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Angewandte Chemie (International Ed. in... Jun 2024Proton-coupled electron transfer (PCET) imparts an energetic advantage over solo electron transfer in activating inert substances. Natural PCET enzyme catalysis...
Proton-coupled electron transfer (PCET) imparts an energetic advantage over solo electron transfer in activating inert substances. Natural PCET enzyme catalysis generally requires tripartite preorganization of proton relay, substrate-bound active center, and redox mediator, making the processes efficient and precluding side reactions. Inspired by this, a heterogeneous photocatalytic PCET system was established to achieve higher PCET driving forces by modifying proton relays into anthraquinone-based anionic coordination polymers. The proximally separated proton relays and photoredox-mediating anthraquinone moiety allowed pre-assembly of inert substrate between them, merging proton and electron into unsaturated bond by photoreductive PCET, which enhanced reaction kinetics than the counter catalyst without proton relay. This photocatalytic PCET method was applied to a broad-scoped reduction of aryl ketones, unsaturated carbonyls, and aromatic compounds. The distinctive regioselectivities for the reduction of isoquinoline derivatives were found to occur on the carbon-ring sides. PCET-hydrogenated radical intermediate of quinoline could be trapped by alkene for proton relay-assisted Minisci addition, forming the pharmaceutical aza-acenaphthene scaffold within one step. When using heteroatom(X)-H/C-H compounds as proton-electron donors, this protocol could activate these inert bonds through photooxidative PCET to afford radicals and trap them by electron-deficient unsaturated compounds, furnishing the direct X-H/C-H functionalization.
PubMed: 38864758
DOI: 10.1002/anie.202406161 -
Redox Report : Communications in Free... Dec 2024Emodin is a naturally occurring anthraquinone derivative with a wide range of pharmacological activities, including neuroprotective and anti-inflammatory activities. We...
Emodin is a naturally occurring anthraquinone derivative with a wide range of pharmacological activities, including neuroprotective and anti-inflammatory activities. We aim to assess the anticancer activity of emodin against hepatocellular carcinoma (HCC) in rat models using the proliferation, invasion, and angiogenesis biomarkers. After induction of HCC, assessment of the liver impairment and the histopathology of liver sections were investigated. Hepatic expression of both mRNA and protein of the oxidative stress biomarkers, HO-1, Nrf2; the mitogenic activation biomarkers, ERK5, PKCδ; the tissue destruction biomarker, ADAMTS4; the tissue homeostasis biomarker, aggregan; the cellular fibrinolytic biomarker, MMP3; and of the cellular angiogenesis biomarker, VEGF were measured. Emodin increased the survival percentage and reduced the number of hepatic nodules compared to the HCC group. Besides, emodin reduced the elevated expression of both mRNA and proteins of all PKC, ERK5, ADAMTS4, MMP3, and VEGF compared with the HCC group. On the other hand, emodin increased the expression of mRNA and proteins of Nrf2, HO-1, and aggrecan compared with the HCC group. Therefore, emodin is a promising anticancer agent against HCC preventing the cancer prognosis and infiltration. It works through many mechanisms of action, such as blocking oxidative stress, proliferation, invasion, and angiogenesis.
Topics: Animals; Emodin; Carcinoma, Hepatocellular; Rats; Thioacetamide; Liver Neoplasms; Antioxidants; ADAMTS4 Protein; Male; Protein Kinase C; Oxidative Stress; Antineoplastic Agents; Signal Transduction; Cell Proliferation
PubMed: 38861483
DOI: 10.1080/13510002.2024.2365590 -
International Journal of Developmental... Jun 2024Rhein is an anthraquinone compound with anti-inflammatory pharmacological activity. It has been found to play a neuroprotective role in neurological diseases, but the...
BACKGROUND
Rhein is an anthraquinone compound with anti-inflammatory pharmacological activity. It has been found to play a neuroprotective role in neurological diseases, but the neuroprotective mechanism of rhein remains unclear.
