Medicinal chemistry of anthranilic acid derivatives: A mini review

Antifungal and Antibiofilm Activities of 2-Aminobenzoic Acid Derivatives Against a Clinical Ocular Candida albicans Isolate for Biomedical Applications

Ocular fungal infections are slow-progressing conditions that primarily affect the cornea but can also involve the entire eyeball. Candida albicans is one of the most involved species. Both diagnosing and treating these infections require prompt and effective action. However, the currently available treatment options mainly rely on azoles and polyenes, which are known for their poor penetration into ocular tissue and associated toxicity. Moreover, conventional antifungals are usually ineffective when tested against biofilm-associated infections, mainly due to the metabolically inactive state of dormant cells embedded in the extracellular biofilm matrix. Here, analysis of the in vitro antifungal activity of four 2-aminobenzoic acid derivatives synthesized using a green method and their combination with Fluconazole (FLC) showed efficacy against the FLC-resistant clinical isolate of C. albicans under both planktonic and biofilm formation conditions. Results showed that compounds 1 and 2 exhibited the best antifungal activity in the checkerboard association test, presenting a synergistic effect towards antifungal action. The downregulation of HWP, ERG11, and ASL3 genes during biofilm inhibition suggested a reduced capacity of the four compounds for hyphal growth and adhesion, as well as a decrease in pathogenicity due to the downregulation of some SAP genes. In vitro and in vivo toxicity profiles indicated that these compounds exhibited low toxicity, as well as the absence of genotoxic effects. Therefore, green-synthetized 2-aminobenzoic acid derivatives may have potential as antifungal agents for the inhibition of C. albicans growth and biofilm formation.

Design, Synthesis, and Biological Evaluation of New Ureido (Thioureido) Anthranilic Acid Isosteres: Molecular Docking, In Silico ADMET Predictions, and In Vivo Anti-Inflammatory Activity

A novel series of anthranilic acid isosteres were designed and synthesized as antiinflammatory agents. The in silico absorption, distribution, metabolism, excretion, and toxicity (ADMET) study predicted a favorable pharmacokinetic profile and respect for Lipinski's rule of five. Density functional theory (DFT) calculations revealed an improvement in some target compounds' electronic parameters compared to diclofenac (DCF) and aspirin (ASA), predicting an improvement in their biological activity. Docking investigations demonstrated a strong affinity toward the cyclooxygenase (COX)-1 and COX-2 enzymes, with a relative preference for COX-2, predicting antiinflammatory activity. The MolDock scores were between -140.59 and -91.81 kcal/mol for COX-1 and between -148.10 and -108.9 kcal/mol for COX-2. The experimental pharmacological investigation confirmed these theoretical findings. Indeed, target compounds demonstrated a significant inhibition of the carrageenan-induced paw edema in rats and probable inhibition of COX. Particularly, compounds 4e and 4h devoid of COOH group, which provoke serious gastrointestinal irritation, exhibited antiinflammatory activity comparable to that of salicylic acid (ASA) and surpassed the effectiveness of DCF. Cpmpounds 4e and 4h showed 91.72% inhibition after 3h, against 91.03% and 83.44% for ASA and DCF, respectively, with a greater onset effect, and also surpassing the reference compounds after 1 and 2 h. The results also indicate good pharmacokinetic profile of the target compounds similar to ASA and DCF.

Metabolomic analysis of the intrinsic resistance mechanisms of Microtus fortis against Schistosoma japonicum infection

Microtus fortis (M. fortis) is the only mammal known in China that is intrinsically resistant to Schistosoma japonicum (S. japonicum) infection. Nevertheless, the underlying resistance mechanism of M. fortis against schistosomes are still unclear. In this study, we detected and compared colon aqueous extracts and serum metabolic profiles between M. fortis and ICR mice before and after S. japonicum infection using liquid chromatography-mass spectrometry (LC-MS). We identified 232 specific colon aqueous extract metabolites and 79 specific serum metabolites of M. fortis infected with or without S. japonicum at two weeks compared with those of ICR mice, which might be closely correlated with the time-course of schistosomiasis progression and could also be used as indicators for the M. fortis against S. japonicum, for example, nonadecanoic acid, hesperetin, glycocholic acid, 2-Aminobenzoic acid, 6-hydroxydaidzein and spermidine. And the enriched pathways were further identified, our findings revealed that S. japonicum infection induced the metabolic changes involved in a variety of metabolic pathways including amino acid metabolism, lipid metabolism, ABC transporters, central carbon metabolism in cancer and bile secretion. These results indicated that the colon aqueous extracts and serum metabolic profiles were significantly different between M. fortis and ICR mice before and after S. japonicum infection and will provide new insights into the underlying resistance mechanism of M. fortis against S. japonicum infection and identify promising candidates for the use of drugs against schistosomes.

