7-Hydroxycoumarin modulates the oxidative metabolism, degranulation and microbial killing of human neutrophils

Modulating Charge Transfer Pathways to Enhance Photocatalytic Performance of the Metal-Organic Layer Nanosheet

Two-dimensional metal-organic layer (MOL) nanosheets, as nonhomogeneous catalysts, show better optical activity in the field of photocatalysis due to their unique structural advantages. Current research focuses on how to modify the structure of 2D nanosheets by means of crystal engineering to modulate the intralayer electron transfer pathway and systematically investigate the impacts of size effect and electron transfer pathway on the energy utilization efficiency of crystalline materials. In the present work, a triple lophine-derived ligand was designed and prepared, which exhibits a large π-conjugation system and multiple D-A (D: donor, A: acceptor) electron transfer pathways. 2D MOL constructed with Cd ions can be exfoliated by physical sonication to obtain double-walled 2D MOL nanosheets. Compared with the bulk crystalline material, the 2D nanosheets exhibit better photovoltaic properties. Benefiting from the excellent structural advantages, 2D MOL nanosheets could be used as photocatalysts for a variety of aerobic oxidation reactions under mild conditions (10 W white LED, room temperature), such as the trifluoromethylation of coumarins, the synthesis of benzimidazole derivatives from aromatic diamines and aromatic aldehydes, and the preparation of 2,4,6-triarylpyridine derivatives, all with high conversion rates and selectivity (yield typically greater than 88%). The related results illustrate that the introduction of the photoactive triple-lophine unit into 2D MOL nanosheets can effectively modulate the electron transport mode and enhance energy utilization, which provides a new research idea for the development of nonhomogeneous photocatalysts aimed at the applications of visible light-driven organic conversion.

Umbelliferon: a review of its pharmacology, toxicity and pharmacokinetics

Coumarin, a plant secondary metabolite, has various pharmacological activities, including antioxidant stress and anti-inflammatory effects. Umbelliferone, a common coumarin compound found in almost all higher plants, has been extensively studied for its pharmacological effects in different disease models and doses with complex action mechanisms. This review aims to summarize these studies and provide useful information to relevant scholars. The pharmacological studies demonstrate that umbelliferone has diverse effects such as anti-diabetes, anti-cancer, anti-infection, anti-rheumatoid arthritis, neuroprotection, and improvement of liver, kidney, and myocardial tissue damage. The action mechanisms of umbelliferone include inhibition of oxidative stress, inflammation, and apoptosis, improvement of insulin resistance, myocardial hypertrophy, and tissue fibrosis, in addition to regulation of blood glucose and lipid metabolism. Among the action mechanisms, the inhibition of oxidative stress and inflammation is the most critical. In short, these pharmacological studies disclose that umbelliferone is expected to treat many diseases, and more research should be conducted.

Metabolic profiles of Sri Lankan cassava mosaic virus-infected and healthy cassava (Manihot esculenta Crantz) cultivars with tolerance and susceptibility phenotypes

BACKGROUND

Cassava mosaic disease (CMD) of cassava (Manihot esculenta Crantz) has expanded across many continents. Sri Lankan cassava mosaic virus (SLCMV; family Geminiviridae), which is the predominant cause of CMD in Thailand, has caused agricultural and economic damage in many Southeast Asia countries such as Vietnam, Loas, and Cambodia. The recent SLCMV epidemic in Thailand was commonly found in cassava plantations. Current understanding of plant-virus interactions for SLCMV and cassava is limited. Accordingly, this study explored the metabolic profiles of SLCMV-infected and healthy groups of tolerant (TME3 and KU50) and susceptible (R11) cultivars of cassava. Findings from the study may help to improve cassava breeding, particularly when combined with future transcriptomic and proteomic research.

