μM Concentration Research Articles

Phenolic Compounds: Investigating Their Anti-Carbonic Anhydrase, Anti-Cholinesterase, Anticancer, Anticholinergic, and Antiepileptic Properties Through Molecular Docking, MM-GBSA, and Dynamics Analyses

Abstract Phenolic compounds are a new class of Carbonic Anhydrase inhibitors (CAIs). Despite numerous advancements in treatment approaches, cancer continues to be a growing health problem worldwide. In our study, we tested the effects of 4-hydroxy-3-methoxyacetophenone (1), doxycycline hydrochloride (2), 5,7-dichloro-8-hydroxyquinoline (3), methyl 3,4,5-trihydroxybenzoate (4), 2-hydroxy-4-methylacetophenone (5), 6-hydroxy-4-methylcoumarin (6), and 2,5-dihydroxyacetophenone (7) on Achetylcholynesterase (AChE), Butrycholynesterase (BChE), and Human Carbonic anhydrase I (hCA I) enzymes. The U2OS human osteosarcoma cell line was used to determine the anticancer potential of these phenolic compounds. The effects of the compounds on proliferation and colony formation were analyzed using the Neutral Red Uptake (NRU) assay and the clonogenic assay. The Ki values of arachidonoyl dopamine, 2,4,6-trihydroxybenzaldehyde, and 3,4-dihydroxy-5-methoxybenzoic acid were 203.80, 1170.00, and 910.00 mM, respectively, for hCA I, and 75.25, 354.00, and 1510.00 mM, respectively, for Human Carbonic anhydrase II (hCA II). Additionally, IC50 values from in vivo studies were found to range from 173.25 to 1360.00 mM for CA I and CA II, respectively, using CO2-hydratase activity methods. The NRU assay results revealed that the compounds had a dose-dependent cytotoxic effect on U2OS cells. The IC50 values of the compounds in U2OS osteosarcoma cells were determined to be > 100, 93.7, 81.4, 26.9, > 100, 53.1, and > 100 µM, respectively. Notably, methyl 3,4,5-trihydroxybenzoate (4), the compound with the lowest IC50 value, significantly suppressed colony formation at 5 and 10 µM concentrations. These results demonstrated that the phenolic compounds used in in vivo studies could inhibit approximately 30% of the CO2-hydratase activity of the total CA enzyme of rat erythrocytes. Furthermore, the anticancer potential of the tested compounds suggests that these molecules could pave the way for the development of new approaches in cancer treatment. The activities of the seven molecules studied were compared against AChE (PDB ID: 4M0E), BChE (PDB ID: 5NN0), hCA I (PDB ID: 2CAB), and E3 ubiquitin-protein ligase (PDB ID: 4HG7) proteins. The binding free energy of the molecule with the highest docking score is computed using MM/GBSA techniques. Finally, molecular dynamics simulations were performed between 6-hydroxy-4-methylcoumarin and the 4M0E protein over a 0–200 ns interval. Graphical abstract

Distinctive dust weather intensities in North China resulted from two types of atmospheric circulation anomalies

Abstract. Dust weather in North China (NC; 34–42° N, 105–120° E) has worsened in recent years, posing adverse impacts on the environment, human health, and the economy. A super dust storm that occurred on 15 March 2021 raised Beijing's PM10 (particulate matter with a diameter less than 10 µm) concentrations above 7000 µg m−3, while 2023 witnessed the highest spring dust weather frequency in nearly a decade. Previous research has primarily focused on the role of the Mongolian cyclone in influencing dust weather in NC, with less attention given to other synoptic systems. Additionally, the differences in PM10 concentrations in NC caused by different synoptic systems have not yet been quantified. This study demonstrates that the Mongolian cyclone was responsible for 61.7 % of the dust weather in NC, while the remaining 38.3 % was primarily caused by the cold high. The dust intensity induced by the Mongolian cyclone was stronger than that of the cold high, with average maximum PM10 concentrations of 3076 and 2391 µg m−3, respectively. The three-dimensional structure of atmospheric circulation anomalies and related dynamic mechanisms of the two types were concluded. To comprehensively forecast the two types of dust weather, a common predictor was constructed based on the 500 hPa cyclonic anomaly and anticyclonic anomaly circulation systems. These findings contribute to enhancing the comprehension of dust weather in NC and offer insights for both dust weather forecasting and climate prediction.