Tear Fluid-Based Metabolomics Profiling in Chronic Dacryocystitis Patients

Chronic dacryocystitis (CD) can result in severe complications and vision impairment due to ongoing microbial infections and persistent tearing. Tear fluid, which contains essential components vital for maintaining ocular surface health, has been investigated for its potential in the noninvasive identification of ocular biomarkers through metabolomics analysis. In this study, we employed UHPLC-MS/MS to analyze the tear metabolome of CD patients. UHPLC-MS/MS analysis of tear samples from CD patients revealed significant metabolic alterations. Compared with the control group, 298 metabolites were elevated, while 142 were decreased. KEGG pathway analysis suggested that these changes primarily affected arginine and proline metabolism, biosynthesis of amino acids, and phenylalanine biosynthesis in CD. Notably, 3-dehydroquinic acid, anthranilic acid, citric acid, and l-isoleucine emerged as potential biomarker candidates of CD with high diagnostic accuracy (AUC = 0.94). These findings suggest that tear fluid metabolism, particularly amino acid biosynthesis, plays a significant role in the pathogenesis of CD. Uncovering these metabolic products and pathways provides valuable insights into the mechanisms underlying CD and paves the way for the development of diagnostic tools and targeted therapies.

Metabolomic profiling of saliva from cystic fibrosis patients

The development of targeted therapies that correct the effect of mutations in patients with cystic fibrosis (CF) and the relevant heterogeneity of the clinical expression of the disease require biomarkers correlated to the severity of the disease useful for monitoring the therapeutic effects. We applied a targeted metabolomic approach by LC-MS/MS on saliva samples from 70 adult CF patients and 63 age/sex-matched controls to investigate alterations in metabolic pathways related to pancreatic insufficiency (PI), Pseudomonas aeruginosa (PA) colonization, CF liver disease (CFLD), and CF related diabetes (CFRD). Sixty salivary metabolites were differentially expressed, with 11 being less abundant and 49 more abundant in CF patients. Among these, the most relevant alterations involved salivary ADMA, N-acetylornithine, methionine and methionine sulfoxide levels. Furthermore, methionine was significantly lower in CF patients with PI and salivary histamine levels were significantly lower in patients colonized by PA. Moreover, ADMA as well as N-acetylornithine and methionine were significantly lower in CF patients with CFRD than in patients without CFRD. Finally, the levels of DOPA resulted significantly lower in saliva from patients with liver disease. Our study revealed an imbalance in arginine methylation and tryptophan pathway related to CFRD and PI as well as alterations in dopaminergic pathway and Krebs cycle related to CFLD. This study also highlights different salivary metabolites as new potential biomarkers in a non-invasive sample that could represent a useful tool for the stratification and management of CF patients.

Synthesis and biological evaluation of lappaconitine analogues as potential anti-neuroinflammatory agents by side chain modification and scaffold hopping strategy

Neuroinflammation mediated by microglia is widely recognized as a key pathophysiological mechanism in neurodegenerative diseases. Lappaconitine (LA) is a natural C18-diterpenoid alkaloid isolated from Aconitum sinomontanum Nakai, and previous study showed that LA and its derivatives inhibited lipopolysaccharide (LPS)-induced nitric oxide (NO) production in RAW264.7 cells. However, the anti-neuroinflammatory effects of LA and its derivatives on microglia are still not clear. Here, LA analogues were designed and synthesized, and the anti-neuroinflammatory activity of the synthesized compounds was screened using LPS-induced overexpression of NO in BV-2 microglia. The screening results showed that compound 10 displayed the highest ability to inhibit NO production (IC50 = 9.98 ± 1.6 µM). Mechanistic investigations revealed that compound 10 attenuated LPS-activated neuroinflammation through suppression of TLR4/MyD88/NF-κB pathway in BV-2 microglia. Acute toxicity assays showed that compound 10 (LD50 = 508.1 mg/kg) was safer relative to LA (LD50 = 30.6 mg/kg). Collectively, our findings show that compound 10 could have potential as anti-neuroinflammatory agents.

Fenamates: Forgotten treasure for cancer treatment and prevention: Mechanisms of action, structural modification, and bright future

Fenamates as classical nonsteroidal anti-inflammatory agents are widely used for relieving pain. Preclinical studies and epidemiological data highlight their chemo-preventive and chemotherapeutic potential for cancer. However, comprehensive reviews of fenamates in cancer are limited. To accelerate the repurposing of fenamates, this review summarizes the results of fenamates alone or in combination with existing chemotherapeutic agents. This paper also explores targets of fenamates in cancer therapy, including COX, AKR family, AR, gap junction, FTO, TEAD, DHODH, TAS2R14, ion channels, and DNA. Besides, this paper discusses other mechanisms, such as regulating Wnt/β-catenin, TGF-β, p38 MAPK, and NF-κB pathway, and the regulation of the expressions of Sp, EGR-1, NAG-1, ATF-3, ErbB2, AR, as well as the modulation of the tumor immune microenvironment. Furthermore, this paper outlined the structural modifications of fenamates, highlighting their potential as promising leads for anticancer drugs.

