Nickel- and cobalt-based heterogeneous catalytic systems for selective primary amination of alcohol with ammonia

It is one of the critical fields of green chemistry to catalyze the selective conversion of biomass-derived alcohol and ammonia to primary amines with extensive application. Recently, catalytic systems consisting of non-noble metal nickel- and cobalt-based catalysts have been developed for catalytic alcohol amination. This paper reviewed these two types of catalytic systems, which are classified as skeleton Co and Ni catalytic systems, supported and modified Co and Ni catalytic systems, emphasized on catalysts and catalysis, and clearly explained where zero-valent cobalt or nickel is active species for catalytic reaction. In supported catalysts, the catalytic active sites constituted by the catalytic active species and its micro-environment can regulate the efficiency of catalytic the reaction. While in modified catalysts, modifiers such as metal Fe, Re and Bi may modulate the catalytic active sites and change the catalytic selectivity. There are differences in structure and size between catalysts prepared by different methods, resulting in distinct interface and electronic properties for alcohol amination, which determines the structure–activity relationships of the catalytic system.     

SAR studies of quinoline and derivatives as potential treatments for Alzheimer’s disease

Quinoline analogs are an important class of N-based heterocyclic compounds, which have received extensive attention because of their use in medicinal chemistry and organic synthesis. Over the past few decades, several new scaffold-based functionalization synthesis strategies have been reported for quinolines. Quinoline derivatives have a wide range of biological activities, including anti-Alzheimer’s disease activity. Herein, we review research on quinoline and related analogs as anti-Alzheimer’s disease agents from 2001 to 2022 and particularly highlight the structure–activity relationships and molecular binding modes. This review provides information for the rational design of more effective and target-specific drugs for Alzheimer's disease.     

Antihypertensive activity of indole and indazole analogues: A review

Heterocyclic compounds occupy an important position in chemistry because of their wide range of uses in drug design, photochemistry, agrochemicals, and other fields. Indole and indazole scaffolds are available from natural and synthetic sources, and molecules containing these scaffolds have been shown to have various biological effects, including anti-inflammatory, antibacterial, antiviral, antifungal, analgesic, anticancer, antioxidant, anticonvulsant, antidepressant, and antihypertensive activities. Indole and indazole molecules bind to receptors with high affinity, and thus are useful for the study of bioactive compounds involved in multiple pathways. In this review, we highlight the antihypertensive activity and the mechanisms of action of indole and indazole derivatives. In addition, structure–activity relationship studies of the antihypertensive effect are presented.     

Biological activities from andiroba (Carapa guianensis Aublet.) and its biotechnological applications: A systematic review

Carapa guianensis is a tree from Meliaceae family traditionally known as andiroba that has a wide range of biological properties, including therapeutic effects, antioxidant activities, insecticidal and repellent effects that can be used in biotechnological approaches to medicine, agriculture, and cosmetic products. Therefore, we aim to explore the biological activities exhibited by this species and their respective biotechnological applications of interest. For this, a systematic review was carried out following the PRISMA guidelines dated from 1993 to 2022 through the Scopus, Web of Science and Agricultural Research Database (Base de Dados da Pesquisa Agropecuária - BDPA), screened for biological activity/bioactive compounds. A total of 129 studies were included in the PRISMA flow analysis. Biological properties and major bioactive compounds, as well as biotechnological approaches could be identified. The biological activity from C. guianensis could be observed in different vegetative parts through diverse methods of extractions. These activities are mainly due to the unsaturated fatty acids and bioactive compounds, such as the limonoids and a small fraction of phenolic compounds. Gedunin-type limonoids, like gedunin and its derivatives, represent the class of compounds that show the highest bioactivities in different applications.     

