CXCR4/CXCL12 axis: "old" pathway as "novel" target for anti-inflammatory drug discovery.

Inflammation is the body's defense response to exogenous or endogenous stimuli, involving complex regulatory mechanisms. Discovering anti-inflammatory drugs with both effectiveness and long-term use safety is still the direction of researchers' efforts. The inflammatory pathway was initially identified to be involved in tumor metastasis and HIV infection. However, research in recent years has proved that the CXC chemokine receptor type 4 (CXCR4)/CXC motif chemokine ligand 12 (CXCL12) axis plays a critical role in the upstream of the inflammatory pathway due to its chemotaxis to inflammatory cells. Blocking the chemotaxis of inflammatory cells by CXCL12 at the inflammatory site may block and alleviate the inflammatory response. Therefore, developing CXCR4 antagonists has become a novel strategy for anti-inflammatory therapy. This review aimed to systematically summarize and analyze the mechanisms of action of the CXCR4/CXCL12 axis in more than 20 inflammatory diseases, highlighting its crucial role in inflammation. Additionally, the anti-inflammatory activities of CXCR4 antagonists were discussed. The findings might help generate new perspectives for developing anti-inflammatory drugs targeting the CXCR4/CXCL12 axis.

Discovery of plant-derived anti-tumor natural products: Potential leads for anti-tumor drug discovery.

Natural products represent a paramount source of novel drugs. Numerous plant-derived natural products have demonstrated potent anti-tumor properties, thereby garnering considerable interest in their potential as anti-tumor drugs. This review compiles an overview of 242 recently discovered natural products, spanning the period from 2018 to the present. These natural products, which include 69 terpenoids, 42 alkaloids, 39 flavonoids, 21 steroids, 14 phenylpropanoids, 5 quinolines and 52 other compounds, are characterized by their respective chemical structures, anti-tumor activities, and mechanisms of action. By providing an essential reference and fresh insights, this review aims to support and inspire researchers engaged in the fields of natural products and anti-tumor drug discovery.

Novel druggable mechanism of Parkinson's disease: Potential therapeutics and underlying pathogenesis based on ferroptosis.

Genetics, age, environmental factors, and oxidative stress have all been implicated in the development of Parkinson's disease (PD); however, a complete understanding of its pathology remains elusive. At present, there is no cure for PD, and currently available therapeutics are insufficient to meet patient needs. Ferroptosis, a distinctive iron-dependent cell death mode characterized by lipid peroxidation and oxidative stress, has pathophysiological features similar to those of PD, including iron accumulation, reactive oxygen species-induced oxidative damage, and mitochondrial dysfunction. Ferroptosis has been identified as a specific pathway of neuronal death and is closely related to the pathogenesis of PD. Despite the similarities in the biological targets involved in PD pathogenesis and ferroptosis, the relationship between novel targets in PD and ferroptosis has been neglected in the literature. In this review, the mechanism of ferroptosis is discussed, and the potential therapeutic targets implicated in both PD and ferroptosis are compared. Furthermore, the anti-PD effects of several ferroptosis inhibitors, as well as clinical studies thereof, and the identification of novel lead compounds for the treatment of PD and the inhibition of ferroptosis are reviewed. It is hoped that this review can promote research to further elucidate the relationship between ferroptosis and PD and provide new strategies for the development of novel ferroptosis-targeting PD therapy.

Microwave-assisted rapid synthesis of chiral oxazolines.

Chiral oxazoline compounds play an extremely important role in asymmetric synthesis and drug discovery. Herein a simpler, greener and more efficient microwave-assisted protocol to rapidly access chiral oxazolines is developed using aryl nitriles or cyano-containing compounds and chiral ß-amino alcohols as starting materials. The reaction proceeds smoothly in the presence of a recoverable heterogeneous catalyst in either concentrated solution or under solvent-free conditions. The advantages of this method include rapidness, convenience, environmental protection, high atom economy, and excellent yields. The protocol should find wider application in the community in the future.