One step aqueous synthesis of unprotected glycosyl C-sulfonates.

A one-step reaction for the production of unprotected glycosyl C-sulfonates directly from reducing sugars in aqueous solution has been developed, avoiding the use of any protecting groups. The reaction is equally applicable to disaccharides. The structure of the β-gluco C-sulfonate was confirmed by X-ray crystallography. Investigations showed that it did not inhibit almond β-glucosidase at a concentration of 100μM.

Physiological and metabolome characterization of Amaranthus hybridus L. grown under cypermethrin stress: an insight of Jasmonic acid treatment

The indiscriminate use of pesticides compromises physiology and metabolism in crops, posing health risks through residue accumulation in edible tissues. Amaranthus hybridus L., a fast growing, nutritionally and medicinally valuable crop was studied here to assess the impact of cypermethrin (CYP) at recommended (R1, 100 ppm) and double dose (R2, 200 ppm) alongside foliar application of jasmonic acid (JA) at 50 µM, 100 µM, and 200 µM concentrations. CYP at R1 dose induced hormesis, while R2 was toxic, elevating the production of ROS molecules (H2O2, SOR, MDA). JA application upregulated the antioxidant activity of SOD, POD, APX, GST, DHAR, GSH, and proline to alleviate oxidative stress and improve growth indicators, including shoot length, leaf area, chlorophyll content, Fv/Fm ratio, and biomass. JA at 100 µM yielded the highest increase in biomass, 11.52% and 13.7% for R1 and R2 treated plants, respectively and also led to reduced accumulation of CYP residues. The UHPLC-MS analysis of leaf tissue revealed increase in the contents of carotenoids, flavonoids, phenolics, phenylpropanoids, steroids content in the plant group combinedly treated with JA and CYP compared to those treated with CYP alone, indicating a protective and growth-promoting role of JA under pesticide stress conditions. Overall, 100 µM concentration of JA proved to be effective against the stress induced by the either dose of CYP in the study. These insights could offer strategies to reduce pesticide-induced damage in vegetable crops, advancing sustainable agriculture.

Discovery of the first examples of right open reading frame kinase 2 (RIOK2) molecular glue degraders.

Right open reading frame kinase 2 (RIOK2) is an atypical serine threonine kinase which plays an important role in regulating ribosome synthesis and cell cycle progression. RIOK2 has been implicated in multiple human cancers and is a potential target for cancer treatment. We previously reported the discovery of CQ211 as a potent and selective RIOK2 inhibitor. Herein we present the design, synthesis, and evaluation of the first RIOK2 molecular glue degrader CQ627 based on the structure of CQ211. CQ627 can effectively induce the degradation of RIOK2 with a DC50 value of 410nM in MOLT4 leukemia cell line via UPS by recruiting E3 ubiquitin ligase RNF126, while the corresponding small molecular inhibitor CQ211 barely induces any degradation at higher concentration of 10μM. Moreover, CQ627 dose-dependently induces apoptosis and blocks cell cycles in G2/M phase in MOLT4 leukemia cells. Importantly, it also displays stronger antiproliferative activities in a variety of cancer cell lines than RIOK2 inhibitor CQ211 and demonstrates promising in vivo efficacy in a mouse MOLT4 xenograft model.

Engagement of peroxisome proliferator-activated receptor gamma (PPARγ) and mammalian target of rapamycin (mTOR) in the triclosan-induced disruption of Cyp450 enzyme activity in an in vitro model of mouse embryo fibroblasts (3T3-L1).

