Quinazolinone Alkaloid Research Articles

Aniquinazoline B, a Fungal Natural Product, Activates the μ-Opioid Receptor.

The development of new μ-opioid receptor (MOR) agonists without the undesirable side effects, such as addiction or respiratory depression, has been a difficult challenge over the years. In the search for new compounds, we screened our chemical database of over 40.000 substances and further assessed the best 100 through molecular docking. We selected the top 10 compounds and evaluated them for their biological activity and potential to influence cyclic adenosine monophosphate (cAMP) levels. From the tested compounds, compound 7, called aniquinazoline B, belonging to the quinazolinone alkaloids class and isolated from the marine fungus Aspergillus nidulans, showed promising results, by inhibiting cAMP levels and in vitro binding to MOR, verified through microscale thermophoresis. Transcriptomic data investigation profiled the genes affected by compound 7 and discovered activation of different pathways compared to opioids. The western blot analysis revealed compound 7 as a balanced ligand, activating both p-ERK1/2 and β-arrestin1/2 pathways, showing this is a favorable candidate to be further tested.

A New Quinazolinone Alkaloid along with Known Compounds with Seed-Germination-Promoting Activity from Rhodiola tibetica Endophytic Fungus Penicillium sp. HJT-A-6.

A new quinazolinone alkaloid named peniquinazolinone A (1), as well as eleven known compounds, 2-(2-hydroxy-3-phenylpropionamido)-N-methylbenzamide (2), viridicatin (3), viridicatol (4), (±)-cyclopeptin (5a/5b), dehydrocyclopeptin (6), cyclopenin (7), cyclopenol (8), methyl-indole-3-carboxylate (9), 2,5-dihydroxyphenyl acetate (10), methyl m-hydroxyphenylacetate (11), and conidiogenone B (12), were isolated from the endophytic Penicillium sp. HJT-A-6. The chemical structures of all the compounds were elucidated by comprehensive spectroscopic analysis, including 1D and 2D NMR and HRESIMS. The absolute configuration at C-13 of peniquinazolinone A (1) was established by applying the modified Mosher's method. Compounds 2, 3, and 7 exhibited an optimal promoting effect on the seed germination of Rhodiola tibetica at a concentration of 0.01 mg/mL, while the optimal concentration for compounds 4 and 9 to promote Rhodiola tibetica seed germination was 0.001 mg/mL. Compound 12 showed optimal seed-germination-promoting activity at a concentration of 0.1 mg/mL. Compared with the positive drug 6-benzyladenine (6-BA), compounds 2, 3, 4, 7, 9, and 12 could extend the seed germination period of Rhodiola tibetica up to the 11th day.

Nickel‐Catalyzed Intramolecular Dual Annulation Reaction of Alkyl Nitrile‐Containing 1,2,3‐Benzotriazin‐4(3H)‐ones: A Pathway to Access Diversely Polycyclic Quinazolinone Alkaloids

AbstractHerein, we report a nickel‐catalyzed intramolecular dual annulation reaction of alkyl nitrile‐containing 1,2,3‐benzotriazin‐4(3H)‐ones to synthesize polycyclic quinazolinones. This catalytic reaction can construct the core structure of polycyclic quinazolinone alkaloids; therefore, we also apply this reaction as the critical step to access fifteen relevant alkaloids to demonstrate efficacy.