Design, synthesis and biological evaluation of novel histone deacetylase (HDAC) inhibitors derived from ß-elemene scaffold.

ß-Elemene is the major active ingredient of TCM anticancer drug elemene extracts. To further improve its antitumor activity and poor solubility, a polar HDACi pharmacophore was incorporated its scaffold. Systematic SAR studies led to the discovery of compounds 27f and 39f, which exhibited potent inhibitory activity against HDACs (HDAC1: IC50 = 22 and 9 nM; HDAC6: 8 and 14 nM, respectively). In cellular levels, 27f and 39f significantly inhibited cell proliferation of five tumour cell lines (IC50: 0.79 - 4.42 µM). Preliminary mechanistic studies indicated that 27f and 39f efficiently induced cell apoptosis. Unexpectedly, compound 39f could also stimulate cell cycle arrest in G1 phase. Further in vivo study in WSU-DLCL-2 xenografted mouse model validated the antitumor activities of 27f, without significant toxicity. The results suggest the therapeutic potential of these HDACs inhibitors in lymphoma and provide valuable insight and understanding for further structural optimisation around ß-elemene scaffold.

Combination of chemotherapy and gaseous signaling molecular therapy: Novel ß-elemene nitric oxide donor derivatives against leukemia.

This study aimed to design and synthesize active hybrids of ß-elemene and nitric oxide (NO) donor pharmacophore as potential agents for treating leukemia. Derivatives reported herein exerted better inhibitory effects against human chronic myeloid leukemia K562 cells compared to ß-elemene (IC50 > 100 µM). The most potent compound 18f showed an IC50 value of 0.53 µM against K562 cells, as well as a high NO release level in vitro. In the K562 xenograft tumor mice model, compound 18f effectively inhibited the growth of the tumor, with a significant inhibition rate of 73.18%. After treatment with compound 18f, the body weight of mice did not decrease, indicating that it possessed good safety profile. All these proved that compound 18f was an excellent potential agent against leukemia.

Design, synthesis and antitumor efficacy evaluation of a series of novel ß-elemene-based macrocycles.

ß-Elemene is the major constituent of the antitumor drugs elemene extract approved in China. By incorporating macrocyclization strategy into the ß-elemene skeleton, we designed a series of novel macrocycles retaining three key carbon-carbon double bonds. Four different methods have been successfully developed for these challenging ring systems. A total of twenty-eight 14- to 24-membered macrocycles were synthesized. Most of these macrocycles exhibited good antitumor activity against several cancer cell lines (PC-3, A549, U87MG, U251 and HCT116), with up to 40 folds improvement of activity comparing to ß-elemene. Additionally, X-ray single crystal structures of compounds Ic, Ip, and IIh were successfully solved as the proof of macrocycle formation. The results warrant the further investigation of this novel class macrocycles in pharmacokinetic and pharmacodynamics studies, which will be reported in due course.

Natural terpenoids with anti-inflammatory activities: Potential leads for anti-inflammatory drug discovery.

Natural products are mainly secondary metabolites produced by plants, microorganisms, and animals, which are still abundant in modern drug discovery. Terpenoids are the most diverse group of natural products, attracting extensive attention owing to their various biological activities. This manuscript reviewed the chemical structures, anti-inflammatory activities, and mechanisms of action of 281 terpenoid natural products reported from 2010 to the present. Their biological targets and both in vitro and in vivo screening models were also surveyed and statistically summarized. This review will provide potential anti-inflammatory lead compounds and helpful information to researchers engaged in natural products and anti-inflammatory drug discovery.

HDAC1/MAO-B dual inhibitors against Alzheimer's disease: Design, synthesis and biological evaluation of N-propargylamine-hydroxamic acid/o-aminobenzamide hybrids.