Triclosan (TCS) is commonly used worldwide due to its bactericidal and antifungal properties. There are data suggesting the involvement of aryl hydrocarbon receptors (AhR) and peroxisome proliferator-activated receptors (PPARγ). Since the effect of TCS on mouse fibroblasts has not been described so far, we decided to investigate the mechanism of action of this compound in the mouse embryonic fibroblast cell line (3T3-L1). Our results showed that high µM concentrations of TCS increased caspase-3 activity and decreased cell viability after 24-h exposure. The molecular analysis confirmed that 1 µM TCS decreased Ki67 mRNA expression and PCNA protein expression with a similar tendency to that of AhR. The analyses of mRNA levels after treatment with αNF or βNF alone and αNF in combination with TCS showed an increase in Ki67 mRNA expression. TCS alone increased AhR mRNA but had different effects on Cyp1a1 and Cyp1b1 expression. These results suggest the involvement of the PPARγ pathway in the inhibition of Cyp1b1 by TCS. After the TCS exposure, we observed a decrease in PPARγ, and this effect was enhanced in the presence of an AhR agonist and antagonist. These results support the theory about the interaction between the AhR and PPARγ pathways. In the experiments, the strongest increase in PI3K protein expression was observed in the group treated simultaneously with TCS and βNF. Changes in the PI3K level were reflected in changes in the examined mTOR protein. TCS caused a decrease in both mTOR and Cyp1b1 after 24 hours, while opposite effects were observed after 48 hours. Given the crucial role of Cyp1b1, PPARγ, and mTOR in cellular metabolism, we can conclude that TCS is able to disrupt a number of cellular processes. Our data suggest that TCS reduces the metabolism of this xenobiotic in mouse preadipocytes.

Cannabidiol Toxicity Driven by Hydroxyquinone Formation.

Oxidative byproducts of cannabidiol (CBD) are known to be cytotoxic. However, CBD susceptibility to oxidation and resulting toxicity dissolved in two common solvents, ethanol (EtOH) and dimethyl sulfoxide (DMSO), is seldom discussed. Furthermore, CBD products contain a wide range of concentrations, making it challenging to link general health risks associated with CBD cytotoxicity. Here, we report on the effect of CBD and CBD analogues dissolved in EtOH or DMSO at various concentrations. The cells used in these studies were human umbilical vascular endothelial cells (HUVECs). Our findings show significant CBD oxidation to cannabidiol-quinone (CBD-Q) and subsequent cytotoxicity, occurring at 10 μM concentration, regardless of the solution delivery vehicle. Moreover, a new analogue of CBD, cannabidiol-diacetate (CBD-DA), exhibits significantly more stability and reduced toxicity compared with CBD or CBD-Q, respectively. This knowledge is important for determining concentration-dependent health risks of complex cannabinoid mixtures and establishing legal limits.

Analysis of the protective effect of hydrogen sulfide over time in ischemic rat skin flaps.

