Letters in Drug Design & Discovery - Volume 21, Issue 19, 2024

Activated Protein C (APC) is a plasma serine protease with antithrombotic function. APC acts as an anticoagulant by promoting the degradation of factors Va and VIIIa, thus inhibiting the formation of thrombin. Specific inhibition of APC has been proposed to benefit hemophilia therapy.

We used chromogenic tripeptide substrate hydrolysis assay to screen a series of arginine and arginine-like containing small molecules to identify inhibitors of APC. Similar hydrolysis assays were used to determine selectivity against other serine proteases and blood-clotting enzymes. Molecular modeling was exploited to illustrate the binding of the most potent and selective inhibitor onto the putative binding site.

We identified inhibitor 2 as a potent inhibitor with an IC50 value of 1.1 µM. The molecule demonstrated >100-fold selectivity against thrombin, factor XIa, and neutrophil elastase, >50-fold selectivity against factor XIIIa, 10-fold selectivity against factor Xa, and 8-fold selectivity against human plasmin. Molecular modeling reveals that inhibitor 2 binds to the active site of APC with the best-docked structure, indicating that one protonated amidino group establishes a salt bridge to the side chain carboxylate of Asp189 residue. Another inhibitor was identified, yet it was not as selective to APC. Importantly, inhibitor 2 demonstrates favorable physicochemical, pharmacokinetic, and drug-likeness properties.

Inhibitor 2 is a selective and potent inhibitor of APC that serves as a powerful lead for the development of hemophilia therapy.

The underlying mechanisms of Oxysophocarpine (OSC) in Cerebral Ischemia (CI) treatment were investigated through network pharmacology, molecular docking, and in vitro experiments.

The potential targets of OSC were predicted using the PubChem, SwissTargetPrediction, and PharmMapper databases. Relevant CI targets were identified through the GeneCards and Online Mendelian Inheritance in Man (OMIM) databases, and common targets between OSC and cerebral ischemia were determined using Venny2.1.0. Drug-disease Protein-Protein Interaction (PPI) networks were analyzed using the String database. Gene Ontology (GO) and Kyoto Encyclopedia of Genes and Genomes (KEGG) enrichment analyses of key targets were conducted using the DAVID database. Molecular docking verification was performed using Autodock Vina. The results of the network pharmacological analysis were validated through in vitro experiments.

Mapping the drug and disease targets yielded 126 common targets. GO and KEGG enrichment analysis revealed that OSC's therapeutic mechanism in CI involves multiple pathways, including those related to cancer, MAPK signaling, and PI3K-Akt signaling. Molecular docking results demonstrated strong binding activity of OSC to core protein targets. In vitro experiments indicated that OSC enhances the survival rate of four hours of sugar deprivation and 12 hours of reoxygenation (OGD4h/R12h) in bEnd.3 cells and reduces the protein expression of p-PI3K and p-Akt.

The “multi-target and multi-mechanism” actions of OSC in CI treatment were elucidated through network pharmacology and molecular docking, providing a scientific basis for further investigation.

This study aimed to examine the active constituents and therapeutic targets of Ginkgo biloba extract (GBE) through a network pharmacology methodology to elucidate the mechanisms underlying the efficacy of GBE in treating tinnitus.

The active constituents and potential targets of GBE were identified via the Traditional Chinese Medicine Systems Pharmacology (TCMSP) database, while tinnitus-related targets were sourced from the GeneCards database. Protein-protein interaction (PPI) data relevant to tinnitus were retrieved from the STRING database. Subsequently, an active constituent-target network was constructed, and Gene Ontology (GO) enrichment and Kyoto Encyclopedia of Genes and Genomes (KEGG) pathway analyses were conducted using Cytoscape 3.7.1.