RESULTS

SLCMV-infected and healthy leaves were subjected to metabolite extraction followed by ultra-high-performance liquid chromatography high-resolution mass spectrometry (UHPLC-HRMS/MS). The resulting data were analyzed using Compound Discoverer software, the mzCloud, mzVault, and ChemSpider databases, and published literature. Of the 85 differential compounds (SLCMV-infected vs healthy groups), 54 were differential compounds in all three cultivars. These compounds were analyzed using principal component analysis (PCA), hierarchical clustering dendrogram analysis, heatmap analysis, and Kyoto Encyclopedia of Genes and Genomes (KEGG) pathway annotation. Chlorogenic acid, DL-carnitine, neochlorogenic acid, (E)-aconitic acid, and ascorbyl glucoside were differentially expressed only in TME3 and KU50, with chlorogenic acid, (E)-aconitic acid, and neochlorogenic acid being downregulated in both SLCMV-infected TME3 and KU50, DL-carnitine being upregulated in both SLCMV-infected TME3 and KU50, and ascorbyl glucoside being downregulated in SLCMV-infected TME3 but upregulated in SLCMV-infected KU50. Furthermore, 7-hydroxycoumarine was differentially expressed only in TME3 and R11, while quercitrin, guanine, N-acetylornithine, uridine, vorinostat, sucrose, and lotaustralin were differentially expressed only in KU50 and R11.

CONCLUSIONS

Metabolic profiling of three cassava landrace cultivars (TME3, KU50, and R11) was performed after SLCMV infection and the profiles were compared with those of healthy samples. Certain differential compounds (SLCMV-infected vs healthy groups) in different cultivars of cassava may be involved in plant-virus interactions and could underlie the tolerance and susceptible responses in this important crop.

A 7-Hydroxy 4-Methylcoumarin Enhances Melanogenesis in B16-F10 Melanoma Cells

The objectives of this study were to investigate the melanogenetic potentials of the naturally occurring 7-hydroxy coumarin derivatives 7-hydroxy 5,6-dimethoxycoumarin (7H-5,6DM), 7-hydroxy 6,8-dimethoxycoumarin (7H-6,8DM), 7-hydroxy 6-methoxycoumarin (7H-6M), and 7-hydroxy 4-methylcoumarin (7H-4M) in the melanogenic cells model for murine B16F10 melanoma cells. The initial results indicated that melanin production and intracellular tyrosinase activity were significantly stimulated by 7H-4M but not by 7H-5,6DM, 7H-6,8DM, or 7H-6M. Therefore, our present study further investigated the melanogenic effects of 7H-4M in B16-F10 cells, as well as its mechanisms of action. In a concentration-dependent manner, 7H-4M increased intracellular tyrosinase activity, leading to the accumulation of melanin without affecting the viability of B16-F10 cells. Our study further investigated the effects of 7H-4M on melanogenesis, including its ability to promote tyrosinase activity, increase melanin content, and activate molecular signaling pathways. The results indicate that 7H-4M effectively stimulated tyrosinase activity and significantly increased the expression of melanin synthesis-associated proteins, such as microphthalmia-associated transcription factor (MITF), tyrosinase, tyrosinase-related protein-1 (TRP1), and TRP2. Based on our findings, we can conclude that 7H-4M has the ability to activate the melanogenesis process through the upregulation of cAMP-dependent protein kinase (PKA) and the cAMP response element-binding protein (CREB). Additionally, our study showed that 7H-4M induced melanogenic effects by downregulating the extracellular signal-regulated kinase (ERK) and the phosphatidylinositol 3 kinase (PI3K)/protein kinase B (Akt)/glycogen synthesis kinase-3β (GSK-3β) cascades, while upregulating the JNK and p38 signaling pathways. Finally, the potential of using 7H-4M in topical applications was tested through primary human skin irritation tests. During these tests, no adverse reactions were induced by 7H-4M. In summary, our results indicate that 7H-4M regulates melanogenesis through various signaling pathways such as GSK3β/β-catenin, AKT, PKA/CREB, and MAPK. These findings suggest that 7H-4M has the potential to prevent the development of pigmentation diseases.