Hydrogen sulfide (H2S) is a widely studied gasotransmitter, and its protective effect against ischemia-reperfusion damage has been explored in several studies. Therefore, a requirement exists for a comprehensive study about H2S effects on ischemia-reperfusion damage in flap surgery. The aim of this study is to examine the effect of hydrogen sulfide by creating ischemia-reperfusion injury in the vascular-stemmed island flap prepared from the rat groin area. "Wistar albino" rats weighing between 250 and 300grams were divided into 4 groups (group 1, group 2, group 3, group 4). Each group was divided into 2 subgroups: subgroup A (control) and subgroup B (H2S). In each group, skin flaps were elevated as an island flap with a superficial epigastric artery pedicle, 6×4cm from the groin area. In subgroup B (H2S), liquid hydrogen sulfide was injected through the tail vein 20minutes before ischemia at a final concentration of 10μM. Femoral artery and vein blood flows were stopped with separate microclips and left in ischemia, according to the planned ischemia hours of the flaps: group 1 as 1hour, group 2 as 2hours, group 3 as 3hours, and group 4 as 6hours. Later, microclips were removed, and blood flow restored again. After 12hours of reperfusion, the rats were sacrificed by cervical dislocation, and tissue samples were taken. From the samples taken, neutrophil count in ischemic tissue, MDA (malondialdehyde) measurement, and damage in the tissue were evaluated by electron microscopy. On electron microscopy inspection at all hours (1, 2, 3, and 6), hydrogen sulfide was found to provide protection against ischemia, reperfusion damage, and apoptosis at the cellular level. There was a statistically significant (P=0.035) decrease in the tissue neutrophil count at the 1st, 2nd, and 3rd hours. In the tissue MDA measurement, a statistically significant (P=0.026) decrease in hydrogen sulfide was detected at the first hour. There was no statistically significant difference in the 6th hour tissue neutrophil count and 2nd, 3rd, and 6th hour tissue MDA measurement. Electron microscopy results in this study showed that hydrogen sulfide had antiapoptotic effects on reperfusion damage in skin flaps at all hours. However, the neutrophil counts showed it had cytoprotective and anti-inflammatory properties during the 1st, 2nd, and 3rd hours following ischemia, but not during the 6th hour. Tissue MDA levels indicate that H2S mitigates significant I/R injury during the 1st hour but not in the subsequent 2nd, 3rd, and 6th hours. These results led to the hypothesis that, in order to offer a strong enough protective effect against I/R damage, H2S should be administered repeatedly or at varying concentrations. After more research on how H2S affects skin flaps, we believe that it can be used in plastic surgery practices.

Cyclic Lipopeptides as Selective Anticancer Agents: In vitro Efficacy on B16F10 Mouse Melanoma Cells.

In this study, 25 synthetic cyclic lipopeptides (CLPs) were investigated for their anticancer potential against mouse melanoma (B16F10) cells, human prostate cancer (PC-3), human colorectal adenocarcinoma (HT-29) and mouse embryonic fibroblast (NIH3T3) cells. The cytotoxic activity of investigated compounds was evaluated using MTT and CV assays. In order to examine the mechanism of action of the most potent compound cell cycle analysis, apoptosis assay, caspase activity, CFSE and DHR staining, DAF-FM, autophagy and immunocytochemistry caspase-3 assays were performed. During the fast screening, compound 9, was identified as prospective active CLP against B16F10 cell line at 10 μM concentration. MTT and CV assays exhibited at least four times higher cytotoxic potential of 9 (IC50 = 8.4±1.3 μM, MTT; 10.6±1.1 μM, CV) in comparison to control drug natural occurring CLP surfactin (IC50 = 50.3±0.6 μM, MTT; 40.4±0.3 μM, CV). The use of flow cytometry analysis confirmed that apoptosis was involved in the death of B16F10 cells after treatment with 9, as demonstrated also by DAPI staining. Caspase activity could be detected during cell death (ApoStat assay, immunocytochemistry caspase-3 assay). Compound 9 provokes enhancement of nitric oxide (NO) production in B16F10 cells but does not trigger ROS/RNS generation or autophagy. The study highlights synthetic compound 9 superior tumor-specificity and potential as an anticancer agent compared to surfactin and cisplatin. These findings could guide the development of more selective and less harmful macrocyclic lipopeptides for cancer therapy.

Synthesis and Anticancer Activity Evaluation of N-(3,4,5- Trimethoxycinnamoyl)anthranilic Acid Derivatives