The analysis identified 27 active constituents and 73 potential therapeutic targets of GBE relevant to tinnitus treatment. A total of 418 GO terms were identified, including 408 biological processes, 4 cellular components, and 6 molecular functions, which were associated with processes, such as cell cycle regulation, apoptosis, inflammatory response, oxidative stress, and angiogenesis. Additionally, 116 KEGG pathways were identified, including pathways involved in cancer, the AGE-RAGE signaling pathway in diabetic complications, human cytomegalovirus infection, and apoptosis, among others.

The treatment of tinnitus with GBE may target several potential therapeutic candidates, including MYC, TNF, AKT1, CXCL8, CASP3, IL6, TP53, VEGFA, PTGS2, EGFR, EGF, JUN, ESR1, MMP9, CCND1, and MAPK1. This approach may involve various mechanisms, such as anti-inflammatory, antioxidant, and anti-apoptotic pathways. Network pharmacology provides a robust framework for further investigation into the pharmacological targets and molecular mechanisms through which GBE may exert its effects in the context of tinnitus.

At present, the therapeutic drugs for Toxoplasmosis have serious side effects and limitations in application, so it is urgent to develop low-toxicity and high-efficiency drugs.

A series of new derivatives based on arctigenin were designed and synthesized, aiming to obtain target derivatives with superior anti-Toxoplasma activity.

A series of quinoline groups were introduced into the phenolic hydroxyl group of arctigenin compound, and 29 novel arctigenin derivatives were designed and synthesized. The chemical structures were confirmed by ¹H NMR, ¹³C NMR, and HRMS spectra. The cytotoxicity of all compounds to host cells (HeLa) and the half inhibitory concentration of HeLa cells infected with Toxoplasma gondii were determined by the MTT assay, and the selectivity index (SI) was calculated.

The selectivity index of compounds B8 and B12 was 1.45, indicating the anti-Toxoplasma activity of compound B8 and B12 to be higher than that of the lead compound arctigenin (SI= 0.99) and the positive control drug spiramycin (SI= 0.92).

Compounds B8 and B12 demonstrated the most potent anti-Toxoplasma activity, with an SI value of 1.45. This offers valuable guidance for the subsequent screening of more effective anti-Toxoplasma drugs.

Echinacea purpurea is a medicinal plant recognized for its rich array of bioactive constituents, making it a valuable resource for drug development. However, the potential antitumor effects and underlying mechanisms of Echinacea remain largely unexplored.

This study aims to elucidate the active ingredients, targets, and pathways mediating the anti-lung cancer effects of Echinacea through the lens of network pharmacology and to further validate the efficacy of the extract of Echinacea purpurea against lung cancer in vitro.

An 'Echinacea-lung cancer-target' network was constructed using network pharmacology, identifying quercetin, β-sitosterol, rutin, dibutyl phthalate, ferulic acid, and protocatechuic acid as the primary active components contributing to Echinacea's anti-lung cancer activity. These components may exert antitumor effects by modulating key targets, including TP53, AKT1, HSP90AA1, JUN, and IL6, through the PI3K-Akt, MAPK, IL-17, HIF-1, and TNF signaling pathways. Subsequently, MEPT was administered to human lung cancer PC-9 cells, revealing that the Echinacea extract inhibited cell proliferation, migration, and the expression of cell cycle proteins in a concentration- and time-dependent manner while also inducing early apoptosis in tumor cells.

These findings suggest that the anti-lung cancer activity of Echinacea operates through a synergistic mechanism involving multiple components, targets, and pathways, potentially leading to cell cycle arrest and the induction of apoptosis.

Obstructive sleep apnea (OSA) is characterized by recurrent stenosis or collapse of the upper airway during sleep. This directly leads to reduced ventilation or apnea, followed by arterial hypoxemia and hypercapnia.

The study aims to explore whether hydrogen sulfide (H2S) could serve as a protective factor for the hypoglossal nucleus (HN) against chronic intermittent hypoxia (CIH) in rats.