METHODS
SH-SY5Y cells serving as neuron-like cells and BV2 microglia were used. The toxicity of rhein on BV2 microglia and the viability of SH-SY5Y cells were measured by CCK-8 assay. The mRNA expression and secretion of pro-inflammatory cytokines were detected by qPCR and ELISA. Iba1, CD86 and pathway signalling protein in BV2 microglia were assessed by Western blot and immunofluorescence. Apoptosis of SH-SY5Y cells exposed to neuroinflammation was analysed through flow cytometry.
RESULTS
Rhein inhibited MAPK/IκB signalling pathways. Further studies revealed that rhein inhibited the production of pro-inflammatory cytokines TNF-α, IL-6, IL-1β and iNOS in BV2 cells and also inhibited the expression of M1 polarization markers Iba1 and CD86 in BV2 cells. Furthermore, rhein reduced the apoptotic rate and restored cell viability of SH-SY5Y cells exposed to neuroinflammation.
CONCLUSIONS
Our study demonstrated that rhein inhibited microglia M1 polarization via MAPK/IκB signalling pathway and protected nerve cells through suppressing neuroinflammation.
PubMed: 38858813
DOI: 10.1002/jdn.10352 -
Phytomedicine : International Journal... Aug 2024Rheum palmatum, R. tanguticum, and R. officinale, integral species of the genus Rheum, are widely used across global temperate and subtropical regions. These species are... (Review)
Review
BACKGROUND
Rheum palmatum, R. tanguticum, and R. officinale, integral species of the genus Rheum, are widely used across global temperate and subtropical regions. These species are incorporated in functional foods, medicines, and cosmetics, recognized for their substantial bioactive components.
PURPOSE
This review aims to synthesize developments from 2014 to 2023 concerning the botanical characteristics, ethnopharmacology, nutritional values, chemical compositions, pharmacological activities, mechanisms of action, and toxicity of these species.
METHODS
Data on the three Rheum species were gathered from a comprehensive review of peer-reviewed articles, patents, and clinical trials accessed through PubMed, Google Scholar, Web of Science, and CNKI.
RESULTS
The aerial parts are nutritionally rich, providing essential amino acids, fatty acids, and minerals, suitable for use as health foods or supplements. Studies have identified 143 chemical compounds, including anthraquinones, anthrones, flavonoids, and chromones, which contribute to their broad pharmacological properties such as laxative, anti-diarrheal, neuroprotective, hepatoprotective, cardiovascular, antidiabetic, antitumor, anti-inflammatory, antiviral, and antibacterial effects. Notably, the materials science approach has enhanced understanding of their medicinal capabilities through the evaluation of bioactive compounds in different therapeutic contexts.
CONCLUSION
As medicinal and economically significant herb species, Rheum species provide both edible aerial parts and medicinal underground components that offer substantial health benefits. These characteristics present new opportunities for developing nutritional ingredients and therapeutic products, bolstering the food and pharmaceutical industries.
Topics: Rheum; Humans; Phytochemicals; Plant Extracts; Animals; Ethnopharmacology
PubMed: 38852474
DOI: 10.1016/j.phymed.2024.155772 -
Biomedicine & Pharmacotherapy =... Jul 2024Mitoxantrone resistant variant of SW620 line was developed, characterized and subsequently used as a model system to determine oncostatin M ability to modulate MDR...
Mitoxantrone resistant variant of SW620 line was developed, characterized and subsequently used as a model system to determine oncostatin M ability to modulate MDR phenomenon. The selection regimen allowed for overexpression of ABCG2 and ABCB1 both at the RNA and protein level, which was further confirmed by functional assays. Oncostatin M supplementation resulted in partial reversal of MDR phenotype by decreasing overexpression of ABCG2 demonstrating for the first time the ability of this cytokine for selective down-regulation of one of MDR proteins.
Topics: ATP Binding Cassette Transporter, Subfamily G, Member 2; Mitoxantrone; Drug Resistance, Neoplasm; Humans; Neoplasm Proteins; Oncostatin M; Cell Line, Tumor; Drug Resistance, Multiple; ATP Binding Cassette Transporter, Subfamily B
PubMed: 38850649
DOI: 10.1016/j.biopha.2024.116861 -
Environmental Geochemistry and Health Jun 2024Dyes, considered as toxic and persistent pollutants, must be removed from organic wastes prior to their composting and application in sustainable agriculture. Azo dyes,...