There is an urgent need to search for more efficient, better-tolerated anticancer drugs. Tranilast, a synthetic analog of tryptophan metabolite, has been shown to inhibit the growth of various cancer cells. In our previous study, the tranilast analog TRA01 [N-(3,4,5- trimethoxycinnamoyl)anthranilic acid] was identified as a promising agent against the proliferation of MCF-7 and HepG2 cell lines along with good binding affinity on the transforming growth factor beta 1 (TGFβ1) target. To further explore the structure-activity relationship, a series of N-(3,4,5- trimethoxycinnamoyl)anthranilic acid derivatives (5a–i) were successfully synthesized via a two-step synthetic procedure based on N-acylation and Knoevenagel-Doebner reactions and their structures were determined using 1 H-NMR, 13C-NMR, and MS spectra. The derivatives (5a–i) were evaluated for in vitro activity using MTT assay and in silico docking on TGFβ1 target by AutoDockTools–1.5.6 software. The bioactivity results of 5a–i showed 12.30–27.04% and 19.13–46.23% inhibition on proliferation of MCF-7 and HepG2 cell lines at 100 µM concentration, respectively, with the fluorinated derivatives (5a and 5e) possessing the strongest inhibitory activities. The molecular docking also found the best binding affinity of 5a (-8.70 Kcal/mol) and 5e (-8.71 Kcal/mol) on the TGFβ1 target. The SAR result revealed that substituents on the benzene ring of anthranilic acid were not favored for anticancer activity. Although these derivatives exhibited weak anticancer properties, the good binding affinity to the TGFβ1 target suggested certain potential of this scaffold for further study on this target.

Nimodipine ameliorates subarachnoid hemorrhage-induced neuroinflammation and injury by protecting mitochondrial function and regulating autophagy.

Subarachnoid hemorrhage (SAH) is a type of hemorrhagic stroke, and the neuroprotective effects of nimodipine following SAH have been well-documented. Sirtuin 3 (SIRT3), a mitochondrial nicotinamide adenine dinucleotide (NAD+)-dependent deacetylase, plays a significant role in mitigating oxidative stress in various neurodegenerative conditions. However, the role of SIRT3 in the neuroprotective mechanisms of nimodipine after SAH remains unclear. In this study, the in vitro cytotoxicity of neurons exposed to 2% ethanol (to stimulate oxidative stress) was assessed. An in vivo experimental SAH model was established in adult mice through internal carotid perforation. A series of in vitro and in vivo experiments were conducted to investigate the function of SIRT3 and its potential mechanisms in nimodipine-treated SAH. Nimodipine, at a concentration of 10μM within 48h of incubation, exerted significant neuroprotective effects, enhancing SIRT3 protein expression under oxidative stress. Functional in vitro studies revealed that elevated SIRT3 expression improved mitochondrial function and promoted neuronal autophagy. Additional studies unveiled that SIRT3 knockdown or inhibition of autophagosome formation using inhibitor 3-methyladenine suppressed nimodipine-induced autophagy. The absence of autophagy increased neuronal cytotoxicity and mitochondrial dysfunction, decreased the release of anti-inflammatory cytokines, and increased the release of proinflammatory cytokines. Furthermore, blocking autophagy exacerbated neuronal apoptosis worsened neurological outcomes, and nullified the neuroprotective effects of nimodipine in the SAH mouse model. These findings highlight a mechanism where SIRT3 mediates nimodipine's neuroprotective effects by regulating mitochondrial function and autophagy. This suggests that SIRT3 serves as a promising therapeutic target for SAH.

Evaluation of the antiproliferative effect of histone deacetylase inhibitor (HDACi) CI-994 and Liposomal Cisplatin LipoPlatin on MCF-7 and MDA-MB-231 cells as monotherapy and combined therapy.

In this study, the effects of histone deacetylase inhibitor CI-994 and nanotechnological drug liposomal cisplatin LipoPlatin on Luminal A breast cancer and triple-negative breast cancer were explored using agents alone and in combination. MCF-7 and MDA-MB-231 cell lines were used. Cell viability, and cell index values obtained from xCELLigence System, MI, BrdU LI and AI were evaluated in experiments. In monotherapy applications, 10 μM, 20 μM and 40 μM concentrations of CI-994 and 80 μM, 160 μM, and 250 μM concentrations of LipoPlatin were applied to both cell lines. IC50 concentration of CI-994 was 10 μM for both cell lines. While IC50 concentration of LipoPlatin was 80 μM for Luminal A breast cancer cell line, this concentration was 160 μM for triple-negative breast cancer cell line. The application of a combination of CI-994 and Lipoplatin for each cell line has shown that while there was a significant decrease in cell viability, mitotic index (MI), and BrdU labeling index (LI), there was a significant increase in AI. Consequently, it was thought that combined treatments were more efficient than single medication applications and decreased the cell prognosis with a synergistic and additive impact.