A series of N-propargylamine-hydroxamic acid/o-aminobenzamide hybrids inhibitors combining the typical pharmacophores of hydroxamic acid/o-aminobenzamide and propargylamine were designed and synthesized as HDAC1/MAO-B dual inhibitors for the treatment of Alzheimer's disease. Most of the hybrids displayed moderate to good MAO-B inhibitory activities. Among them, Hybrid If exhibited the most potent activity against MAO-B and HDAC1 (MAO-B, IC50 = 99.0 nM; HDAC1, IC50 = 21.4 nM) and excellent MAO selectively (MAO-A, IC50 = 9923.0 nM; SI = 100.2). Moreover, compound If significantly reversed Aß1-42-induced PC12 cell damage and decreased the production of intracellular ROS, exhibiting favorable antioxidant activity. More importantly, hybrid If instantly penetrated the BBB and accumulated in brain tissue as well as markedly ameliorated cognitive dysfunction in a Morris water maze ICR mice model. In summary, HDAC1/MAO-B dual inhibitor If is a promising potential agent for the therapy of Alzheimer's disease.

Second generation ß-elemene nitric oxide derivatives with reasonable linkers: potential hybrids against malignant brain glioma.

Elemene is a second-line broad-spectrum anti-tumour drug that has been used in China for more than two decades. However, its main anti-tumour ingredient, ß-elemene, has disadvantages, including excessive lipophilicity and relatively weak anti-tumour efficacy. To improve the anti-tumour activity of ß-elemene, based on its minor molecular weight character, we introduced furoxan nitric oxide (NO) donors into the ß-elemene structure and designed six series of new generation ß-elemene NO donor hybrids. The synthesised compounds could effectively release NO in vitro, displayed significant anti-proliferative effects on U87MG, NCI-H520, and SW620 cell lines. In the orthotopic glioma model, compound Id significantly and continuously suppressed the growth of gliomas in nude mice, and the brain glioma of the treatment group was markedly inhibited (>90%). In short, the structural fusion design of NO donor and ß-elemene is a feasible strategy to improve the in vivo anti-tumour activity of ß-elemene.

Novel hydroxyl carboximates derived from ß-elemene: design, synthesis and anti-tumour activities evaluation.

A series of novel N-alkyl-N-hydroxyl carboximates derived from ß-elemene were fortuitously discovered. Most of them showed more potent anti-proliferative activities than their lead compound ß-elemene (1). Notably, compound 11i exhibited significant inhibitory effects on the proliferation of three lung cell lines (H1975, A549 and H460) and several other tumour cell lines (H1299, U87MG, MV4-11, and SU-DHL-2). Preliminary mechanistic studies revealed that compound 11i could significantly induce cell apoptosis. Further in vivo study in the H460 xenograft mouse model validated the anti-tumour activities of 11i with a greater tumour growth inhibition (TGI, 68.3%) than ß-elemene and SAHA (50.1% and 55.9% respectively) at 60 mg/kg ip dosing, without obvious body weight loss and toxicity. Thus, such N-alkyl-N-hydroxyl carboximate class of compounds exemplified as 11i demonstrated potent anticancer activities both in vitro and in vivo, and should warrant further investigation for potential anticancer therapy.

Races of small molecule clinical trials for the treatment of COVID-19: An up-to-date comprehensive review.

The coronavirus disease-19 (COVID-19) pandemic has become a global threat since its first outbreak at the end of 2019. Several review articles have been published recently, focusing on the aspects of target biology, drug repurposing, and mechanisms of action (MOAs) for potential treatment. This review gathers all small molecules currently in active clinical trials, categorizes them into six sub-classes, and summarizes their clinical progress. The aim is to provide the researchers from both pharmaceutical industries and academic institutes with the handful information and dataset to accelerate their research programs in searching effective small molecule therapy for treatment of COVID-19.

Recent Advances in Synergistic Antitumor Effects Exploited from the Inhibition of Ataxia Telangiectasia and RAD3-Related Protein Kinase (ATR).