Photoinduced Regioselective Decarbonylative and Decarboxylative C-O Bond Functionalizations: Approach toward Chemoselective Scissions of Isatoic Anhydride and Unraveling the Enroutes through Control Experiments and DFT Studies

Distinctive, green, innovative, and well-organized photoinduced (metal- or photocatalyst-free) regioselective decarbonylative and decarboxylative C-O bond functionalization protocols to access aryl 2-aminobenzoates and 2-substituted benzoxazinone derivatives in excellent yields have been devised. These are achieved through the chemoselective scission of isatoic anhydride with ketones, diaryliodonium triflate, nitroalkene, phthalazinone, and phenol derivatives, which, in turn, served as the representative "electrophilic and nucleophilic" coupling partners. Control experiments and DFT calculations reveal that electrophilic radical-bearing coupling partners specifically follow the decarbonylation pathway, while nucleophilic radical-bearing conjugates facilitate the decarboxylation process. Thus, the devised methods represent the chemoselective fragmentation of isatoic anhydride, which occurs due to the electronic nature of the coupling partners. Again, the regioselective C-O/O-C bond formation is also a novel outcome of this methodology. We have also devised a green method for synthesizing 2-aminobenzoate-subtituted paracetamol through a decarboxylation route. A fluorescence quenching study indicates that phenyl 2-aminobenzoate specifically detects Fe(II) ions, exhibiting no reactivity toward various other metal ions. Additionally, transition-metal-catalyzed C-H bond functionalization of 2-substituted benzoxazinone with phenyl vinyl sulfone was performed at ease with significant yields, which appreciated the strategy developed by us.

Unraveling Cross-Organ Impacts of Airborne Pollutants: A Multiomics Study on Respiratory Exposure and Gastrointestinal Health

Poor air quality is increasingly linked to gastrointestinal diseases, suggesting a potential correlation with human intestine health. However, this relationship remains largely unexplored due to limited research. This study used a controlled mouse model exposed to cooking oil fumes (COFs) and metagenomics, transcriptomics, and metabolomics to elucidate interactions between intestine microbiota and host metabolism under environmental stress. Our findings reveal that short-term COF inhalation induces pulmonary inflammation within 3 days and leads to gastrointestinal disturbances, elucidating a pathway connecting respiratory exposure to intestinal dysfunction. The exposure intensity significantly correlates with changes in intestinal tissue integrity, microbial composition, and metabolic function. Extended exposure of 7 days disrupts intestine microbiota and alters tryptophan metabolism, with further changes observed after 14 days, highlighting an adaptive response. These results highlight the vulnerability of intestinal health to airborne pollutants and suggest a pathway through which inhaled pollutants may affect distant organ systems.

Redetermined structure of 4-(benz-yloxy)benzoic acid

In the title compound, C14H14O3, the dihedral angle between the aromatic rings is 39.76 (9)°. In the crystal, the mol-ecules associate to form centrosymmetric acid-acid dimers linked by pairwise O-H⋯O hydrogen bonds. The precision of the geometric parameters in the present single-crystal study is about an order of magnitude better than the previous powder diffraction study [Chattopadhyay et al. (2013 ▸). CrystEngComm, 15, 1077-1085].

Inhibitory Potential of Bifidobacterium longum FB1-1 Cell-Free Supernatant against Carbapenem-Resistant Klebsiella pneumoniae Drug Resistance Spread

The widespread dissemination of carbapenem-resistant Klebsiella pneumoniae (CRKP) and its drug resistance transfer poses a global public health threat. While previous studies outlined CRKP's drug resistance mechanism, there is limited research on strategies inhibiting CRKP drug resistance spread. This study investigates the potential of Bifidobacterium longum (B. longum) FB1-1, a probiotic, in curbing the spread of drug resistance among CRKP by evaluating its cell-free supernatant (CFS) for antibacterial activity. Evaluating the inhibitory effect of FB1-1 CFS on CRKP drug resistance spread involved analyzing its impact on drug resistance and virulence gene expression; drug resistance plasmid transfer FB1-1 CFS exhibited an MIC range of 125 μL/mL against CRKP. After eight hours of co-culture, CFS achieved a 96% and 100% sterilization rate at two and four times the MIC, respectively. At sub-inhibitory concentrations (1/2× MIC), FB1-1 CFS reduced the expression of the bla_KPC gene, which is pivotal for carbapenem resistance, by up to 62.13% across different CRKP strains. Additionally, it markedly suppressed the expression of the uge gene, a key virulence factor, by up to 91%, and the fim_H gene, essential for bacterial adhesion, by up to 53.4%. Our study primarily focuses on determining the inhibitory effect of FB1-1 CFS on CRKP strains harboring the bla_KPC gene, which is a critical resistance determinant in CRKP. Furthermore, FB1-1 CFS demonstrated the ability to inhibit the transfer of drug resistance plasmids among CRKP strains, thus limiting the horizontal spread of resistance genes. This study highlights FB1-1 CFS's inhibitory effect on CRKP drug resistance spread, particularly in strains carrying the bla_KPC gene, thus offering a novel idea and theoretical foundation for developing antibacterial drugs targeting CRKP resistance.