An Oxazole Alkaloid, Terpenoids, and Cyclodipeptides With Cytotoxic and Nitric Oxide Inhibitory Effects From a Mangrove-Derived Fungus Trichoderma sp. GXT-22.1.

Chemical investigation of the mangrove-derived fungus Trichoderma sp. GXT-22.1 led to the isolation and identification of 10 secondary metabolites, including one new compound, 5'-(4-methoxyphenyl)-1',3'-oxazole (1), one new natural compound, (E)-6,10-dimethyl-5-undecene-2,9,10-triol (2), along with eight known compounds, tricholumin A (3), harzianol J (4), cyclonerodiol (5), 10,11-dihydro-11-hydroxycyclonerodiol (6), cyclonerodiol B (7), epicyclonerodiol oxide (8), cyclo(Val-Pro) (9), and cyclo-(4-hydroxyprolinyl-leucine) (10). The structural feature of oxazole in 1 was unusually found among the fungal metabolites. Compounds 1 and 4 exhibited weak cytotoxicity toward HepG2 and MCF-7 human carcinoma cell lines at the concentration of 100µM, with induction of 41.5 ± 3.0% and 39.3 ± 2.3% cell death, respectively. Compounds 1-5, 8, and 10 showed their inhibitory effect against nitric oxide (NO) overproduction in lipopolysaccharide-stimulated RAW264.7 cells, with half inhibition concentration values ranging from 37.5 ±2.6 to 86.5 ±5.1µM. Molecular docking simulation suggested that 1 inhibits NO overproduction via modulating the action of the inducible NO synthase protein.

Ionizing Radiation Combined with Gold Complex Compounds Causes Apoptosis in Colorectal Cancer Cells by Increasing the Level of Caspase-3.

The anticancer activity and radiosensitizing effect of Auranofin, an an-tirheumatic and an approved gold metallic drug, have been investigated from multiple perspectives. In this study, the action of the new gold complex compound TPN-Au(I)-MM4 was compared with that of auranofin. The inhibitory effect of 10 μM and 50 μM concentrations on cell proliferation was investigated using the human colon cancer cell lines HCT116 and SW480. The radiosensitizing effect of HCT116 cells was evaluated by measuring the ability to induce apoptotic cell death. The mechanism of action was qualitatively determined via western blotting analysis of the level of cleaved caspase-3 protein. Auranofin completely inhibited cell proliferation in both cell lines at both concentrations. In contrast, only 50 μM of TPN-Au(I)-MM4 significantly inhibited the proliferation of SW480 cells, but did not affect the proliferation of HCT116 cells. On the other hand, both compounds effectively increased the apoptotic cell death rate when combined with 4 Gy of X-ray irradiation. This mechanism was caused by a significant increase in the level of caspase-3, which is an apoptosis execution factor, by the combination of these two treatments. Both compounds promoted the significant expression of caspase-3, an apoptosis execution factor, and exhibited radio-sensitizing effects. In particular, TPNAu( I)-MM4 showed no inhibitory effect on cell proliferation alone, but had a significant radiosensitising effect on HCT116 cells. Therefore, TPN-Au(I)-MM4 has the potential for use as a new radiosensitizer.

The Ivermectin Related Compound Moxidectin Can Target Apicomplexan Importin α and Limit Growth of Malarial Parasites.