As one of the key phosphatidylinositol 3-kinase-related kinases (PIKKs) family members, ataxia telangiectasia and RAD3-related protein kinase (ATR) is crucial in maintaining mammalian cell genomic integrity in DNA damage response (DDR) and repair pathways. Dysregulation of ATR has been found across different cancer types. In recent years, the inhibition of ATR has been proven to be effective in cancer therapy in preclinical and clinical studies. Importantly, tumor-specific alterations such as ATM loss and Cyclin E1 (CCNE1) amplification are more sensitive to ATR inhibition and are being exploited in synthetic lethality (SL) strategy. Besides SL, synergistic anticancer effects involving ATRi have been reported in an increasing number in recent years. This review focuses on the recent advances in different forms of synergistic antitumor effects, summarizes the pharmacological benefits and ongoing clinical trials behind the biological mechanism, and provides perspectives for future challenges and opportunities. The hope is to draw awareness to the community that targeting ATR should have great potential in developing effective anticancer medicines.

Metal-free regioselective C-H amination for the synthesis of pyrazole-containing 2H-indazoles.

A general and practical regioselective approach for the C-H amination of 2H-indazoles under transition-metal-free conditions was developed. A series of substrates were tested showing eminent functional group tolerance and affording the C-N functionalization products in good to excellent yields. Mechanism studies revealed that a radical process was involved in this transformation.

Structural exploration of multifunctional monoamine oxidase B inhibitors as potential drug candidates against Alzheimer's disease.

AD is one of the most typical neurodegenerative disorders that suffer many seniors worldwide. Recently, MAO inhibitors have received increasing attention not only for their roles involved in monoamine neurotransmitters metabolism and oxidative stress but also for their additional neuroprotective and neurorescue effects against AD. The curiosity in MAO inhibitors is reviving, and novel MAO-B inhibitors recently developed with ancillary activities (e.g., Aß aggregation and AChE inhibition, anti-ROS and chelating activities) have been proposed as multitarget drugs foreshadowing a positive outlook for the treatment of AD. The current review describes the recent development of the design, synthesis, and screening of multifunctional ligands based on MAO-B inhibition for AD therapy. Structure-activity relationships and rational design strategies of the synthetic or natural product derivatives (chalcones, coumarins, chromones, and homoisoflavonoids) are discussed.

N-Propargylamine-hydroxypyridinone hybrids as multitarget agents for the treatment of Alzheimer's disease.

AD is a progressive brain disorder. Because of the lack of remarkable single-target drugs against neurodegenerative disorders, the multitarget-directed ligand strategy has received attention as a promising therapeutic approach. Herein, we rationally designed twenty-nine hybrids of N-propargylamine-hydroxypyridinone. The designed hybrids possessed excellent iron-chelating activity (pFe3+ = 17.09-22.02) and potent monoamine oxidase B inhibitory effects. Various biological evaluations of the optimal compound 6b were performed step by step, including inhibition screening of monoamine oxidase (hMAO-B IC50 = 0.083 ± 0.001 µM, hMAO-A IC50 = 6.11 ± 0.08 µM; SI = 73.5), prediction of blood-brain barrier permeability and mouse behavioral research. All of these favorable results proved that the N-propargylamine-hydroxypyridinone scaffold is a promising structure for the discovery of multitargeted ligands for AD therapy.

Design, synthesis and biological evaluation of potential anti-AD hybrids with monoamine oxidase B inhibitory and iron-chelating effects.

A series of active hybrids combining 3-hydroxypyridin-4(1H)-one and coumarin pharmacophores were designed and synthesized as potential agents for the treatment of Alzheimer's disease (AD). All the compounds exhibited excellent iron-chelating activities (pFe3+ = 14.8-19.2) and showed favorable monoamine oxidase B (MAO-B) inhibitory effects compared to the reference drug Pargyline (IC50 = 86.9 nM). Among them, compound 11 g displayed the best MAO-B inhibitory activity with an IC50 value of 99.3 nM. Molecular docking analysis showed that compound 11 g could enter the entrance cavity and substrate cavity of MAO-B. Furthermore, the compound 11 g had an excellent antioxidant effect and was capable of protecting from the amyloid-ß1-42 (Aß1-42) induced PC12 cell damage. In silico tools were applied for predicting the blood-brain barrier (BBB) penetration and compound 11 g was proved to overcome the brain exposure challenge. In the mice behavioral study, compound 11 g significantly ameliorated cognitive impairment induced by Scopolamine. More importantly, compound 11 g displayed favorable pharmacokinetic profiles in a rat model. In summary, compound 11 g, with both anti-MAO-B and iron-chelating ability, was proved to be a promising potential anti-AD agent for further optimization.