Alkaloid chemistry in pill-millipedes: Defensive secretion in two species of Typhloglomeris Verhoeff, 1898 (Diplopoda, Glomerida, Glomeridellidae)

AbstractMillipedes of the order Glomerida are known to produce quinazolinone alkaloids as defensive substances. However, chemical data are rather scarce and all hitherto available publications refer to a single glomeridan family, the Glomeridae. To contribute to the knowledge of the chemical ecology of glomeridans, we collected species, Typhloglomeris coeca Verhoeff, 1898 and T. varunae Makarov, Lučić, Tomić & Karaman, 2003, from a second family – Glomeridellidae. The defensive exudates were extracted in methylene chloride and analyzed by gas chromatography-mass spectrometry. Our results show that the secretions of the two glomeridellids contain the quinazolinone alkaloid homoglomerin (2-ethyl-1-methylquinazolin-4(1H)-one) as the sole defensive constituent. This report provides initial data on the chemoprofiles of members of the family Glomeridellidae and supports the phenomenon of chemical homogeneity of glomeridan defensive secretions. So far, all analyzed representatives of the order possess glomerin and/or homoglomerin as defensive equipment. The phylogenetic origin of alkaloidal compounds in the secretions of millipedes in general, and particularly the origin of quinazolinone alkaloids in Glomerida is discussed. Considering that the quinazolinone alkaloid defensive secretions may be the same (or very similar) in other Glomerida, our results have important implication for further studies of defensive secretions in these arthropods. Also, as data are available only for a limited number of glomeridan and colobognathan species, additional analyses are necessary to elucidate the evolution of alkaloid defensive secretion in Diplopoda.

Synthesis of Thiazole-fused Tricyclic Quinazolinone Alkaloids and Their Derivatives

AbstractThe synthesis of thiazole-fused derivatives of tricyclic quinazolinones hitherto undescribed was successfully achieved by replacing anthranilic acid or its derivatives by isomeric polyfunctionalized benzothiazole analogues of anthranilic methyl esters. Some of the new heterocyclic systems are inspired by natural alkaloids such as mackinazolinone, deoxyvasicinone, and isaindigotone, showing interesting biological properties. The microwave-assisted method developed is a variant of the Niementowski reaction and was also applied to the synthesis of ring-extended rutaecarpine derivatives.

New Anti-Hypoxic Metabolites from Co-Culture of Marine-Derived Fungi Aspergillus carneus KMM 4638 and Amphichorda sp. KMM 4639.

The KMM 4639 strain was identified as Amphichorda sp. based on two molecular genetic markers: ITS and β-tubulin regions. Chemical investigation of co-culture marine-derived fungi Amphichorda sp. KMM 4639 and Aspergillus carneus KMM 4638 led to the identification of five new quinazolinone alkaloids felicarnezolines A-E (1-5), a new highly oxygenated chromene derivative oxirapentyn M (6) and five previously reported related compounds. Their structures were established using spectroscopic methods and by comparison with related known compounds. The isolated compounds showed low cytotoxicity against human prostate and breast cancer cells but felicarnezoline B (2) protected rat cardiomyocytes H9c2 and human neuroblastoma SH-SY5Y cells against CoCl2-induced damage.

A novel approach to 2-arylmethyl-2,3-dihydro-4(1H)-quinazolinones. Total synthesis of the alkaloids glycozolone-A and glycozolone-B

2-Arylmethyl-2,3-dihydro-4(1H)-quinazolinones are a small subgroup of the class of quinazolin-4-one alkaloids, and most published total syntheses require the use of unstable and poorly accessible arylacetaldehydes. Here we show that easily available, stable ω-methoxystyrenes are versatile substitutes for arylacetaldehydes. This new methodology was applied to the total synthesis of the alkaloids glycozolone-A and glycozolone-B. The limitations of this new approach were analyzed as well. In this course, new total syntheses of two 2-arylmethyl-4(1H)-quinazolinone alkaloids (glycosminine, 2-(4-hydroxybenzyl)-4(1H)-quinazolinone) were developed as well.