Characterization of anthranilic acid produced by Virgibacillus salarius MML1918 and its bio-imaging application

Anthranilic acid (AA) holds significant importance in the chemical industry. It serves as a crucial building block for the amino acid tryptophan by manipulating the tryptophan biosynthesis pathway, it is possible to increase the production of anthranilic acid. In this study, we utilized metabolic engineering approaches to produce anthranilic acid from the halophilic bacterium Virgibacillus salarius MML1918. The halophilic bacteria were grown in an optimized production medium, and mass production of secondary metabolites was made in ATCC medium 1097 Proteose peptone-for halophilic bacteria and subjected to column chromatography followed by sub-column chromatography the single band for the purified compound was confirmed. Further, various spectral analyses were made for the partially purified compounds, and fluorescence microscopy for fungal cell observation was performed. The purified compound was confirmed by single crystal X-ray diffraction (XRD) analysis, and it was identified as 2-amino benzoic acid. The Fourier transform infrared Spectroscopy (FT-IR) spectrum and nuclear magnetic resonance (NMR) spectrum also confirm the structural characteristic of 2-amino benzoic acid. The UV-Vis absorption spectrum of AA shows the maximum absorption at 337.86 nm. The emission spectrum of 2-amino benzoic acid showed the maximum emission at 453 nm. The bio-imaging application of 2-amino benzoic acid was examined with fungal mycelium of Rhizoctonia solani. It was effectively bound and emitted the blue color at the concentration of 200 and 300 µg/mL. The halophilic bacterium (V. salarius), may have unique metabolic pathways and requirements compared to non-halophilic organisms, to produce AA effectively. This could have implications for industrial biotechnology, particularly in manufacturing environments where high salt concentrations are present and also it can be used as bio-imaging agent.

The contemplation of amylose for the delivery of ulcerogenic nonsteroidal anti-inflammatory drugs

This manuscript proposes an innovative approach to mitigate the gastrointestinal adversities linked with nonsteroidal anti-inflammatory drugs (NSAIDs) by exploiting amylose as a novel drug delivery carrier. The intrinsic attributes of V-amylose, such as its structural uniqueness, biocompatibility and biodegradability, as well as its capacity to form inclusion complexes with diverse drug molecules, are meticulously explored. Through a comprehensive physicochemical analysis of V-amylose and ulcerogenic NSAIDs, the plausibility of amylose as a protective carrier for ulcerogenic NSAIDs to gastrointestinal regions is elucidated. This review further discusses the potential therapeutic advantages of amylose-based drug delivery systems in the management of gastric ulcers. By providing controlled release kinetics and enhanced bioavailability, these systems offer promising prospects for the development of more effective ulcer therapies.

Protective effects of hepatic diseases by bioactive phytochemicals in Fusarium oxysporum - A review

Lately, liver diseases were categorized as one of the most prevalent health problems globally as it causes a severe threat to mankind all over the world due to the wide range of occurrence. There are multiple factors causing hepatic disorders, such as alcohol, virus, poisons, adverse effects of drugs, poor diet, inherited conditions and obesity. Liver diseases have various types including alcoholic liver disease, non-alcoholic fatty liver disease, autoimmune hepatitis, liver cancer, hepatocellular carcinoma, liver fibrosis and hepatic inflammation. Therefore, it is imperative to find effective and efficacious agents in managing liver diseases. Fusarium oxysporum, an endophytic fungus and containing many bioactive compounds, could be served as a forked medication for enormous number and types of maladies. It was characterized by producing biochemical compounds which had rare pharmacological properties as it may be found in a limit number of other medicinal plants. The majority of the past researches related to Fusarium oxysporum recited the fungal negative field either on the pathogenic effects of the fungus on economical crops or on the fungal chemical components to know how to resist it. The present review will highlight on the bright side of Fusarium oxysporum and introduce the functional activities of its chemical compounds for treating its target diseases. The key point of illustrated studies in this article is displaying wide range of detected bioactive compounds isolated from Fusarium oxysporum and in other illustrated studies it was elucidated the therapeutical and pharmacological potency of these biologically active compounds (isolated from medicinal plants sources) against different types of liver diseases including non-alcoholic fatty liver disease, alcoholic liver disease, cirrhosis and others. It was demonstrated that F. oxysporum contains unique types of isoflavones, flavonoids, phenols and another active chemical compounds, and these compounds showed recently a fabulous clinical contribution in the therapy of liver injury diseases, which opens new and unprecedented way for evaluating the maintaining efficacy of Fusarium oxysporum bioactive compounds in dealing with hepatic complications and its remedy impacting on liver diseases and injured hepatocytes through recommending implement a practical study.

"Fluorine Effects" in Conformational Orchestration of α/β Hybrid Peptide with a 9-membered Pseudo β-Turn Motif

Fluorine, the tiny robust atom, with its unique features has captured the attention of scientists in recent times, especially in drug discovery with its integration in small molecules, peptides, and proteins. However, studies to understand the 'fluorine effects' on the conformation of molecules that follow 'beyond the rule of 5' are in the infancy yet significant in molecular design and function. For the first time, using short hybrid peptide sequence as an appropriate model, we examined the substitution effect (size, stereoelectronic effect, and hydrogen bonding) using X-ray diffraction, 2D-NMR, and CD studies. The comparative study on their folding patterns with hydrogen-substituted analogs can provide valuable insights into fluorinated substrates' design.

