A New Harziane Diterpene, Harziaketal A, and a New Sterol, Trichosterol A, from the Marine‐Alga‐Epiphytic Trichoderma sp. Z43

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A New Harziane Diterpene, Harziaketal A, and a New Sterol, Trichosterol A, from the Marine-Alga-Epiphytic Trichoderma sp. Z43


Abstract

One new diterpene, harziaketal A (1), and one new highly degraded sterol, trichosterol A (2), along with three known compounds, including one diterpene, harzianone (3), and two steroids, (22E,24R)-5α,6α-epoxy-ergosta-8(14),22-dien-3β,7α-diol (4) and isoergokonin B (5), were isolated from the culture of the marine-alga-epiphytic fungus Trichoderma sp. Z43 by silica gel column chromatography (CC), Sephadex LH-20 CC, and preparative thin-layer chromatography (TLC). Their structures and relative configurations were assigned by nuclear magnetic resonance (NMR) and high resolution electrospray ionisation mass spectrometry (HR-ESI-MS) data, and the absolute configuration of 1 was established by X-ray diffraction. Compound 1 features a hemiketal unit situated at the four-membered ring of harziane-type diterpenes for the first time, while 2 represents the rare occurrence of sterols with rings A and B being degraded. Compounds 1 and 2 displayed weak inhibition against the tested phytoplankton (Amphidinium carterae, Heterocapsa circularisquama, Heterosigma akashiwo, and Prorocentrum donghaiense) with half maximal inhibitory concentration (IC50) ranging from 14 to 53 μg/mL.

Quantification of Phytochemicals and Metal Ions as well as the Determination of Volatile Compounds, Antioxidant, Antimicrobial and Antacid Activities of the Mimosa pudica L. Leaf: Exploration of Neglected and Under‐Utilized Part

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Quantification of Phytochemicals and Metal Ions as well as the Determination of Volatile Compounds, Antioxidant, Antimicrobial and Antacid Activities of the Mimosa pudica L. Leaf: Exploration of Neglected and Under-Utilized Part


Abstract

Mimosa pudica L. (MP) is well-known plant in traditional medicinal system, especially in India. Unfortunately, leaves of MP are less explored. To determine the food and nutritional value of the neglected part of Mimosa pudica L. (MP), that is MP leaves, phytochemicals and metal ions of MP were quantified by newly developed HPLC and ICPOES-based methods. The content of phytochemicals observed using HPLC analysis for chlorogenic acid, catechin, and epicatechin was 141.823 (±8.171), 666.621 (±11.432), and 293.175 (±12.743) μg/g, respectively. Using GC/MS/MS analysis, fatty acid like oleic acid were identified. In ICP-OES analysis, a significant content of Na, K, Ca, Cu, Fe, Mg, Mn, and Zn was observed. The observed TPC and TFC for MP leaf extracts was 44.327 (±1.041) mg GAE/ g of wt. and 214.217 (±4.372) mg QCE/ g of wt., respectively. The DPPH assay depicted a strong antioxidant activity of MP leaf extracts with IC50 values of 0.796 (±0.081) mg/mL and a TEAC value of 0.0356 (±0.0003). A significant antacid activity (666 mg MP+400 mg CaCO3 >400 mg CaCO3 ≫666 mg Gelusil) of MP leaves was noticed. The methanolic extract of MP leaves demonstrated anti-microbial activity against Staphylococcus aureus (15±2mm), Pseudomonas aeruginosa (12±2mm) and Escherichia coli (10±2mm). In silico studies confirmed the in vitro results obtained for antioxidant, antiacid, and anti-microbial activities. In addition, in silico studies revealed the anti-cancerous and anti-inflammatory potential of the MP leaves. In summary, this study demonstrated the medicinal significance of MP leaves and the conversion of agro-waste or the under-utilized part of MP into pharmaceutical potent materials. Consequently, the present study highlighted that MP leaves alone have medicinal importance with good nutritional utility and possess large promise in the pharma industry along with improving bio-valorization and the environment.

Isocucurbic Acid Derivatives and Soluble Epoxide Hydroxylase Inhibitors from the Flowers of Chrysanthemum indicum L.

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Isocucurbic Acid Derivatives and Soluble Epoxide Hydroxylase Inhibitors from the Flowers of Chrysanthemum indicum L.


Abstract

Soluble epoxide hydrolase (sEH) inhibitory activity guided fractionation and isolation of two new isocucurbic acid derivatives (1 and 2) and nine known compounds (3–11) from the flowers of Chrysanthemum indicum L. Their structures were elucidated on the basis of spectroscopic data interpretation and comparison with those reported in previous studies. Luteolin (3), acacetin-7-O-β-D-glucopyranoside (6), and methyl 3,4-di-O-caffeoylquinate (10) displayed sEH inhibitory activities with IC50 values ranging from 13.7±3.6 to 20.8±0.4 μM. Enzyme kinetic analysis revealed that 3, 6, and 10 were non-competitive inhibitors with K i values of 14.8±0.5, 31.2±0.8, and 3.9±0.2 μM, respectively. Additionally, molecular docking studies indicated compound 10 had the ability to form six hydrogen bonds at sEH active site, resulting binding energy as low as −9.58 Kcal/mol.