Quinazolinone Alkaloid Febrifugine and Its Analogues To Control Phytopathogenic Diseases Caused by Oomycete Fungi

AbstractControlling phytopathogenic diseases caused by oomycete fungi is still a challenge in crop protection research. Studies on identifying new starting points to control phytopathogens revealed that the quinazolinone alkaloids febrifugine (1) and halofuginone (2) are efficiently inhibiting the growth of Phytophthora infestans in microtiter tests. However, despite the very good in vitro activity of 0.13 and 0.06 ppm in IC50, respectively, both compounds did not exhibit a good control of P. infestans on tomato plants. Creating a homology model of prolyl‐tRNA synthetase – the molecular target of halofuginone – helped to understand the interactions between 2 and the binding pocket and guided the synthesis of further derivatives. Ultimately, we found that deoxy‐febrifugine (14) and halofuginol (17) and its derivatives were able to control P. infestans also on the plant.

Structurally diverse alkaloids produced by Aspergillus creber EN-602, an endophytic fungus obtained from the marine red alga Rhodomela confervoides

Thirteen alkaloids, which include three new diketopiperazines, namely, 3-hydroxyprotuboxepin K (4), 3,15-dehydroprotuboxepin K (5), and versiamide A (6), together with ten known alkaloid derivatives (1–3 and 7–13), were isolated from the marine red algal-derived fungus Aspergillus creber EN-602. Versiamide A (6) represents the first example of a naturally occurring quinazolinone alkaloid with a diketopiperazine ring that is derived from phenylalanine (Phe) and leucine (Leu). The structures of these compounds were elucidated by detailed interpretation of their 1D/2D NMR spectroscopic and mass spectrometric data, while the absolute configurations of compounds 1–6 were established on the basis of X-ray crystallographic analysis and time-dependent density functional (TDDFT) calculations of the ECD spectra. Compounds 1, 2, and 4 exhibited inhibitory activity against the angiotensin converting enzyme (ACE) with IC50 values of 11.2, 16.0, and 22.4 μM, respectively, and compounds 5 and 6 inhibited various aquatic bacteria with MIC values that ranged from 8 to 64 μg/mL. The intermolecular interactions and potential binding sites between compounds 1–6 and ACE were investigated via molecular docking simulations.

Bioactive aromatic butenolides from a mangrove sediment originated fungal species, Aspergillus terreus SCAU011

Seven new compounds including five aromatic butenolide analogues (1–5), one quinazolinone alkaloid (6) and one benzoic acid derivative (7), along with eleven known co-metabolites (8–18), were isolated from Aspergillus terreus SCAU011, a fungus from the rhizosphere sediment of a mangrove plant Rhizophora stylosa. The structures of these isolates were established by a combination of MS, NMR and ECD data analyses, as well as chemical method. Compound 3 is a rare ring-open aromatic butenolide, while 6 represents the first natural ring-open benzomalvin-type quinazolinone alkaloid. Also, the previously reported structures for asperlides A–C were proposed to be revised in the present work. The COX-2 inhibitory, α-glucosidase inhibitory, antioxidant and antibacterial activities of all the compounds were assessed. While compounds 4, 6, 11 and 18 exhibited better COX-2 inhibitory activity than the positive control celecoxib, compounds 9 and 10 showed significant α-glucosidase inhibitory activity with IC50 values of 56.1 and 12.9 μM, respectively. Meanwhile, half of the tested samples (1, 8–11 and 15–17) exerted similar or better antioxidant activity compared with the reference drug curcumin, and compounds 3, 9, 17 and 18 displayed moderate antibacterial effect against Staphylococcus aureus.

Encapsulating Halofuginone Hydrobromide in TPGS Polymeric Micelles Enhances Efficacy Against Triple-Negative Breast Cancer Cells.