Exploration of the Specific Pathology of HXMM Tablet Against Retinal Injury Based on Drug Attack Model to Network Robustness

Retinal degenerative diseases are related to retinal injury because of the activation of the complement cascade, oxidative stress-induced cell death mechanisms, dysfunctional mitochondria, chronic neuroinflammation, and production of the vascular endothelial growth factor. Anti-VEGF therapy demonstrates remarkable clinical effects and benefits in retinal degenerative disease patients. Hence, new drug development is necessary to treat patients with severe visual loss. He xue ming mu (HXMM) tablet is a CFDA-approved traditional Chinese medicine (TCM) for retinal degenerative diseases, which can alleviate the symptoms of age-related macular degeneration (AMD) and diabetic retinopathy (DR) alone or in combination with anti-VEGF agents. To elucidate the mechanisms of HXMM, a quantitative evaluation algorithm for the prediction of the effect of multi-target drugs on the disturbance of the disease network has been used for exploring the specific pathology of HXMM and TCM precision positioning. Compared with anti-VEGF agents, the drug disturbance of HXMM on the functional subnetwork shows that HXMM reduces the network robustness on the oxidative stress subnetwork and inflammatory subnetwork to exhibit the anti-oxidation and anti-inflammation activity. HXMM provides better protection to ARPE-19 cells against retinal injury after H₂O₂ treatment. HXMM can elevate GSH and reduce LDH levels to exhibit antioxidant activity and suppress the expression of IL-6 and TNF-α for anti-inflammatory activity, which is different from the anti-VEGF agent with strong anti-VEGF activity. The experimental result confirmed the accuracy of the computational prediction. The combination of bioinformatics prediction based on the drug attack on network robustness and experimental validation provides a new strategy for precision application of TCM.

Inhibitor of Hyaluronic Acid Synthesis 4-Methylumbelliferone Suppresses the Secretory Processes That Ensure the Invasion of Neutrophils into Tissues and Induce Inflammation

Integrin-dependent adhesion of neutrophils to tissue, accompanied by the development of neutrophil-induced inflammation, occurs both in the focus of infection and in the absence of infection in metabolic disorders such as reperfusion after ischemia, diabetes mellitus, or the development of pneumonia in patients with cystic fibrosis or viral diseases. Hyaluronic acid (HA) plays an important role in the recruitment of neutrophils to tissues. 4-methylumbilliferon (4-MU), an inhibitor of HA synthesis, is used to treat inflammation, but its mechanism of action is unknown. We studied the effect of 4-MU on neutrophil adhesion and concomitant secretion using adhesion to fibronectin as a model for integrin-dependent adhesion. 4-MU reduced the spreading of neutrophils on the substrate and the concomitant secretion of granule proteins, including pro-inflammatory components. 4-MU also selectively blocked adhesion-induced release of the free amino acid hydroxylysine, a product of lysyl hydroxylase, which can influence cell invasion by modifying the extracellular matrix. Finally, 4-MU inhibited the formation of cytonemes, the extracellular membrane secretory structures containing the pro-inflammatory bactericides of the primary granules. The anti-inflammatory effect of 4-MU may be associated with the suppression of secretory processes that ensure the neutrophil invasion and initiate inflammation. We suggest that HA, due to the peculiarities of its synthesis, can promote the release of secretory carriers from the cell and 4-MU can block this process.

Pro-oxidant versus anti-oxidant effects of seeds aglycone extracts of Lepidium sativum and Eruca vesicaria Linn., in vitro, and on neutrophil nitro-oxidative functions

This study evaluated the anti-inflammatory and antioxidant properties of seeds aglycone extracts from Lepidium sativum (LS) and Eruca vesicaria (EV) Linn., on oxidative damages in vitro and on neutrophil nitro-oxidative functions. The results showed that LS and EV aglycone extracts attenuated liver microsomal lipids and proteins oxidation through a potent antioxidant effect as attested by the dose dependent quenching of DPPH radical scavenging activity. LS and EV aglycone extracts inhibited dose dependently the production of superoxide anion by BALB/c mice-derived peritoneal neutrophils, whereas they slightly enhanced exocytosis of myeloperoxidase (MPO), a marker of azurophilic granules. Interestingly, only LS replenished glutathione (GSH) and nitric oxide levels, indicating a fine differential effect. This study highlighted the subtle oxidative and antioxidant capacity of LS and EV seeds aglycone extracts. These health promoting compounds could be used to finely modulate critical events involved in microbial infection, inflammation and nitro-oxidative stress.