Signal-dependent transport into and out of the nucleus mediated by members of the importin (IMP) superfamily is crucial for eukaryotic function, with inhibitors targeting IMPα being of key interest as anti-infectious agents, including against the apicomplexan Plasmodium species and Toxoplasma gondii, causative agents of malaria and toxoplasmosis, respectively. We recently showed that the FDA-approved macrocyclic lactone ivermectin, as well as several other different small molecule inhibitors, can specifically bind to and inhibit P. falciparum and T. gondii IMPα functions, as well as limit parasite growth. Here we focus on the FDA-approved antiparasitic moxidectin, a structural analogue of ivermectin, for its IMPα-targeting and anti-apicomplexan properties for the first time. We use circular dichroism and intrinsic tryptophan fluorescence measurements to show that moxidectin can bind directly to apicomplexan IMPαs, thereby inhibiting their key binding functions at low μM concentrations, as well as possessing anti-parasitic activity against P. falciparum in culture. The results imply a class effect in terms of IMPα's ability to be targeted by macrocyclic lactone compounds. Importantly, in the face of rising global emergence of resistance to approved anti-parasitic agents, the findings highlight the potential of moxidectin and possibly other macrocyclic lactone compounds as antimalarial agents.

Five new bisabolane-type sesquiterpenoids with oxygen-containing heterocyclic systems from Curcuma longa.

Five new bisabolane-type sesquiterpenoids (1-5) were isolated from the rhizomes of Curcuma longa, and all of them were oxygen-containing heterocyclic compounds. The structures of the compounds were elucidated using comprehensive spectroscopic techniques, and their absolute configurations were confirmed through electronic circular dichroism (ECD) calculations. All of the compounds were evaluated for their vasorelaxant and anti-inflammatory activities. The results showed that only compound 4 exhibited a vasorelaxant effect against KCl-induced contraction of rat aortic rings, and it achieved a diastolic ratio that exceeded 25% at a concentration of 25μM.

Synthesis and biological evaluation of novel pyrrolo[2,3-b]pyridine derivatives as potent GSK-3β inhibitors for treating Alzheimer's disease.

The development of potent glycogen synthase kinase-3β (GSK-3β) inhibitor has been increasingly recognized as the candidate treatment against the multifactorial pathogenic mechanism of Alzheimer's disease (AD). This study prepared various new pyrrolo[2,3-b]pyridine derivatives, evaluated the anti-AD activities and detected the security based on the structure-guided rational design. Our results indicated that many pyrrolo[2,3-b]pyridine derivatives had strong GSK-3β inhibitory activities, particularly compounds 41, 46 and 54, with the half maximal inhibitory concentrations (IC50) of 0.22, 0.26 and 0.24nM, respectively, and each of them generally possessed GSK-3β selectivity over 24 structurally similar kinases. In addition, further targeting studies at the cellular level revealed that compound 41 increased GSK-3β phosphorylation at Ser9 site dose-dependently for inhibiting GSK-3β activity, therefore inhibiting the hyperphosphorylation of tau protein by decreasing the p-tau-Ser396 abundance. Moreover, 41 up-regulated β-catenin and neurogenesis-related markers (GAP43 and MAP-2), thereby promoting neurite outgrowth of neurons in SH-SY5Y cells. According to the in vitro cells assay, 41 showed the lower cytotoxicity to SH-SY5Y cells with a survival rate of over 70% at the concentration of 100μM. In vivo efficacy and acute toxicity experiments showed that, 41 effectively ameliorated the dyskinesia in AlCl3-induced zebrafish AD models and exhibited its low-toxicity nature in C57BL/6 mice. Overall, the pyrrolo[2,3-b]pyridine derivative 41 could serve as a promising GSK-3β inhibitor for treating AD.

Chromones from Saposhnikovia divaricata and their inhibition of IL-1β-induced proliferative activity in SW982cells.

Nine previously undescribed chromones, named sadivamones O-W (1-9), and five known analogues (10-14), were isolated from the roots of Saposhnikovia divaricata (Turcz.) Schischk. The detailed structural analysis of each compound was finalized by a variety of methods including NMR (1D and 2D), mass spectrometry (HR-ESI-MS) spectroscopic data, and sugar hydrolysis. The absolute configurations of compounds (4-5) were determined by CD. Moreover, compounds 1-14 were evaluated for their inhibition of IL-1β-induced proliferative activity in SW982cells. The results demonstrated that compounds 2-4 and 11-12 exhibited notable inhibitory effects on IL-1β-induced proliferation in a concentration-dependent manner, with the most pronounced inhibition observed at a concentration of 20μM.