A total of 12 adult male Sprague-Dawley (SD) rats were randomly and equally divided into two groups (CIH and control group). Rats in the CIH group were housed in a hypoxic chamber with the oxygen volume fraction alternating between 21% and 5% by providing air for 60 s and nitrogen for 60 s from 8:30am to 16:30pm each day for 35 days. The control group was housed in a chamber with a normal oxygen level. After 5 weeks, expressions of different synthases in the HN were detected using Western blot analysis and qRT-PCR.

Transcriptions of synthetase gene CBS (p < 0.01) and 3MST (p < 0.05) in the CIH group were significantly reduced compared to those in the control group. Expression of H2S synthetase 3MST was significantly down-regulated in the hypoglossal nucleus of CIH rats compared to that in the control group (p < 0.05). The expression of CBS was significantly reduced in the CIH group compared to that in control group (p < 0.05).

CBS and 3MST-H2S pathways may be involved in regulating hypoglossal nerve activity related to respiration and protecting the HN from CIH-induced injury. This study suggests that the CBS and 3MST-H2S pathways could be one of the important pathogenesis of OSA.

A mechanism has been proposed for the targeted transfer of an antimalarial drug, which involves 1, 2, and 4 trioxane (TRX) reagents. The trioxane ring is sensitive to ferrous iron, Fe(II), and when exposed to it, it breaks down into smaller pieces, releasing the antimalarial drug mML (a mock form of DPA1 inhibitor ML4118S).

The oxane ring is attached to a nanoparticle called adamantane, which helps facilitate the reaction. The mechanism has been investigated using two reactants: TRX-R-mML and TRX-H-mML complexes (R is a side chain). The researcher used the transition state theory, the Hartree-Fock level (HF), and the ground state series 6-31G** to investigate the mechanism. The physicochemical and geometric properties of the components involved in the reaction were measured to explain the mechanism better.

The results indicate that the R as a side chain significantly affects the mentioned mechanism and properties. Additionally, the results of the calculations show the stability of the complexes required as reactants in the reaction.

The TRX-mML-R complex has more strength, and polarity than TRX-mML-H, and the energy level of the transition state of TRX-mML-R is lower than that of TRX-mML-H, indicating faster passage of raw materials.

Infections caused by parasites continue to pose a risk to both human and animal health. The most popular drug classes for treating these infections include thiabendazole, imidazo-thiazoles, levamisole, and avermectins (obtained from the fermentation products of Streptomyces avermitilis). The majority of bacteria that we come across in any form of infection are successfully combatted by β- lactam medicines. Similar to the majority of treatments, problems with treatment resistance to these drugs have evolved over time, necessitating the development of new anthelmintic medications. This study aims to investigate a series of quinazoline-bearing β-lactam rings as potent anthelmintic agents.

The new series of quinazoline bearing β-lactam was synthesized via reaction of 5-bromo anthranilic acid with acetic anhydride to produce 6-bromo-2-methyl-4H-benzo (1,3) oxazin-4-one which was then converted into 3-amino-6-bromo-2-methylquinazolin-4(3H)-one by the reaction of hydrazine hydrate in the presence of anhydrous pyridine. The resultant intermediate then goes through a Schiff reaction with various aromatic aldehydes, followed by reflux with triethylamine and chloroacetyl chloride.

Structural assignments of these compounds have been made by elemental analysis, FTIR,¹HNMR and Mass spectral data and the purity of the compounds was determined by TLC. Molecular docking studies showed the effective binding of synthesized derivatives with tubulin in comparison to the orientation of standard drugs. The anthelmintic activities of all the synthesized compounds were evaluated separately for their possible using common Indian earthworm Pheritima posthuma.

A total of ten derivatives of quinazoline bearing β-lactam ring were designed, synthesized and evaluated against the Indian earthworm Pheritima posthuma. Out of ten derivatives, SQD2 and SQD6, showed promising anthelmintic activity when compared with standard drugs albendazole and piperazine citrate.