BackgroundHalofuginone hydrobromide (HF) is a synthetic analogue of the naturally occurring quinazolinone alkaloid febrifugine, which has potential therapeutic effects against breast cancer, however, its poor water solubility greatly limits its pharmaceutical application. D-α-tocopherol polyethylene glycol 1000 succinate (TPGS) is a water-soluble derivative of vitamin E, which can self-assemble to form polymeric micelles (PMs) for encapsulating insoluble anti-tumor drugs, thereby effectively enhancing their anti-cancer effects.MethodsHF-loaded TPGS PMs (HTPMs) were manufactured using a thin-film hydration technique, followed by a series of characterizations, including the hydrodynamic diameter (HD), zeta potential (ZP), stability, drug loading (DL), encapsulation efficiency (EE), and in vitro drug release. The anti-cancer effects and potential mechanism of HTPMs were investigated in the breast cell lines MDA-MB-231 and MCF-7, and normal breast epithelial cell line Eph-ev. The breast cancer-bearing BALB/c nude mouse model was successfully established by subcutaneous injection of MDA-MB-231 cells and used to evaluate the in vivo therapeutic effect and safety of the HTPMs.ResultsThe optimized HTPMs had an HD of 17.8±0.5 nm and ZP of 14.40±0.1 mV. These PMs exhibited DL of 12.94 ± 0.46% and EE of 90.6 ± 0.85%, along with excellent storage stability, dilution tolerance and sustained drug release in pH-dependent manner within 24 h compared to free HF. Additionally, the HTPMs had stronger inhibitory effects than free HF and paclitaxel against MDA-MB-231 triple-negative breast cancer cells, and little toxicity in normal breast epithelial Eph-ev cells. The HTPMs induced cell cycle arrest and apoptosis of MDA-MB-231 by disrupting the mitochondrial membrane potential and enhancing reactive oxygen species formation. Evaluation of in vivo anti-tumor efficacy demonstrated that HTPMs exerted a stronger tumor inhibition rate (68.17%) than free HF, and exhibited excellent biocompatibility.ConclusionThe findings from this study indicate that HTPMs holds great clinical potential for treating triple-negative breast cancer.

Alkaloids and monoterpenes from the leaves of Isatis tinctoria Linnaeus and their chemotaxonomic significance

Phytochemical investigation of the leaves of Isatis tinctoria Linnaeus led to the isolation of thirty compounds, including thirteen indole alkaloids (1–13), seven quinazolinone alkaloids (14–20), two quinoline alkaloids (21–22), one quindoline alkaloid (23), one simple amide alkaloid (24) and six monoterpenes (25–30). According to spectroscopic data analysis and comparison with the previously reported literature, their structures were elucidated. Among them, six compounds (12, 13, 17, and 22–24) have not been reported from the family Brassicaceae and eight compounds (3, 7, and 25–30) were isolated from the genus Isatis for the first time. Furthermore, the chemotaxonomic significance of isolated compounds has also been elaborated.

Halofuginone functions as a therapeutic drug for chronic periodontitis in a mouse model.

Periodontitis is an inflammatory disease caused by host immune response, resulting in a loss of periodontium and alveolar bone. Immune cells, such as T cells and macrophages, play a critical role in the periodontitis onset. Halofuginone, a natural quinazolinone alkaloid, has been shown to possess anti-fibrosis, anti-cancer, and immunomodulatory properties. However, the effect of halofuginone on periodontitis has never been reported. In this study, a ligature-induced mice model of periodontitis was applied to investigate the potential beneficial effect of halofuginone on periodontitis. We demonstrated that the administration of halofuginone significantly reduced the expression levels of pro-inflammatory cytokines (IL-1β, IL-6, and TNF-α) in vivo, and markedly suppressed immune cell infiltration into the infected sites. Furthermore, we also observed that halofuginone treatment blocked the T-helper 17 (Th17) cell differentiation in vivo and in vitro. We demonstrated for the first time that halofuginone alleviated the onset of periodontitis through reducing immune responses.

