxylic acids.

A series of trimethyltin(IV) carboxylates (1-7), having general formula [(CH3)3SnOOCR], where R = 3-CF3C6H4- (1), 3,4-(OCH2CH3)2 C6H3- (2), 3-FC6H4- (3), 4-ClC6H5- (4), 2,4-(OCH3)2C6H3- (5), 4-NO2C6H4- (6), 5-CH3C4H2N2- (7) have been synthesized and are characterized by using analytical techniques like, FT-IR, 1H, 13C and 119Sn NMR spectroscopy in addition to elemental analyses. To validate the structural motif, one of the complex (2) was also analyzed by single crystal XRD technique. The single crystal X-ray diffraction analysis revealed that the molecular species exist in one dimensional polymeric chain, wherein five coordinated tin is attached to two oxygens of the carboxyl and three carbon atoms of CH3 groups, whereas the bond angles for C-Sn-C (117.20-121.65°), C-Sn-O (87.87-98.60°) and O-Sn-O (173.75°) lie in the predictable range of distorted trigonal bipyramidal geometry. All the synthesized complexes were also subjected to preliminary screening for various biocidal applications such as antimicrobial, anti-diabetic, protein kinase inhibition and brine shrimp lethality test to check their efficacy. The compound 6 exhibits very good antibacterial activity having MIC value 6.25 µg/mL against K. pneumoniae, whereas antidiabetic and protein kinase inhibition data revealed that 1 and 2 may serve as good to moderately effective inhibitors, respectively.

Prophylactic rectal nsaids in the prevention of post-ercp pancreatitis

Objective: To evaluate the effectiveness of rectal non-steroidal anti-inflammatory drugs [NSAIDs] using diclofenac in preventing pancreatitis following ERCP

Methodology: It was a randomized, double blinded, placebo controlled study carried out at Surgical Unit-l, Holy Family Hospital, Rawalpindi from May 2013 to April 2014. A total of 108 patients were included and randomly assigned in each of study and placebo groups. Group I patients received 100 mg of diclofenac per rectally while group II patients received a glycerine suppository per rectally [placebo] before the start of ERCP. Post ERCP pancreatitis [PEP] was diagnosed by clinical evaluation and raised serum amylase levels after four hours of the procedure in both groups [study vs control]

Results: Out of 108 patients 32 were males and 76 were females. Mean age was 46.09 +/- 12.31 in group I, while it was 42.93 +/- 14.69 in Group II. Mean serum amylase level, 4 hours after ERCP, was 184.70 +/- 36.34 in the diclofenac group, while it was 388.20 +/- 57.27 IU/L in the control group. Thirty one patients were diagnosed with Post ERCP pancreatitis, out of which nine patients belonged to the study group and twenty two were of the control group [P = 0.000]

Conclusion: Per-rectal administration of diclofenac suppository prior to ERCP results in significant reduction in the frequency of ERCP induced pancreatitis