Symbiotic Antimicrobial Effects of Cellulose‐Based Bio‐Nanocomposite for Disease Management of Agricultural Crops

Posted on 14 September 2023 by nChhavi Sharma, nDinesh Singh, nRitu Srivastava, nShailesh Narain Sharman

Abstract

In the present work, a bionanocomposite for plant crop protection was prepared by non-toxic biocompatible & biodegradable nanomaterials (Cellulose & TiO₂) to utilize its synergistic effects against antimicrobial pathogens. The commercially available microcrystalline cellulose has been reduced to a nanometric scale regime using acid hydrolysis, while the standard TiO₂ nano-powder of particle size ~20 nm has been used to prepare their nanocomposite (NC). The antibacterial studies via agar well diffusion method demonstrated that after 72 h of incubation, parent nanomaterials Ncell and TiO₂ were not showing any activity against phytopathogens X. campestris pv. campestris, and Clavibacter while the nanocomposite's NC's were still effective depicting both bacteriostatic and bactericidal actions. However, the bacterial growth of biocontrol P. fluorescence was not affected by Ncell, TiO₂ NPs and NC after 72 h of incubation. The antifungal testing results via poison food agar assay method suggest that the nanocomposite, along with Ncell and TiO₂ NPs, exhibited strong inhibition of fungal growth of Phytophthora Spp at 0.125 mg/ml concentration while for F. graminearum, similar effect was observed at 0.25 mg/ml concentration. The nanocomposite has proved its potential by exhibiting longer & stronger synergistic effects against plant pathogens as a good antimicrobial agent for protection of agricultural crops.

A Homochiral Diphenylalanine Analog Based Mechanoresponsive Hydrogel: An Insight Towards Its Wound Healing Efficacy

Posted on 14 September 2023 by

Abstract

Deciphering the most promising strategy for the evolution of potential wound-healing therapeutics is one of the greatest challenging affairs to date. The development of peptide-based smart scaffolds with innate antimicrobial, anti-inflammatory, and antioxidant properties is an appealing way out. Aligned to the goal a set of Hydrogelators I–IV were developed utilizing the concept of chiral orchestration in diphenylalanine fragment, such that the most potent construct with all the bench marks namely mechanoresponsiveness, biocompatibility, consistent antimicrobial and antioxidant properties, could be fished out from the design. Interestingly, our in vitro Antifungal and Lipid peroxidation analysis identified the homochiral isomer Boc-δ-Ava-L-Phe-L-Phe-OH (Hydrogelator I), as an ideal candidate for the wound healing experiment, so we proceeded for the in vivo histopathological and antioxidant measurements in Wister rats. Indeed the wound images obtained from the different sets of animals on the 14^th day of treatment demonstrated that with increased recovery time, hydrogelator I displayed a significant reduction in the lesion diameter compared to the marketed drug, and negative control. Even the histopathological measurements using H & E staining demonstrated diminished tissue destruction, neutrophil infiltration necrosis, and lymphatic proliferation in the hydrogelators, in comparison to others, backed by in vivo lipid peroxidation data. Overall our investigation certifies hydrogelator I as an effective therapeutic for managing the wound healing complication.

Synthesis towards Phainanoid F: Photo‐induced 6π‐Electrocyclization for Constructing Contiguous All‐Carbon Quaternary Centers

Posted on 14 September 2023 by

Photoinitiated 6π-electrocyclization was developed as an efficiently strategy to construct vicinal quaternary carbons. Combined with homoallylic elimination, the 13,30-cyclodammarane skeleton of phainanoid F was constructed.

Abstract

In this paper, we report an efficient strategy for synthesizing the DEFGH rings of phainanoid F. The key to the construction of the 13,30-cyclodammarane skeleton of the molecule was a photo-induced 6π-electrocyclization and a homoallylic elimination. Notably, this is a rare example of using electrocyclization reaction to simultaneously construct two vicinal quaternary carbons in total synthesis. The strategy outlined here forms the basis of our total synthesis of Phainanoid F, and it could also serve as a generally applicable approach for synthesizing other natural products containing similar 13,30-cyclodammarane skeletons.

Triphenylamine‐Based N,O‐Bidentate BF2‐Enolimine Initiator for Three‐Arm Star Polymethacrylates with Dual‐State Fluorescent Emission

Posted on 14 September 2023 by nDong Yang, nGuangming Tian, nJianhua Man

Three-arm star polymethacrylates with dual-phase (solution and solid-state) fluorescent emission were synthesized via ATRP using a triphenylamine-derived organoboron complex TAPA-BKI-3Br as initiator.