The 3-phenylcoumarin derivative 6,7-dihydroxy-3-[3',4'-methylenedioxyphenyl]-coumarin downmodulates the FcγR- and CR-mediated oxidative metabolism and elastase release in human neutrophils: Possible mechanisms underlying inhibition of the formation and release of neutrophil extracellular traps

In this study, we report the ability of a set of eight 3-phenylcoumarin derivatives bearing 6,7- or 5,7-dihydroxyl groups, free or acetylated, bound to the benzopyrone moiety, to modulate the effector functions of human neutrophils. In general, (i) 6,7-disubstituted compounds (5, 6, 19, 20) downmodulated the Fcγ receptor-mediated neutrophil oxidative metabolism more strongly than 5,7-disubstituted compounds (21, 22, 23, 24), and (ii) hydroxylated compounds (5, 19, 21, 23) downmodulated this neutrophil function more effectively than their acetylated counterparts (6, 20, 22, 24, respectively). Compounds 5 (6,7-dihydroxy-3-[3',4'-methylenedioxyphenyl]-coumarin) and 19 (6,7-dihydroxy-3-[3',4'-dihydroxyphenyl]-coumarin) effectively downmodulated the neutrophil oxidative metabolism elicited via Fcγ and/or complement receptors. Compound 5 also downmodulated the immune complex-stimulated phagocytosis, degranulation of elastase, and production and release of neutrophil extracellular traps, as well as the human neutrophil chemotaxis towards n-formyl-methionyl-leucyl-phenylalanine, without altering the expression level of formyl peptide receptor type 1. Both compounds 5 and 19 did not impair the neutrophil capacity to recognize and kill Candida albicans. Docking calculations revealed that compounds 5 and 19 directly interacted with three catalytic residues - Gln-91, His-95, and Arg-239 - inside the myeloperoxidase active site. Together, these findings indicate that (i) inhibition of reactive oxygen species generation and degranulation of elastase are closely associated with downmodulation of release of neutrophil extracellular traps; and (ii) compound 5 can be a prototype for the development of novel immunomodulating drugs to treat immune complex-mediated inflammatory diseases.

Aminoguanidine treatment increased NOX2 response in diabetic rats: Improved phagocytosis and killing of Candida albicans by neutrophils

In this study, we show that aminoguanidine (AMG), an inhibitor of protein glycation, increases the NOX2 (phagocyte NADPH oxidase) response and microbicidal activity by neutrophils, regardless of diabetic status. The non-enzymatic glycation of proteins, yielding irreversible advanced glycation end products (AGEs), is involved in the development of diabetes complications, including alterations of signaling pathways and the generation of reactive oxygen species by phagocytes. The phagocytes produce ROS (reactive oxygen species) through activation of the NOX2 complex, which generates superoxide. The purpose of this study was to evaluate the effect of hyperglycemia and the glycation of proteins on the NOX2 activity of neutrophils and its implications for cellular physiology, with a focus on the microbicidal activity of these cells. We treated diabetic rats with AMG and evaluated neutrophil ROS generation and Candida albicans killing ability. We observed a large increase in the microbicidal activity of peritoneal neutrophils from AMG-treated rats. The increase was independent of diabetic status and myeloperoxidase activity. Collectively, our results suggest that AMG has an immunomodulator role that triggers an increase in the microbicidal response of neutrophils mainly related to reactive oxygen species production by NOX2.

A mild and fast continuous-flow trifluoromethylation of coumarins with the CF3 radical derived from CF3SO2Na and TBHP

A mild and fast Cu(I)-catalyzed trifluoromethylation of coumarins with CF3SO2Na and TBHP in a continuous-flow reactor has been developed. This method is experimentally simple and carried out under mild conditions, affording the corresponding products in moderate to good yields, and showing wide substrate tolerance. The scale-up flow process results in an isolated yield of 68% and a productivity of 305 mg h(-1) of 3-trifluoromethyl-7-diethylamino-4-methyl coumarin when the concentration was increased five-fold. Given these features and the widespread applications of coumarins, this method may find use from laboratory to manufacturing.