Regulation of calcium entry by cyclic GMP signaling in Toxoplasma gondii

Ca2+ signaling impacts almost every aspect of cellular life. Ca2+ signals are generated through the opening of ion channels that permit the flow of Ca2+ down an electrochemical gradient. Cytosolic Ca2+ fluctuations can be generated through Ca2+ entry from the extracellular milieu or release from intracellular stores. In Toxoplasma gondii, Ca2+ ions play critical roles in several essential functions for the parasite, like invasion of host cells, motility, and egress. Plasma membrane Ca2+ entry in T. gondii was previously shown to be activated by cytosolic calcium and inhibited by the voltage-operated Ca2+ channel blocker nifedipine. However, Ca2+ entry in T. gondii did not show the classical characteristics of store regulation. In this work, we characterized the mechanism by which cytosolic Ca2+ regulates plasma membrane Ca2+ entry in extracellular T. gondii tachyzoites loaded with the Ca2+ indicator Fura-2. We compared the inhibition by nifedipine with the effect of the broad spectrum TRP channel inhibitor, anthranilic acid or ACA, and we find that both inhibitors act on different Ca2+ entry activities. We demonstrate, using pharmacological and genetic tools, that an intracellular signaling pathway engaging cyclic GMP, protein kinase G, Ca2+, and the phosphatidyl inositol phospholipase C affects Ca2+ entry and we present a model for crosstalk between cyclic GMP and cytosolic Ca2+ for the activation of T. gondii's lytic cycle traits.

A condition-tuned unorthodox approach to indole-3-carboxylic acids and anthranilic acids via carbon atom translocation

We describe a robust one-pot cascade method for the synthesis of indole-3-carboxylic acids using isatins and DMSO via a one-carbon translocation involving in situ generation of α,β-unsaturated methylvinylsulfoxide followed by amide bond cleavage and ring closure. The methodology has been extended to afford anthranilic acid derivatives by tuning the reaction conditions in the presence of molecular oxygen. Importantly, easy access to commercially available drugs, including tropisetron, is demonstrated.

Ortho-Selective amination of arene carboxylic acids via rearrangement of acyl O-hydroxylamines

Direct amination of arene C-H bonds is an attractive disconnection to form aniline-derived building blocks. This transformation presents significant practical challenges; classical methods for ortho-selective amination require strongly acidic or forcing conditions, while contemporary catalytic processes often require bespoke directing groups and/or precious metal catalysis. We report a mild and procedurally straightforward ortho-selective amination of arene carboxylic acids, arising from a facile rearrangement of acyl O-hydroxylamines without requiring precious metal catalysts. A broad scope of benzoic acid substrates are compatible and the reaction can be applied to longer chain arene carboxylic acids. Mechanistic studies probe the specific requirement for trifluoroacetic acid in generating the active aminating agent, and suggest that two separate mechanisms may be operating in parallel in the presence of an iron catalyst: (i) an iron-nitrenoid intermediate and (ii) a radical chain pathway. Regardless of which mechanism is followed, high ortho selectivity is obtained, proposed to arise from the directivity (first) or attractive interactions (second) arising with the carboxylic acid motif.

Sequential analysis for identification of byproduct from N-benzylation reaction: wound healing and anti-inflammatory potential of the byproduct 4-chlorobenzyl 2-((4-chlorobenzyl)amino)benzoate

A very common reaction, N-benzylation of isatoic anhydride in the presence of sodium hydride base, produces byproducts. The yield of one of the byproducts was greater than that of the desired product; therefore, we identified the anonymous undisclosed structure of the byproduct using sequential spectroscopy methods and SC-XRD. This byproduct was found to be effective as a wound-healing and anti-inflammatory agent. The 10% formulation of byproduct and standard (nitrofurazone) showed complete wound closure with a large number of cell migrations within 16 days. Hydroxyproline contents of 5% and 10% formulations were found to be slightly increased as compared with that of the standard. The byproduct also had anti-inflammatory potential. It was effective in inhibiting COX-2, heat-induced albumin denaturation, and formalin-induced paw edema.

Microbial-Derived Tryptophan Metabolites and Their Role in Neurological Disease: Anthranilic Acid and Anthranilic Acid Derivatives

The gut microbiome provides the host access to otherwise indigestible nutrients, which are often further metabolized by the microbiome into bioactive components. The gut microbiome can also shift the balance of host-produced compounds, which may alter host health. One precursor to bioactive metabolites is the essential aromatic amino acid tryptophan. Tryptophan is mostly shunted into the kynurenine pathway but is also the primary metabolite for serotonin production and the bacterial indole pathway. Balance between tryptophan-derived bioactive metabolites is crucial for neurological homeostasis and metabolic imbalance can trigger or exacerbate neurological diseases. Alzheimer's, depression, and schizophrenia have been linked to diverging levels of tryptophan-derived anthranilic, kynurenic, and quinolinic acid. Anthranilic acid from collective microbiome metabolism plays a complex but important role in systemic host health. Although anthranilic acid and its metabolic products are of great importance for host-microbe interaction in neurological health, literature examining the mechanistic relationships between microbial production, host regulation, and neurological diseases is scarce and at times conflicting. This narrative review provides an overview of the current understanding of anthranilic acid's role in neurological health and disease, with particular focus on the contribution of the gut microbiome, the gut-brain axis, and the involvement of the three major tryptophan pathways.