Quinazoline derivatives as novel bacterial sphingomyelinase enzyme inhibitors.

Bacillus cereus sphingomyelinase C (B. cereus SMase), which plays a crucial role in bacterial virulence, has emerged as a new therapeutic target for treating opportunistic infections caused by this pathogen. It also shares catalytic domain similarity with human neutral sphingomyelinase 2 (nSMase2), which is implicated in Alzheimer's disease. In this study, a series of quinazoline derivatives were synthesized and evaluated for their inhibition of B. cereus SMase, electric eel acetylcholinesterase (EeAChE), and equine butyrylcholinesterase (eqBuChE). Moreover, the antibacterial, anti-hemolytic and metal chelation properties of the selected compounds were determined. Among the synthesized compounds, 6-chloro-2-thioxo-2,3-dihydroquinazolin-4(1H)-one (compound 4) and 6-fluoro-2-thioxo-2,3-dihydroquinazolin-4(1H)-one (compound 5) exhibited promising inhibition of B. cereus SMase, with IC50 values of 6.43 and 6.50µM, respectively. The mode of inhibition of compound 4 was determined as mixed-type inhibition by enzyme kinetic study. In addition, compounds 4 and 5 showed 59.50% and 51.66% eqBuChE inhibition at 50µM concentration, respectively. Furthermore, compound 4 reduced B. cereus-induced hemolysis on sheep erythrocytes and able to form a complex with Cu2+ in ligand:metal ratio of 2:1. Additionally, cambinol, an inhibitor of both nSMase2 and B. cereus SMase, was found to exhibit inhibitory activity against eqBuChE, with IC50 value of 7.40µM. The biological data were also supported by the results of molecular docking studies and in-silico physicochemical properties/ADME predictions of the selected compounds were determined.

Synthesis of cationic N-acylated thiazolidine for selective activity against Gram-positive bacteria and evaluation of N-acylation's role in membrane-disrupting activity.

The evolution of antimicrobial-resistant strains jeopardizes the existing clinical drugs and demands new therapeutic interventions. Herein, we report the synthesis of cationic thiazolidine bearing a quaternary pyridinium group, in which thiazolidine was N-acylated with fatty acid to establish a hydrophilic-lipophilic balance that disrupts bacterial membranes. The bacterial growth inhibition assays and hemolytic activity against human red blood cells indicate that the N-acylated cationic thiazolidine (QPyNATh) inhibits Gram-positive bacteria at lower minimum inhibitory concentrations (MIC) and is selective for bacteria over mammalian cells. N-Acylation modulates MIC, and it is found that the N-palmitoylated compound, QPyN16Th, had the lowest MIC (1.95 μM) against Gram-positive, Enterococcus faecalis, Staphylococcus aureus and methicillin-resistant Staphylococcus aureus (MRSA). In contrast, the N-myristoylated compound, QPyN14Th, showed the lowest MIC (31.25 μM) against Gram-negative, Escherichia coli, uropathogenic Escherichia coli, and Pseudomonas aeruginosa. At 1× MIC, QPyNATh permeabilizes the bacterial membrane, depolarizes the cytoplasmic membranes, and produces excess reactive oxygen species to kill the bacteria, as evidenced by live and dead staining. Interestingly, only QPyNATh containing a palmitoyl acyl chain demonstrated membrane-damaging activity at 2 μM concentrations, suggesting that the optimal hydrophilic-lipophilic balance enables QPyN16Th to selectively kill Gram-positive bacteria at lower doses. S. aureus develops resistance to ciprofloxacin quickly; however, no resistance to QPyN16Th is observed after several passages. As a proof of concept, the animal study revealed that QPyN16Th treatment reduced the bacterial burden in MRSA-infected zebrafish, allowing them to recover from infection and resume normal life. The results imply that lipidation and derivatizing thiazolidine with cationic charge offer an antimicrobial that is selective to treat Gram-positive bacterial infections, biocompatible, and less prone to develop resistance.