Discovery of benzamide-hydroxypyridinone hybrids as potent multi-targeting agents for the treatment of Alzheimer's disease.

A novel class of benzamide-hydroxypyridinone (HPO) derivatives were innovatively designed, synthesised, and biologically evaluated as potential multitargeting candidates for the treatment of Alzheimer's disease (AD) through pharmacophores-merged approaches based on lead compounds 18d, benzyloxy phenyl analogs, and deferiprone (DFP). These hybrids possessed potent Monoamine oxidase B (MAO-B) inhibition as well as excellent iron chelation, with pFe3+ values ranging from 18.13 to 19.39. Among all the compounds, 8g exhibited the most potent selective MAO-B inhibitor (IC50 = 68.4 nM, SI = 213). Moreover, 8g showed favourable pharmacokinetic properties and had great potential to penetrate the BBB in silico and PAMPA-BBB assay. Molecular modelling showed that 8g could adopt an extended conformation and have more enhanced interactions with MAO-B than 18d. In vitro and in vivo assays demonstrated that 8g remarkably resisted Aß-induced oxidation and ameliorated cognitive impairment induced by scopolamine. Taken collectively, these results suggest that compound 8g is a potential multifunctional candidate for anti-AD treatment.

Anti-Tumor Drug Discovery Based on Natural Product ß-Elemene: Anti-Tumor Mechanisms and Structural Modification.

Natural products are important sources for drug discovery, especially anti-tumor drugs. ß-Elemene, the prominent active ingredient extract from the rhizome of Curcuma wenyujin, is a representative natural product with broad anti-tumor activities. The main molecular mechanism of ß-elemene is to inhibit tumor growth and proliferation, induce apoptosis, inhibit tumor cell invasion and metastasis, enhance the sensitivity of chemoradiotherapy, regulate the immune system, and reverse multidrug resistance (MDR). Elemene oral emulsion and elemene injection were approved by the China Food and Drug Administration (CFDA) for the treatment of various cancers and bone metastasis in 1994. However, the lipophilicity and low bioavailability limit its application. To discover better ß-elemene-derived anti-tumor drugs with satisfying drug-like properties, researchers have modified its structure under the premise of not damaging the basic scaffold structure. In this review, we comprehensively discuss and summarize the potential anti-tumor mechanisms and the progress of structural modifications of ß-elemene.

Rational design, synthesis and biological evaluation of novel multitargeting anti-AD iron chelators with potent MAO-B inhibitory and antioxidant activity.

A series of (3-hydroxypyridin-4-one)-coumarin hybrids were developed and investigated as potential multitargeting candidates for the treatment of Alzheimer's disease (AD) through the incorporation of iron-chelating and monoamine oxidase B (MAO-B) inhibition. This combination endowed the hybrids with good capacity to inhibit MAO-B as well as excellent iron-chelating effects. The pFe3+ values of the compounds were ranging from 16.91 to 20.16, comparable to more potent than the reference drug deferiprone (DFP). Among them, compound 18d exhibited the most promising activity against MAO-B, with an IC50 value of 87.9 nM. Moreover, compound 18d exerted favorable antioxidant activity, significantly reversed the amyloid-ß1-42 (Aß1-42) induced PC12 cell damage. More importantly, 18d remarkably ameliorated the cognitive dysfunction in a scopolamine-induced mice AD model. In brief, a series of hybrids with potential anti-AD effect were successfully obtained, indicating that the design of iron chelators with MAO-B inhibitory and antioxidant activities is an attractive strategy against AD progression.