Abstract

Three-arm star polymethacrylates with dual-phase (solution and solid-state) fluorescent emission have been synthesized via atom transfer radical polymerization (ATRP) using a triphenylamine-derived organboron complex (TAPA-BKI-3Br) as initiator. The as-synthesized three-arm star polymethacrylates exhibited bright emission in both solution and the solid states due to the highly twisted structure and intramolecular charge transfer (ICT) effect of TAPA-BKI core, as well as the steric effect and restriction of intramolecular motions from the polymer arms. And the polymer chains have an important influence on the photophysical behavior of the as-synthesized three-arm star polymethacrylates in the aggregated state.

Diastereoselective Construction of α‐Fluoroalkyl Cycloalkanols via Radical Alkylation of α‐Fluoroalkyl Ketones

Posted on 14 September 2023 by nYi Liu, nJi Li, nYulu Zhou, nHanliang Zheng, nZhenlu Shen, nGangguo Zhun

A visible-light-induced cascade radical cyclization of alkenyl fluoroalkyl ketones is developed, producing various α-R_f cycloalkanols in promising yields with up to >20 : 1 dr selectivity. DFT calculations suggest that the fluorine effect plays an important role in this reaction.

Comprehensive Summary

α-Fluoroalkyl (R_f) alcohols are privileged motifs in drugs and pharmaceutically active compounds. As such, it is highly desirable to develop efficient methods for assembling these scaffolds. Herein, a visible-light-induced cascade radical cyclization of alkenyl fluoroalkyl ketones is developed, producing a variety of decorate α-R_f cycloalkanols in promising yields with up to >20 : 1 dr selectivity. A radical chain mechanism involving an intramolecular radical addition to the α-R_f carbonyl group and a subsequent intermolecular hydrogen atom transfer (HAT) has been proposed. Density functional theory (DFT) calculations indicate that a fluorine effect contributes to the radical addition to carbonyls by lowering the π* (C=O) orbital energy of COR_f and energy barrier of the HAT between alkoxy radicals and THF, which may be valuable for controllable transformations of fluorinated molecules.

Zwitterionic “Solutions” for Reversible CO2 Capture

Posted on 14 September 2023 by

A new class of basic aqueous sorbents for CO₂ based on zwitterions that present environmental and safety advantages that significantly reduce the risks of possible human and environmental contamination and they may be used in the nowadays employed amine scrubbing industrial plants with little or no modifications.

Abstract

The zwitterions resulting from the covalent attachment of 3- or 4-hydroxy benzene to the 1,3-dimethylimidazolium cation represent basic compounds (pKa of 8.68 and 8.99 in aqueous solutions, respectively) that chemisorb in aqueous solutions 0.58 mol/mol of carbon dioxide at 1.3 bar (absolute) and 40 °C. Equimolar amounts of chemisorbed CO₂ in these solutions are obtained at 10 bar and 40 °C. Chemisorption takes place through the formation of bicarbonate in the aqueous solution using imidazolium-containing phenolate. CO₂ is liberated by simple pressure relief and heating, regenerating the base. The enthalpy of absorption was estimated to be −38 kJ/mol, which is about 30 % lower than the enthalpy of industrially employed aqueous solutions of MDEA (estimated at −53 kJ/mol using the same experimental apparatus). The physisorption of CO₂ becomes relevant at higher pressures (>10 bar) in these aqueous solutions. Combined physio- and chemisorption of up to 1.3 mol/mol at 40 bar and 40 °C can be attained with these aqueous zwitterionic solutions that are thermally stable and can be recycled at least 20 times.

Green Alternatives in Treatment of Liver Diseases: the Challenges of Traditional Medicine and Green Nanomedicine

Posted on 14 September 2023 by

Abstract

Over the last decade, liver diseases have become a global problem, with approximately two million deaths per year. The high increase in the mortality rate of these diseases is mostly related to the limitations in the understanding of the evolutionary clinical cases of liver diseases, the low delivery of drugs in the liver, the non-specific administration of drugs, and the side effects generated at the systemic level by conventional therapeutic agents. Today it is common knowledge that phytochemicals have a high curative potential, even in the prevention and/or reversibility of liver disorders; however, even using these green molecules, researchers continue to deal with the same challenges implemented with conventional therapeutic agents, which limits the pharmacological potential of these friendly molecules. On the other hand, the latest advances in nanotechnology have proven that the use of nanocarriers as a delivery system for green active ingredients, as well as conventional ones, increases the pharmacological potential of these active ingredients due to their physicochemical characteristics (size, Zeta potential, etc.,) moldable depending on the therapeutic objective; in addition to the above, it should be noted that in recent years, nanoparticles have been developed for the specific delivery of drugs towards a specific target (stellar cells, hepatocytes, Kupffer cells), depending on the clinical state of the disease in the patient. The present review addresses the challenges of traditional medicine and green nanomedicine as alternatives in the treatment of liver diseases.