Antimicrobial Secondary Metabolites from the Seawater-Derived Fungus Aspergillus sydowii SW9

Marine-derived fungi are considered to be valuable producers of bioactive secondary metabolites used as lead compounds with medicinal importance. In this study, chemical investigation of the seawater-derived fungus Aspergillus sydowii SW9 led to the isolation and identification of one new quinazolinone alkaloid, 2-(4-hydroxybenzyl)-4-(3-acetyl)quinazolin-one (1), one new aromatic bisabolene-type sesquiterpenoid, (2) and one new chorismic acid analogue (3), as well as two known alkaloids (compounds 4 and 5). Their structures were determined by extensive 1D/2D NMR and mass spectrometric data, and the absolute configurations of 2 and 3 were assigned by the analysis of ECD spectra aided by quantum chemical computations. Compounds 1, 2, and 4 exhibited selective inhibitory activities against the human pathogenic bacteria Escherichia coli, Staphylococcus aureus, S. epidermidis, and Streptococcus pneumoniae, with MIC values ranging from 2.0 to 16 μg/mL.

Synthesis and Biological Evaluation of Isofebrifugine Analogues

: Isofebrifugine, as a kind of natural quinazolinone alkaloid with important physiological activities and good pharmacological effects, was isolated from a Chinese medicinal plant, Chang Shan (Dichroa febrifuga). In this paper, the synthesis of a series of novel isofebrifugine analogues was accomplished by employing the N-alkylation of 4(3H)-quinazolinones with benzyl (3aR,7aR)-rel-2- (bromomethyl)hexahydrofuro[3,2-b]pyridine-4(2H)carboxylates and the subsequent N-deprotection. These analogues were characterized by 1H NMR, 13C NMR and HRMS spectra. The MTT assay was used to examine the inhibitory effects of these analogues on the growth of human hepatoma cells (HepG2). The results indicated that some halogenated or hemiketal analogues showed interesting inhibition activity.

Penicamide A, A Unique N,N'-Ketal Quinazolinone Alkaloid from Ascidian-Derived Fungus Penicillium sp. 4829.

Previously unreported N,N′-ketal quinazolinone enantiomers [(−)-1 and (+)-1] and a new biogenetically related compound (2), along with six known compounds, 2-pyrovoylaminobenzamide (3), N-(2-hydroxypropanoyl)-2 amino benzoic acid amide (4), pseurotin A (5), niacinamide (6), citreohybridonol (7), citreohybridone C (8) were isolated from the ascidian-derived fungus Penicillium sp. 4829 in wheat solid-substrate medium culture. Their structures were elucidated by a combination of spectroscopic analyses (1D and 2D NMR and Electron Circular Dichroism data) and X-ray crystallography. The enantiomeric pair of 1 is the first example of naturally occurring N,N′-ketal quinazolinone possessing a unique tetracyclic system having 4-quinazolinone fused with tetrahydroisoquinoline moiety. The enantiomeric mixtures of 1 displayed an inhibitory effect on NO production in lipopolysaccharide-activated RAW264.7 cells, while the optically pure (–)-1 showed better inhibitory effect than (+)-1.

Ammonium Acetate Supplement Strategy for Enhancement of Chaetominine Production in Liquid Culture of Marine-Derived Aspergillus fumigatus CY018.

Pharmacological research on (CHA), a marine-derived quinazolinone alkaloid with significant cytotoxic activity, is restricted by low yields and is a problem that needs to be settled urgently. In this work, the selection of additional nitrogen sources and the optimization of additional concentrations and longer fermentation times using ammonium acetate, were investigated. CHA production was optimized to 62.1 mg/l with the addition of 50 mM ammonium acetate at 120 h of the fermentation in the shaker flask. This feeding strategy significantly increased 3- deoxy-arabino-heptulosonate-7-phosphate synthase activity and transcript levels of critical genes (laeA, dahp and trpC) in the shikimate pathway compared with the non-treatment group. In addition, the selection of the feeding rate (0.01 and 0.03 g/l/h) was investigated in a 5-L bioreactor. As a result, CHA production was increased by 57.9 mg/l with a 0.01 g/l/h ammonium acetate feeding rate. This work shows that the strategy of ammonium acetate supplementation had an effective role in improving CHA production by Aspergillus fumigatus CY018. It also shows that this strategy could serve as an important example of large-scale fermentation of a marine fungus in submerged culture.