Novel liquid chromatography/mass spectrometry-based approaches for the determination of glyphosate and related compounds: A review

Although glyphosate (Gly) is one of the most widely used agrochemicals, it is also of the most difficult to measure. Gly, its metabolites, and related compounds cannot be sought within the scope of multi-residue methods. Specific so-called single-residue methods are used instead. Liquid chromatography-mass spectrometry (LC-MS) is currently the most widely used technique for determining Gly and its metabolites. This review addresses the different LC-MS-based methods proposed for the determination of Gly and related species in food and environment matrices. Sample preparation (food and environment), as well as their determination based in novel liquid chromatography/mass spectrometry approaches including different specific stationary phases are presented and the specific analytical challenges, strengths and drawbacks are critically discussed.     

Paramagnetic surface active ionic liquids: synthesis,properties, and applications

Paramagnetic surface active ionic liquids (PMSAILs) classify task-specific ionic liquids with magnetic properties by incorporating metal into the cationic or anionic part of the ionic liquid. Paramagnetic ionic liquids had long-chain either in cations or anions and showed excellent surface activity and magnetic properties without any need for the magnetic nanoparticles. These PMSAILs have inherent unique ionic liquid properties and self-assembled into various nano-aggregates such as micelles, vesicles, rod-like micelles, and etc., by modification in the structure of cations or anions. PMSAILs provide stimuli-responsive properties, which is one of the essential aspects of targeted applications. The appropriate functional tunability of anions and cations in PMSAILs leads to various multifaceted chemical and biological applications. A new emerging trend in PMSAIL research is hybridization with flexible materials. This review will mainly deal with the synthesis, characterization, and brief history of PMSAILs and their potential advantages in the various applications in micellar catalysis, purification and separation of biomolecules, compaction and decompaction of DNA, drug delivery, and other biomedical applications.     

Light-assisted and remote delivery of carbon monoxide to malignant cells and tissues: Photochemotherapy in the spotlight

The recent discovery of the salutary effects of carbon monoxide (CO) in chronic obstructive pulmonary disease (COPD), ischemic perfusion damage, graft implantation, as well as its pro-apoptotic effects on hyper-proliferating cells has raised interest in delivering small doses of CO to biological targets under controlled conditions. In such attempts, photoactive metal carbonyl complexes (photoCORMs) have shown promise and several accounts of cancer cell eradication with light-triggered CO release from photoCORMs have been reported. CO releasing molecules (CORMs) and photoCORMs have been incorporated within biocompatible drug delivery vehicles such as carboxymethyl chitosan or mesoporous silica-based nanoparticles and the composite materials (photoCORs) have been successfully employed in controlled CO delivery to cancer cells to cause rapid CO-induced apoptosis. Fiber optic technology has also been utilized for remote delivery of CO to not easily accessible targets. Reports on all these therapeutic modalities for on-demand CO delivery to malignant targets in a highly localized fashion have opened up the possibility of phototherapy of cancer with the use of an unusual so-called “toxic” molecule. This review highlights the methodologies used in CO photochemotherapy reported so far along with analysis of their therapeutic outcomes, and possible improvements for better applicability.     

Pitanga (Eugenia uniflora L.) as a source of bioactive compounds for health benefits: A review

The pitangueira (Eugenia uniflora) is a tree native to Brazil but is cultivated in several subtropical countries. A great diversity of nutrients and bioactive compounds have been found in the leaves and fruits of E. uniflora, which supports its use in folk medicine to treat diseases such as stomach and intestinal disorders, fever and general inflammation. Antimicrobial, antiviral, antifungal and antioxidant effects on metabolism have been reported for this plant. This review discusses the phytochemical profile, toxicity and pharmacological action of E. uniflora leaves and fruits and points out that gaps in the literature that need to be investigated further. This review also discusses studies developed with E. uniflora demonstrating its promising therapeutic potential for several diseases with an apparent low toxicity in mammals. The compilation of the main pharmacological and toxicological results, as well as the phytochemical characterization of the varieties and constituents of E. uniflora are general aspects that this review attempts to demonstrate in order to contribute to the new approaches and developments to plant-derived natural product drug discovery. However, further studies are required to establish the nutraceutical effects and uses of E. uniflora as an important and safe supplement for human health.     