Avenanthramides, Distinctive Hydroxycinnamoyl Conjugates of Oat, Avena sativa L.: An Update on the Biosynthesis, Chemistry, and Bioactivities

Avenanthramides are a group of N-cinnamoylanthranilic acids (phenolic alkaloid compounds) that are produced in oat plants as phytoalexins, in response to pathogen attack and elicitation. The enzyme catalysing the cinnamamide-generating reaction is hydroxycinnamoyl-CoA: hydroxyanthranilate N-hydroxycinnamoyltransferase (HHT, a member of the super family of BAHD acyltransferases). HHT from oat appears to have a narrow range of substrate usage, with preferred use of 5-hydroxyanthranilic acid (and to a lesser extent, other hydroxylated and methoxylated derivatives) as acceptor molecules, but is able to use both substituted cinnamoyl-CoA and avenalumoyl-CoA thioesters as donor molecules. Avenanthramides thus combine carbon skeletons from both the stress-inducible shikimic acid and phenylpropanoid pathways. These features contribute to the chemical characteristics of avenanthramides as multifunctional plant defence compounds, as antimicrobial agents and anti-oxidants. Although avenanthramides are naturally and uniquely synthesised in oat plants, these molecules also exhibit medicinal and pharmaceutical uses important for human health, prompting research into utilisation of biotechnology to enhance agriculture and value-added production.

Pd-Catalyzed Aryl C-H Amination with Diaziridinone

This work describes an efficient Pd-catalyzed ortho-C-H amination of N-(quinolin-8-yl)benzamides with di-t-butyldiaziridinone, providing a variety of anthranilic amides in good yields. The reaction likely involves the formation of a pallada(II)heterocycle via aryl C-H activation and subsequent amination with di-t-butyldiaziridinone.

Structural and Biological Properties of Heteroligand Copper Complexes with Diethylnicotinamide and Various Fenamates: Preparation, Structure, Spectral Properties and Hirshfeld Surface Analysis

Herein, we discuss the synthesis, structural and spectroscopic characterization, and biological activity of five heteroligand copper(II) complexes with diethylnicotinamide and various fenamates, as follows: flufenamate (fluf), niflumate (nifl), tolfenamate (tolf), clonixinate (clon), mefenamate (mef) and N, N-diethylnicotinamide (dena). The complexes of composition: [Cu(fluf)2(dena)2(H2O)2] (1), [Cu(nifl)2(dena)2] (2), [Cu(tolf)2(dena)2(H2O)2] (3), [Cu(clon)2(dena)2] (4) and [Cu(mef)2(dena)2(H2O)2] (5), were synthesized, structurally (single-crystal X-ray diffraction) and spectroscopically characterized (IR, EA, UV-Vis and EPR). The studied complexes are monomeric, forming a distorted tetragonal bipyramidal stereochemistry around the central copper ion. The crystal structures of all five complexes were determined and refined with an aspheric model using the Hirshfeld atom refinement method. Hirshfeld surface analysis and fingerprint plots were used to investigate the intermolecular interactions in the crystalline state. The redox properties of the complexes were studied and evaluated via cyclic voltammetry. The complexes exhibited good superoxide scavenging activity as determined by an NBT assay along with a copper-based redox-cycling mechanism, resulting in the formation of ROS, which, in turn, predisposed the studied complexes for their anticancer activity. The ability of complexes 1–4 to interact with calf thymus DNA was investigated using absorption titrations, viscosity measurements and an ethidium-bromide-displacement-fluorescence-based method, suggesting mainly the intercalative binding of the complexes to DNA. The affinity of complexes 1–4 for bovine serum albumin was determined via fluorescence emission spectroscopy and was quantitatively characterized with the corresponding binding constants. The cytotoxic properties of complexes 1–4 were studied using the cancer cell lines A549, MCF-7 and U-118MG, as well as healthy MRC-5 cells. Complex 4 exhibited moderate anticancer activity on the MCF-7 cancer cells with IC50 = 57 μM.