Chemiresistive Gas Sensing using Graphene‐Metal Oxide Hybrids

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Chemiresistive Gas Sensing using Graphene-Metal Oxide Hybrids

This review focuses on graphene-functionalized metal oxide nanostructures designed for gaseous molecules detection, mainly hydrogen gas sensing applications. Perfect structured pristine graphene (left-top), electron-hole transport mechanism in metal-graphene system (center) and a typical metal/metal oxide-graphene-based gas sensor (right-top) along with functional metal/metal oxide-graphene for hydrogen sensing material (background) is shown.


Abstract

Chemiresistive sensing lies in its ability to provide fast, accurate, and reliable detection of various gases in a cost-effective and non-invasive manner. In this context, graphene-functionalized metal oxides play crucial role in hydrogen gas sensing. However, a cost-effective, defect-free, and large production schemes of graphene-based sensors are required for industrial applications. This review focuses on graphene-functionalized metal oxide nanostructures designed for gaseous molecules detection, mainly hydrogen gas sensing applications. For the convenience of the reader and to understand the role of graphene-metal oxide hybrids (GMOH) in gas sensing activities, a brief overview of the properties and synthesis routes of graphene and GMOH have been reported in this paper. Metal oxides play an essential role in the GMOH construct for hydrogen gas sensing. Therefore, various metal oxides-decorated GMOH constructs are detailed in this review as gas sensing platforms, particularly for hydrogen detection. Finally, specific directions for future research works and challenges ahead in designing highly selective and sensitive hydrogen gas sensors have been highlighted. As illustrated in this review, understanding of the metal oxides-decorated GMOH constructs is expected to guide ones in developing emerging hybrid nanomaterials that are suitable for hydrogen gas sensing applications.

Easy Access to Tertiary Amines from Carbonyl Compounds with Substituted Amine‐Boranes: A Substrate, Catalyst, and Additive‐Free Approach Under Mild Conditions

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Easy Access to Tertiary Amines from Carbonyl Compounds with Substituted Amine-Boranes: A Substrate, Catalyst, and Additive-Free Approach Under Mild Conditions

An operationally simple and efficient protocol for the transformation of carbonyl compounds to tertiary amines with various secondary amine-boranes is reported. The reaction proceeds at room temperature and requires a short reaction time under mild conditions. The reaction encompasses a broad substrate scope and furnishes good-to-excellent yields of the amines in a chemoselective fashion.


Abstract

Tertiary amines are ubiquitous and play an essential role in organocatalysis, pharmaceuticals, and fine chemicals. Amongst various synthetic procedures known for their synthesis, the reductive amination of carbonyl compounds has been found to be a proficient method. Over the past few decades, different synthetic strategies for reductive amination have been developed. Most of them suffer from the use of transition metals and/or harsh reaction conditions. Herein, we present an efficient, operationally simple protocol for the chemoselective transformation of carbonyl compounds to tertiary amines under benign conditions. The strategy encompasses a broad substrate scope under the metal-free condition at room temperature and does not require any solvent. A detailed mechanistic investigation was performed with the aid of control experiments and computational study to shed light on the reaction pathway.

New Molecular Design, Step‐Saving Synthesis, and Applications of Indolocarbazole Core‐Based Oligo(hetero)arenes

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New Molecular Design, Step-Saving Synthesis, and Applications of Indolocarbazole Core-Based Oligo(hetero)arenes

The introduction of 3, 4-ethylenedioxythiophene (EDOT) into indolocarbazole-based hole-transporting materials (HTMs) as π-spacers significantly promoted the PCEs of up to 17.5 % of their corresponding perovskite solar cells (PSCs).


Abstract

In this work, we have successfully synthesized 15 new examples (LLA01-06; LinLi01-10) of small-molecule hole-transporting materials (HTM) using the less explored indolocarbazole (ICbz) as core moiety. Different from previously reported ICbz HTMs, LinLi01-10 exhibit new molecular designs in which 3,4-ethylenedioxythiophene (EDOT) units are inserted as crucial π-spacers and fluorine atoms are introdcued into end-group molecules. These substantially improve the materials solubility and device power conversion efficiencies (PCEs) while fabricated in perovskite solar cells (PSC). More importantly, LinLi01-10 are generated by a sustainable synthetic approach involving the use of straightforward C−H/C−Br couplings as key transformations, thus avoiding additional synthetic transformations including halogenation and borylation reactions called substrate prefunctionalizations usually required in Suzuki reactions. Most HTM molecules can be purified simply by reprecipitations instead of conducting column chromatography. In contrast to LLA01-06 without additional EDOT moieties, PSC devices using LinLi01-10 as hole-transport layers display promising PCEs of up to 17.5 %. Interestingly, PSC devices employing seven of the LinLi01-10 as hole-transport molecules, respectively, are all able to show an immediate >10 % PCE (t=0) without any device oxidation/aging process that is necessary for the commercial spiro-OMeTAD based PSCs.