Water oxidation with inhomogeneous metal-silicon interfaces

Silicon (Si) is a prime candidate for manufacturing water-splitting photoelectrochemical cells, however, the stability of this material remains a serious bottleneck. This is particularly true for the photoanode, subject to severe deactivation mechanisms. So far, thin film homogeneity has been the paradigm in the quest for stable and efficient Si-based photoanodes, which involved the use of vapor deposition methods to produce conformal thin films ensuring Si protection and efficient catalysis during operation. Conversely, recent reports on n-Si/metal thin film junctions have highlighted the benefits of the junction heterogeneity, generated in situ. In addition, results obtained from n-Si photoanodes partially covered with discontinuous films of Co and Ni nanoparticles lately suggested that homogeneity is not a prerequisite to reach efficiency and stability. Such findings may open new protection routes for Si-based photoanodes, breaking with classical strategies and allowing the use of liquid phase modification methods such as electrodeposition.     

Traditional uses,phytochemistry, pharmacology and other potential applications of Vitellaria paradoxa Gaertn. (Sapotaceae): A review

Vitellaria paradoxa Gaertn. is a multipurpose medicinal plant of the family Sapotaceae, and it has been widely used usually in the clinical traditional medicine as remedy for a wide range of diseases for several decades. In addition, the plant has also found applications in confectionery, cosmetics and soaps, and pharmaceuticals both locally and internationally. V. paradoxa, which has been identified with >150 phytoconstituents, is rich in oleanane-type triterpene acids and glycosides, such as paradoxosides A-E, tieghemelin A, parkiosides A-C, bassic acid, as well as flavonoids such as quercetin and catechin-type compounds. The extracts and the active constituents of V. paradoxa have been investigated for various pharmacological activities, including but not limited to anticancer, melanogenesis-inhibitory, antibacterial, anti-diabetic, antioxidant, anti-inflammatory, anti-diarrhoeal, and antifungal activities. Additionally, V. paradoxa has also been utilized in nanoparticles (NPs) synthesis. These NPs among other things have shown significant antinociceptive and antiedematogenic activities as well as environmental friendly adsorptive properties for the removal of pollutants from pharmaceutical effluents. Overall, this review comprehensively examines the traditional uses, phytochemistry, pharmacology, toxicology, clinical studies, and nanoparticles synthesized from V. paradoxa and their applications.     

Cyclometalated complexes containing ferrocenyl Schiff base: Preparation,characterization, DFT calculations,application in cancer and biological researches and MOE studies

A series of transition metal (II/III) complexes containing organometallic Schiff base ligand (H₂L) had been synthesized and characterized by using elemental analysis (C, H, N, M), molar conductivity, IR, UV–Vis, ¹H NMR and mass spectral analysis. Also, their TG and DTG behaviors were investigated. The ligand was prepared by condensation of 4-aminosalicylic acid with 2-acetylferrocene in 1:1 M ratio. The data of elemental analysis indicated that the prepared complexes were synthesized also in a 1:1 M ratio. The ligand behaved as neutral bidentate ligand that coordinated to metal ions through protonated O-phenolic and protonated carboxylic-OH groups. All complexes had octahedral structure. DFT calculations for H₂L ligand were determined with some parameters such as HOMO-LUMO energy gab, electronegativity and chemical hardness–softness. Antimicrobial activity of both H₂L Schiff base ligand and its metal complexes was tested against different strains of bacteria and fungi species. Furthermore, all compounds had been screened for their anticancer activities against breast cancer (MCF-7) cell line. [Cu(H₂L)(H₂O)₂Cl₂]·2H₂O complex had the lowest IC₅₀ value = 47.3 µg/mL. For determining the more effective and probable binding mode between the H₂L ligand, Co(II) and Zn(II) complexes with different active sites of 4K3V, 2YLB and 3DJD receptors, so molecular docking studies were investigated.     