Investigation of Two Zr‐p‐NO2Bn‐DOTA Isomers via NMR and Quantum Chemical Studies

Posted on 14 September 2023 by nYong Sok Lee, nRobert D. O'Connor, nOlga Vasalatiyn

Two regioisomers of Zr-p-NO₂Bn-DOTA were isolated and characterized by NMR studies and quantum chemical calculations. As opposed to the side regioisomer, the corner regioisomer exists exclusively as the SAP isomer.

Abstract

A combination of NMR studies and quantum chemical calculations were employed to investigate the structure and energetics of Zr⁴⁺ chelates of pNO₂Bn-DOTA. We have demonstrated that two discrete regioisomeric chelates are generated during the complex formation. The nitrobenzyl substituent can adopt either an equatorial corner or side position on the macrocyclic ring. These regioisomers are incapable of interconversion and were isolated by HPLC. The corner isomer is more stable than the side, and the SAP conformer of both regioisomers is energetically more favorable than the corresponding TSAP conformer.

Click Chemistry and Targeted Degradation: A Winning Combination for Medicinal Chemists?

Posted on 14 September 2023 by

“Click chemistry” and targeted protein degradation – two flourishing trends in medicinal chemistry. May they be a winning combination? In this review, we provide the reader with selected examples offered by the combination of these two approaches trying to find a response to this question.

Abstract

Click chemistry is universally recognized as a powerful strategy for the fast and precise assembly of diverse building blocks. Targeted Protein Degradation (TPD) is a new therapeutic modality based on heterobifunctional small-molecule degraders that provides new opportunities to medicinal chemists dealing with undruggable targets and incurable diseases. Here, we highlight how very recently the TPD field and that of click chemistry have merged, opening up the possibility for fine-tuning the properties of a degrader, chemically assembled through a “click” synthesis. By reviewing concrete examples, we want to provide the reader with the insight that the application of click and bioorthogonal chemistry in the TDP field may be a winning combination.

Green synthesis and theoretical study of new 1,3,4‐oxadiazoles: Application of Cu/Fe3O4@MWCNT magnetic nanocomposites

Posted on 14 September 2023 by nElham Ezzatzadeh, nMarziyeh Mohammadi, nMehdi Ghambarian, nZinatossadat Hossainin

Cu/Fe3O4@MWCNT MNCs as an effective catalyst was synthesized by using water extract of Petasits hybridus leaves and promoted producing of novel derivatives of 1,3,4-oxadiazols in high yields. These new compounds were synthesized by using multicomponent reaction of ninhydrins, diamines or hydroxyamines, ester of acetylene with electron deficient, α-haloketones, hydrazoyl chloride and synthesized nanocatalyst in aqueous media. It should be mentioned that the high performance of nanocatalyat was synthesized by using water extract of Petasits hybridus leaves, which was utilized in these reactions for many times to confirm the reusability of nanocatalyst.

Cu/Fe₃O₄@MWCNT magnetic nanocomposites (MNCs) as an effective catalyst was promoted producing of novel derivatives of 1,3,4-oxadiazols in high yields. These new compounds were synthesized by using multicomponent reaction of ninhydrins, diamines or hydroxyamines, ester of acetylene with electron deficient, α-haloketones, hydrazoyl chloride, and synthesized nanocatalyst in aqueous media. It should be mentioned that the high performance of nanocatalyat was synthesized by using water extract of Petasits hybridus leaves, which was utilized in these reactions for many times to confirm the reusability of nanocatalyst. The antioxidant property of new synthesized 1,3,4-oxadiazols is owing to having NH group which was evaluated by two procedures named diphenyl-picrylhydrazine (DPPH) radical trapping and Ferric ions (Fe³⁺) reducing potential (FRAP) experiment. Also, the antimicrobial activity of new generated 1,3,4-oxadiazols was evaluated by disk distribution process utilizing two kinds of Gram-negative bacteria and Gram-positive bacteria, proving bacterial growth was stopped by using of these compounds. This employed procedure for preparation of 1,3,4-oxadiazols derivatives conveys benefits including reaction with low time, products with high yields, and possibility of separating catalyst and products using an easy procedure.