Dyes, considered as toxic and persistent pollutants, must be removed from organic wastes prior to their composting and application in sustainable agriculture. Azo dyes, capable of altering the physicochemical properties of soil, are difficult to expel by conventional wastewater treatments. C.I. Acid Black 1 (AB 1), a sulfonated azo dye, inhibits nitrification and ammonification in the soil, lessens the nitrogen use efficacy in crop production and passes substantially unaltered through an activated sludge process. The retention of C.I. Acid Black 1 by raw and expanded perlite was investigated in order to examine the potential effectiveness of this aluminosilicate material toward organic waste cleanup. Dye adsorption proved spontaneous and endothermic in nature, increasing with temperature for both perlites. Expanded perlite having a more open structure exhibited a better performance compared to the raw material. Several of the most widely recognized two-parameter theoretical models, i.e., Langmuir, Freundlich, Temkin, Brunauer-Emmett-Teller (BET), Harkins-Jura, Halsey, Henderson, and Smith, were applied to reveal physicochemical features characterizing the adsorption. The Langmuir, Freundlich, Temkin, BET, Henderson, and Smith equations best fitted experimental data indicating that the adsorption of anionic dye on perlites is controlled by their surface, i.e., non-uniformity in structure and charge. This heterogeneity of surface is considered responsible for promoting specific dye adsorption areas creating dye "islands" with local dye supersaturations.
Topics: Aluminum Oxide; Adsorption; Silicon Dioxide; Coloring Agents; Naphthalenesulfonates; Waste Management; Azo Compounds; Anthraquinones
PubMed: 38849572
DOI: 10.1007/s10653-024-02013-3 -
ChemSusChem Jun 2024The two-electron electrocatalytic oxygen reduction reaction (ORR) to hydrogen peroxide (H2O2) is a valuable alternative to the more conventional and energy-intensive...
The two-electron electrocatalytic oxygen reduction reaction (ORR) to hydrogen peroxide (H2O2) is a valuable alternative to the more conventional and energy-intensive anthraquinone process. From a circularity viewpoint, metal-free catalysts constitute a sustainable alternative for the process. In particular, lightweight hetero-doped C-materials are cost-effective and easily scalable samples that replace - more and more frequently - the use of critical raw elements in the preparation of highly performing (electro)catalysts. Anyhow, their large-scale exploitation in industrial processes still suffers from technical limits of samples upscale and reproducibility other than a still moderate comprehension of their action mechanism in the process. This concept article offers a comprehensive and exhaustive "journey" through the most representative lightweight hetero-doped C-based electrocatalysts and their performance in the 2e- ORR process. It provides an interpretation of phenomena at the triple-phase interface of solid catalyst, liquid electrolyte and gaseous oxygen based on the doping-driven generation of ideal electronic microenvironments at the catalyst surface.
PubMed: 38847086
DOI: 10.1002/cssc.202400660 -
Nanoscale Horizons Jun 2024On-demand electrocatalytic hydrogen peroxide (HO) production is a significant technological advancement that offers a promising alternative to the traditional... (Review)
Review
On-demand electrocatalytic hydrogen peroxide (HO) production is a significant technological advancement that offers a promising alternative to the traditional anthraquinone process. This approach leverages electrocatalysts for the selective reduction of oxygen through a two-electron transfer mechanism (ORR-2e), holding great promise for delivering a sustainable and economically efficient means of HO production. However, the harsh operating conditions during the electrochemical HO production lead to the degradation of both structural integrity and catalytic efficacy in these materials. Here, we systematically examine the design strategies and materials typically utilized in the electroproduction of HO in acidic environments. We delve into the prevalent reactor conditions and scrutinize the factors contributing to catalyst deactivation. Additionally, we propose standardised benchmarking protocols aimed at evaluating catalyst stability under such rigorous conditions. To this end, we advocate for the adoption of three distinct accelerated stress tests to comprehensively assess catalyst performance and durability.
PubMed: 38847073
DOI: 10.1039/d4nh00109e -
Planta Medica Jun 2024Antimicrobial photodynamic therapy (aPDT) is an evolving treatment strategy against human pathogenic microbes such as the species, including the emerging pathogen ....