PPARs and the Kynurenine Pathway in Melanoma-Potential Biological Interactions

Peroxisome proliferator-activated receptors (PPARs) are ligand-activated transcription factors involved in various physiological and pathological processes within the skin. PPARs regulate several processes in one of the most aggressive skin cancers, melanoma, including proliferation, cell cycle, metabolic homeostasis, cell death, and metastasis. In this review, we focused not only on the biological activity of PPAR isoforms in melanoma initiation, progression, and metastasis but also on potential biological interactions between the PPAR signaling and the kynurenine pathways. The kynurenine pathway is a major pathway of tryptophan metabolism leading to nicotinamide adenine dinucleotide (NAD+) production. Importantly, various tryptophan metabolites exert biological activity toward cancer cells, including melanoma. Previous studies confirmed the functional relationship between PPAR and the kynurenine pathway in skeletal muscles. Despite the fact this interaction has not been reported in melanoma to date, some bioinformatics data and biological activity of PPAR ligands and tryptophan metabolites may suggest a potential involvement of these metabolic and signaling pathways in melanoma initiation, progression, and metastasis. Importantly, the possible relationship between the PPAR signaling pathway and the kynurenine pathway may relate not only to the direct biological effect on melanoma cells but also to the tumor microenvironment and the immune system.

Synergism of Fe/Ti Enabled Regioselective Arene Difunctionalization

Regioselective difunctionalization of arenes remains a long-standing challenge in organic chemistry. We report a novel and general Fe/Ti synergistic methodology for regioselective synthesis of various polysubstituted arenes through either E/E' or Nu/E ortho difunctionalizations of arenes. Preliminary results showed that an unprecedented 1,2-Fe/Ti heterobimetallic arylene intermediate bearing two distinct C-M bonds is essential to the regioselective difunctionalization.

Anthranilic Acid Accumulation in Saccharomyces cerevisiae Induced by Expression of a Nonribosomal Peptide Synthetase Gene from Paecilomyces cinnamomeus BCC 9616

Heterologous expression of nrps33, a nonribosomal peptide synthetase gene, from Paecilomyces cinnamomeus BCC 9616 in Saccharomyces cerevisiae unexpectedly resulted in the accumulation of anthranilic acid, an intermediate in tryptophan biosynthesis. Based on transcriptomic and real-time quantitative polymerase chain reaction (RT-qPCR) results, expression of nrps33 affected the transcription of tryptophan biosynthesis genes especially TRP1 which is also the selectable auxotrophic marker for the expression vector used in this work. The product of nrps33 could inhibit the activity of Trp4 involved in the conversion of anthranilate to N-(5'-phosphoribosyl)anthranilate and therefore caused the accumulation of anthranilic acid. This accumulation could in turn result in down-regulation of downstream tryptophan biosynthesis genes. Anthranilic acid is typically produced by chemical synthesis and has been used as a substrate for synthesising bioactive compounds including commercial drugs; our results could provide a new biological platform for production of this compound.

Organoselenocyanates Tethered Methyl Anthranilate Hybrids with Promising Anticancer, Antimicrobial, and Antioxidant Activities

Novel methyl anthranilate-based organoselenocyanate hybrids were developed, and their structures were confirmed by the state-of-the-art spectroscopic techniques. Their antimicrobial potency was estimated against various microbial strains (e.g., Candida albicans, Escherichia coli, and Staphylococcus aureus). The S. aureus and C. albicans strains were more sensitive than E. coli toward the organoselenocyanates. Interestingly, the azoic derivatives 4 and 9, methyl ester 6, and phenoxy acetamide 15 showed promising antimicrobial activity. Moreover, the antitumor potential was estimated against liver and breast carcinomas, as well as primary fibroblasts. Interestingly, the anticancer properties were more pronounced in the HepG2 cells. The organoselenocyanates 4, 6, 9, 10, and 15 showed interesting anti-HepG2 cytotoxic patterns. Additionally, organoselenocyanates 3, 4, and 10 exhibited promising antioxidant activities in the 2,2′-azino-bis(3-ethylbenzothiazoline-6-sulfonic acid and 2,2-diphenyl-1-picrylhydrazyl in vitro assays compared to ascorbic acid. These data point to promising antimicrobial, anticancer, and antioxidant activities of organoselenocyanates 6, 9, and 15 warrant further studies.

Anticancer, Antimicrobial, and Antioxidant Activities of Organodiselenide-Tethered Methyl Anthranilates

Novel methyl anthranilate-based organodiselenide hybrids were synthesized, and their chemical structures were confirmed by state-of-the-art spectroscopic techniques. Their antimicrobial properties were assessed against Staphylococcus aureus, Escherichia coli, and Candida albicans microbial strains. Moreover, the antitumor potential was estimated against liver and breast carcinomas, as well as primary fibroblast cell lines. The Staphylococcus aureus and Candida albicans strains were more sensitive than Escherichia coli toward the OSe compounds. Interestingly, methyl 2-amino-5-(methylselanyl) benzoate (14) showed similar antifungal activity to the standard drug clotrimazole (IA% = 100%) and manifested promising antibacterial activity against E. coli (IA% = 91.3%) and S. aureus (IA% = 90.5%). Furthermore, the minimum inhibitory concentration experiments confirmed the antimicrobial activity of the OSe 14, which in turn was comparable to clotrimazole and ampicillin drugs. Interestingly, the anticancer properties were more pronounced in the HepG2 cells. The OSe 14 was the most cytotoxic (IC₅₀ = 3.57 ± 0.1 µM), even more than the Adriamycin drug (IC₅₀ = 4.50 ± 0.2 µM), and with therapeutic index (TI) 17 proposing its potential selectivity and safety. Additionally, OSe compounds 14 and dimethyl 5,5'-diselanediylbis(2-aminobenzoate) (5) exhibited promising antioxidants in the 2,2'-azino-bis (3-ethylbenzothiazoline-6-sulfonic acid (ABTS) and 2,2-diphenyl-1-picrylhydrazyl (DPPH) in vitro assays with 96%, 92%, 91%, and 86% radical scavenging activities compared to 95% by vitamin C in the DPPH and ABTS assays, respectively. These results point to promising antimicrobial, anticancer, and antioxidant activities of OSe 14 and 5 and warrant further studies.