Photocatalytic remediation of persistent organic pollutants (POPs): A review

The release of persistent organic pollutants (POPs) into the environment is an issue of global concern, as the chemicals are stable over a prolonged period resulting in their accumulation in many animals and plants. Although POPs are banned in several countries, many chemicals have been proposed as POP candidates to be added to the existing compounds as defined by the United Nations Stockholm Convention committee. To address the safe disposal and clean-up of such chemicals, new, and especially cost-effective, remediation technologies for POPs are urgently required. This review focuses on existing POPs and the types of remediation processes available for their removal. Particular attention is paid towards photocatalysis using nanocatalysts in this review, due to their effectiveness towards POP degradation, technological feasibility, and energy and cost-efficiency. The underlying principles and the key mechanisms of the photocatalysts based on TiO₂ based materials, metal oxides, light-assisted Fenton systems, framework materials e.g. metal-organic frameworks and polyoxometalates, including metal-free and hybrid photocatalysts for POPs cleanup are described for advance applications in solving the POPs contamination in the environment. The improvements of photocatalytic performance especially the POPs removal mechanism using the conventional and modified process, the design and optimization of photoreactors, and the integration technology are the critical challenges for the emerging pollutants and require intensive research for the forthcoming future.     

Synthesis,characterization, and application of griseofulvin surface molecularly imprinted polymers as the selective solid phase extraction sorbent in rat plasma samples

In present study, an investigation was carried out to develop and validate an analytical method for the selective extraction and determination of griseofulvin (GSF) from plasma samples. For this purpose, a rational approach was made to synthesize and characterize the surface molecularly imprinted polymers (SMIPs). The SMIPs were utilized as solid phase extraction (SPE) sorbents. The SMIPs were prepared by using GSF as template molecule on the surface of modified silica particles through a non-covalent technique. The particles demonstrated high adsorption capacity (119.1 µg/mL), fast adsorption equilibrium time (30 min) and good recognition selectivity for the template drug. The scanning electron microscopy and infrared spectroscopy were used to explain the structural and morphological characteristics of the SMIPs and surface non-imprinted polymers. The SPE method was combined with HPLC for plasma analysis. The method validation results demonstrated that the established method possessed good linearity for GSF ranging from 0.1 to 50 µg/mL (R² = 0.997). The limit of detection for this method was 0.02 µg/mL for rat plasma samples. The recoveries of GSF from spiked plasma samples were (90.7–97.7%) and relative standard deviations were (0.9–4.5%). Moreover, the SMIPs as selective SPE sorbent can be reused more than 8 times which is a clear advantage over commercial SPE sorbents. Finally, the usefulness of the proposed strategy was assessed by extraction and detection of GSF in real rat plasma samples.     

Differential distribution of phytochemicals in Scutellariae Radix and Scutellariae Amoenae Radix using microscopic mass spectrometry imaging

Scutellariae Radix, the root of Scutellaria baicalensis Georgi, is widely applied in China for the treatment of fever, ulcer, bronchitis, hepatitis and inflammatory symptoms. Sctuellariae Amoenae Radix, the root of Scutellaria amoena C.H. Wright, is often prescribed as the substitute for Scutellariae Radix. Up to now, no attempt has been made to unveil and compare the localization of phytochemicals in Scutellariae Radix and its succedaneum. This investigation succeeded to look into the differential distribution of natural compounds in Scutellariae Radix and Scutellariae Amoenae Radix using microscopic mass spectrometry imaging. Compounds presenting different distribution modes in two kinds of roots were sorted out, then a quick method for the differentiation between Scutellariae Radix and Scutellariae Amoenae Radix was established. Accumulation sites of baicalein, baicalin, wogonin and wogonoside in Scutellariae Radix were also uncovered using microscopic mass spectrometry imaging. Moreover, the application of matrix assisted laser desorption ionization-quadrupole-time of flight mass spectrometry allowed the on-tissue dissociation of major flavonoids. Overall, the utilization of microscopic mass spectrometry imaging and matrix assisted laser desorption ionization-quadrupole-time of flight mass spectrometry provided a novel perspective for the discovery of natural compounds within medicinal plants.     