Antimicrobial photodynamic therapy (aPDT) is an evolving treatment strategy against human pathogenic microbes such as the species, including the emerging pathogen . Using a modified EUCAST protocol, the light-enhanced antifungal activity of the natural compound parietin was explored. The photoactivity was evaluated against three separate strains of five yeasts, and its molecular mode of action was analysed via several techniques, i.e., cellular uptake, reactive electrophilic species (RES), and singlet oxygen yield. Under experimental conditions ( = 428 nm, H = 30 J/cm, PI = 30 min), microbial growth was inhibited by more than 90% at parietin concentrations as low as c = 0.156 mg/L (0.55 µM) for and , c = 0.313 mg/L (1.10 µM) for , c = 0.625 mg/L (2.20 µM) for , and c = 1.250 mg/L (4.40 µM) for . Mode-of-action analysis demonstrated fungicidal activity. Parietin targets the cell membrane and induces cell death via ROS-mediated lipid peroxidation after light irradiation. In summary, parietin exhibits light-enhanced fungicidal activity against all species tested (including ) and , covering three of the four critical threats on the WHO's most recent fungal priority list.
Topics: Antifungal Agents; Cryptococcus neoformans; Microbial Sensitivity Tests; Candida auris; Light; Candida; Reactive Oxygen Species; Photochemotherapy; Anthraquinones; Photosensitizing Agents
PubMed: 38843798
DOI: 10.1055/a-2249-9110 -
BMC Genomics Jun 2024The search for new bioactive natural compounds with anticancer activity is still of great importance. Even though their potential for diagnostics and treatment of cancer...
BACKGROUND
The search for new bioactive natural compounds with anticancer activity is still of great importance. Even though their potential for diagnostics and treatment of cancer has already been proved, the availability is still limited. Hypericin, a naphthodianthrone isolated essentially from plant source Hypericum perforatum L. along with other related anthraquinones and bisanthraquinones belongs to this group of compounds. Although it has been proven that hypericin is synthesized by the polyketide pathway in plants, none of the candidate genes coding for key enzymes has been experimentally validated yet. Despite the rare occurrence of anthraquinones in plants, their presence in microorganisms, including endophytic fungi, is quite common. Unlike plants, several biosynthetic genes grouped into clusters (BGCs) in fungal endophytes have already been characterized.
RESULTS
The aim of this work was to predict, identify and characterize the anthraquinone BGCs in de novo assembled and functionally annotated genomes of selected endophytic fungal isolates (Fusarium oxysporum, Plectosphaerella cucumerina, Scedosporium apiospermum, Diaporthe eres, Canariomyces subthermophilus) obtained from different tissues of Hypericum spp. The number of predicted type I polyketide synthase (PKS) BGCs in the studied genomes varied. The non-reducing type I PKS lacking thioesterase domain and adjacent discrete gene encoding protein with product release function were identified only in the genomes of C. subthermophilus and D. eres. A candidate bisanthraquinone BGC was predicted in C. subthermophilus genome and comprised genes coding the enzymes that catalyze formation of the basic anthraquinone skeleton (PKS, metallo-beta-lactamase, decarboxylase, anthrone oxygenase), putative dimerization enzyme (cytochrome P450 monooxygenase), other tailoring enzymes (oxidoreductase, dehydrogenase/reductase), and non-catalytic proteins (fungal transcription factor, transporter protein).
CONCLUSIONS
The results provide an insight into genetic background of anthraquinone biosynthesis in Hypericum-borne endophytes. The predicted bisanthraquinone gene cluster represents a basis for functional validation of the candidate biosynthetic genes in a simple eukaryotic system as a prospective biotechnological alternative for production of hypericin and related bioactive anthraquinones.
Topics: Hypericum; Multigene Family; Polyketides; Endophytes; Anthraquinones; Fungi; Genome, Fungal; Computer Simulation; Polyketide Synthases; Perylene; Anthracenes; Genomics; Phylogeny
PubMed: 38831295
DOI: 10.1186/s12864-024-10475-z