Copper-Catalyzed Intramolecular α-C–H Amination via Ring-Opening Cyclization Strategy to Quinazolin-4-ones: Development and Application in Rutaecarpine Synthesis

A copper-catalyzed intramolecular α-C–H amination has been developed for the synthesis of quinazolin-4(3H)-one derivatives from commercially available isatoic anhydride and primary and secondary benzylamines via ring-opening cyclization (ROC). This method shows good functional group tolerance and allows access to a range of 2-aryl, 2-alkyl, and spiroquinazolinone derivatives. However, 2-methylquinazolin-4(3H)-one was synthesized from 2-amino-N-isopropylbenzamide by C–C bond cleavage, and N-benzyl-2-(methylamino)benzamide afforded 1-methyl-2-phenylquinazolin-4(1H)-one along with 2-phenylquinazolin-4(3H)-one by N–C bond cleavage for aromatization. It is the first general method to construct the potentially useful 2-methylquinazolin-4(3H)-one by copper-catalyzed intramolecular C–H amination. Also this ROC strategy has been successfully applied to the synthesis of quinazolinone alkaloid rutaecarpine.

Synthesis of New Proteomimetic Quinazolinone Alkaloids and Evaluation of Their Neuroprotective and Antitumor Effects.

New quinazolinone derivatives of the marine-derived alkaloids fiscalin B (3) and fumiquinazoline G (1), with neuroprotective and antitumor effects, were synthesized. Eleven quinazolinone-containing indole alkaloids were synthesized, proceeding the anti analogs via a one-pot method, and the syn analogs by the Mazurkiewicz-Ganesan approach. The neuroprotection capacity of these compounds on the rotenone-damage human neuroblastoma cell SH-SY5y was evaluated using the MTT assay. Compounds 1, 3, 5, and 7 showed more than 25% protection. The antitumor activity was investigated using the sulforhodamine B assay and some compounds were tested on the non-malignant MCF-12A cells. Fumiquinazoline G (1) was the most potent compound, with GI50 values lower than 20 µM. Compounds 5, 7, and 11 were more active in all tumor cell lines when compared to their enantiomers. Compounds 5, 7, 10, and 11 had very little effect in the viability of the non-malignant cells. Differences between enantiomeric pairs were also noted as being essential for these activities the S-configuration at C-4. These results reinforce the previously described activities of the fiscalin B (3) as substance P inhibitor and fumiquinazoline G (1) as antitumor agent showing potential as lead compounds for the development of drugs for treatment of neurodegenerative disorders and cancer, respectively.

Isolation of Tryptanthrin and Reassessment of Evidence for Its Isobaric Isostere Wrightiadione in Plants of the Wrightia Genus.

A series of Wrightia hanleyi extracts was screened for activity against Mycobacterium tuberculosis H37Rv. One active fraction contained a compound that initially appeared to be either the isoflavonoid wrightiadione or the alkaloid tryptanthrin, both of which have been previously reported in other Wrightia species. Characterization by NMR and MS, as well as evaluation of the literature describing these compounds, led to the conclusion that wrightiadione (1) was misidentified in the first report of its isolation from W. tomentosa in 1992 and again in 2015 when reported in W. pubescens and W. religiosa. Instead, the molecule described in these reports and in the present work is almost certainly the isobaric (same nominal mass) and isosteric (same number of atoms, valency, and shape) tryptanthrin (2), a well-known quinazolinone alkaloid found in a variety of plants including Wrightia species. Tryptanthrin (2) is also accessible synthetically via several routes and has been thoroughly characterized. Wrightiadione (1) has been synthesized and characterized and may have useful biological activity; however, this compound can no longer be said to be known to exist in Nature. To our knowledge, this misidentification of wrightiadione (1) has heretofore been unrecognized.