Exploring the promoting mechanisms of bovine serum albumin,lignosulfonate, and polyethylene glycol for lignocellulose saccharification from perspective of molecular interactions with cellulase

Bovine serum albumin (BSA), polyethylene glycol (PEG) and lignosulfonate (LS) have been extensively employed as synergistic agents in lignocellulose saccharification. Nevertheless, the promoting mechanisms have not been fully understood and there are a number of controversial opinions existed. All attention has been paid to the interactions between respective additive and substrate. However, rarely attention has been paid to the interactions between additives and enzymes (cellulase from Trichoderma reesei in this investigation). This interaction is actually more important since cellulase interacts with the additives before it contacts with substrate. Therein, Quartz crystal microbalance with dissipation monitoring (QCM-D), surface plasma resonance (SPR) and small angel X-ray scattering (SAXS) were incorporated to study the interaction between enzyme and additives. The results showed synergistic agents have different interaction modes with cellulase. BSA and LS can form complexes with cellulase and the formed complexes prevent them from nonproductive binding by residue lignin; what’s more, the cellulase-BSA complexes improve the hydrolytic capability of pristine enzyme whereas cellulase-LS complexes reduce. PEG prevents the unproductive binding of cellulase to the residual lignin by forming a thin layer that actually acts as a steric hindrance to the residual lignin. This investigation helps us to understand the sophisticated interactions among the components in the complicated enzymatic system, especially the interactions between enzymes and synergistic agents. It will be helpful in the design and utilization of synergistic additives in the lignocellulose biorefinery process as well.     

Camellia sinensis: Insights on its molecular mechanisms of action towards nutraceutical,anticancer potential and other therapeutic applications

The Camellia sinensis plant provides a wide diversity of black, green, oolong, yellow, brick dark, and white tea. Tea is one of the majorly used beverages across the globe, succeeds only in the water for fitness and pleasure. Generally, green tea has been preferred more as compared to other teas due to its main constituent e.g. polyphenols which contribute to various health benefits. The aim of this updated and comprehensive review is to bring together the latest data on the phytochemistry and pharmacological properties of Camellia sinensis and to highlight the therapeutic prospects of the bioactive compounds in this plant so that the full medicinal potential of Camellia sinensis can be realised. A review of published studies on this topic was performed by searching PubMed/MedLine, Scopus, Google scholar, and Web of Science databases from 1999 to 2022. The results of the analysed studies showed that the main polyphenols of tea are the four prime flavonoids catechins: epigallocatechin gallate (EGCG), epicatechin gallate (ECG), epigallocatechin (EGC), and epicatechin (EC) along with the beneficial biological properties of tea for a broad heterogeneity of disorders, including anticancer, neuroprotective, antibacterial, antiviral, antifungal, antiobesity, antidiabetes and antiglaucoma activities. Poor absorption and low bioavailability of bioactive compounds from Camellia sinensis are limiting aspects of their therapeutic use. More human clinical studies and approaching the latest nanoformulation techniques in nanoparticles to transport the target phytochemical compounds to increase therapeutic efficacy are needed in the future.     