Dynamic flux regulation for high-titer anthranilate production by plasmid-free, conditionally-auxotrophic strains of Pseudomonas putida

Anthranilate, an intermediate of the shikimate pathway, is a high-value aromatic compound widely used as a precursor in the production of dyes, fragrances, plastics and pharmaceuticals. Traditional strategies adopted for microbial anthranilate production rely on the implementation of auxotrophic strains-which requires aromatic amino acids or complex additives to be supplemented in the culture medium, negatively impacting production costs. In this work, we engineered the soil bacterium Pseudomonas putida for high-titer, glucose-dependent anthranilate production by repurposing elements of the Esa quorum sensing (QS) system of Pantoea stewartii. The P_esaS promoter mediated a self-regulated transcriptional response that effectively knocked-down the expression of the trpDC genes. Next, we harnessed the synthetic QS elements to engineer a growth-to-anthranilate production switch. The resulting plasmid-free P. putida strain produced the target compound at 3.8 ± 0.3 mM in shaken-flask cultures after 72 h-a titer >2-fold higher than anthranilate levels reported thus far. Our results highlight the value of dynamic flux regulation for the production of intermediate metabolites within highly-regulated routes (such as the shikimate pathway), thereby circumventing the need of expensive additives.

Synthesis of Evodileptin B, a Natural Anthranilate Derivative Isolated from Evodia lepta, and Evaluation of Its Therapeutic Potential against Parkinson's Disease

Evodileptin B (1) is a natural anthranilate derivative isolated from the ethanol extract of the aerial parts of Evodia lepta (Spreng.) Merr., a traditional medicinal plant of the family Rutaceae. We readily synthesized 1 via the amidation of phloretic with methyl anthranilate and evaluate its neuroprotective activity using a C. elegans Parkinson's disease (PD) model. The results showed that evodilpetin B ameliorated MPP⁺ -induced dopaminergic (DA) neurodegeneration in a dose-dependent manner. Evodileptin B treatment also significantly improved the DA neurotransmission-related behavioral defects such as reduced locomotory and food-sensing ability of worms under MPP⁺ exposure conditions, suggesting its potential application for the functional restoration of DA neurons. In addition, we found that 1 has an ability to regulate aggregation of α-synuclein by increasing proteasome activity in the human α-synuclein-expressing mutant worms. These results demonstrate that evodileptin B has strong neuroprotective properties and may be useful in the treatment of PD.

Mild Copper-Catalyzed, l-Proline-Promoted Cross-Coupling of Methyl 3-Amino-1-benzothiophene-2-carboxylate

Cu-catalyzed N-arylation is a useful tool for the chemical modification of aromatic heterocycles. Herein, an efficient carbon–nitrogen cross-coupling of methyl 3-amino-1-benzothiophene-2-carboxylate with a range of (hetero)aryl iodides using CuI, l-proline and Cs₂CO₃ in dioxane at moderate temperature is described. The procedure is an extremely general, relatively cheap, and experimentally simple way to afford the N-substituted products in moderate to high yields. The structures of the new heterocyclic compounds were confirmed by NMR spectroscopy and HRMS investigation.

Bright Side of Fusarium oxysporum: Secondary Metabolites Bioactivities and Industrial Relevance in Biotechnology and Nanotechnology

Fungi have been assured to be one of the wealthiest pools of bio-metabolites with remarkable potential for discovering new drugs. The pathogenic fungi, Fusarium oxysporum affects many valuable trees and crops all over the world, producing wilt. This fungus is a source of different enzymes that have variable industrial and biotechnological applications. Additionally, it is widely employed for the synthesis of different types of metal nanoparticles with various biotechnological, pharmaceutical, industrial, and medicinal applications. Moreover, it possesses a mysterious capacity to produce a wide array of metabolites with a broad spectrum of bioactivities such as alkaloids, jasmonates, anthranilates, cyclic peptides, cyclic depsipeptides, xanthones, quinones, and terpenoids. Therefore, this review will cover the previously reported data on F. oxysporum, especially its metabolites and their bioactivities, as well as industrial relevance in biotechnology and nanotechnology in the period from 1967 to 2021. In this work, 180 metabolites have been listed and 203 references have been cited.