Dual Pd‐Acid Sites Confined in a Hierarchical Core‐Shell Structure for Hydrogenation of Nitrobenzene

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Dual Pd-Acid Sites Confined in a Hierarchical Core-Shell Structure for Hydrogenation of Nitrobenzene

A core-shell structured catalyst with dual active sites (Pd and acidic sites) was designed to investigate the synergistic effect of Pd and acid sites in TS-1 during the hydrogenation of nitrobenzene.


Abstract

A core-shell structured Pd@TS-1@meso-SiO2 catalyst with confined Pd nanometals has been fabricated by one-pot synthesis, impregnation method and sol-gel method. With the promotion of acid sites and protection of mesoporous silica shell, Pd@TS-1@meso-SiO2 shows higher activity than commercial comparison and higher stability than sample without mesoporous silica shell in the hydrogenation of nitrobenzene. The schematic illustration of the synergy effect is also proposed.

A Pincer Cobalt Complex as Catalyst with Dual Hydrogenation Activities for Hydrodeoxygenation of Ketones with H2

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A Pincer Cobalt Complex as Catalyst with Dual Hydrogenation Activities for Hydrodeoxygenation of Ketones with H2†

A homogeneous cobalt catalyst with dual hydrogenation activities was developed for deoxygenation of ketones with a Lewis acid as the co-catalyst. This protocol features a broad substrate scope and excellent functional group tolerance. Mechanistic studies supported a hydrogenation-dehydration-hydrogenation pathway for this hydrodeoxygenation reaction.


Comprehensive Summary

Reductive deoxygenation of ketones using H2 is a highly desirable but also challenging transformation in both chemical synthesis, industrial-scale petroleum and biomass feedstock reforming processes. Herein, we report a cooperative cobalt/Lewis acid (LA)-catalyzed hydrodeoxygenation of ketones using H2 as the reductant. In particular, the newly developed pincer cobalt catalyst possesses dual hydrogenation activities for both ketones and alkenes under the same reaction conditions. This reaction features a broad substrate scope, excellent functional-group compatibility, and potential applicability.

Equatorial Perturbation Driven Reaction Bifurcation in Non‐Heme Iron Complexes for Chlorite Oxidation

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Equatorial Perturbation Driven Reaction Bifurcation in Non-Heme Iron Complexes for Chlorite Oxidation

An experimental study is presented involving biomimetic models of iron complexes, namely N4Py and its methyl-substituted analogs (MeN4Py, N4PyMe). These complexes were reacted with sodium chlorite at room temperature and physiological pH of 5.0. Our results demonstrate that the iron complexes efficiently oxidize chlorite via formation of iron(IV) oxo intermediates albeit via different reaction pathways.


Abstract

Chlorine oxyanions have various applications, such as bleaching and oxidizers in rocket fuels. However, their high solubility in water and long environmental lifetimes have led to ecological concerns, especially regarding drinking water quality. This study focuses on the conversion of chlorite to chlorine dioxide, which is of significant interest as it exhibits superior antimicrobial activity and generates less harmful byproducts for water treatment. Two nonheme iron(II) complexes capable of producing chlorine dioxide from chlorite at room temperature and pH 5.0 are presented. These complexes oxidize chlorite through high-valent iron (IV)-oxo intermediates formed in-situ. The study establishes second-order rate constants for chlorite oxidation and investigates the effects and mechanisms involved by substituting a methyl group in the secondary coordination sphere of the FeIV(O)(N4Py) system. By employing kinetic analysis and spectroscopic investigations, the crucial elements for the reaction mechanism in chlorite oxidation are identified. These findings pave the way for future advancements in this field.

Zwitterionic Polymer: A New Paradigm for Protein Conjugation beyond PEG

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Zwitterionic Polymer: A New Paradigm for Protein Conjugation beyond PEG

PEGylation was usually recognized as a gold standard to improve the stability and half-life of protein drugs. Although hugely succussed, the drawbacks of PEGylated proteins, such as accumulated toxicity and anti-PEG antibodies, compromise the full therapeutic potential of protein drugs. With super-hydrophilicity and superior anti-fouling properties, zwitterionic polymer is gradually accepted as an alternative to PEG for protein conjugation. In this review, we discuss a series of features exhibited by protein-zwitterionic polymer conjugate that outperform PEGylated protein.


Abstract

To render protein drugs more suitable for clinical treatment, PEGylation has been widely used to ameliorate their inherent deficiencies, such as poor stability, rapid elimination in the bloodstream, and high immunogenicity. While increasingly PEGylated protein drugs have been approved by the FDA, the non-degradability of PEG and the emergence of anti-PEG antibodies after injection raise concerns about their cumulative chronic toxicity and long-term therapeutic efficacy. Zwitterionic polymer, with a unique structure containing equal amounts of positively charged and negatively charged groups, shows a different hydration behavior to PEG, which may be a superior PEG alternative for protein conjugation. In this concept review, a series of features beyond that of PEGylated protein exhibited by protein-zwitterionic polymer conjugate are discussed and some suggestions are presented for their future direction.