Integrating approach to discover novel bergenin derivatives and phenolics with antioxidant and anti-inflammatory activities from bio-active fraction of Syzygium brachythyrsum

Syzygium brachythyrsum is an important folk medicinal and edible plant in Yunnan ethnic minority community of China, however, little is known about the chemical and bio-active properties. The present study is aimed to identify the bioactive constituents with antioxidant and anti-inflammatory properties by an integrating approach. First, two new bergenin derivatives, brachythol A (1) and brachythol B (2), together with eleven known phenolic compounds (3–13) were isolated from bioactive fractions by phytochemical method. Among these isolated chemicals, five bergenin derivatives, along with 3 phenolics were found in Syzygium genus for the first time. Then, a further chemical investigation based on ultra-high-performance liquid chromatography-Q Exactive Orbitrap mass spectrometry resulted in a total of 107 compounds characterized in the bio-active fractions, including 50 bergenin derivatives, among which 14 bergenin derivatives and 14 phenolics were potential new natural chemicals. Most of the isolated compounds showed obvious antioxidant activities, while compounds 11, 12, and 13 had favorable performance. Eight compounds (2–5, 7, and 9–11) showed good inhibitory activity on nitric oxide (NO) production in macrophage RAW 264.7 cells. The structure–activity correlation analysis indicated that the antioxidation and anti-inflammatory activities enhanced when bergenin was esterified with gallic acid, caffeic acid or ferulic acid. This is the first report of bergenins in Syzygium genus and the richness in new bio-active bergenins and gallic acid derivatives indicated that Syzygium brachythyrsum is a promising functional and medicinal resource.     

Tuning of graphitic carbon nitride (g-C3N4) for photocatalysis: A critical review

Graphitic carbon nitride (g-C₃N₄) is a remarkable semiconductor catalyst that has attracted widespread attention as a visible light photo-responsive, metal-free, low-cost photocatalytic material. Pristine g-C₃N₄ suffers fast recombination of photogenerated electron-hole pairs, low surface area, and insufficient visible light absorption, resulting in low photocatalytic efficiency. This review presents the recent progress, perspectives, and persistent challenges in the development of g-C₃N₄-based photocatalytic materials. Several approaches employed to improve the visible light absorption of the materials including metal and non-metal doping, co-doping, and heterojunction engineering have been extensively discussed. These approaches, in general, were found to decrease the material’s bandgap, increase the surface area, reduce charge carrier recombination, and promote visible light absorption, thereby enhancing the overall photocatalytic performance. The material has been widely used for different applications such as photocatalytic hydrogen production, water splitting, CO₂ conversion, and water purification. The work has also identified various limitations and weaknesses associated with the material that hinders its maximum utilization under visible illumination and presented state-of-the-art solutions that have been reported recently. The summary presented in this review would add an invaluable contribution to photocatalysis research and facilitate the development of efficient visible light-responsive semiconducting materials.     

Study of electrodeposited zinc selenide (ZnSe) nanostructure thin films for solar cell applications

Electrodeposition approach was used to grow the ZnSe nanostructure on indium doped tin oxide (ITO) layered glass substrate. Due to low cost and high degree of absorption, binary semiconductors made from chalcogens such as CdSe, ZnO, ZnS and ZnSe provide significant features in photovoltaic and photoelectrochemical cells. The structural and morphological properties of deposited nanostructures were examined by XRD and SEM. X-ray diffraction analysis informed about cubic structure with a preferred orientation and the calculated crystal size was approximately 75 nm. The optical properties were examined by UV–visible absorbance spectra and optical band gap was measured using Tauc plot. The deposited ZnSe nanostructure has direct band gap ∼2.52 eV at room temperature which was less than 2.82 eV which is the band gap of bulk ZnSe. Investigations also focused on additional qualities like excellent optical transmission, low electrical resistance, and good photosensitivity. Because of the presence of defect states in the deposited nanostructure, the band gap energy is smaller than that of bulk material. The current-voltage characteristics were measured in dark mode and under illumination of normal tungsten filament light and LED. There was notable change in the current for both normal light and LED in comparison to dark mode. The findings of all the characterization methodologies suggested that for the production of solar cells low cost ZnSe may be used as an alternative environment friendly Cd-free window layer.